1.1 Background of the Study
Madagascar periwinkle or rose periwinkle, with the scientific name Catharanthus roseus (L) G. Don is an evergreen perennial shrub of the dogbane family (Apocynaceae). It was formerly classified under the genus Vinca, who share the common name, periwinkle. The plant reaches up to 2-3 feet in height and spreads out just as wide. Leaves are glossy, opposite; flowers are five in number and rose pink in color, although some cultivars have red, purple or white petals. Plant secretes a milky sap, typical of the dogbane family. Catharanthus roseus, originally endemic in Madagascar, can now be found on most tropical and subtropical regions worldwide (Christman, 2004).
Aside from its ornamental properties, C. roseus has been noted for its medicinal uses. It is used to treat insect stings, indigestion, dyspepsia, rheumatism, laryngitis, asthma, high blood pressure, dysmenorrhea, hemorrhage and malaria. Recent studies, however, have focused on its hypoglycemic and anti-cancer properties (“Catharanthus roseus”,n.d.).
Chemical analyses have shown that all parts of the plant contain alkaloids. In 1977, 73 alkaloids were identified in the plant and today, its number exceeds 130 (Hejiden, Snoeijer, Hallard, Jacobs & Verpoorte, 2004).Concentrations vary depending on the plant organ and region of harvest. Roots in India, for example, have yielded 1.22% in alkaloids. Reserpine and alstonine, which are hypotensive alkaloids, have been isolated from the root in concentrations of less than 0.03%. Reserpine, together with serpentine, is used as tranquilizer. Alkaloids such as ajmalicine, raubasine, vinceine were found to be structurally similar to yohimbine, a hypoglycemic drug and treatment for sexual dysfunction. Other alkaloids are referred to as the “vinca” alkaloids include vinblastine, vincristine, vindesine and vinorelbine, which are used widely as antineoplastic agents due to their anti-mitotic and anti-microtubule properties (“Periwinkle”, n.d.). A study shows that although potent, the absolute levels of the “vinca” alkaloids, vinblastine and vincristine are far too low to explain the activity of crude extracts of Catharanthus. This supports the hypothesis that botanical medicine works due to a synergy among many different components and that it does not matter that these two particular alkaloids are present in relatively minute amounts (Yarnell, 2004).
Methanol, methanol-water(1:1) and water extracts of Catharanthus roseus had significant antiproliferative activities against many cell types in vitro (Ueda, et al. 2002). Greatest activity was seen against multidrug resistant tumor types, suggesting there were compounds in Catharanthus that were synergistic or additive with antineoplastic elements by inhibiting resistance to them.
Vinblastine, also known as vincaleukoblastine and sold as Velban, has shown growth inhibition effect in certain human tumors and has been used for treating resistant choriocarcinoma and Hodgkin's lymphoma. Vincristine or vincristine sulfate, which is sold as Oncovin, is used to treat leukemia in children. According to the National Tropical Botanical Gardens of US, combination chemotherapy of both Vinblastine and vincristine, has resulted in 80% remission in Hodgkin's disease, 99% remission in acute lymphocitic leukemia, 80% remission in Wilm's tumor, 70% remission in gestational choricarcinoma, and 50% remission in Burkitt's lymphoma. Also, vincristine produced by C. roseus in vitro is only 20% as effective as the vincristine produced by C. roseus in vivo. (“Catharanthus roseus”,n.d.).
Catharanthus roseus . (n.d.). National Tropical Botanical Garden - Tropical Plant Research, Education, and Conservation.. Retrieved February 7, 2010, from http://www.ntbg.org/plants/plant_details.php?rid=413&plantid=2497
Christman, S. (2004, August 21). Catharanthus roseus. Floridata. Retrieved February 7, 2010, from http://www.floridata.com/ref/C/cath_ros.cfm
Heijden, R. v, Snoeijer, W., Hallard, D., Jacobs, D. I., & Verpoorte, R. (2004). The Catharanthus Alkaloids:Pharmacognosy and Biotechnology . Current Medicinal Chemistry, 11(5), 607-628. Retrieved February 8, 2010, from http://www.ncbi.nlm.nih.gov/pubmed/15032608
Periwinkle. (n.d.). Drugs.com | Prescription Drugs - Information, Interactions & Side Effects. Retrieved February 7, 2010, from http://www.drugs.com/npp/periwinkle.html
Ueda JY, Tezuka Y, Banskota AH, et al. (2002) “Antiproliferative activity of Vietnamese medicinal plants” Biol Pharm Bull 25(6):753-60. Retrieved February 8, 2010, from
Yarnell, E. (n.d.). Catharanthus roseus (Madagascar periwinkle): A Natural Antineoplastic and Antidiabetic. Heron Botanicals. Retrieved February 8, 2010, from www.heronbotanicals.com/Articles/Catharanthus_roseus.pdf