Post-harvest and Extraction Conditions for the Optimum Alpha Glucosidase Inhibitory Activity of Stenochlaena palustris

Abstract

Stenochlaena palustris has been studied for its anti-diabetic potency related to its alphaglucosidase inhibitory (AGI) activity. This study aimed to evaluate the impact of post-harvest and extraction conditions on the AGI activity of S. palustris and isolate the AGI bioactive principal component. AGI activity was calculated based on the inhibition of S. palustris samples against in vitro rat intestinal maltase and sucrase hydrolytic activities in enzymatic reactions. The selected extracts were subjected to activity-guided fractionation using liquid-liquid sequential separation, followed by silica N60 column chromatography. This study showed that post-harvest treatment significantly protected the AGI activity of S. palustris, while its optimum extract condition was observed with methanol and a smaller particle size (< 250 µm) at a sample to solvent ratio of 1:20 (w/v) for 24 h. Further fractionation, followed by Liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance (NMR) evaluation of the S. palustris extracts from optimum postharvest and extraction conditions, also resulted in the identification of kaempferol 3-O-β-glucopyranoside (astragalin) as the responsible bioactive AGI compound. This study’s findings are expected to contribute to further study and utilization of S. palustris as an anti-diabetic agent based on its AGI activity.