In vitro enzyme inhibition, antibacterial, UHPLC-MS chemical profiling and in silico studies of Indigofera argentea Burm. f. for potential biopharmaceutical application

Abstract

The study aimed to assess the phytochemical composition and enzyme inhibitory potential of methanol, n-hexane, chloroform, and n-butanol extracts/fractions of Indigofera argentea Berm. f. (whole plant), a medicinal plant from Pakistan. Chemical profiling of I. argentea crude methanol extract was done via ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS) in both the positive and negative ionization modes. Standardin vitro bioassays were used to evaluate the enzyme inhibition potential against carbonic anhydrase, xanthine oxidase, and α-glucosidase. Additionally, nine dominant compounds as tentatively identified by UHPLC-MS profiling were docked against the tested enzymes to provide additional insights into the binding affinities against the target enzymes. UHPLC-MS chemical profiling showed the tentative presence of seventy-six secondary metabolites. The identified compounds include flavonoids and lithocholic acid derivatives of steroids in major amounts along with terpenes. Lithocholic acid derivatives were first reported from this plant and consider being potential candidates for treating diabetes. All extracts showed promising results against α-glucosidase with percentage inhibition of 82.8–21.2%, while for the xanthine oxidase the percentage inhibition values varying from 67.8–47.3%. Furthermore, moderate inhibition was observed against carbonic anhydrase. The methanolic extracts showed good inhibition against B. subtilis, K. pneumonia, P. vulgaris and P. aeruginosa as compared to Ciprofloxacin. Docking studies showed that atalanine showed higher inhibition affinity against the three studied enzymes as compared to morphine. Indigofera argentea showed promising enzyme inhibitory activities and can be considered as a potential source of bioactive secondary metabolites. Isolation of the bioactive compounds and further mechanistic studies could provide further insights into the biopharmaceutical potential of this plant as a nutraceutical and/or dietary supplement.