Antioxidant, Anti-Inflammatory, and Analgesic Properties of Chemically Characterized Polyphenol-Rich Extract from Withania adpressa Coss. ex Batt

The current work was undertaken to investigate the chemical composition, antioxidant, anti-inflammatory, and analgesic properties of a polyphenol-rich fraction from Withania adpressa Coss. ex Batt. After being extracted, the polyphenol-rich fraction was chemically characterized through use of high-performance liquid chromatography (HPLC). Antioxidant potency was assessed through the use of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and total antioxidant capacity (TAC). Inflammatory and analgesic properties were assessed in vivo through the use of carrageenan and heat stimulus assays, respectively. Chromatographic analysis of polyphenol-rich fraction revealed the presence of potentially bioactive phenols including epicatechin, apigenin, luteolin, quercetin, caffeic acid, p-coumaric acid, and rosmarinic acid. The polyphenol-rich fraction showed interesting anti-free-radical potency with a calculated IC(50) value of 27.84 ± 1.48 µg/mL. At the highest dose used (1000 µg/mL), the polyphenol-rich fraction scored good total antioxidant capacity with a calculated value of 924.0 ± 28.29 µg EAA/mg. The polyphenol-rich fraction strongly alleviated the inflammatory effect of carrageenan injected into the plantar fascia of rats resulting in inhibition up to 89.0 ± 2.08% at the highest tested dose (500 mg/kg). The polyphenol-rich fraction showed a good analgesic effect wherein the delay in reaction time to a thermal stimulus caused by 500 mg/kg had a highly similar effect to that induced by Tramadol used as a positive control. The findings of the current work highlight the importance of polyphenol-rich fractions from W. adpressa Coss. ex Batt. as an alternative source of natural antioxidant, inflammatory, and analgesic drugs to control relative diseases.