Antioxidant activity of polyphenolic extract of Terminalia chebula Retzius fruits

The objective of this study was to investigate the in vitro antioxidant activities of polyphenolic extract of Terminalia chebula Retzius (Combretaceae) fruits. The polyphenolic extract of T. chebula fruits was evaluated for antioxidant activity by determining the reducing power, total antioxidant capacity, DPPH radical concentration (IC50 14 μg/mL), nitric oxide radical concentration (IC50 30.51 μg/mL) and hydrogen peroxide scavenging activity (IC50 265.53 μg/mL) under in vitro conditions. Moreover, the phytochemical characterisation of the extract was also measured by determining the total phenolic, flavonoid, tannin and ascorbic acid contents. Characterisation of the extract was also performed by HPLC profiling with the standard gallic acid. The present study demonstrated that the extract has significant reducing capacity and nitric oxide scavenging activity. It also scavenges hydrogen peroxide-induced radicals. The activity of the extract may be due to the total polyphenolic content. The antioxidant activity of the extract is significantly higher than the standard ascorbic acid, and its activity is concentration-dependent. It is concluded that a polyphenolic-rich fraction of T. chebula fruits is a potential source of natural antioxidants.