Investigation of the chemical composition, antioxidant, and enzyme inhibitory activities of Ononis natrix subsp. natrix, performance of in silico analyses of its major compounds

Abstract

In this study, phytochemical composition, antioxidant, anti-Alzheimer, anti-diabetic, tyrosinase activities and in silico analyses of methanol, ethyl acetate and water extracts obtained from the aerial parts of Ononis natrix subsp. natrix, which is naturally distributed in the flora of Mediterranean area, were performed. The extracts were first analyzed for their phytochemical composition using quantitative chromatographic techniques. As a result of spectrophotometric analyses (Agilent Technologies 1260 Infinity liquid chromatography system with 6420 Triple Quad mass spectrometer), it was determined that the methanol extract was the richest in terms of total phenolics (74.60 mg GAEs/g dry weight), while the water extract was found to be richest in terms of total flavonoids (27.88 mg REs/g dry weight). As a result of quantitative phytochemical analyses, taxifolin, hyperoside, eriodictiol and quercetin were found to be present in high concentrations. As a result of quantitative phytochemical analyses, taxifolin, hyperoside, eriodictyol, and quercetin were found to be present in high concentrations. The methanol extract displayed higher activity in all test systems except for DPPH radical scavenging activity. The results from the phosphomolybdenum, ABTS radical scavenging, CUPRAC, FRAP, and metal chelating tests for the methanol extract were: 1.71, 1.07, 1.02 mg, 0.91, and 1.47 mg /ml, respectively. When the AChE, BChE and α-glucosidase inhibitory activity tests were evaluated in terms of IC50, the methanol extract showed higher activity with IC50 values of 1.02, 1.70 and 1.02 mg/ml, respectively. In contrast, the ethyl acetate extract showed higher activity in the tyrosinase and α-amylase tests, with IC50 values of 1.42 and 1.78 mg/ml, respectively. It was found that there was a strong correlation between the total phenolic and flavonoid contents of the extracts and their antioxidant and enzyme inhibitor activities. The study also conducted in silico molecular docking, MM/GBSA, drug-likeness, and ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analyses to describe the pharmacokinetic and pharmacodynamic properties of bioactive compounds with potential pharmacological action present in O. natrix subsp. natrix extracts. The compounds studied were eriodictyol, hyperoside, quercetin, and taxifolin. Researchers have found that, based on molecular docking, MM/GBSA, and key interactions within the enzyme active sites, hyperoside may inhibit α-amylase and BChE, eriodictyol may inhibit α-glucosidase and AChE, and both hyperoside and eriodictyol may inhibit tyrosinase. The presented data on antioxidant and enzyme inhibitory activity, along with in silico studies, represent the first recorded findings in the literature.