Narenda
SINGH, et al.
Artemisinin vs Cancer
http://www.australiannationalreview.com/wormwood-iron-annihilate-98-cent-cancer-cells-16-hours/
Dec 1, 2015
Wormwood and iron annihilate 98 per cent of cancer
cells in 16 hours
Doctors and pharmaceutical companies reject the idea that diet
and healthy lifestyle choices can lead to a cancer-free life and
can prevent or delay the evolution of this deadly disease.
According to a study published by Life Sciences, artemisinin, a
derivate of the wormwood plant can kill 98 per cent of breast
cancer cells in just 16 hours when paired with iron. On its own,
the herb managed to reduce the breast cancer cells by 28 per
cent, but when it joined forces with iron, normal cells were not
affected by the treatment and had a better outcome.
The problem with mainstream cancer treatment is that it attacks
not only cancer cells, but also the healthy ones, making the
road to recovery heavier and in some cases even impossible
because an acidic system with a stagnant lymphatic system that
stems from poor dietary and lifestyle choices allows the disease
to thrive. However, the body can be quickly alkalized and
flooded with nutrients when people consume a predominantly
plant-based and unprocessed diet.
Artemisinin has been used in the past as a tool against malaria,
but new studies show it can fight against cancer too. In the
study published by Life Sciences last year, when subjects were
given an iron supplement, the artemisinin was able to target
only “bad” cells and left the “good” ones untouched.
Researchers’ results demonstrated that it “mediates the cell
cycle arrest of human breast cancer cells and represents a
critical transcriptional pathway by which artemisinin controls
human reproductive cancer cell growth.”
Scientists Narendra Singh and Henry Lai from the University of
Washington made the initial discovery. Lai synthesized to
compound to target only the diseased cells, which picked it up
without knowing that there is a “bomb” (wormwood derivate)
hidden inside. The compound is being licensed by the University
of Washington to Artemisia Biomedical Inc., a company founded by
Singh and Lai in Newcastle, Washington for development and
commercialisation.
According to the study’s abstract, “artemisinin reacts with iron
to form free radicals that kill cells.” Previous studies have
shown that the compound is “more toxic to cancer cells than to
normal cells.”
Tomikazu Sasaki, chemistry professor at University of Washington
and senior author of the study which focuses on artemisinin’s
anti-cancer benefits judged that “side effects are a major
limitation to current chemotherapies.” Although the compound
kills about 100 cancer cells for every healthy cell, the
researchers added a small chemical tag to artemisinin which
sticks to the “iron needed here” protein signal. The cancer cell
waited for the protein machinery to deliver iron molecules and
engulfed everything. As Lai described it, “the compound is like
a little bomb-carrying monkey riding on the back of a Trojan
horse.”
During ancient times, wormwood was used to treat stomach
disorders. Now, the herb is being used to bring down high
temperature due to fever and can be applied directly to the skin
to treat minor wounds, burns or insect bites.
http://depts.washington.edu/bioe/resources/artemisinin-cancer/
The Department of Bioengineering and University of Washington do
not advocate the use of artemisinin to treat cancer.
The US Food and Drug Administration does not currently approve
the use of artemisinin for the treatment of any disease.
Research on artemisinin and cancer is still in very early
stages. Human use of artemisinin should be considered
experimental and taking artemisinin or any other drug should be
approached with extreme caution and responsibility. Always
consult with your physician before beginning any new therapy or
treatment.
Please contact UW Bioengineering Research Professor Narendra
Singh for further information.
http://depts.washington.edu/bioe/wp-content/uploads/2013/11/Artemisinin-and-Cancer1.pdf
Publications Relating to Effects of Artemisinin & Analogs on
Cancer ( 10 December 2015 )
US5578637
Methods
of inhibition or killing cancer cells using an endoperoxide
Inventor(s): LAI HENRY C [US]; SINGH NARENDRA
Methods of inhibiting or killing cancer cells are disclosed
wherein compounds having an endoperoxide moiety that is reactive
with heme are administered under conditions which enhance
intracellular iron concentrations. Representative endoperoxide
compounds include endoperoxide bearing sesquiterpene compounds
such as artemisinin and its analogs, arteflene and its analogs,
1,2,4-trioxanes and 1,2,4,5-tetraoxanes. Intracellular iron
concentrations may be enhanced by the administration of iron
salts or complexes.
FIELD OF
THE INVENTION
The present invention relates to the inhibition or killing of
cancer cells. More particularly, the present invention relates
to the systemic and topical treatments of cancer cells with
sesquiterpene compounds.
BACKGROUND
OF THE INVENTION
Artemisinin (Qinghaosu) and its analogs are the treatments of
choice for cerebral or chloroquine resistant malaria or for
patients with chloroquine allergy. Artemisinin is a naturally
occurring substance, obtained by purification from sweet
wormwood, Artemisia annua L. Artemisinin and its analogs are
sesquiterpene lactones with a peroxide bridge, and are
characterized by very low toxicity and poor water solubility.
Artemisinin is known as a humoral immunosuppressive agent which
is less active than cyclophosphamide, the latter being one of
the major chemotherapeutic agents for carcinomas. Artemisinin
stimulates cell-mediated immunity, and yet decreases abnormally
elevated levels of polyamine regulatory proteins. It also
markedly inhibits nucleic acid and protein syntheses. Further,
it affects cellular membrane functions and decreases hepatic
cytochrome oxidase enzyme system activity. Still further, it is
virustatic against influenza and cidal against three groups of
pathogenic parasites.
Known analogs of artemisinin which have higher solubility in
water are dihydroartemisinin, artemether, artesunate, arteether,
propylcarbonate dihydroartemisinin and artelinic acid.
Dihydroartemisinin has an antimalarial potency which is 60%
higher than that of artemisinin. Artemether and artesunate have
antimalarial potencies which are 6 times and 5.2 times,
respectively, that of artemisinin. In terms of their ability to
inhibit nucleic acid synthesis, dihydroartemisinin, artemether,
artesunate, arteether, and propylcarbonate dihydroartemisinin
all have 100 times the activity of artemisinin, and protein
synthesis is stimulated to an even greater extent by these
compounds. Artesunate stimulates the immune system at low doses
and inhibits it at high doses. Artelinic acid is the most
water-soluble and the most stable of the group. Two of the
compounds in this group have been demonstrated to display
synergistic activity with doxorubicin (a chemotherapeutic agent)
and miconazole (an antifungal agent) in the in vitro killing of
Plasmodium falciparum, the etiologic agent of malaria.
The very low toxicity of these compounds to humans is a major
benefit. Artesunate, for example, is twice as safe as artemether
and only one-fiftieth as toxic as chloroquinine, the most common
antimalarial. The first manifestation of toxicity of these
compounds is generally a decreased reticulocyte count. Other
manifestations include transient fever, decreased appetite and
elevated blood transaminase levels, the latter an indication of
hepatotoxicity.
U.S. Pat. No. 4,978,676 discloses the use of artemisinin and
artemisinin analogs in the treatment of skin conditions such as
psoriasis, blistering skin diseases, viral warts, and
hemorrhoids.
U.S. Pat. No. 4,978,676 discloses the use of combinations
artemisinin and artemisinin analogs with monocarboxylic acids,
esters or amides in the treatment of papulosquamous skin
diseases, including psoriasis, an eczematous skin diseases,
including seborrheic and atopic dermatitis.
U.S. Pat. No. 5,219,880 discloses the use of artemisinin and
artemisinin analogs in the treatment of warts, molluscum
contagiosum and hemorrhoids.
U.S. Pat. No. 5,225,427 discloses certain 10-substituted ether
derivatives of dihydroartemisinin alleged to exhibit
antimalarial and antiprotozoal activity.
