Chemical screening of Hibiscus rosa-sinensis for their phytochemicals and their in vitro/in silico evaluation as α-amylase inhibitors.

Since ancient times, flowers of Hibiscus rosa-sinensis have been a prominent ingredient of medicinal recipes. The understudied research article is a part of our experimental work to isolate bioactive molecules of flowers of Hibiscus rosa-sinensis and assess the biological potential of these molecules. Currently, we subjected the hexane and ethyl acetate fractions of crude methanolic floral extract of Hibiscus rosa-sinensis to repeated column and thin-layer chromatography. Consequently, eight known compounds were isolated and identified using spectroscopic techniques (1D and 2D NMR) as follows: taraxerol (HF1), 3,4-dimethoxycinnamic acid (HF2), β-stigmasterol glycoside (HF3), 2-hydroxy-1,7-dimethoxyanthraquinone (HF4), (E)-1-(4-hydroxyphenyl) undec-1-en-3-one (HF5), dihydroxyacetone (HF6), 1,5-dihydroxypentane-2,4-dione (HF7), and methylparaben (HF8). Further, we assessed the α-amylase inhibition capacity of isolated molecules against human pancreatic α-amylase (3BAJ) via in vitro and in silico approaches; however, the structures of isolated molecules were optimized by density functional theory (DFT). As a result of in vitro and in silico α-amylase inhibition assessment of isolated ligands, compound HF3 was explored as the most potential inhibitor of α-amylase with an IC