Résumé
Objective To study the protective effect of vitamin C on UV-induced photoaged skin structure in rats and provide a basis for clinical medicine and health care.Methods Photoaging skin models were set up by chronic ultraviolet radiation in 24 SPF female Sprague-Dawley rats, irradiated twice weekly for 4 weeks.The rat photoaged skin was induced by exposure to a total dose of 123 J/cm2 UVA and 5 J/cm2 UVB for 4 weeks.Vitamin C was administered by gastric gavage in a dose of 50 mg/kg once daily for 30 days during the model development.We compared the pathological changes in the irradiated skin using HE, Masson’ s trichrome and Victoria blue B staining, and compared the ultrastructural changes by electron microscopy.Results Rat models with photoaged skin were developed successfully.The vitamin C group showed significant reduction of pathological severity including erythema, ulcers, epidermal cell proliferation, epidermal thickness, dermis vasodilation, inflammatory cell infiltration, fibroblast proliferation, endoplasmic reticulum dilatation, mitochondrial swelling and vacuolization, elastic fibers degeneration and focal accumulation, collagen fibers swelling with uneven thickness,compared with the rats of model group at the irradiation site.Conclusions Vitamin C is effective in reducing the structural damage of UV-induced photoaged skin in rats.
Résumé
Ginseng, one of the most widely used herbal medicines, has a wide range of therapeutic and pharmacological applications. Ginsenosides are the major bioactive ingredients of ginseng, which are responsible for various pharmacological activities of ginseng. Ginsenoside Rh2, known as an antitumour ginsenoside, exists as two different stereoisomeric forms, 20(S)-ginsenoside Rh2 [20(S)-Rh2] and 20(R)-ginsenoside Rh2 [20(R)-Rh2]. This work aimed to assess and compare skin anti-photoaging activities of 20(S)-Rh2 and 20(R)-Rh2 in UV-B-irradiated HaCat cells. 20(S)-Rh2, but not 20(R)-Rh2, was able to suppress UV-B-induced ROS production in HaCat cells. Both stereoisomeric forms could not modulate cellular survival and NO level in UV-B-irradiated HaCat cells. Both 20(S)-Rh2 and 20(R)-Rh2 exhibited suppressive effects on UV-B-induced MMP-2 activity and expression in HaCat cells. In brief, the two stereoisomers of ginsenoside Rh2, 20(S)-Rh2 and 20(R)-Rh2, possess skin anti-photoaging effects but possibly in different fashions.
Résumé
Nuruk contributes to the unique characteristics of Korean alcoholic beverages. In this study, the effects of nuruk extracts (NE) on anti-oxidant characters, melanogenesis, and anti-photoaging activity were investigated. NEs were obtained from the 70% ethanol extracts of six types of nuruk, which have been used in brewing of fermented alcohol beverages in Korea. First, various antioxidant characteristics were identified in terms of 2,2'-azino-bis(3-ethylbenzthiozoline-6-sulphonic acid) (ABTS) radical scavenging activity, superoxide dismutase (SOD) expression, and inhibition of xanthine oxidase activity. NE#4 exhibited potent ABTS radical scavenging activity (IC50 = 19.51 microg/mL). Compared with NE#4, relatively lower levels of activity were observed for NE#3 and NE#6, with IC50 values of 90.99 and 76.88 microg/mL, respectively. According to results of western blot analysis for determination of SOD expression in H2O2-treated HepG2 cells, NE#5 and NE#6 induced a dramatic increase in the expression ratio of SOD, compared to the group treated with H2O2 only. Activity of xanthine oxidase, which converts xanthine into uric acid, generating superoxide ions, was inhibited by NE#4 and NE#6 in a dose-dependent manner. NE#4 induced significant inhibition of mushroom tyrosinase activity. A reduction in cellular melanin contents of 80% was observed in B16F1 melanocytes treated with NE#5 and NE#6; these effects were similar to those of arbutin at 100 microM. In addition, gelatin zymography and reverse transcription-PCR analysis were performed for assessment of anti-photoaging activity of Nuruk. Treatment with NE#6 resulted in dramatically inhibited activities of matrix metalloproteinase (MMP)-2/-9, suppressed expression of MMP-1, and increased expression of type-1 procollagen. Results of gelatin zymography for NE#4 and NE#5 were similar, to a slightly lesser degree. These results suggest the potential of NE#4 and NE#6 as natural ingredients for use in functional foods and cosmetics.