In silico insight of microencapsulated quercetin from Cosmos caudatus Kunth extracts toward alpha amylase

Quercetin, a flavonoid compound, is one of the major compounds in the Cosmos caudatus Kunth extract which proposed to have biological activity. Nonetheless, bioactive compounds are commonly very sensitive to environmental conditions such as temperature or oxygen; hence, encapsulation is supposed to protect these components. This study aims to determine interactions between free quercetin and encapsulated quercetin with chitosan and sodium tripolyphosphate (Na-TPP) as wall materials. These ligands were docked to alpha amylase to investigate their potential as inhibitor for the enzyme. Results showed that interactions between encapsulated quercetin to alpha amylase resulted in more interactions, with binding energy of -550.60 cal/mol, compared to the free quercetin, with binding energy of -261.24 cal/mol, indicating a stronger bond between encapsulated quercetin to the enzyme. Amino acid residues involved in the interactions were Arg257, Arg267, Lys268, Trp269, Phe315, Trp316, Arg346, Phe348, Asn373, Cys378, and Asn380. The mechanism of inhibition of the alpha-amylase enzyme is thought to be a non-competitive inhibition.