Unlocking the biochemical secrets of Onosma angustissima: Aqueous extract profiling via ultrasound-assisted extraction coupled with bioactivity insights

Abstract

Amid the growing interest in natural bioactive compounds with therapeutic potential, Onosma species, particularly Onosma angustissima, have garnered attention due to their diverse phytochemical profiles and established ethnopharmacological significance. This study aimed to characterize the chemical composition, antioxidant potential, and enzyme inhibitory properties of an aqueous extract obtained from O. angustissima using ultrasound-assisted extraction. Total phenolic and flavonoid contents were quantified as 18.21 mg GAE/g and 1.59 mg RE/g, respectively. LC–ESI–MS/MS analysis revealed a distinct phytochemical profile dominated by p-coumaric acid (575 µg/g) and apigenin 7-glucoside (299 µg/g), alongside notable levels of hydroxybenzoic acids and flavone glycosides. Antioxidant capacity, evaluated via six in vitro assays, demonstrated moderate activity with EC₅₀ values of 0.92 mg/mL (phosphomolybdenum), 3.45 mg/mL (CUPRAC), and 1.08 mg/mL (FRAP), and IC₅₀ values of 5.97 mg/mL (DPPH), 1.25 mg/mL (ABTS), and 1.15 mg/mL (metal chelation). Enzyme inhibition assays indicated weak to moderate activity, with IC₅₀ values of 10.47 mg/mL (BChE), 2.48 mg/mL (tyrosinase), 19.90 mg/mL (α-amylase), and 2.48 mg/mL (α-glucosidase), while AChE was not inhibited. These results suggest the aqueous extract exerts multi-target biological effects, albeit with lower potency than conventional standards. The observed compositional diversity may synergistically enhance the bioactivities measured, thereby necessitating further exploration through activity-guided fractionation and in vivo validation. Future studies should also explore the pharmacokinetics and safety profile of key constituents to better elucidate their therapeutic potential and application in functional formulations.