Phytochemical screening and antioxidant property of shoot extracts of Alpinia nigra (Gaertn.) Burtt (Family - Zingiberaceae)

Aqueous extract of Alpinia nigra (Gaertn.) is a widely used traditional medicine by Tripuri tribe of North-east India against intestinal helminthiasis. Our earlier studies have established the anthelminthic properties of the plant; however, very few literature is available about its antioxidant properties. The present study tries to explore its phytochemical constituents and antioxidant properties. The antioxidant activities of the plant was investigated using 1, 1’diphenyl›2’picrylhydrazyl(DPPH), FRAP assay, Ferric reducing power test and hydrogen peroxide (H₂O₂) free radical scavenging power tests. Qualitative test for alkaloids, carbohydrate, flavonoids, glycosides, phenols and saponins were also determined along with the quantitative test for total phenolic compounds (TPC). The extracts showed positive results for all the phytochemicals studied. The total phenolic content (TPC) was found to be 40.65±0.43 and 25.66±0.3 mgGAE/g for ethanol-and aqueous extracts, respectively. Good antioxidant and free radical scavenging power have also been seen compared to the standard ascorbic acid. Ethanol extract was found more active compared to the aqueous extract. Therefore, the shoot-extract the Alpinia nigra could be used as a potential source of natural antioxidant and may be a good candidate for plant based pharmaceutical products.