Study of antioxidant and α-amylase inhibitory activity of Aconogonon molle (D. DON) and Polygala arillata buch, of Nepal

Abstract

Aconogonon molle (leaves and stems) and Polygala arillata (roots) were selected for comparative investigation based on their ethnomedicinal relevance and their traditional use as plant ingredients in marcha, as reported by local Limbu community members during _eld collection. Methanolic extracts of both species were evaluated under identical experimental conditions for phytochemical composition, antioxidant activity, α-amylase inhibition, and antibacterial activity. A. molle showed higher total phenolic content (55.36 ± 1.16 mg GAE/g) and total flavonoid content (11.02 ± 0.32 mg QE/g) than P. arillata. It also exhibited stronger antioxidant activity, with a DPPH IC50 of 42.35 ± 1.05 μg/mL and FRAP value of 670.94 ± 2.50 mM Fe²⁺/L. A. molle showed moderate α-amylase inhibitory activity (IC₅₀ = 867.78 μg/mL) compared with acarbose (IC₅₀ = 26.28 μg/mL) and modest antibacterial activity against Staphylococcus aureus (7.75 mm inhibition zone), while no activity was detected against Salmonella typhi. P. arillata showed weak DPPH radical-scavenging and α-amylase inhibitory activities, and its IC₅₀ values could not be determined within the tested concentration ranges. It also showed no detectable antibacterial activity against either test organism. Overall, A. molle exhibited stronger biological activities than P. arillata under the tested conditions. These findings provide comparative baseline information for further isolation and characterization of bioactive constituents from these ethnobotanically related medicinal plants.