Tea catechins and flavonoids from the leaves of Camellia sinensis inhibit yeast alcohol dehydrogenase.

Four new quercetin acylglycosides, designated camelliquercetisides A-D, quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][ß-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-ß-D-glucoside (17), quercetin 3-O-[2-O″-(E)-p-coumaroyl][ß-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-ß-D-glucoside (18), quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-ß-d-glucoside (19), and quercetin 3-O-[2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-ß-D-glucoside (20), together with caffeine and known catechins, and flavonoids (1-16) were isolated from the leaves of Camellia sinensis. Their structures were determined by spectroscopic (1D and 2D NMR, IR, and HR-TOF-MS) and chemical methods. The catechins and flavonoidal glycosides exhibited yeast alcohol dehydrogenase (ADH) inhibitory activities in the range of IC(50) 8.0-70.3µM, and radical scavenging activities in the range of IC(50) 1.5-43.8 µM, measured by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.

Tea triterpenoidal saponins from the roots of Camellia sinensis have inhibitory effects against alcohol dehydrogenase.

Ten new polyhydroxyolean-12-ene pentacyclic triterpenoidal saponins, named rogchaponins 1-10, were isolated from the methanolic extract of the roots of Camellia sinensis by a series of chromatographic methods (silica gel flash column and C18 MPLC followed by C18 HPLC). Their structures were established by 1D and 2D-NMR techniques along with IR and HR-TOF-MS. Rogchaponins R4 ( 4) and R5 (5) showed inhibitory activities against yeast alcohol dehydrogenase (ADH) with IC (50) values of 16.1 ± 3.2 and 15.4 ± 3.3 µM, respectively. A 4-methylpyrazole positive control exhibited an IC (50) of 2750 ± 50 µM. However, the saponins showed no inhibitory activity against yeast aldehyde dehydrogenase (ALDH).

Loss of elastic fibers causes skin wrinkles in sun-damaged human skin.

BACKGROUND: Although wrinkling is the most obvious sign of aged skin, the detailed pathomechanism of wrinkle development has not been elucidated. OBJECTIVES: In this study, we investigated the role of elastic fibers in the formation of skin wrinkles. METHODS: Loss of elastic fibers was measured quantitatively in the facial skins of subjects representing seven decades, and then compared with wrinkle severities. We also investigated whether topical retinoic acid treatment to photoaged human skin can restore destroyed elastic fiber, and the correlation between wrinkle improvement with increase in elastic fibers in RA-treated facial skin. RESULTS: We found a significant correlation between decreases in the length, width, number and total area of oxytalan fibers and wrinkle severity. Furthermore, we found that topical application of retinoic acid (0.025%) to chronically photodamaged skin regenerated and restored elastic fibers, and that there was a significant positive correlation between the amount of newly regenerated elastic fiber and the wrinkle improvement caused by retinoic acid. CONCLUSIONS: Our results provide an objective insight into the role of elastic fibers in skin wrinkle formation by providing a quantitative correlation between changes in oxytalan fibers and the severity of skin wrinkling.

Topical application of 17beta-estradiol increases extracellular matrix protein synthesis by stimulating tgf-Beta signaling in aged human skin in vivo.

To investigate the effects of topically applied 17beta-estradiol on the expression of extracellular matrix proteins in aged human skin, 17beta-estradiol (0.01%) and its vehicle (70% propylene glycol, 30% ethanol) were applied to aged (68-82 y, eight females and five males) human buttock skin under occlusion for 2 wk (three times per week). Topical 17beta-estradiol was found to increase the expression of type 1 procollagen mRNA and protein significantly in human aged skin in vivo. In addition, metalloproteinase (MMP-1 protein levels were reduced by topical 17beta-estradiol. The expressions of TGF-beta1, TGF-beta type II receptor, and Sma and Mad related (Smad)3 were increased by topical 17 beta-estradiol in aged human skin, and TGF-beta1 neutralizing antibody inhibited 17beta-estradiol-induced procollagen synthesis in cultured fibroblasts. We also found that the expressions of tropoelastin and fibrillin-1 mRNA and protein, and elastic fibers in aged skin were also increased by topical 17beta-estradiol. Topical 17beta-estradiol also increased keratinocyte proliferation and the epidermal thickness in aged human skin. We also observed the same effects of topical 17beta-estradiol in young skin. In conclusion, our results suggest that topical 17beta-estradiol treatment may improve the cutaneous function of aged human skin by improving the connective tissue and increasing epidermal thickness.