Artemisinin alone has been shown to be toxic to cancer cells in
vitro at 20 to 180 .mu.M range (Sun et al., "Antitumor
Activities of 4 Derivatives of Artemisic Acid and Artemisinin B
in vitro," Chung-Kuo-Yao-Li-Hsueh-Pao 13:541-543 (1992)). The
effect was found to be more effective for hepatoma and embryonic
lung cells than against human gastric cancer cells. In another
study (Woerdenbag et al., "Cytotoxicity of Artimisinin-related
Endoperoxides to Erlich Ascites Tumor Cells," J. Nat. Prod.
56(6):849-856 (1993)), artemisinin was shown to have an IC50
value of 29.8 .mu.M on Ehrlich ascites tumor cells. Several
derivatives of dihydroartemisinin (artemether, arteether, sodium
artesunate, artelinic acid, and sodium artelinate) had IC50
values ranged from 12.2 to 19.9 .mu.M. A ether dimer of
dihydroartemisinin was found to have an IC50 of 1.4 .mu.M.
However, the toxicity of the dimer to normal cells was not
tested. The authors of the latter paper concluded that, "The
artemisinin-related endoperoxides showed cytotoxicity to Ehrlich
ascites tumor cells at higher concentrations than those needed
for in vitro antimalarial activity, as reported in the
literature." However, serum concentrations at the levels
reported by the two papers cannot be reached in vivo.
Artemisinin is a relatively safe drug with little side-effects
even at high doses. Oral dose of 70 mg/kg/day for 6 days has
been used in humans for malaria treatment. Furthermore, more
potent analogs of this and similar compounds are also available.
Higher efficacy of artemisinin action also can be achieved by
other means. For example, artemisinin is more reactive with heme
than free iron (Hong, et al. "The Interaction of Artemisinin
with Malarial Hemozoin," Mol. Biochem. Parasit. 63:121-128
(1974)). Heme can be introduced into cells using transferrin
(Stout, D. L., "The Role of Transferrin in Heme Transport,"
Biochim. Biophy. Res. Comm. 189:765-770 (1992)) or the
heme-carrying compound hemoplexin (Smith et al., "Expression of
Haemopexin-Transport System in Cultured Mouse Hepatoma Cells,"
Biochem. J. 256:941-950 (1988); Smith et al., "Hemopexin Joins
Transferrin as Representative Members of a Distinct Class of
Receptor-Mediated Endocytic Transport System," Europ. J. Cell
Biol. 53:234-245 (1990)). The effectiveness of artemisinin also
can be enhanced by increasing oxygen tension, decreasing intake
of antioxidants, and blockade of peroxidase and catalase by
drugs such as miconazole (Meshnick et al., "Activated Oxygen
Mediates the Antimalarial Activity of Qinghaosu," Prog. Clin.
Biol. Res. 313:95-104 (1989); Krungkrai et al., "The
Antimalarial Action on Plasmodium falciparum of Qinghaosu and
Artesunate in Combination with Agents Which Modulate Oxidant
Stress," Tran. Roy. Soc. Trop. Med. Hyg. 81:710-714 (1989);
Levander et al., "Qinghaosu, Dietary Vitamin E, Selenium, and
Cod Liver Oil: Effect on the Susceptibility of Mice to the
Malarial Parasite Plasmodium yoelii," Am. J. Clin. Ntr.
50:346-352 (1989)).
The endoperoxide moiety of artemisinin and its analogs has been
found to be necessary for antimalarial activity, and analogs
lacking this group have been found to be inactive. In the
presence of heme, the endoperoxide bridge undergoes reductive
decomposition to form a free radical and electrophilic
intermediates. Accordingly, endoperoxide bearing compounds other
than artemisinin and its analogs have been found to have
antimalarial activity. For example, arteflene (Ro. 42-1611;
Biirgen et al., "Ro. 42-1611, A New Effective Antimalarial:
Chemical Structure and Biological Activity," Sixth International
Congress for Infectious Diseases, Abst. 427, p. 152, April 1994,
Prague), and the 1,2,4-trioxanes, such as the fenozans (Peters
et al., "The Chemotherapy of Rodent Malaria. XLIX. The
Activities of Some Synthetic 1,2,4-Trioxanes Against
Chloroquinine-Sensitive and Chloroquinine-Resistant Parasites.
Part 2: Structure-Activity Studies on cis-fused
Cyclopenteno-1,2,4-Trioxane (Fenozans) Against Drug-Sensitive
and Drug-Resistant Lines of Plasmodium berghei and P. yoelii
spp. NS In Vivo," Annals of Tropical Medicine and Parasitology,
87(1):9-16 (1993)), and the 1,2,4,5-tetraoxanes (Vennerstrom et
al., "Dispiro-1,2,4,5-tetraoxanes: A New Class of Antimalarial
Peroxides," J. of Medicinal Chemistry, 35( 16):3023-3027
(1992)).
SUMMARY OF
THE INVENTION
It has been discovered that the anticancer activity of compounds
having an endoperoxide moiety that is reactive with heme and
iron, of which artemisinin and its analogs, arteflene and its
analogs, 1,2,4-trioxanes and 1,2,4,5-tetraoxanes are
representative examples, is substantially enhanced both in vitro
and in vivo when administered under conditions which enhance
intracellular iron concentrations.
In one embodiment of the invention, the endoperoxide bearing
compounds have a sesquiterpene structure, particularly an
oxygenated tricyclic sesquiterpene structure with an
endoperoxide group, and preferably those which are sesquiterpene
lactones or alcohols, carbonates, esters, ethers and sulfonates
thereof. Examples of such compounds include artemisinin;
dihydroartemisinin; carbonate, sulfonate, ester and ether
derivatives of dihydroartemisinin, notably artemether,
arteether, artesunate and artesunate salts, and
dihydroartemisinin propyl carbonate; and the bis-ether artelinic
acid.
Iron agents useful for enhancing intracellular iron
concentrations in connection with the practice of the invention
include pharmaceutically acceptable iron salts and iron
complexes.
In addition to the sesquiterpene compounds and the iron
enhancing agents, compositions of the present invention may
further comprise the administration of conventionally used
antineoplastic agents, such as androgen inhibitors,
antiestrogens, cytotoxic agents, hormones, nitrogen mustard
derivatives, steroids and the like, as a means of further
enhancing clinical efficacy.
BRIEF
DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of
this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, wherein:
FIG. 1 is a time response curve of molt-4 human leukemia cells
incubated in holotransferrin (12 .mu.M) and dihydroartemisinin
(200 .mu.M), as described in Example 1. Dihydroartemisinin was
added at time zero, one hour after the addition of
holotransferrin. Each response curve is the average from four
experiments.
FIG. 2 is a time response curve of normal human lymphocytes
incubated in holotransferrin (12.mu.M) and dihydroartemisinin
(200 .mu.M), as described in Example 1. Dihydroartemisinin was
added at time zero, one hour after the addition of
holotransferrin. Each response curve is the average from four
experiments.
FIG. 3 is a dose-response relationship of molt-4 cells (FIG. 3A)
and lymphocytes (FIG. 3B) exposed to holotransferrin and
dihydroartemisinin. Treatment 1 is control samples with no drug
added. Samples in treatments 2-6 contained 0, 1, 10, 50, and 200
.mu.M of dihydroartemisinin, respectively, plus 12 .mu.M of
holotransferrin. Holotransferrin was added at 1 hr before the
addition of dihydroartemisinin. Cell counts were done at 8 hours
after addition of dihydroartemisinin. Each bar represents the
average from four experiments.
DETAILED
DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with the present invention, it has been discovered
that the ability to kill cancer cells of compounds having an
endoperoxide moiety that is reactive with heme and iron,
particularly artemisinin and artemisinin analogs, arteflene and
its analogs, 1,2,4-trioxanes and 1,2,4,5-tetraoxanes, can be
significantly enhanced by increasing the iron concentration in
the body of a patient, such as by the administration of iron
salts or complexes, followed by administration of the
endoperoxide compound. Analogs of artemisinin, in general
molecules containing sesquiterpene lactone with a peroxide,
arteflene and its analogs, 1,2,4-trioxanes and
1,2,4,5-tetraoxanes are particularly preferred for this purpose.
