plants used in cancer treatment part - i. cancer n what is cancer? n us cancer statistics n cancer...
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Plants Used In Cancer Treatment
Part - I
Cancer
What is cancer? US cancer statistics Cancer costs Most frequent cancers by organ effected
Cost of cancer per year in U.S.
Major types of cancers
Over 200 types of cancer are known grouped into major categories Carcinomas Sarcomas Melanomas Teratomas Leukemias and Lymphomas
History of Cancer Therapy
Folk remedies NCI – 1955 NCI-USDA – late 1950s NCI – 1985 21st century
Current Plant Based Therapies
Periwinkle Mayapple Yew Camptotheca Lapachol Others: Aspergillus fumigatus, Viscum
album
Madagascar Periwinkle – Vinca alkaloids
Catharanthus roseus is known as the common or Madagascar periwinkle,
Formerly classified as Vinca rosea
Perennial evergreen herb in Apocynaceae
Originally native to island of Madagascar
Traditional uses of periwinkle
Used to treat a wide assortment of diseases In Europe, folk remedy for diabetes for centuries In India, juice from the leaves to treat wasp stings. In Hawaii, boiled to make a poultice to stop bleeding. In China, an astringent, diuretic and cough remedy. In Central and South America, homemade cold remedy to
ease lung congestion and inflammation and sore throats Throughout the Caribbean, an flower extract to treat eye
irritation and infections
Interest in Periwinkle
Two groups began independently working on periwinkle in 1950s when they learned of a tea Jamaicans were drinking to treat diabetes Univ of Western Ontario - Beer and Noble -interested
in plant as a possible “oral insulin” - they isolated alkalod - vinblastin
Eli Lilly Pharmaceuticals - Svoboda
More alkaloids in periwinkle
Overall 70 alkaloids have been identified in periwinkle with various uses– anticancer properties– lower blood sugar levels – hemostatics (arrest bleeding) – reserpine and serpentine - tranquilizers
Vincristine and vinblastine
Vincristine has been especially effective for treating acute childhood leukemia, often with 99% remission rates
Vinblastine has been especially effective for treating Hodgkin's disease - which had been considered a fatal up to that point
Mode of action of vinca alkaloids
Vinblastine, vincristine, and two semi-synthetic derivatives (vindesine and vinorelbine) all have the same mode of action
Inhibit mitosis in metaphase by binding tubulin
Vinblastine
Marketed as Velban Half-life in the bloodstream of 24 hours Vinblastine is mainly useful for treating Hodgkin's
disease, lymphocytic lymphoma, histiocytic lymphoma, advanced testicular cancer, advanced breast cancer, Kaposi's sarcoma
Another action: It also seems to fight cancer by interfering with glutamic acid metabolism
Side effects of vinblastine
Side effects include hair loss, nausea, lowered blood cell counts, headache, stomach pain, numbness, constipation and mouth sores
Bone marrow damage is the typical dose-limiting factor
Caused severe birth defects in lab animals so not used on pregnant patients
Vincristine
Marketed as Oncovin Serum half-life of about 85 hours. Used mainly to treat acute leukemia,
rhabdomyosarcoma, neuroblastoma, Hodgkin's disease and other lymphomas
Also Wilms' tumor (80%) and Burkitt's lymphoma (50%), when used in combination with other drugs
Neurotoxicity is the dose limiting factor (it can cause damage to the peripheral nervous system)
Side effects of vincristine
Same as those found with vinblastine Nervous system problems such as sensory
impairment Breathing problems or lung spasms shortly after
the drug is administered Secondary cancers if they receive the drug along
with other anticancer drugs that are known to be carcinogens
Severe birth defects in animal tests
Vindesine -semi synthetic
Marketed as Eldisine and Fildesin Serum half-life of about 24 hours Mainly to treat melanoma and lung cancers
(carcinomas) and, with other drugs, to treat uterine cancers
Toxicity and side effects are similar to those of vinblastine
Vinorelbine - semi-synthetic
Marketed as Navelbine Approved for non-small cell lung cancer and breast
cancer – usually in combination with other drugs Clinical trials on-going as a treatment for ovarian,
cervical, prostrate and other cancers Seems to have a wider range of antitumor activity
than the other vinca alkaloids Side effects include diarrhea, nausea, hair loss,
leukopenia