Whitening Activity of Various Parts of Taiwanese Mahogany

This study aimed to evaluate the whitening potential of various parts of Taiwanese mahogany (iSwietenia macrophylla/i) through both extracellular and intracellular assays. The inhibitory effects on tyrosinase activity and the impact on B16F10 melanoma cell viability and melanin content were systematically investigated using various extracts, including crude methanol extracts and partitioned fractions (ethyl acetate, n-butanol, and water). Extracellular results demonstrated that most large-leaf mahogany extracts at 100 ppm exhibited higher tyrosinase inhibition rates than the positive control, kojic acid (48.9%), particularly the hot water leaf (86.86%) and methanol peel (78.10%) extracts. Intracellularly, the n-butanol fraction of mahogany stones (50 ppm, 39.10%) and the water-soluble fraction (12.5-50 ppm, up to 50.13%) significantly reduced tyrosinase activity. Furthermore, methanol extracts from small-leaf mahogany leaves showed a superior ability to reduce cellular melanin content compared to large-leaf varieties. These findings suggest that specific parts and solvent fractions of Taiwanese mahogany possess significant whitening activities, supporting their potential application in cosmetic and therapeutic formulations.