Both iron salts or complexes and the endoperoxide compound can
be administered orally. It is presently particularly preferred
that iron salt or complex be administered before the
endoperoxide compounds such that cancer cells will be preloaded
with iron to induce free radical formation with the endoperoxide
compound.
Transferrin is an endogenous protein which transports iron and
heme from the circulation into cells. Transferrin binds to
transferrin receptors on cell surface, and via endocytosis is
taken inside the cell and iron is then released. Most cancer
cells express higher cell surface concentration of transferrin
receptors than normal cells and have high rates of iron influx
via transferrin receptors, because iron is needed in cell growth
and division. For example, human hepatoma cells can express
800,000 transferrin receptors per cell on the cell surface,
whereas normal lymphocytes generally express no transferrin
receptors. The entire population of transferrin receptors on a
mouse teratocarcinoma stem cell can be internalized within 6
min.
An artemisinin molecule, as a representative endoperoxide
compound of the invention, is a sesquiterpene lactone containing
an endoperoxide bridge that can be catalyzed by iron to form
free radicals. Its antimalarial action is due to its reaction
with-the iron in free heme molecules in malaria parasite with
the generation of free radicals leading to cellular destruction.
The present invention takes advantage of this property of
artemisinin and targets it towards cancer cells. This
selectivity in action is because cancer cells have higher
concentration of transferrin receptors on their cell membrane
and pick up iron at a higher rate than normal cells. In the
presence of artemisinin, increase in iron concentration inside
cancer cells will lead to free radical formation intracellularly
and cell death.
In accordance with the present invention, a human or animal
patient is treated by enhancing the iron concentration in
extracellular fluids in the patient and administering to the
patient a compound comprising an endoperoxide group that is
reactive with heme or iron.
In connection with the present invention, compounds may be
employed, in general, that possess an endoperoxide group that
reacts in the presence of heme to form free radicals.
Representative, presently preferred endoperoxide compounds are
set forth herein, although it will be apparent that other
endoperoxide compounds will be useful for this purpose.
Preferred endoperoxide bearing sesquiterpene compounds of the
present comprise compounds of the formula: ##STR1## wherein R is
##STR2## where R1 is hydrogen, hydroxyl, alkyl, or has the
formula: ##STR3## wherein R2 is alkyl or aryl and n is 1 to 6,
and the pharmaceutically acceptable salts thereof. As used
herein, the term "alkyl" means lower alkyl having from 1 to 6
carbon atoms, preferably 1 to 4 carbon atoms. Alkyl groups of
the invention may be straight-chain or branched-chain groups,
with straight-chain groups preferred. The term "aryl" preferably
refers to phenyl and benzyl, with phenyl the most preferred.
Pharmaceutically acceptable salts include the alkali or alkaline
earth metal salts, preferably sodium or potassium, with sodium
the most preferred.
The presently particularly preferred sesquiterpene compounds of
the invention include artemisinin, where R is ##STR4##
dihydroartemisinin (R1 .dbd.--OH), artesunic acid (R1
.dbd.--OCO(CH2)2 CO2 H), and artesunate, artemether (R1
.dbd.--OCH3) and arteether (R1 .dbd.--OC2 H5). The presently
most particularly preferred sesquiterpene compound of the
invention is dihydroartemisinin.
Other representative endoperoxide compounds of the invention
include arteflene (Ro. 42-1611) and its analogs (Biirgen et al.,
supra), 1,2,4-trioxanes (Peters et al., supra) and
1,2,4,5-tetraoxanes (Vennerstrom et al., supra).
Preferred agents for enhancing intracellular iron levels for use
in combination with the sesquiterpenes of the present invention
include pharmaceutically acceptable iron salts and iron
complexes. Iron salts useful in the practice of the invention
include ferrous fumarate, ferrous sulfate, ferrous carbonate,
ferrous citrate, ferrous gluconate and ferrous lactate. Iron
complexes useful in the practice of the invention generally
include pharmaceutically acceptable complexes comprising iron,
such as, for example, ferrocholinate, ferroglycine sulfate,
dextran iron complex, peptonized iron, iron sorbitex, ferric
oxide and saccharated iron, as well as iron complexed with iron
binding proteins and glycoproteins, such as the holoferritins
and holotransferrins.
The concentrations of the endoperoxide compounds in the
formulations to be applied in the practice of the present
invention will generally range up to the maximally tolerated
dosage, but the concentrations are not critical and may vary
widely. For artemisinin and its analogs, however, best results
will be obtained using formulations containing the compounds at
levels of from about 0.1 to about 100 mg per kilogram of body
weight per day, preferably from about 1 to about 90 mg per
kilogram of body weight per day, and most preferably from about
1 to about 75 mg per kilogram of body weight per day. The
precise amounts employed by the attending physician will vary,
of course, depending on the compound, route of administration,
physical condition of the patent and other factors. The daily
dosage may be administered as a single dosage or may be divided
into multiple doses for administration. The amount of the
compound actually administered for treatment will be a
therapeutically effective amount, which term is used herein to
denote the amount needed to produce a substantial clinical
improvement. Optimal amounts will vary with the method of
administration, and will generally be in accordance with the
amounts of conventional medicaments administered in the same or
a similar form. Topical or oral administration, for instance,
may typically be done from once to three times a day.
The concentrations of agents for enhancing intracellular iron
concentrations in the practice of the present invention will
generally range up to the maximally tolerated dose for a
particular subject and agent, which will vary depending on the
agent, subject, disease condition and other factors. Dosages
ranging from about 1 to about 100 mg of iron per kilogram of
subject body weight per day will generally be useful for this
purpose.
This procedure will be most effective for the treatment of
aggressive cancer, in which large number of transferrin
receptors are expressed on the cell surface. However, the
procedure may not be effective in the treatment of certain types
of cancer. For example, some adult T-cell leukemia have
defective internalization of transferrin receptors and may not
be susceptible to this treatment. (Vidal et al., "Human T
Lymphocyte Virus I Infection Deregulates Surface Expression of
the Transferrin Receptors," J. Immunol. 141:984-988 (1988))
Furthermore, this procedure can be used in prophylactic cancer
prevention, prevention of cancer recurrence and metastases after
surgery, and as an adjuvant of other traditional cancer therapy.
More potent and water soluble analogs of artemisinin and similar
compounds, e.g., dihydroartemisinin, artesunate, artether, and
artemether, etc., are available. Higher efficacy of artemisinin
action also can be achieved by other means. For example,
artemisinin is more reactive with heme than free iron. Heme can
be introduced into cells using transferrin or the heme-carrying
compound hemoplexin. The effectiveness of artemisinin also can
be enhanced by increasing oxygen tension, decreasing intake of
antioxidants, and blockade of peroxidase and catalase by drugs
such as miconazole.
The topical formulations may further include one or more of the
wide variety of agents known to be effective as skin or stratum
corneum penetration enhancers. Examples of these are
2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylacetamide,
dimethylformamide, propylene glycol, methyl or isopropyl
alcohol, dimethyl sulfoxide, and azone. Additional agents may
further be included to make the formulation cosmetically
acceptable. Examples of these are fats, waxes, oils, dyes,
fragrances, preservatives, stabilizers, and surface active
agents. Keratolytic agents such as those known in the art may
also be included. Examples are salicylic acid and sulfur.
The amounts of each of these various types of additives will be
readily apparent to those skilled in the art, optimal amounts
being the same as in other, known formulations designed for the
same type of administration. Stratum corneum penetration
enhancers, for example, will typically be included at levels
within the range of about 0.1% to about 15%.
