Unveiling the Antioxidant and Alpha-Amylase Inhibitory Activity of Capparis spinosa L from Algeria: Synergistic Effects and Molecular Docking Insights

Objective This study aims at identifying the chemical structure of hydromethanolic extracts from Capparis spinosa L. aerial part. In addition, it evaluates the antioxidant activity, studies the synergistic interactions of the various extracts and fractions, and evaluates the extracts’ inhibitory activity against alpha-amylase enzyme. Methods We used maceration and decoction to obtain hydro-methanolic extracts, and liquid chromatography LC-MS/MS to ascertain the extracts’ chemical structure. Three techniques were employed to assess antioxidant activity, amylase inhibition was assessed in vitro, and compounds that could inhibit amylase were found using in silico docking simulations. Results LC-MS/MS investigation revealed 17 phytochemical compounds, 03 of them, namely salicylic acid, salicin, and curcumin have not before been found in the aerial parts of the caper plant in North African countries. The butanolic fraction F3 showed the highest antioxidant activity, with IC50 values of 74.77 ± 6.08 ug/mL and 41.59 ± 5.89 ug/mL in DPPH and ABTS, respectively. Besides, A 0.5 value was 28.64 ± 0.15 ug/mL in the O-Phenanthroline. In addition, most of the mixtures showed synergy, as in f2 + f4 + CSED (1:1:1) with CI effect = 0.22 and IC50 values (43.00 ± 0.76 ug/mL, 19.42 ± 2.36 ug/mL) in DPPH and ABTS, respectively. The results of alpha-amylase in vitro inhibition showed a high ability for all extracts and fractions to inhibit the enzyme compared to acarbose. Conclusion Findings show a significant variety of phenolic compounds in the extracts of C. spinosa aerial parts. Based on the molecular docking study, eight compounds were found to be able to occupy the enzyme's active site and form strong bonds with alpha-amylase; this is how they inhibit the enzyme.