Antioxidant profiling of Hippophae salicifolia growing in sacred forests of Sikkim, India.

Hippophae commonly known as sea-buckthorn, is a versatile plant with multipurpose uses including the control of soil erosion, biological nitrogen fixation and medicinal properties. In India, two species of sea-buckthorn; namely, Hippophae salicifolia D. Don and Hippophae rhamnoides L., are very common. H. salicifolia has a shrub-to-tree habit and is restricted to the Himalayan region, whereas H. rhamnoides is bushy, growing at higher altitude in India, and widely distributed in Europe and Asia. In this study, aqueous, methanol and acetone extracts of various parts of female and male plants of H. salicifolia were evaluated for total antioxidant activity, phenolic and flavonoid contents, and correlations were made. The total phenolic and flavonoid content in all the samples ranged from 99±32 to 1459±53mg gallic acid equivalent g-1, 135±12 to 707±62mg quercetin equivalent g-1 of dry extract, respectively. The highest free radical (DPPH) scavenging activity was found in methanol extracts of female bark and male leaf. Methanol extracts of male bark and male leaf showed maximum H2O2 activity at a concentration of 1mgmL-1. Antioxidant activity (FRAP method) ranged from 0.021 to 1.041 at concentrations ranging from 20 to 200µgmL-1 with a reducing capacity of extracts as water>methanol>acetone. Strong correlation (P<0.05) was observed between DPPH scavenging activity and total phenolic content from all the extracts under study.