The optimal systemic formulation of the basic combination of the
present invention, i.e., the combination of sesquiterpene
lactone with an intracellular iron enhancing agent, may vary
from one such combination to the next.
The formulations of the present invention may further include as
optional ingredients one or more agents already known for their
use in the inhibition of cancer cells, for added clinical
efficacy. Such combinations will in some cases provide added
benefit. These agents include, for example, androgen inhibitors,
such as flutamide and luprolide, antiestrogens, such as
tomoxifen, antimetabolites and cytotoxic agents, such as
daunorubicin, fluorouracil, floxuridine, interferon alpha,
methotrexate, plicamycin, mecaptopurine, thioguanine,
adriamycin, carmustine, lomustine, cytarabine, cyclophosphamide,
doxorubicin, estramustine, altretamine, hydroxyurea, ifosfamide,
procarbazine, mutamycin, busulfan, mitoxantrone, carboplatin,
cisplatin, streptozocin, bleomycin, dactinomycin and idamycin,
hormones, such as medroxyprogesterone, estramustine, ethinyl
estradiol, estradiol, leuprolide, megestrol, octreotide,
diethylstilbestrol, chlorotrianisene, etoposide, podophyllotoxin
and goserelin, nitrogen mustard derivatives, such as melphalan,
chlorambucil, methlorethamine and thiotepa, steroids, such as
betamethasone, and other antineoplastic agents, such as live
Mycobacterium bovis, dicarbazine, asparaginase, leucovorin,
mitotane, vincristine, vinblastine and taxotere. Appropriate
amounts in each case will vary with the particular agent, and
will be either readily known to those skilled in the art or
readily determinable by routine experimentation.
The endoperoxide compounds and iron agents of the invention may
be employed in vitro, in vivo or ex vivo for killing of target
cancer cells. For in vivo applications, compositions of the
endoperoxide compounds of the invention generally comprise an
amount of the endoperoxide compounds effective, when
administered to a human or other animal subject, to localize a
sufficient amount of the endoperoxide compounds at target tissue
sites to facilitate target cell killing, together with a
pharmaceutically acceptable carrier. Any pharmaceutically
acceptable carrier may be generally used for this purpose,
provided that the carrier does not significantly interfere with
the stability or bioavailability of the sesquiterpene compounds
of the invention.
The compositions of the invention can be administered in any
effective pharmaceutically acceptable form to warm blooded
animals, including human and other animal subjects, e.g., in
topical, lavage, oral, suppository, parenteral, or infusable
dosage forms, as a topical, buccal, or nasal spray or in any
other manner effective to deliver the agents to a site of target
cells. The route of administration will preferably be designed
to optimize delivery and localization of the agents to the
target cells.
For topical applications, the pharmaceutically acceptable
carrier may take the form of liquids, creams, lotions, or gels,
and may additionally comprise organic solvents, emulsifiers,
gelling agents, moisturizers, stabilizers, surfactants, wetting
agents, preservatives, time release agents, and minor amounts of
humectants, sequestering agents, dyes, perfumes, and other
components commonly employed in pharmaceutical compositions for
topical administration.
Compositions designed for injection may comprise
pharmaceutically acceptable sterile aqueous or nonaqueous
solutions, suspensions or emulsions. Examples of suitable
nonaqueous carriers, diluents, solvents, or vehicles include
propylene glycol, polyethylene glycol, vegetable oils, such as
olive oil, and injectable organic esters such as ethyl oleate.
Such compositions may also comprise adjuvants such as
preserving, wetting, emulsifying, and dispensing agents. They
may be sterilized, for example, by filtration through a
bacteria-retaining filter, or by incorporating sterilizing
agents into the compositions. They can also be manufactured in
the form of sterile solid compositions which can be dissolved or
suspended in sterile water, saline, or other injectable medium
prior to administration.
Solid dosage forms for oral or topical administration include
capsules, tablets, pills, suppositories, powders, and granules.
In solid dosage forms, the compositions may be admixed with at
least one inert diluent such as sucrose, lactose, or starch, and
may additionally comprise lubricating agents, buffering agents,
enteric coatings, and other components well known to those
skilled in the art.
Actual dosage levels of the compositions of the invention may be
varied so as to obtain amounts of the sesquiterpene compound and
iron at the site of target cells, especially tumor cells,
effective to obtain the desired therapeutic or prophylactic or
diagnostic response. Accordingly, the selected dosage level will
depend on the nature and site of the target cells, the desired
quantity of sesquiterpene compound and iron required at the
target cells for target cell inhibition or killing purposes, the
nature of the sesquiterpene compound and iron agent employed,
the route of administration, and other factors. Generally, for
oral delivery routes of administration, effective administration
doses will include from about 1 to about 100 mg/kg of iron
containing agent, more preferably from about 10 to about 90
mg/kg of iron containing agent per kilogram of body weight of
the subject per day, and from about 0.1 to about 100 mg/kg of an
endoperoxide compound of the invention, more preferably from
about 1 to about 90 mg/kg of the endoperoxide compound per
kilogram of body weight of the subject per day. The foregoing
doses may be administered as a single dose or may be divided
into multiple doses for administration, e.g., up to three times
per day.
EXAMPLES
EXAMPLE 1
In Vitro Cancer Cell Inhibition
Molt-4-lymphoblastoid cells and human lymphocytes were used in
the experiment. Molt-4-lymph cells were purchased from the
American Type Culture Collection (Rockville, Md.). They are
acute lympoblastic leukemia cells from human peripheral blood.
Cultures were maintained in RPMI-1640 (Gibco, Long Island, N.Y.)
supplemented with 10% fetal bovine serum (Hyclone, New Haven,
Conn.). Cells were cultured at 37 DEG C. in 5% CO2 /95% air and
100% humidity, and were split 1:2 at a concentration of
approximately 1.times.10@6 /ml. Approximate cell number before
experiment were between 150.times.10@3 to 300.times.10@3 per ml.
Human lymphocytes were isolated from fresh blood obtained from a
healthy donor and isolated using a modification of the
Ficoll-hypaque centrifugation method of Boyum, A., "Isolation of
Mononuclear Cells and Granulocytes from Human Blood," Scand.
Clin. Lab. Invest. 21:77-89 (1968). In this method, 20-100 .mu.l
of whole blood obtained from a finger prick was mixed with 0.5
ml of ice-cold RPMI-1640 without phenol red (GIBCO, N.Y.) in a
1.5 ml heparinized microfuge tube (Kew Scientific Inc.,
Columbus, Ohio). Using a Pipetman, 100 .mu.l of cold lymphocyte
separation medium (LSM) was layered at the bottom of the tube.
The samples were centrifuged at 3500 rpm for 2 min in a
microfuge (Sorvall, Microspin model 245) at room temperature.
The lymphocytes in the upper portion of the Ficoll layer were
pipetted out. Cells were washed twice in 0.5 ml RPMI-1640 by
centrifugation for 2 min at 3500 rpm in the microfuge. The final
pellet consisting of approximately 0.4-2.0.times.10@5
lymphocytes was resuspended in RPMI-1640. Cell viability was
determined before experiments using trypan blue exclusion and
found to be more than 95%.
Cells (Molt-4 and lymphocytes) were aliquoted in 0.1 ml volumes
into microfuge tubes. Human holotransferrin (Sigma Chemicals,
St. Louis, Mo.) was added to samples of the cells. Different
concentrations of freshly prepared dihydroartemisinin dissolved
in complete medium were added 1 hr later to the tubes. The final
concentration of holotransferrin was 12 .mu.M and
dihydroartemisinin was either 1, 10, 50, or 200 .mu.M. Equal
volume of medium was added to control samples (i.e., samples
without holotransferrin nor dihydroartemisinin). Cells were kept
in an incubator at 37 DEG C. under 5% CO2 and 95% air during the
experiment. At 1, 2, 4, and 8 hrs after the addition of
dihydroartemisinin, the cell number was counted from a 10 .mu.l
aliquot from the samples using a hemocytometer. The cells were
thoroughly mixed by repeated pipeting before an aliquot was
taken for counting. In the case of Molt-4 cells, cell viability
was not determined because it is not correlated with cell loss
as rapid cell disintegration was observed.
