Antioxidant and Antimicrobial Activities of Extracts from a Medicinal Plant, Sea Buckthorn

This study was performed to evaluate the antioxidant and antimicrobial activities from the methanol extracts of the root and stem of Hippophae rhamnoides and their further partitioned fractions including hexane, ethyl acetate, butanol, and water. Antioxidant activities of the plant parts were measured by 1,1-dephenyl-2-picryl-hydrazyl (DPPH), superoxide dismutase (SOD)-like activity, and ferric thiocyanate (FTC) assays, and compared to standard antioxidants of butylated hydroxyl anisole, butylated hydroxyl toluene, alpha-tocopherol, and ascorbic acid. Antimicrobial activity of the plant extracts and fractions were evaluated by determining the minimum inhibitory concentration values. DPPH assay showed that the overall strong antioxidant activities from the methanol extracts and fractions. The values of SOD-like activities in hexane fractions of the root and stem were close to the measurement of a reference, ascorbic acid at 1,000 ppm. The methanol extract of the root in FTC assay showed a remarkable antioxidant and free radical scavenging activity. The extracts and fractions of the root and stem showed better antimicrobial activity than compared antimicrobial agents, (+)-catechin, ketoconazol, and mycostantin. This study indicates that the plant root and stem contain a variety of compounds contributing to antioxidant and antimicrobial activity, which could be used for food additives and the development of useful natural compounds.