Franklin Ibana | Von Novi O. De Leon | Agnes Castillo | Allan Patrick G. Macebeo
Diabetes mellitus is growing to epidemic proportions, leading to devastating complications if left untreated. This study investigated the enzyme inhibitory activity, LC-MS analysis of the leaf extracts of S. lineatum (DC). Merr. & L.M. Perry and computational-based studies on the binding mechanisms of the putative bioactive compounds. The dichloromethane-methanol crude extract was subjected to solvent partitioning to yield petroleum ether, dichloromethane and n-butanol sub-extracts. Enzyme inhibitory assays against α-glucosidase and α-amylase were conducted. Identification of putative compounds were conducted through LC-HRMS analysis. Molecular docking was conducted to identify the best-suited receptor sites. In the α-glucosidase inhibitory assay, the n-butanol sub-extract of S. lineatum displayed an IC50 value of 48.31 ± 0.890 ug/mL whereas, the crude extract has shown an IC50 value of 13.60 ± 0.050 ug/mL in the α–amylase inhibition assay. LC-HRMS analysis of the crude and n-butanol sub-extract yielded staphylionoside J (1), quercetin-3-glucoside (2), myricetin (3), quercitrin (4), kaempferol-3-rhamnoside (5), arjunolic acid (6), and asiatic acid (7). Molecular docking studies revealed strong binding affinities (ca. -9 kJ/mol) on the catalytic site of α-glucosidase for the flavonoids myricetin (3), quercitrin (4), kaempferol-3-rhamnoside (5). Thus, the plant-derived bioactive compounds contribute to the inhibition of the enzymes in the in vitro assays complemented by in silico experiments. This is a pioneering study of S. lineatum leaf extracts which presents potential benefits on inhibition of intestinal enzymes.
ISSN 2719-1990 (Print)
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