Potential of Korean Forest Tree Seed Extracts as Multifunctional Bioresources: Evaluation of Antioxidant, Anti-inflammatory, Whitening, and Anticancer Activities

Forest tree seeds are mass produced for afforestation and forest restoration programs, but are mostly underutilized beyond propagation. Here, we aimed to evaluate the antioxidant, anti-inflammatory, anticancer, and tyrosinase-inhibitory activities of seed extracts of seven economically important forest tree species in the Republic of Korea to explore their potential as multifunctional natural bioresources. The seed extracts of Alnus japonica, Chamaecyparis obtusa, Cornus kousa, Phellodendron amurense, Pinus densiflora, Prunus sargentii, and Quercus glauca were comparatively assessed using multiple in vitro assays. The results revealed clear species-dependent functional profiles rather than uniform bioactivities across species. Quercus glauca exhibited strong antioxidant activity and significant anti-inflammatory and tyrosinase-inhibitory activities, suggesting multifunctional potential, while C. obtuse presented considerable anticancer activity against several cancer cell lines. Alnus japonica exhibited the highest tyrosinase-inhibitory activity, followed by Q. glauca and C. obtuse; A. japonica extract also showed a strong antioxidant capacity. Overall, the results demonstrated that forest tree seed extracts possess diverse and complementary bioactivities, supporting their potential as underexplored multifunctional natural materials. By focusing on seed resources generated within existing afforestation systems, we highlight a sustainable approach to valorize forest-derived by-products without additional pressure on natural ecosystems. Nevertheless, as bioactivities were evaluated using crude extracts, further studies are required to identify and elucidate the active compounds and their mechanisms of action.