TYR and melanoma: The melanogenesis inhibitory activities in theophylline-stimulated murine B16 melanoma 4A5 cells of these isolates including the new diterpenes (1–3, IC50 = 4.4, 8.6, and 4.6 μM, respectively) were found to be more than 6–87-fold higher than that of arbutin (174 μM), a commercially used tyrosinase inhibitor.