In vitro study on antioxidant activity and phenolic content of three Piper species from North East India

The antioxidant activities of water (W) methanol (ME), water: methanol (1:1), ethanol (ET), chloroform (CH), ethyl acetate (EA) and petroleum ether (PE) extracts of the leaf of three Piper species viz; Piper betle L, Piper betleoides C.DC and Piper wallichii (Miq.) Hand-Mazz was investigated using several in vitro antioxidant assays. The scavenging activity was evaluated by using DPPH (2,2′-diphenyl-1-picryl hydrazyl), FRAP (ferric reducing antioxidant power), ABTS [2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)], hydrogen peroxide scavenging, hydroxyl radicals scavenging, chelating power and reducing power assay. These methods were used for evaluating the best solvent system for extracting the antioxidants. The total phenolic content (TPC) and total flavonoid content (TFC) were also determined for all the extract. The phenolic acid and flavonoids i.e. catechin, quercetin, gallic acid, coumaric acid and protocatechuic acid which may be responsible for antioxidant activity in the fraction of best solvent system were evaluated. The catechin found to be higher (>1.1 mg/g) in all the species in water: methanol extract. The study revealed that Piper species may be used as one of the source of potential antioxidants.