Benzylamide derivative compound attenuates the ultraviolet B-induced hyperpigmentation in the brownish guinea pig skin.

This study evaluated the effects of synthetic benzylamide compound I (2,6-dimethoxy-N-phenylbenzamide) on the ultraviolet B (UV B)-induced hyperpigmentation of the skin. UV B-induced hyperpigmentation was elicited on brownish guinea pig skin according to the method reported by Hideya et al. [Arch Dermatol Res 290 (1998) 375] with minor modifications. A lightening effect was observed following the topical application of compound I on UV-stimulated hyperpigmentation. The skin returned to its original color after treatment with compound I. Fontana-Masson staining indicated that melanin level in the hyperpigmented area was significantly decreased in the compound I-treated animals. However, the number of melanocytes were not changed in the compound I-treated groups using the S-100 stain, which is an immunohistochemical method. In vitro experiments using the cultured melanoma cells showed a 31.7% inhibition of melanin production by compound I at 100 microM. In addition, this compound had no effect on the tyrosinase enzyme function. However, it exhibited a catalyzing effect on the dopachrome transformation into 5,6-dihydroxyindole-2-carboxylic acid. Overall, the pigment-lightening effects of the compound I may due to the dopachrome tautomerase stimulation.

The extract of Thujae occidentalis semen inhibited 5alpha-reductase and androchronogenetic alopecia of B6CBAF1/j hybrid mouse.

BACKGROUND: The conversion of testosterone to dihydrotestosterone; 5alpha-androstan-17beta-ol-3-one by 5alpha-reductase plays a crucial role in hair baldness and prostatomegaly. Recent approach showed specific inhibitors for 5alpha-reductase type 2 such as finasteride promoted hair growth in male pattern alopecia. OBJECTIVE: In order to search for effective medicinal plant extracts applied topically for androgenetic alopecia, we screened natural plant extracts having inhibitory activities of 5alpha-reductase type 2 and demonstrated its biological function in androgen-related animal models. METHODS: We evaluated the inhibition activities of numerous plant extracts by contact cell based metabolic method using a stable HEK 293 cell line expressing human 5alpha-reductase (type 2). To elucidate the biological activity in vivo, the Thujae occidentalis semen (TOS) extract was topically applied to fuzzy rat and androchronogenetic alopecia (AGA) mouse, respectively. The secreted sebum and the size of sebaceous glands of fuzzy rat were measured after 6 weeks. Also, after the topical treatment with TOS extract and androgen receptor antagonist (cyproterone acetate) simultaneously with subcutaneous injection of testosterone (1 mg/mice/day), hair loss patterns of female B6CBAF1/j hybrid mouse were observed. RESULTS: TOS extract showed higher inhibition activity of 5alpha-reductase type 2(IC(50) value=2.6 microg/ml) than that of gamma-linolenic acid, but lower than that of finasteride. When applied to fuzzy rat, the amount of sebum and sebaceous gland size decreased remarkably. In AGA model, alopecia degrees of two groups, treated with TOS extract (P<0.015) or cyproterone acetate (P<0.01), were lower than that of vehicle (propylene glycol:ethanol=7:3) and there was no difference between above two groups. CONCLUSION: We have demonstrated the inhibitory activity of TOS extract for 5alpha-reductase type 2 and its biological action in two animal models, suggesting that TOS extract would be used as an effective agent for male pattern baldness by modifying androgen conversion.

Influence of N-glycan processing disruption on tyrosinase and melanin synthesis in HM3KO melanoma cells.