Data are expressed as percentage of cell count at a certain time
point compared to cell count at the time when dihydroartemisinin
was added (time zero in FIGS. 1 and 2). Time-response curves
were compared by the method of Krauth, J., "Nonparametric
Analysis of Response Curves," J. Neurosci. Method 2:239-252
(1980). The level of the curves, i.e., ao of the orthogonal
polynomial coefficient, were compared with the median test.
.chi.@2 was calculated with Yates's correction for continuity.
The difference between two data points was also compared by the
median test. A difference at p<0.05 was considered
statistically significant. The Probit analysis was used to
determine LD50 s, i.e., the concentration of dihydroartemisinin
that causes a decrease in cell count by 50% in 8 hrs, from the
dose-response data.
The percent cell count at different times after the addition of
200 .mu.M of dihydroartemisinin of Molt-4 cells and lymphocytes
are shown in FIGS. 1 and 2, respectively. In both Molt-4 and
lymphocytes, no significant difference in cell counts was
observed between control samples and samples exposed to
holotransferrin (12 .mu.M) alone (.chi.@2 =0.5, df=1,
non-significant) during the 8-hr incubation period. Compared to
controls, a significant decrease in cell count (FIG. 1) was
observed in Molt-4 cells exposed to dihydroartemisinin alone
(.chi.@2 =4.5, df=1, p<0.035 compared to control), and a
combination of dihydroartemisinin and holotransferrin (.chi.@2
=4.5, df=1, p<0.035 compared to control). In addition,
percent cell counts of the combined drug treatment were
significantly less than those treated with dihydroartemisinin
alone (.chi.@2 =4.5, df=1, p<0.035 compared to control).
In the case of lymphocytes, exposure to dihydroartemisinin alone
or dihydroartemisinin plus holotransferrin, cell counts were
significantly less than those of the controls (.chi.@2 =4.5,
df=1, p<0.035 compared to control). However, the addition of
holotransferrin did not significantly further enhance the effect
of dihydroartemisinin alone (.chi.@2 =0.5, df=1, no significant
difference between the dihydroartemisinin alone and
holotransferrin+dihydroartemisinin response curves).
FIGS. 3A and 3B show the dose-response relationship of
dihydroartemisinin for Molt-4 and lymphocytes, respectively,
incubated in 12 .mu.M of holotransferrin. The percent cell
counts from samples at 8 hrs after addition of various
concentrations of dihydrotransferrin is presented.
Dose-dependent decreases in cell counts were observed. For
Molt-4 cells, a significant difference (from control samples,
.chi.@2 =4.5, df=1, p<0.035) was observed at 1 .mu.M of
dihydroartemisinin and higher. Smaller decreases in cell counts
were observed with lymphocytes under similar treatment
conditions. A significant difference from control samples was
observed only at a concentration of dihydroartemisinin of 50
.mu.M and higher. Probit analysis of the data showed that the
LD50 s for Molt-4 cells and lymphocytes were 2.59 and 230 .mu.M,
respectively.
The foregoing results demonstrate that combined incubation in
holotransferrin and dihydroartemisinin can selectively destroy
human cancer cells, whereas the effect is significantly less on
normal lymphocytes. Artemisinin alone has been shown to be toxic
to cancer cells in vitro at 20 to 180 .mu.M range (Sun et al.,
supra). The effect was found to be more effective for hepatoma
and embryonic lung cells than against human gastric cancer
cells. However, serum concentrations at these levels cannot be
reached in vivo. Addition of holotransferrin increases the
potency and selectivity of the drug and may decrease the time of
cell killing. In the combined treatment, considerable cell death
was observed at a concentration of dihydroartemisinin of 1 .mu.M
after 8 hrs of incubation. Furthermore, there is reason to
believe that artemisinin can work at lower concentrations in
vivo than in vitro. Culture medium may contain 19-30 .mu.M of
free iron and could cause destruction of dihydroartemisinin
molecules before they can gain entry into cells.
EXAMPLE 2
In Vivo Dog Study 1
A 7 year old male canine basset hound was diagnosed with
lymphosarcoma of the lymph nodes. Artemisinin (10 mg per day,
i.v., approx. 0.3 mg/kg) and ferrous sulfate (10 mg per day,
p.o.) was given in three settings of five days each, with an
interval between each treatment period of three to five days.
The ferrous sulfate was administered six hours before
artemisinin administration. The diameter size of inguinal and
submandibular, right and left lymph nodes was reduced to half
within five days of treatment. A reduction in size was observed
in prescapular and popliteal lymph nodes. The diameter of all
lymph nodes increased within two weeks of cessation of therapy.
The dog survived for five months after treatment and then was
euthanised.
EXAMPLE 3
In Vivo Dog Study 2
A female canine retriever was operated on for hemangiopericytoma
of the right thigh. One week after the operation, artemisinin
(10 mg per day, p.o.) plus ferrous sulfate (10 mg per day, p.o.)
therapy was initiated and continued for 23 consecutive days. As
in Example 2, iron sulfate was given six hours before
artemisinin each day. No signs of tumor recurrence were seen
during or at three months after therapy period.
EXAMPLE 4
In Vivo Dog Study 3
A 12 years old, female canine was diagnosed with a malignant
mast cell tumor, grade 11, on the right thoracic wall. The dog
underwent surgery, and was treated with ferrous sulfate (10 mg
per day, p.o.) and artemisinin (10 mg per day, p.o. ) for seven
days and then on artemisinin alone (10 mg per day, p.o.) for the
next ten days. Examination after four weeks of therapy, showed
no signs of tumor recurrence. The canine owner reported no sign
of recurrence at four months after treatment.
http://www.sciencedaily.com/releases/2014/11/141118091609.htm
Cheap malaria drug could treat colorectal cancer effectively
too, say experts
Medical experts say a common malaria drug could have a
significant impact on colorectal cancer providing a cheap
adjunct to current expensive chemotherapy.
A pilot study by researchers at St George's, University of
London, has found the drug artesunate, which is a widely used
anti-malaria medicine, had a promising effect on reducing the
multiplication of tumour cells in colorectal cancer patients who
were already going to have their cancer surgically removed.
Colorectal cancer (CRC) makes up about 10 percent of the annual
746,000 global cancer cases in men and 614,000 cases in women.
In the UK, 110 new cases are diagnosed daily, with older
patients particularly at risk of death. Prognosis even with the
best available treatments does not increase disease free or
overall survival beyond 60 percent, five years after diagnosis.
Professor Sanjeev Krishna, an infectious disease expert at St
George's who jointly-led the study, said: "There is therefore a
continuing and urgent need to develop new, cheap, orally
effective and safe colorectal cancer treatments.
"Our approach in this study was to take a close look at an
existing drug that already had some anticancer properties in
experimental settings, and to assess its safety and efficacy in
patients.
"The results have been more than encouraging and can offer hopes
of finding effective treatment options that are cheaper in the
future."
"Larger clinical studies with artesunate that aim to provide
well tolerated and convenient anticancer regimens should be
implemented with urgency, and may provide an intervention where
none is currently available, as well as synergistic benefits
with current treatment regimens," added Professor Devinder
Kumar, a leading expert in colorectal cancer at St George's and
joint-lead of this study.
For most patients globally, access to advanced treatments is
difficult as they are too expensive to be widely available, or
associated with significant morbidity thereby further
compromising their survival.
"In the St George's study, patients were examined and then were
given either the anti-malaria drug artesunate or a placebo.
