The attenuating effects of green tea supplements (GTS) against the ultraviolet (UV) radiation induced skin damages are distinguished. However, the concomitant effects of GTS on the large intestinal microbiomes and associated metabolomes are largely unclear. Herein, we performed an integrated microbiome-metabolome analysis to uncover the esoteric links between gut microbiome and exo/endogenous metabolome maneuvered in the large intestine of UVB-exposed mice subjected to dietary GTS. In UVB-exposed mice groups (UVB), class Bacilli and order Bifidobacteriales were observed as discriminant taxa with decreased lysophospholipid levels compared to the unexposed mice groups subjected to normal diet (NOR). Conversely, in GTS fed UVB-exposed mice (U+GTS), the gut-microbiome diversity was greatly enhanced with enrichment in the classes, Clostridia and Erysipelotrichia, as well as genera, Allobaculum and Lachnoclostridium. Additionally, the gut endogenous metabolomes changed with an increase in amino acids, fatty acids, lipids, and bile acids contents coupled with a decrease in nucleobases and carbohydrate levels. The altered metabolomes exhibited high correlations with GTS enriched intestinal microflora. Intriguingly, the various conjugates of green tea catechins viz., sulfated, glucuronided, and methylated ones including their exogenous derivatives were detected from large intestinal contents and liver samples. Hence, we conjecture that the metabolic conversions for the molecular components in GTS strongly influenced the gut micro-environment in UVB-exposed mice groups, ergo modulate their gut-microbiome as well as exo/endogenous metabolomes.

β-Lapachone is an ortho naphthoquinone obtained from the bark of the lapacho tree (Tabebuia avellanedae), which has been used medicinally for centuries. The purpose of this study was to investigate the effects of β-lapachone on inhibitory mechanism of melanogenesis. β-Lapachone inhibited melanin synthesis and tyrosinase activity at 0.8 μM in melan-a cells. Also, β-lapachone reduced the expression of tyrosinase and tyrosinase-related protein-1 at transcriptional and translational levels. The decreased expression of tyrosinase and tyrosinase-related protein-1 might result from the reduced microphthalmia-associated transcription factor (MITF) level which regulates major melanogenic proteins. The reduced level of MITF was associated with delayed ERK activation by β-lapachone. Furthermore, β-lapachone reduced melanogenesis in the human 3D skin tissue culture; besides, it dramatically inhibited body pigmentation of zebrafish and decreased melanin content and tyrosinase activity. These results show that β-lapachone may be useful as a potential depigmentation agent for various hyperpigmentation disorders.

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