Antioxidant activities of several Scutellaria taxa and bioactive phytoconstituents from Scutellaria hastifolia L.

•All Scutellaria species mainly S. hastifolia displayed marked total antioxidant capacity.•S. hastifolia MeOH extract significantly inhibited LOX enzyme at 5 mg/mL.•A new cornoside derivative phenylethanoid glycoside was isolated from S. hastifolia.

This study was designed to evaluate the phenolic profiles and antioxidant potentials of different solvent extracts of four Scutellaria L. (Lamiaceae) taxa, S. hastifolia, S. velenovskyi, S. albida ssp. albida and S. orientalis ssp. pinnatifida, which are used in traditional medicines for various purposes. Among the investigated species, S. hastifolia was selected for further biological and phytochemical studies according to the results of preliminary screening assays. Phytochemical studies on S. hastifolia yielded a new phenylethanoid glycoside (hastifolioside) together with 16 known metabolites. The structures of the compounds were established on the basis of spectroscopic analyses. The antioxidant potentials and the antiinflammatory activities of the crude extracts of S. hastifolia as well as the isolates were evaluated through DPPH radical scavenging capability, linoleic acid lipid peroxidation inhibition and soybean LOX inhibition assays.