Antioxidant capacity of piper longum and piper nigrum fruits grown in Bangladesh

Abstract

The study is performed to determine and compare the antioxidant capacity of water and ethanol extracts of Piper longum and Piper nigrum fruits grown in Bangladesh. DPPH, ABTS and nitric oxide free radical scavenging activity, FRAP, superoxide dismutase, Fe²⁺ ion chelating ability, total antioxidant capacity, reducing power assay, total flavonoid, and total phenolic content determination assays were used for evaluation of antioxidant capacity. The ethanol extracts of P. longum (long pepper from Dhaka, long pepper from Rajshahi) and P. nigrum (white pepper, black pepper) fruits showed significant activities compared to the water extracts in most of the antioxidant assays in a dose dependent manner. The total phenolic and flavonoid contents ranged between 32.83 to 174.92 mg of GAE/g of dry extract and 33.44 to 172.98 mg of QE/g of dry extract, respectively. In total antioxidant capacity and FRAP assay, the activity of the extracts ranged from 9.05 to 199.17 mg AAE/g extract and 5.32 to 18.33 mg FeSO₄E/g extract. In DPPH scavenging and SOD assay, the percent inhibitions were found to be similar. However, ABTS, Fe²⁺ scavenging, and reducing power assay showed better results for ethanol extracts, while nitric oxide scavenging activity showed better activity for water extracts.