Antioxidant constituents from Ribes glaciale Wall.: bioassay targeted in-vitro and in-silico evaluation

Bioassay targeted phyto-investigation of dried green walnut husk of Ribes glaciale Wall. yielded one new compound as β-D-glucopyrano (4′→3)-β-D-glucopyranose (1) and four known compounds namely scoparone (2), apigenin (3), β-sitosterol (4) and β-sitosterol-D-glucoside (5). The structure of new compound was elucidated with the help of 1D, 2D and HRESIMS analysis. The antioxidant activity of extract, fractions and pure were evaluated using 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric ion reducing antioxidant power (FRAP) assays that found in the following order: butanol fr. (BF) > chloroform fr. (CF) > ethylacetate fr. (EF) > Petroleum ether fr. (PF). To search for potent antioxidant agents in extract, the isolated compounds 1, 2, 3, 4 and 5 were docked on the enzyme human NADPH oxidase, lipoxygenase, cytochrome P450 and myeloperoxidase. The compound 1 was found a potent inhibitor of target enzyme revealing its high free radical scavenging potential.