Tyrosinase, a type I membrane glycoprotein, is synthesized and glycosylated in the endoplasmic reticulum (ER) and Golgi. The enzyme is subsequently transported to melanosomes where it participates in melanogenesis. Previous studies showed that the disruption of early ER N-glycan processing by deoxynojirimycin (DNJ), an inhibitor of alpha-glucosidase, suppresses tyrosinase enzymatic activity and melanogenesis. However, the disruption of late glycan processing, mainly performed by ER and Golgi alpha-1,2-mannosidases, on tyrosinase enzymatic activity and melanogenesis remains to be investigated. Following treatment of HM3KO human melanoma cells with deoxymannojirimycin (DMJ), an inhibitor of alpha-1,2-mannosidase, transport of tyrosinase to the melanosome, enzymatic activity, and melanogenesis were reduced in a dose-dependent manner. However, DMJ did not directly inhibit tyrosinase enzymatic activity and expression. Interestingly, an extract of Streptomyces subrutilus culture medium (ESSCM) containing DMJ and DNJ as the main components inhibited glycosylation and transport of tyrosinase to the melanosome as well as melanin synthesis, but with no negative effects on cell viability. These inhibitory effects of ESSCM were stronger than those of DMJ or DNJ alone. Tyrosinase glycosylation and melanogenesis in HM3KO melanoma cells were more effectively inhibited by DMJ and DNJ combined than DMJ or DNJ alone. Accordingly, we propose that ESSCM is a potential candidate for treating undesirable hyperpigmentation conditions, such as melasma, postinflammatory melanoderma, and solar lentigo.

(-)-Catechin suppresses expression of Kruppel-like factor 7 and increases expression and secretion of adiponectin protein in 3T3-L1 cells.

Adiponectin is an adipocyte-specific secretory hormone that can increase insulin sensitivity and promote adipocyte differentiation. Administration of adiponectin to obese or diabetic mice reduces plasma glucose and free fatty acid levels. Green tea polyphenols possess many pharmacological activities such as antioxidant, anti-inflammatory, antiobesity, and antidiabetic activities. To investigate whether green tea polyphenols have an effect on the regulation of adiponectin, we measured expression and secretion levels of adiponectin protein after treatment of each green tea polyphenols in 3T3-L1 adipocytes. We found that (-)-catechin enhanced the expression and secretion of adiponectin protein in a dose- and time-dependent manner. Furthermore, treatment of (-)-catechin increased insulin-dependent glucose uptake in differentiated adipocytes and augmented the expression of adipogenic marker genes, including PPARgamma, CEBPalpha, FAS, and SCD-1, when (-)-catechin was treated during adipocyte differentiation. In search of the molecular mechanism responsible for inducible effect of (-)-catechin on adiponectin expression, we found that (-)-catechin markedly suppresses the expression of Kruppel-like factor 7 (KLF7) protein, which has recently been reported to inhibit the expression of adiponectin and other adipogenesis related genes, including leptin, PPARgamma, C/EBPalpha, and aP2 in adipocytes. KLF7 is a transcription factor in adipocyte and plays an important role in the pathogenesis of type 2 diabetes. Taken together, these data suggest that the upregulation of adiponectin protein by (-)-catechin may involve, at least in part, suppression of KLF7 in 3T3-L1 cells.

Identification of tyrosinase inhibitors from Glycyrrhiza uralensis.

Tyrosinase is a key enzyme in the production of melanins. Phytochemical studies of a Glycyrrhiza uralensis extract were performed by measuring the tyrosinase and melanin synthesis inhibitory activity. Glycyrrhisoflavone and glyasperin C were identified as tyrosinase inhibitors for the first time. Glyasperin C showed a stronger tyrosinase inhibitory activity (IC (50) = 0.13 +/- 0.01 microg/mL) than glabridin (IC (50) = 0.25 +/- 0.01 microg/mL) and a moderate inhibition of melanin production (17.65 +/- 8.8 % at 5 microg/mL). Glycyrrhisoflavone showed a strong melanin synthesis inhibitory activity (63.73 +/- 6.8 % inhibition at 5 microg/mL). These results suggest that glyasperin C and glycyrrhisoflavone could be promising candidates in the design of skin-whitening agents.

Deoxypodophyllotoxin reduces skin pigmentation of brown Guinea pigs.

