Extracts of Antrodia cinnamomea mycelium as a highly potent tyrosinase inhibitor.

Abstract

Ganoderma has been known as a cure for diseases since ancient times, and been used as a medicinal mushroom for more than 2000 years. By many accounts, Ganoderma lucidum extracts from fruit bodies exhibited the comparable tyrosinase inhibition activity. To validate A. cinnamomea mycelia anti-melanogenesis activity. Ethanolic extracts of A. cinnamomea mycelia were evaluated using in vitro cell-free tyrosinase assay, cell-based and zebrafish phenotype-based method. Meanwhile, safety assessment was also conducted to ensure the feasibility as the novel ingredients in cosmetic and pharmaceutic industries. The major regulatory enzymes being in charge of cutaneous pigmentation, was investigated in both cell-free and cellular enzyme systems, and in phenotype-based zebrafish model. A high-throughput TLC in vitro screening system was introduced to perform the initial evaluation of those with anti-melanin formation activity. Among the fractions, 50% ethanol extracted fraction (AC_Et50_Hex) exhibited highest anti-melanin formation activity. AC_Et50_Hex (at 100 ppm) reduced 30% intracellular melanin of B16-F10 cells through suppression of tyrosinase activity and its protein expression. For animal study, not only does AC_Et50_Hex exhibited similar depigmenting efficacy to kojic acid (56.1% vs 52.3%) with lower dosage (50 ppm vs 1400 ppm), but showed less toxicity to zebrafish. A. cinnamomea mycelium extracts can be an ideal candidate/substitute for skin-whitening since kojic acid has been reported with carcinogenic effect. AC_Et50_Hex was recognized as a potential tyrosinase inhibitor throughout in vitro and in vivo analysis studies. The mass production of A. cinnamomea mycelium from agitated fermentation realizes the natural mushroom extracts for commercial application.