Rheum emodi Wall. (Polygonaceae) commonly known as Indian Rhubarb is an important medicinal herb of Himalayan region widely distributed in China, Nepal, Bhutan and India. It is distributed in the temperate and subtropical regions in India from Kashmir to Sikkim at an altitudinal range from 2800-3000 m. 1-2 The plant is used throughout the world for managing various ailments such as jaundice, headache, migraine, paralysis, sciatica, asthma, diarrhea, cancer and liver disorders etc. 3 The rhizome of R. emodi is the major source of anthraquinones which include emodin, emodin glycoside, chrysophanol, chrysophanol glycoside, physcion, aloe-emodin and rhein. 4 These anthraquinones are widely used in dyeing textile, paints, cosmetics, foods, imaging devices as well as its derivatives show various pharmacological activities viz., antiarthiritic, antiinflammatory, antifungal, antiviral, antibacterial, antidiabetic, laxative and neuro protective effects. 5 Besides, these anthraquinones of R. emodi are also responsible for anticancerous activity. Emodin and aloe-emodin inhibited the proliferation of human gastric cancer cell line MKH45; 6 rhein induced apoptotic cell death in human colon cancer cell line COLO 32DM; 7 physcion is used in treating human cervical cancer and chrysophanol induced necrosis in human liver cancer cells. 8-9 Different phytoconstituents present in R. emodi exhibited antioxidant activities as well. 10