In this report, we have demonstrated that deoxypodophyllotoxin from Anthriscus sylvestris (L.) Hoffm decreases UV-induced skin pigmentation of brown guinea pigs. Deoxypodophyllotoxin (0.05 % in propylene glycol: ethanol: water = 5 : 3:2) was topically applied twice daily for two weeks to dorsal skin of brown guinea pigs that were exposed to UV irradiation using a solar simulator. Visual inspection and Fontana-Masson staining both demonstrated that deoxypodophyllotoxin reduced skin pigmentation and total epidermal melanin when compared to that of vehicle-treated areas, suggesting that deoxypodophyllotoxin maybe applicable to treat hyperpigmentation.

Development of 5-[(3-aminopropyl)phosphinooxy]-2-(hydroxymethyl)-4H-pyran-4-one as a novel whitening agent.

A stable derivative of kojic acid, 5-[(3-aminopropyl)phosphinooxy]-2-(hydroxymethyl)-4H-pyran-4-one (Kojyl-APPA), was synthesized in good yield. The effects of Kojyl-APPA on tyrosinase activity and melanin synthesis were investigated. Kojyl-APPA showed tyrosinase inhibition effect (30%) in situ, but not in vitro. Kojyl-APPA inhibited tyrosinase activity significantly at 24 h after treatment in normal human melanocytes. It means that Kojyl-APPA is not a direct inhibitor of tyrosinase itself, but it is converted to a potential inhibitor kojic acid enzymatically in cells. In addition, Kojyl-APPA decreased melanin content to 75% of control in melanoma cells and decreased neomelanin synthesis to 43% of control in normal human melanocytes. Its permeation through skin increased by about 8 times as compared with kojic acid.

(4-Methoxy-benzylidene)-(3-methoxy-phenyl)-amine, a nitrogen analog of stilbene as a potent inhibitor of melanin production.

The current study was carried out to investigate in vitro the effects of (4-methoxy-benzylidene)-(3-methoxyphenyl)-amine on melanin biosynthesis which is closely related to hyper-pigmentation. (4-Methoxy-benzylidene)-(3-methoxy-phenyl)-amine, a nitrogen analog of stilbene, was synthesized by a single step process. This compound inhibited the tyrosinase activity, which converts dopa to dopachrome in the biosynthetic process of melanin, and showed a UV-blocking effect at UV-B band. The compound also exhibited SOD-like activity, which is involved in the protection against auto-oxidation and inhibited melanin production in melan-a cell line. Our results suggest the possibility that (4-methoxy-benzylidene)-(3-methoxy-phenyl)-amine might be used as a skin whitening agent.

Mulberroside F isolated from the leaves of Morus alba inhibits melanin biosynthesis.

The current study was carried out to investigate the in vitro effects of an 85% methanol extract of dried Morus alba leaves on melanin biosynthesis, which is closely related to hyperpigmentation. These extracts inhibited the tyrosinase activity that converts dopa to dopachrome in the biosynthetic process of melanin. Mulberroside F (moracin M-6, 3'-di-O-beta-D-glucopyranoside), which was obtained after the bioactivity-guided fractionation of the extracts, showed inhibitory effects on tyrosinase activity and on the melanin formation of melan-a cells. This compound also exhibited superoxide scavenging activity that is involved in the protection against auto-oxidation. But its activity was low and was weaker than of kojic acid. These results suggest that mulberroside F isolated from mulberry leaves might be used as a skin whitening agent.

Torilin from Torilis japonica, as a new inhibitor of testosterone 5 alpha-reductase.

The methanolic extract of the fruits of Torilis japonica showed a potent inhibition against 5 alpha-reductase activity in vitro. Bioassay-guided fractionation of the methanol extract of the fruits followed by repeated silica gel chromatography led to the isolation of an active principle and its structure was identified as torilin on the basis of spectroscopic data. Torilin (IC50 = 31.7 +/- 4.23 microM) showed a stronger inhibition of 5 alpha-reductase than alpha-linolenic acid (IC50 = 160.3 +/- 24.62 microM) but was weaker than finasteride. (IC50 = 0.38 +/- 0.06 microM). Simple guaiane-type compounds, such as (-)-guaiol and guaiazulene showed weak inhibitory effects on the 5 alpha-reductase activity with IC50 values of f 81.6 microM and 100.8 microM, respectively, while azulene was not active. These results suggest that both degrees of unsaturation and the side-chain in the guaiane skeleton are important for the manifestation of 5 alpha-reductase inhibition.