Ganoderma lucidum, a species of the class Basidiomycetes, attracts international attention due to the wide variety of its biological activities and great potential as cosmetic ingredient, such as skin care cosmetics including ‘skin-whitening’. However, there is little information available regarding the tyrosinase inhibitory activity. Therefore, the objectives of this study were to investigate the chemical composition and tyrosinase inhibitory activity of the G. lucidum. To isolate active single compound from G. lucidum (GASC), we conducted ethanol extraction and chloroform fractionation. In addition, we assayed the inhibitoty effect of tyrosinase activity and melanin biosynthesis in B16F10 mouse melanoma cells. In the present study, we identified a GASC, which exhibited inhibitory effects of cellular tyrosinase activity, the protein expression of cellular tyrosinase and tyrosinase-related protein-1, 2. In additional, microphthalmia-associated transcription factor (MITF), as known as crucial regulator of melanogenesis-related genes, was down-regulated by treatment with GASC in a concentration-dependent manner. GASC exhibited significant inhibition of tyrosinase activity and melanin synthesis in B16F10. The finding that melanogenesis inhibitory effect of GASC will contribute to facilitate various approaches of this mushroom for use in skin whitening products.

Recently many efforts were focused to understand the mechanical insights of melanogenesis to develop the agents for hyper-pigmentation and hypo-pigmentation. In the melanin biosynthetic pathway, tyrosinase is the rate limiting enzyme, and α-melanocyte stimulating hormone(MSH) stimulate melanogenesis and enhance the melanin synthesis and the tyrosinase activity. This study the effects of Radix Trichosanthis on the basal melanogenic activities of B16/F10 mouse melanoma cells, and on the α-MSH induced melanogenesis. Radix Trichosanthis alone markedly suppressed melanin content and tyrosinase activity in a dose-dependent manner. Pretreatment of the cells with Radix Trichosanthis also suppressed the increase of α-MSH (10 nM) induced melanin content and tyrosinase activity. These results suggest that Radix Trichosanthis inhibits melanogenesis and abrogates α-MSH induced melanogenesis in B16 melanoma cells.

The pathological condition of excessive melanogenesis causing freckles, melasma, senile lentigo, pigmented acne scars, and cancer has a critical impact on the wellness of individuals. The mechanism of melanogenesis is related to the expression of melanogenic enzymes. Here, we evaluated the inhibitory effect of pine cone (Pinus densiflora) extracts on melanogenesis. P. densiflora, the Korean Red Pine, is the predominant tree species in the cool, temperate forests of northeast Asia, occurring in pure stands across Korea, Japan, and parts of northern China and Russia. P. densiflora leaves, pollen, and bark have been widely used for traditional medicine, or edible purposes. However, pine cones are rarely used as natural raw materials, although they contain many bioactive phytochemicals. The pine cone ethyl acetate fraction (PEF) showed no toxicity to B16F10 cells at a concentration of less than 100 ㎍/mL. PEF inhibited the expression of microphthalmiaassociated transcription factor (MITF), tyrosinase and tyrosinase-related factors in B16F10 cells treated with 3-Isobutyl- 1-methylxanthine (IBMX). These results suggest that pine cones can be used as an effective natural melanogenesis inhibitory agent.

This study was conducted to investigate the effect of branch extracts of Vaccinium oldhamii (VOB) on melanin synthesis in B16F10 cells. VOB promoted melanin production in absence or presence of α-melanocyte-stimulating hormone (α-MSH) in B16F10 cells. However, VOB did not affect the expression of tyrosinase and TRP-1 associated with melanin synthesis at the mRNA and protein levels in B16F10. But, VOB decreased TRP-2 protein level and induced tyrosinase activation in B16F10 cells. Inhibition of tyrosinase activity and tyrosinase knockdown attenuated VOB-mediated melanin synthesis. In conclusion, VOB may stimulate melanin synthesis through activating tyrosinase activity.

본 연구에서는 B16 악성흑색종 세포에서 디펩타이드(dipeptide)의 멜라닌생성 저해 효과를 연구하였다. 실험결과 WV (트립토판-발린), WM (트립토판-메치오닌), CQ (시스테인-글루타민)는 멜라닌 생성을 농도 의존적으로 감소 시켰다. 그러나 디펩타이드는 멜라닌 생합성과정의 속도 조절 단계 효소인 타이로시네이즈(tyrosinase)의 활성을 직접 감소시키지는 않았다. 따라서 타이로시네이즈의 발현양상을 조사하였고, 실험 결과 α-MSH가 유도한 타이로시네이즈 발현이 WV, WM, 그리고 CQ에 의해 억제되었다. 그러므로 WV, WM, 그리고 CQ가 타이로시네이즈의 억제성 조절 (down-regulation)을 통해 멜라닌 생성을 감소시킨다고 제안될 수 있다.

본 연구는 찔레 에탄올 추출물의 세포 활성 및 티로시나아제활성 저해를 분석하였다. 찔레 추출물의 세포활성을 분석한 결과 찔레 잎과 뿌리 추출물의 경우에는 추출물을 처리하지 않은 대조군과 유사한 결과를 관찰하였다. 모든 농도에서 세포 활성이 나타나지 않아 티로시나아제 활성 저해 효과를 분석한 결과 찔레 잎과 뿌리추출물은 상대적으로 고농도(200 μg/ml)에서 약 30~32% 정도를 저해하는 효과를 나타냈다. 또한 B16 세포에서 티로시나아제활성 저해 효과를 분석한 결과 상대적으로 고농도(200 μg/ml)에서 양성대조군인 알부틴보다 20~25% 정도 낮은 저해 효과를 나타냈다. 멜라닌 함량 저해 효과를 분석한 결과 찔레 잎과 뿌리 추출물의 경우 티로시나아제의 저해 효과와 유사하게 농도 의존적인 저해효과를 나타내는 것을 관찰하였다. RT-PCR 방법으로 분석한 결과, 추출물 처리군들은 정상대조군과 비교하여 티로시나아제 mRNA 수준이 유의적으로 차이가 나지 않았으며, 또한 농도 의존적인 변화도 없었다.