Molecular Insights into Antityrosinase and Antioxidant Activities of Centaurea behen L. and Salvia haematodes Wall. Roots and Dynamics of Marker Flavonoids

Background and objectives: Hyperpigmentation, caused by excess melanin buildup, prompts the need for safer antityrosinase and skin-whitening agents due to the side effects of existing products. Traditional Persian medicine (TPM) highlights Centaurea behen L. and Salvia haematodes Wall. roots known as “Bahman-e-sefid” and “Bahman-e-sorkh”, respectively, as potential skin-whitening agents. Methods: The present investigation evaluated the antioxidant and antityrosinase properties of ethanol-macerated root extracts of both plants and their various fractions, including n-hexane, ethyl acetate, and n-butanol. Assessment of phenolic and flavonoid contents were conducted by Folin-Ciocalteu and aluminum chloride tests, respectively and the antioxidative capacity was evaluated using DPPH radical scavenging method. Tyrosinase inhibitory effects was determined enzymatically and B16 melanoma cell studies with concurrent cytotoxicity assessments were performed to determine cellular safety. Computational analyses, including docking studies and dynamics simulations, were conducted to identify the principal bioactive constituents of both plants. Results: The ethyl acetate fraction of S. haematodes roots revealed the highest antioxidant activity (DPPH IC50=159 mg/L), tyrosinase inhibition (IC50=0.18±0.02 mg/mL), phenolics content (571.28 mg GAE/g ext.), and the flavonoid composition (11.09 mg QE/g extract), with low cytotoxicity. Centaurea behen fractions were less potent. Molecular docking approach revealed kaempferol-3-glucoside, luteolin, and hesperidin as potent tyrosinase inhibitors, with kaempferol-3-glucoside showing stable binding in simulations. Conclusion: Salvia haematodes roots outperformed C. behen, suggesting potential for managing oxidative stress and hyperpigmentation-related skin conditions. These findings support their use in cosmeceutical and pharmaceutical applications. Further studies are needed to identify active compounds and elucidate their mechanisms of action.