After 42 months following surgery, there were six recurrences of
cancer in the placebo group (of 12 patients) and one recurrence
in an artesunate recipient (of 10 patients).The survival beyond
two years in the artesunate group was estimated at 91% whilst
surviving the first recurrence of cancer in the placebo group
was only 57%.
This is the first randomized, double blind study to test the
anti-CRC properties of oral artesunate. The anticancer
properties of artemisinins have been seen in the laboratory
previously but this is the first time their effect has been seen
in patients in a rigorously designed study.
http://www.ebiomedicine.com/article/S2352-3964%2814%2900034-6/abstract
EBioMedicine, 2014;
DOI: 10.1016/j.ebiom.2014.11.010
A Randomised, Double Blind, Placebo-Controlled Pilot
Study of Oral Artesunate Therapy for Colorectal Cancer
Sanjeev Krishna, et al.
Abstract
Background
Artesunate is an antimalarial agent with broad anti-cancer
activity in in vitro and animal experiments and case reports.
Artesunate has not been studied in rigorous clinical trials for
anticancer effects.
Aim
To determine the anticancer effect and tolerability of oral
artesunate in colorectal cancer (CRC).
Methods
This was a single centre, randomised, double-blind,
placebo-controlled trial. Patients planned for curative
resection of biopsy confirmed single primary site CRC were
randomised (n = 23) by computer-generated code supplied in
opaque envelopes to receive preoperatively either 14 daily doses
of oral artesunate (200 mg; n = 12) or placebo (n = 11). The
primary outcome measure was the proportion of tumour cells
undergoing apoptosis (significant if >7% showed Tunel
staining). Secondary immunohistochemical outcomes assessed these
tumour markers: VEGF, EGFR, c-MYC, CD31, Ki67 and p53, and
clinical responses.
Findings
20 patients (artesunate = 9, placebo = 11) completed the trial
per protocol. Randomization groups were comparable clinically
and for tumour characteristics. Apoptosis in >7% of cells was
seen in 67% and 55% of patients in artesunate and placebo
groups, respectively. Using Bayesian analysis, the probabilities
of an artesunate treatment effect reducing Ki67 and increasing
CD31 expression were 0.89 and 0.79, respectively. During a
median follow up of 42 months 1 patient in the artesunate and 6
patients in the placebo group developed recurrent CRC.
Interpretation
Artesunate has anti-proliferative properties in CRC and is
generally well tolerated.
http://www.wikipedia.org
Artemisinin
Systematic (IUPAC) name:
(3R,5aS,6R,8aS,9R,12S,12aR)-Octahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano[4,3-j]-1,2-benzodioxepin-10(3H)-one
Identifiers
CAS Number 63968-64-9
ATC code P01BE01
PubChem CID: 68827
ChemSpider 62060 Yes
UNII 9RMU91N5K2 Yes
KEGG D02481 Yes
ChEBI CHEBI:223316 Yes
ChEMBL CHEMBL77
Synonyms Artemisinine, qinghaosu
Chemical data
Formula C15H22O5
Molecular mass 282.332 g/mol
Physical data
Density 1.24 ± 0.1 g/cm3
Melting point 152 to 157 °C (306 to 315 °F)
Boiling point decomposes
Artemisinin, also known as qinghaosu (Chinese: 青蒿素), and its
semi-synthetic derivatives are a group of drugs that possess the
most rapid action of all current drugs against Plasmodium
falciparum malaria.[1] It was discovered by Tu Youyou, a Chinese
scientist, who was awarded half of the 2015 Nobel Prize in
Medicine for her discovery.[2] Treatments containing an
artemisinin derivative (artemisinin-combination therapies, ACTs)
are now standard treatment worldwide for P. falciparum malaria.
Artemisinin is isolated from the plant Artemisia annua, sweet
wormwood, an herb employed in Chinese traditional medicine. A
precursor compound can be produced using genetically engineered
yeast.
Chemically, artemisinin is a sesquiterpene lactone containing an
unusual peroxide bridge. This peroxide is believed to be
responsible for the drug's mechanism of action. Few other
natural compounds with such a peroxide bridge are known.[3]
Artemisinin and its endoperoxides derivatives have been used for
the treatment of P. falciparum related infections but low
bioavaibility, poor pharmacokinetic properties and high cost of
the drugs are a major drawback of their use.[4] Use of the drug
by itself as a monotherapy is explicitly discouraged by the
World Health Organization,[5] as there have been signs that
malarial parasites are developing resistance to the drug.
Therapies that combine artemisinin or its derivatives with some
other antimalarial drug are the preferred treatment for malaria
and are both effective and well tolerated in patients. The drug
is also increasingly being used in Plasmodium vivax malaria,[6]
as well as being a topic of research in cancer treatment.
Medical use
Uncomplicated malaria
Artemisinins can be used alone, but this leads to a high rate of
recrudescence (return of parasites) and other drugs are required
to clear the body of all parasites and prevent recurrence. The
World Health Organization (WHO) is pressuring manufacturers to
stop making the uncompounded drug available to the medical
community at large, aware of the catastrophe that would result
if the malaria parasite developed resistance to artemisinins.[7]
The WHO has recommended artemisinin combination therapies (ACT)
be the first-line therapy for P. falciparum malaria
worldwide.[8] Combinations are effective because the artemisinin
component kills the majority of parasites at the start of the
treatment, while the more slowly eliminated partner drug clears
the remaining parasites.[9]
Several fixed-dose ACTs are now available containing an
artemisinin component and a partner drug which has a long
half-life, such as mefloquine (ASMQ[10]), lumefantrine
(Coartem), amodiaquine (ASAQ), piperaquine (Duo-Cotecxin), and
pyronaridine (Pyramax). Increasingly, these combinations are
being made to GMP standard. A separate issue concerns the
quality of some artemisinin-containing products being sold in
Africa and Southeast Asia.[11][12]
Artemisinins are not used for malaria prophylaxis (prevention)
because of the extremely short activity (half-life) of the drug.
To be effective, it would have to be administered multiple times
each day.
Severe
malaria
Artesunate administered by intravenous or intramuscular
injection has proven superior to quinine in large, randomised
controlled trials in both adults [13] and children.[14]
Combining all trials comparing these two drugs, artesunate is
associated with a mortality rate that is approximately 30% lower
than that of quinine.[14] Reasons for this difference include
reduced incidence of hypoglycaemia, easier administration and
more rapid action against circulating and sequestered parasites.
Artesunate is now recommended by the WHO for treatment of all
cases of severe malaria. Effective treatment with ACT
(Artemisinin Combination Therapy) has proven to lower the
morbidity and mortality from malaria within two years by around
70%.[15]
Cancer
treatment
Artemisinin is undergoing early research and testing for the
treatment of cancer.[16] Artemisinin has anticancer effects in
experimental models of hepatocellular carcinoma.[17] Artemisinin
has a peroxide lactone group in its structure, and it is thought
that when the peroxide comes into contact with high iron
concentrations (common in cancerous cells), the molecule becomes
unstable and releases reactive oxygen species. It has been shown
to reduce angiogenesis and the expression of vascular
endothelial growth factor in some tissue cultures. Recent
pharmacological evidence demonstrates the artemisinin derivative
dihydroartemisinin targets human metastatic melanoma cells in
vitro with induction of phorbol-12-myristate-13-acetate-induced
protein 1 dependent mitochondrial apoptosis that occurs
downstream of iron-dependent generation of cytotoxic oxidative
stress.[18] A pilot study on the use of the artemisinin
derivative artesunate yielded promising results for the
treatment of colorectal cancer [19]
Helminth
parasites
A serendipitous discovery was made in China while searching for
novel anthelmintics for schistosomiasis that artemisinin was
effective against schistosomes, the human blood flukes, which
are the second-most prevalent parasitic infections, after
malaria. Artemisinin and its derivatives are all potent
anthelmintics.[20] Artemisinins were later found to possess a
broad spectrum of activity against a wide range of trematodes,
including Schistosoma japonicum, S. mansoni, S. haematobium,
Clonorchis sinensis, Fasciola hepatica, and Opisthorchis
viverrini. Clinical trials were also successfully conducted in
Africa among patients with schistosomiasis.[21] A randomized,
double-blind, placebo-controlled trial also revealed the
efficacy against schistosome infection in Côte d'Ivoire[22] and
China.[23]
Adverse
effects
Artemisinins are generally well tolerated at the doses used to
treat malaria.[24] The side effects from the artemisinin class
of medications are similar to the symptoms of malaria: nausea,
vomiting, anorexia, and dizziness. Mild blood abnormalities have
also been noted. A rare but serious adverse effect is allergic
reaction.[24][25] One case of significant liver inflammation has
been reported in association with prolonged use of a relatively
high-dose of artemisinin for an unclear reason (the patient did
not have malaria).[26] The drugs used in combination therapies
can contribute to the adverse effects experienced by those
undergoing treatment. Adverse effects in patients with acute P.
