Phytochemical screening and metabolomic approach based on Fourier transform infrared (FTIR): Identification of a-amylase inhibitor metabolites in Vernonia amygdalina leaves

Context: Vernonia amygdalina has been reported as a potential antidiabetic agent. One of the mechanisms in diabetes mellitus treatment is the inhibition of the a-amylase enzyme's action. Objective: This study is aimed to identify the presence of secondary metabolites in Vernonia amygdalina leaf extract, which has the potential as a-amylase inhibitors through phytochemical screening combined with metabolomic analysis.Materials and methods: Methanol extract from Vernonia amygdalina leaf was partitioned into n -hexane, dichloromethane (DCM), and ethyl acetate. From this process, methanol, hexane, DCM, and ethyl acetate extracts were obtained. These extracts were then being tested for phytochemical screening, a-amylase inhibition, and FTIR. Then FTIR data were used for metabolomic analysis (PCA and PLS). Results: The results of the a-amylase inhibition test showed that the ethyl acetate extract had the smallest IC50 average value, which was 3.00 lg/mL. Based on the phytochemical screening test results, the extract showed positive for the presence of compounds such as flavonoids, phenols, tan-nins, alkaloids, and saponins. From the PCA analysis (Bi-plot), the wavenumbers that were influ-ential in the ethyl acetate extract were 1436 to 1681 and 3341 to 3348 cm -1. In theory, functional groups such as C-H, C,C, C,O, N-H, and O-H appeared on the absorption. From the PLS analysis, these wavenumbers affected the activity.Conclusion: The most potential extract as an a-amylase inhibitor was the ethyl acetate extract. Based on phytochemical screening tests and metabolomic analysis, it was proven that this extract contained compounds as hypoglycemic agents.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study identified the ethyl acetate extract from Vernonia amygdalina leaf as a potential α-amylase inhibitor through phytochemical screening and metabolomic analysis. The results showed that this extract contained compounds with hypoglycemic activity, confirming its potential as a treatment for diabetes mellitus.