BACKGROUND: Adventitious root (AR) culture is an effective method for the production of Hypericum perforatum raw materials. However, the ARs are seldom utilized in practical applications. Therefore, this study investigated the effects of H. perforatum ARs on antioxidative stress and anti-melanogenesis, aiming for future applications in the development of related products. RESULTS: In the antioxidative stress experiment, tert-butyl hydroperoxide-stimulated HepG2 cells were pre-treated with 12.5-50 μg mL CONCLUSION: HpE efficiently protects HepG2 cells from oxidative stress and safeguards the liver in mice by mitigating oxidative damage. Additionally, HpE inhibits melanin synthesis in B16-F10 cells by suppressing tyrosinase activity. These findings suggest that H. perforatum ARs hold potential for use in the development of healthy foods, cosmetics, and pharmaceutical products aimed at antioxidative stress and anti-melanogenesis. © 2024 Society of Chemical Industry.