Antioxidant and Phytochemical Studies of the Rhizome Extracts of Curcuma amada Roxb and Zingiber officinale Rosc

Various reactive species which are either radicals or non radicals formed during normal metabolic processes. Oxidative stress has been identified as a major causative factor in the development and progression of several life threatening diseases, including neurodegenerative and cardiovascular disease, Antioxidants play a vital role in preventing or delaying oxidation and scavenging free radicals. Plants have been used as exogenous antioxidants from several years. In this contest, the rhizome extracts of two important medicinal plants Curcuma amada Roxb and Zingiber officinale Rosc were investigated for antioxidant properties and phytochemical constituents. Antioxidant capacity of different solvent extracts of these plants was estimated by scavenging diphenyl picryl hydrazyl (DPPH), nitric oxide (NO) and hydrogen peroxide. The petroleum ether and alcohol extracts of Curcuma amada showed stronger antioxidant activity with IC50 values of 26-30 mu g/ml and 25-29 mu g/ml, respectively in all the methods while methanol extract showed moderate activity, while petroleum ether and ethanol extracts Zingiber officinale reported good scavenging activity in all the three methods with IC50 ranging from 25-30 mu g/ml except hydroxyl radical scavenging method. Petroleum ether extracts of both the test plants exhibited good inhibition of free radicals generated by DPPH, hydrogen peroxide and nitric oxide when compared to standard ascorbic acid. The phenolic substances are commonly present in all the studied extracts. Among the two medicinal plants tested, Zingiber officinale has better scavenging activity in all the performed methods followed by Curcuma amada. In the present study, potent antioxidant activity of Zingiber officinale and Curcuma amada extracts leads to scientific validation of these plants. A natural substance which is a part of daily diet and nutritional supplement with antioxidant property constitutes a new source of herbal drug.