falciparum malaria treated with artemisinin derivatives tend to
be higher.[27]
Resistance
Clinical evidence for artemisinin resistance in southeast Asia
was first reported in 2008,[28] and was subsequently confirmed
by a detailed study from western Cambodia.[29][30] Resistance in
neighbouring Thailand was reported in 2012,[31] and in Northern
Cambodia, Vietnam and Eastern Myanmar in 2014.[32][33] Emerging
resistance was reported in Southern Laos, central Myanmar and
North-Eastern Cambodia in 2014.[32][33] The parasite's kelch
gene on chromosome 13 appears to be a reliable molecular marker
for clinical resistance in southeast Asia.[34]
In April 2011, the WHO stated that resistance to the most
effective antimalarial drug, artemisinin, could unravel national
(India) malaria control programs, which have achieved
significant progress in the last decade. WHO advocates the
rational use of antimalarial drugs and acknowledges the crucial
role of community health workers in reducing malaria in the
region.[35]
Mechanism
of action
Most artemisinins used today are prodrugs of the biologically
active metabolite dihydroartemisinin, which is active during the
stage when the parasite is located inside red blood cells.
Although there is no consensus regarding the mechanism of action
through which artemisinin derivatives kill the
parasites,[36][37] several lines of evidence indicate that
artemisinins exert their antimalarial action by radical
formation that depends on their endoperoxide bridge. When the
parasite that causes malaria infects a red blood cell, it
consumes hemoglobin within its digestive vacuole, a process that
generates oxidative stress.[38] In the primary theory of the
mechanism of action, the iron of the heme directly reduces the
peroxide bond in artemisinin, generating high-valent iron-oxo
species and resulting in a cascade of reactions that produce
reactive oxygen radicals which damage the parasite and lead to
its death.[39] However, this mechanism has been debated and
other hypotheses have been described.[40] One alternative is
that artemisinins disrupt cellular redox cycling.[41] Artesunate
has been shown to potently inhibit the essential Plasmodium
falciparum exported protein 1 (EXP1), a membrane glutathione
S-transferase.[42] Recently Shandilya et al. suggested a free
radical mechanism in which artemisinin gets activated by iron
present in the food vacuole which in turn inhibits PfATP6 by
closing the phosphorylation, nucleotide binding, and actuator
domains leading to loss of function of PfATP6 of the parasite
and its death.[43]
Numerous studies have investigated the type of damage oxygen
radicals may induce. For example, Pandey et al. have observed
inhibition of digestive vacuole cysteine protease activity of
malarial parasites by artemisinin.[44] These observations were
supported by ex vivo experiments showing accumulation of
hemoglobin in the parasites treated with artemisinin and
inhibition of hemozoin formation by malaria parasites, although
this inhibition was not seen in an in vitro B-hematin inhibition
assay.[45] Electron microscopic evidence linking artemisinin
action to the parasite's digestive vacuole has been obtained
showing that the digestive vacuole membrane suffers damage soon
after parasites are exposed to artemisinin.[46] This would also
be consistent with data showing that the digestive vacuole is
already established by the mid-ring stage of the parasite's
blood cycle,[47] a stage that is sensitive to artemisinins but
not other antimalarials. However, fluorescently tagged
artemisinin was seen in the Golgi, ER and mitochondria, rather
than the digestive vacuole, suggesting that the vacuolar damage
may be a downstream effect, and also that tiny ring stages
(containing minimal digested material) are highly susceptible to
artemisinins.[48][49][50]
Other suggested targets include the mitochondrial electron
transport chain [51] and the parasite's SERCA pump
(PfATP6/PfSERCA).[52] Evidence to support the PfATP6 hypothesis
includes studies reporting specific interactions between SERCAs
and artemisinins,[52][53] undertaken in a Xenopus oocyte system
that generated valuable results despite the challenges of
working with low amounts of heterologous expressed material.[54]
These findings have subsequently been confirmed in an
independent series of experiments that use yeast expressing this
calcium ATPase. Artemisinins selectively and reproducibly
inhibit the yeast growth by their actions on PfATP6.[55] This
methodology also provided information on the effects of
mutations in PfATP6 on drug sensitivity.[53] In French Guiana
and Senegal reduced sensitivity to artemisinins have been
associated with single nucleotide polymorphisms in PfATP6.[56]
In Tanzania, a significant increase in a predicted but
previously undiscovered polymorphism in PfATP6 has been found
after a period of artemisinin combination therapy.[57] The
mammalian calcium ATPase SERCA1a was also inhibited by
artemisinins in coupled enzyme assays,[58] and mutations in
either SERCA1a or PfATP6 modulate their sensitivity to
artemisinin.[53] Anomalously, if either PfATP6 or SERCA1a are
detergent solubilised, they do not show sensitivity to
artemisinins.[59][60][61]
Dosing
Artemisinin derivatives have half-lives on the order of an hour.
Therefore, they require at least daily dosing over several days.
For example, the WHO-approved adult dose of co-artemether
(artemether-lumefantrine) is four tablets at 0, 8, 24, 36, 48,
and 60 hours (six doses).[62][63]
Artemisinin is not soluble in water, therefore Artemisia annua
tea is postulated not to contain pharmacologically significant
amounts of artemesinin.[64] Artemisia tea is therefore not
recommended as a substitute for the ACTs; however, clinical
studies have been suggested.[65]
Production
and price
China and Vietnam provide 70% and East Africa 20% of the raw
plant material. Seedlings are grown in nurseries and then
transplanted into fields. It takes about 8 months for them to
reach full size. The plants are harvested, the leaves are dried
and sent to facilities where the artemisinin is extracted using
solvent, typically hexane. Alternative extraction methods have
been proposed.[66] The market price for artemisinin has
fluctuated widely, between $120 and $1200 per kilogram from 2005
to 2008.[67]
The Chinese company Artepharm created a combination artimisinin
and piperaquine drug marketed as Artequick.[68] In addition to
clinical studies performed in China and southeast Asia,
Artequick was used in large scale malaria eradication efforts in
the Comoros Islands. Those efforts, conducted in 2007, 2012, and
2013–2014, produced a 95–97% reduction in the number of malaria
cases in the Comoros Islands.[69]
After negotiation with the WHO, Novartis and Sanofi-Aventis
provide ACT drugs at cost on a nonprofit basis; however, these
drugs are still more expensive than other malaria
treatments.[70] Artesunate injection for severe malaria
treatment is made by the Guilin Factory in China where
production has received WHO prequalification,[71] an indicator
of drug quality.
High-yield varieties of Artemisia are being produced by the
Centre for Novel Agricultural Products at the University of York
using molecular breeding techniques.[67]
Using seed supplied by Action for Natural Medicine (ANAMED), the
World Agroforestry Centre (ICRAF) has developed a hybrid, dubbed
A3, which can grow to a height of 3 m and produce 20 times more
artemisinin than wild varieties. In northwestern Mozambique,
ICRAF is working together with a medical organisation, Médecins
sans frontières, ANAMED and the Ministry of Agriculture and
Rural Development to train farmers on how to grow the shrub from
cuttings, and to harvest and dry the leaves to make artemisia
tea.
