2.3. Phytochemical studies
Qualitative analysis for determining the presence of tannins, saponins, glycosides, flavonoids, steroids and alkaloids in the polyphenolic extract was performed using standard methods [21].
2.3.1. Total phenolic content (TPC) The total phenolic content of the polyphenolic extract of T. chebula was estimated by the reported method [22]. Various concentrations of gallic acidwere used to plot the standard curve. The total phenolic content of the extract is expressed as mg gallic acid equivalents/g dry weight of extract.
2.3.2. Flavonoid content The total flavonoid content in the T. chebula polyphenolic extract was estimated by the standard method [23]. The flavonoid content of the extract is expressed as mg quercetin equivalents/g dry weight of extract.
2.3.3. Tannin content The tannin content of the T. chebula polyphenolic extract was estimated by the method described by Hagerman and Butler [24]. The tannin content of the extract is expressed asmg rutin equivalents/g dryweight of extract.
2.3.4. Ascorbic acid content Ascorbic acid, also called vitamin C, is one of the most abundant antioxidantsin T. chebula extract and was quantified according to the previously reported method [25]. The ascorbic content of the extract is expressed as g/g dry weight of extract.