Medicinal plants have been used as a major source of drugs for thousands of years in human history and even today they are basis of the systematic traditional medicine practices in many countries all over the world ID: 1012728
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1. Lec. 4 Drugs from plants:* Medicinal plants have been used as a major source of drugs for thousands of years in human history, and even today they are basis of the systematic traditional medicine practices in many countries all over the world. * The first recorded literature on medicinal plants can be traced back to an earlier age of human history, such as the Ayurveda (2000 BC) in India, the Divine Farmer’s Herb- Root Classic (3000 BC) in China, and the Ebers Papyrus (1550 BC) in Egypt.3/7/20111
2. It is evident that the modern drug industry has been developed to a considerable degree as a result of plant-based traditional medicines. A review published in 2001 indicated that 88 active compounds isolated from 72 medicinal plants have been introduced into modern drug therapy, with many of them being considered as the active principle responsible for their ethno pharmacological use. 3/7/20112
3. Bases of plant Selection:* Biodiversity Prospective:The number and variety of plants found within a specified geographic region. * Screening as much samples as possible for specified biological activities. * Collect as much as possible. About 5- 15% from plant species were screened. Estimated 300,000 to 500,000 are present.* Ethnobotany (Ethnopharmacology) Prospective: In this approach drug discovery is guided by the impressive quantity and quality of information of indigenous cultures that have used plants and animal products to control disease and injury.3/7/20113
4. This information is passed from generation to generation through oral history and it is necessary to record and validate the knowledge of the shaman before it is lost forever. Collection based on Folk uses of samples.3/7/20114
5. Examples of drugs derived from plants:Morphine.Morphine was first isolated in 1806 and manufacturing of an analgesic drug was realized by E. Merck , Germany in 1826.Morphine3/7/20115
6. Papaver somniferum3/7/20116
7. Some of these plant-derived therapeutic agents, such as atropine (anticholinergic) from Atropa belladonna, codeine (cough suppressant) from papaver somniferum, colchicine (antigout), ephedrine (bronchodilator), morphine (analgesic). Codeine Atropine3/7/20117
8. Quinine.Quinine was isolated as pure active principle as antimalaria in 1820, representing the only active antimalaria medicine until the introduction of the synthetic drug pamaquine, the later with severe side effects. Quinine Pamaquine 3/7/20118
9. Acetylsalicylic acid.The bark of Willow-tree was known for its analgesic and antipyretic properties for more than 2000 years by Greeks and the Roman. In 1850’s Salicin was isolated as the active principle of the bark, salicin ( beta glucoside of salicylic alcohol).Degradation of Salicin led to the discovery of Salicylic acid as analgesic and antipyretic. It was commercialized in 1859. Due to the gastric disorders of salicylic, efforts to reduce the side effects resulted in acetylsalicylic acid which was introduced to the market under the trade name Aspirin in 1899 by Bayer. 3/7/20119
10. 3/7/201110
11. Salicin salicylic acid Acetylsalicylic acid (Aspirin )3/7/201111
12. Anticancer drugs from plants: The example of anticancer drugs taxol was discovered at the US National Center Institute in the late 1960s in the course of an in vitro antitumor drug discovery program using human tumor cell lines. Screening of more than 110,000 samples derived from more than 35,000 plant genera collected worldwide resulted in the isolation and structure elucidation of taxol from the bark of the North American yew tree Taxus brevifolia.3/7/201112
13. Taxus brevifolia3/7/201113
14. Semisynthetic Derivative:Docetaxel (trade name Taxotere) is a clinically well established anti-mitotic chemotherapy medication used mainly for the treatment of breast, ovarian, and non-small cell lung cancer. Docetaxel has an approved claim for treatment of patients, who have locally advanced, or metastatic breast or non small-cell lung cancer who have undergone anthracycline-based chemotherapy and failed to stop cancer progression or relapsed.3/7/201114
15. Administered as a one-hour infusion every three weeks generally over a ten cycle course, docetaxel is considered as or more effective than doxorubicin, paclitaxel and fluorouracil as a cytotoxic antimicrotubule agent. Docetaxel is marketed worldwide under the name Taxotere by Sanofi-Aventis. Annual sales approx $2bn. Patent expires in 2010.3/7/201115
16. TaxotereTaxol3/7/201116
17. References:1- Cutler, Stephen J.; Cutler, Horace G. (2000). Biologically active natural products: pharmaceuticals. CRC Press. p. 5. ISBN 9780849318870.2- Newman DJ, Cragg GM Natural products as sources of new drugs over the last 25 years. Journal of Natural Products 70, 461-477 (2007).3- Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble Chinese Herbal Medicine: Materia Medica, Third Edition 20043/7/201117