In April 2013, Sanofi announced the launch[72] of a production
facility in Garessio, Italy, to manufacture the anti-plasmodial
drug on a large scale. The partnership to create a new
pharmaceutical manufacturing process was led by PATH’s Drug
Development program (through an affiliation with OneWorld
Health), with funding from the Bill & Melinda Gates
Foundation and based on a modified biosynthetic process for
artemisinic acid, initially designed by Jay Keasling at the
University of California, Berkeley and optimized by Amyris. The
reaction is followed by a photochemical process creating singlet
oxygen to obtain the end product. Sanofi expects to produce 25
tons of artemisinin in 2013, ramping up the production to 55–60
tons in 2014. The price per kg will be $350–400, roughly the
same as the botanical source.[73] Despite concerns that this
equivalent source would lead to the demise of companies, which
produce this substance conventionally through extraction of A.
annua biomass, an increased supply of this drug will likely
produce lower prices and therefore increase the availability for
ACTs treatment. In August 2014, Sanofi announced the release of
the first batch of semisynthetic artemisinin. 1.7 million doses
of Sanofi's ArteSunate AmodiaQuine Winthrop (ASAQ Winthrop), a
fixed-dose artemisinin-based combination therapy will be shipped
to half a dozen African countries over the next few
months.[74]...
Related
Patents for Artemisinin vs Cancer
KR20150087715
COMPOSITION CONTAINING ARTEMISIA ANNUA EXTRACT, AND
ARTEMISININ OR DIHYDROARTEMISININ FROM ARTEMISIA ANNUA
EXTRACT FOR PREVENTING OR TREATING LIVER CANCER
Inventor(s):
KIM JONG SANG, et al.
The present invention relates to a composition which contains a
mugwort (Artemisia annua) extract as an active ingredient and
used for the prevention and treatment of the liver cancer. More
specifically, the composition includes artemisinin or
dihydroartemisinin in the mugwort extract. The mugwort extract,
artemisinin, or dihydroartemisinin can significantly alleviate
the liver cancer to be utilized for the prevention and treatment
of the liver cancer.
US8940787
Use
of Artemisinin for Treating Tumors Induced by Oncogenic
Viruses and for Treating Viral Infections
In certain aspects,
the invention relates to methods of treating proliferative
cervical disorders (such as cervical cancer and cervical
dysplasia) and treating virus infection by administering
artemisinin-related compounds. In certain aspects, the invention
relates to methods of treating a tumor induced by an oncogenic
virus, methods of killing or inhibiting a squamous cell
carcinoma, and methods of inhibiting the replication of a virus,
by administering artemisinin-related compounds.
US2014275240
Suppression and prevention of tumors and treatment of
viruses
Combinations of
betaine and vitamin C are used to suppress or prevent malignant
tumors or to treat viruses, e.g., by combining the two
ingredients in a product consumed by a human, dog, or cat, such
as an aqueous liquid such as grape juice, the ingredients being
provided in containers with instructions for use, or in finished
products, especially with support of tests demonstrating the
effectiveness of the treatment for, e.g., preventing tumors in
populations known to be at risk of developing tumors, or,
treating existing cancers in combination with other cancer drugs
such as anastrozole and/or fulvestrant and/or artemisinin either
concurrently or sequentially to prevent the cancer from growing
when the cancer drug is not being used, or in the treatment of
viruses.
CN102485237
Sweet
wormwood herb brewed liquid, brewing technology thereof, and
preparation method of starter thereof
Inventor(s):
ZHIFEN BEI, ET AL.
The invention relates to sweet wormwood herb brewed liquid,
which is a pure brewed liquid brewed with a modified ancient
traditional fermentation technology and with sweet wormwood herb
and glutinous rice as raw materials. A main effective component
of sweet wormwood herb, artemisinin, exists in plant cell
glands, and is not soluble in water. Currently, both organic
solvent extraction and chemical synthesis are disadvantaged in
complicated technology, high cost and a problem of toxicity.
According to the invention, a multi-strain starter which has
both functions of saccharification and fermentation, a rice
feeding method, and a composite fermentation technology are
adopted. The technology is characterized in that: the
temperature during the whole brewing process is controlled below
35 DEG C; a fermentation period is long (above 90 days); and
prepared sweet wormwood herb medicinal brewed liquid contains
various nutrients and complete effective components in sweet
wormwood herb. As a result of cytotoxic tests upon breast cancer
cells and lung cancer cells, the cells can be completely killed
within 20h. The brewed liquid is taken by more than 20 people.
It is found that the brewed liquid has certain ideal effects
against some stubborn diseases, and no toxic or side effect is
found.
US2010279976
USE OF
ARTEMISININ AND ITS DERIVATIVES IN CANCER THERAPY
Inventor(s):
WANG HUI, et al.
A method for treating cancer in a mammal includes administering
to the mammal in need thereof a therapeutically effective amount
of artemisinin (ART) or its derivative, such as
dihydroartemisinin (DHA), artemether (ARM), or artesunate (ARS)
alone or in combination with a chemotherapeutic agent, such as
gemcitabine and carboplatin. A method for inhibiting tumor cell
proliferation includes contacting a tumor cell with ART or its
derivative, such as DHA, ARM, and ARS, in an amount effective to
inhibit tumor cell proliferation or in combination with a
chemotherapeutic agent, such as gemcitabine and carboplati
KR20100026030
AN
EXTRACT OF EFFECTIVE COMPONENT FOR PROTECTION AGAINST OTHER
KINDS OF CANCER, METHOD FOR EXTRACTING THE SAME AND AN
ANTI-CANCER MEDICINE COMPRISING IT
Inventor(s):
KWEON OH KWAN, et al.
PURPOSE: A method for isolating a compound isolated from
Artemisa annua extract is provided to easily extract
artemisinin, arteannuin B1, and artemisinic acid and ensure
anti-cancer effect. CONSTITUTION: An Artemisa annua extract
isolated using dichloromethane contains a compound of chemical
formula 1, 2 or 3 as an active ingredient. A method for
isolating from Artemisa annua extract comprises: a step of
extracting Artemisa annua using methylene chloride through
reflux to obtain Artemisa annua methylene chloride extract; a
step of performing silica column chromatography and adding
organic solvent to obtain eluted liquid; a step of fractioning
eluted liquid through silica column chromatography to obtain
first fraction; and a step of performing HPLC to obtain second
fraction.
JP2009051803
DISCOVERY
OF NEW METHOD FOR EXTRACTION
Inventor(s):
NAGAURA YOSHIAKI, et al.
PROBLEM TO BE SOLVED: To provide a new method for extraction,
that is, a prophylactic means and a therapeutic means for
patients suffering from viral diseases such as malaria mediated
by Anopheles or HIV or HCV or HPV or highly virulent H5N1 type
influenza virus or cancer. ;SOLUTION: Bark of Quina or an annual
herb Artemisia annua is finely powdered (hereinafter abbreviated
to the Artemisia annua). A tea bag containing the resultant fine
powder of the Artemisia annua introduced together with sodium
hydrogencarbonate or sodium carbonate into the interior of the
tea bag is formed. An aqueous solution or an alcohol aqueous
solution in the interior of a tea cup in which the pH
concentration of the aqueous solution in the interior of the tea
cup is regulated to >=8.0 is used to carry out alkali
extraction of artemisinin or an artemisinin derivative which is
an active ingredient contained in the fine powder of the
Artemisia annua. The resultant aqueous solution or alcohol
aqueous solution is drunk or internally used as the therapeutic
means for the patients suffering from the viral diseases such as
malaria which is the name of disease or HIV or the cancer.