Antioxidant activity of Platycodonis Radix flavonoids in a Saccharomyces cerevisiae model

Abstract

Platycodonis Radix (PR) is a traditional medicinal herb with notable antioxidant activity. In this study, total flavonoids in PR extract (TFPE) were obtained via ultrasound-assisted extraction and optimised using response surface methodology, yielding 5.92 mg/g of flavonoids. Liquid chromatography–tandem mass spectrometry identified 22 flavonoids, with cynaroside, luteolin, and baicalin as major constituents. TFPE exhibited strong radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), hydroxyl radical, and ferric reducing antioxidant power assays. Using Saccharomyces cerevisiae as a model, TFPE significantly improved cell viability, reduced lipid peroxidation, and decreased reactive oxygen species levels under oxidative stress induced by H2O2 and CdSO4. In gene-deletion strains, TFPE’s protective effects were partially dependent on antioxidant enzymes superoxide dismutase 1 and catalase T (CTT1). Molecular docking revealed strong binding affinities between key flavonoids and antioxidant enzymes, especially CTT1, suggesting both enzymatic and non-enzymatic mechanisms. These findings highlight the structural diversity and antioxidant potential of PR flavonoids and support their development as natural redox-modulating agents.