Bridging Phytochemistry and Cosmetic Science: Molecular Insights into the Cosmeceutical Promise of Crotalaria juncea L.

Crotalaria juncea L. (Fabaceae: Faboideae), traditionally used as green manure due to its nitrogen-fixing capacity, also exhibits therapeutic potential for conditions such as anemia and psoriasis. However, its cosmetic applications remain largely unexplored. This study examined the phytochemical profiles and biological activities of ethanolic extracts from the root, flower, and leaf of C. juncea, focusing on their potential use in cosmetic formulations. Soxhlet extraction with 95% ethanol was employed. Among the extracts, the leaf showed the highest total flavonoid content, while the root contained the highest total phenolic content. The root extract demonstrated the strongest antioxidant activity, as assessed by DPPH, FRAP, and lipid peroxidation assays, along with significant anti-tyrosinase and anti-aging effects via collagenase and elastase inhibition. LC-MS/QTOF analysis identified genistein and kaempferol as the major bioactive constituents in the root extract. Molecular docking confirmed their strong interactions with enzymes associated with skin aging. Additionally, the root extract exhibited notable anti-inflammatory activity. These results suggest that C. juncea root extract is a promising multifunctional natural ingredient for cosmetic applications due to its antioxidant, anti-tyrosinase, anti-aging, and anti-inflammatory properties.