New inhibitors of melanogenesis, OH-3984 K1 and K2. I. Taxonomy, fermentation, isolation and biological characteristics

Improving Cosmetic Activity by OptimizingCentella asiaticaExtraction Process

This study showed the use of Centella asiatica as a good source of compounds for skin therapy and antioxidant activation cosmetics. The goal of this study was to provide cosmeceutical activity data about the extraction yield and total phenol content of C. asiatica by optimizing the focused high ultrasound (INEFU) and ultrasound extraction (UE) conditions. Under optimal extraction conditions, that is, 1800 W for 45 minutes and 500 W for 45 minutes, 28.73% and 30.21% (w/w) of the highest extraction yields and polyphenol contents were obtained, respectively. For the skin whitening activity, tyrosinase inhibitory activity was observed at 61.52% in INEFU extracts, which was circa 20.3% higher than that of UE extracts (51.11%). To reduce melanin production in Clone M-3 cells, 86.9% melanin production was observed following the addition of control, water extraction relative to the control without a sample, and 79.6% and 74.5% were found in UE and INEFU conditions, respectively. In conclusion, the highest total phenol secretion was obtained under optimal conditions and resulted in a significant improvement in the cosmetic activities of C. asiatica extracts.

Beneficial Effects on Cosmetic Activity by Optimizing the Calamondin Orange Extraction Process

This study expands the usage of Citrus madurensis ( Citrofortunella microcarpa), which is a good source of skin whitening and antioxidants activation in cosmetics. The goal of this study is to provide cosmeceutical activity data about the extraction yield and total polyphenol of calamondin orange by optimizing the focused high ultrasound (INEFU), ultrasound extraction (UE), and water extraction (WE) conditions. Under optimal extraction conditions, which consisted of 1800 W for 45 minutes (INEFU) and 500 W for 45 minutes (UE), 21.55% (w/w) and 13.27% (w/w) of the highest extractions yield and total polyphenol content was obtained. For the skin whitening activity, tyrosinase inhibitory activity was observed at 69.28% in the INEFU extracts, which was 69.24% higher than that of the UE extracts (58.82%). To reduce melanin production in Clone M-3 cells, 86.9% melanin production was observed following the addition of control, WE relative to the control without a sample, and 81.2% and 78.9% were found in the UE and INEFU conditions, respectively. The highest total phenol secretion was conclusively obtained under the optimal conditions and resulted in a significant improvement of the cosmetic activities of C. madurensis ( C. microcarpa)-based cosmeceutical ingredient.

Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol

2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L) in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated melanin formation in intact B16 melanoma cells.

Improved cosmetic activity by optimizing the Lithospermum erythrorhizon extraction process

This study was conducted to expand the use of Lithospermum erythrorhizon, which is a good source of natural dye, in skin whitening and immune activation cosmetics. The goal was to provide cosmeceutical data about the extraction yield and shikonin contents of this plant by optimizing the ultrasonic extraction and high pressure extraction conditions. Under optimal extraction conditions, which consisted of 500 MPa for 60 min and 120 kHz for 90 min, 27.49 and 3.19 % (w/w) of the highest extraction yield and shikonin contents were obtained, compared to 16.32 and 1.81 % from a conventional ethanol extract (EE) control. Hyaluronidase inhibition activity was measured as 44.24 % after adding 1.0 mg/ml of ethanol extract, but it was as high as 64.19 % when using extract produced by ultrasonication with high pressure extraction (UE + HPE). The MMP-1 expression levels from skin fibroblast cells (CCD-986sk) treated with or without UV irradiation were also lowered by as much as 110.6 % after adding 1.0 mg/ml of the UE + HPE extract, relative to 126.9 % from the EE. After UVA exposure, prostaglandin E2 production from RAW 264.7 was also lower, at 110.6 %, which also indicates that the extract from the UE + HPE process enhanced skin immune activation activities. For the skin whitening activity, tyrosinase inhibitory activity was observed at 67.15 % in the HPE + UE extract, which was ca. 20 % higher than that of the EE extract (57.48 %). To reduce melanin production in Clone M-3 cells, 79.5 % of the melanin production was estimated after adding 1.0 mg/ml of the UE + HPE extract compared to that of the control (no treatment), which was similar to the 77.4 % result found in an ascorbic acid positive control. The highest shikonin secretion was conclusively obtained under the optimal conditions and resulted in a significant improvement of the cosmetic activities of L. erythrorhizon extracts.

Arenarol isolated from a marine sponge abrogates endothelin-1-stimulated melanogenesis by interrupting MEK phosphorylation in normal human melanocytes

Using B16 melanoma cells for screening, we found that a marine sponge extract has a potent anti-pigmenting effect and identified arenarol as its major active compound. In normal human melanocytes (NHMs), arenarol significantly abrogated the endothelin 1 (EDN1) stimulated expression of tyrosinase, tyrosinase-related protein 1 and dopachrome tautomerase at the transcriptional, translational and enzymatic activity (only for tyrosinase) levels. That effect was accompanied by the attenuation of the increased expression level of microphthalmia-associated transcription factor (MITF) protein at the transcriptional and translational levels. Analysis of EDN1 signaling demonstrated that arenarol significantly suppressed the EDN1-induced phosphorylation of MEK, ERK, MITF and CREB but not of Raf-1s. In contrast, the forskolin-induced phosphorylation of CREB was not down-regulated by arenarol. As for the mode of action of the suppressed phosphorylation of MEK, Raf-1 activity was not directly inhibited by arenarol in vitro and pretreatment with the protein phosphatase inhibitor okadaic acid did not affect the down-regulated phosphorylation of MEK that was induced by arenarol in NHMs. The sum of these findings suggests that arenarol abrogates the EDN1-stimulated expression of melanocyte-specific proteins by interrupting MEK phosphorylation in an as yet unknown Raf-1 inactivation mechanism.

Melanin biosynthesis inhibitors from the bark of Machilus thunbergii

The bioassay-guided fractionation of the methylene chloride soluble portion of a methanol extract of Machilus thunbergii bark led to the isolation of four known lignans, machilin A (1), meso-monomethyl dihydroguaiaretic acid (2), nectandrin A (3) and nectandrin B (4), which exhibited potent inhibitory activity on melanin biosynthesis in cultured B-16 mouse melanoma cells (IC(50): 39.9, 15.1, 19.4 and 37.8 microM, respectively).