Identification of α-amylase inhibitors from flavonoid fraction of Feronia elephantum and its integration with in-silico studies.

Abstract

Postprandial hyperglycemia is associated with an increase in blood glucose levels after a meal, which is further associated with various risk factors like cardiovascular diseases. α-amylase is a digestive enzyme and secreted by the salivary glands and pancreas, which helps to catalyze the hydrolysis of the internal α-1,4-glycosidic linkages in starch breaking them into smaller units. Hence, the present study is aimed to identify flavonoids from the fruit pulp of Feronia elephantum as α-amylase inhibitors via in-silico and in-vitro protocols. In-silico tools like ADVERPred, PubChem, MolSoft, Discovery studio 2019, and Autodock 4.0 were used to predict the information related to phytoconstituents, drug-likeness character, and probable side effects. In-vitro α-amylase inhibitory activity was performed with five different concentrations of flavonoid fraction of hydroalcoholic extract of the fruit pulp of Feronia elephantum using 1% starch solution and DNS reagent. Four flavonoids were identified from 25 bio-actives present in the fruit pulp of Feronia elephantum. Three bio-actives were predicted to possess a positive drug-likeness score, from which 5,4-dihydroxy3-3(3-methyl-but2-enyl)3,5,6-trimethoxy-flavone-7-O-β-d-Glucopyranoside was predicted to possess the highest drug-likeness score of 0.70. Vitexin and 5,4-dihydroxy3-3(3-methyl-but2-enyl)3,5,6-trimethoxy-flavone-7-O-β-d-Glucopyranoside were predicted to possess nephrotoxicity as an adverse effect. The percent inhibition of α-amylase by a flavonoid-rich fraction at 100 μg/ml was found to be 45.95% as compared to standard acarbose with 74.79% inhibition at 100 μg/ml. Further, docking studies predicted that vitexin possessed the highest binding affinity (binding energy - 7.98 kcal/mol) as compared to standard acarbose with binding energy - 5.24 kcal/mol. There were no significant side effects predicted, in-vitro α-amylase inhibitory activity of the flavonoid-rich fraction may be due to the presence of vitexin, predicted via in-silico molecular docking; further, which needs to be further validated via in-vivo protocols.