Skin-whitening effects of Mediterranean herbal extracts by in vitro and in vivo models.

Several plant extracts are able to protect skin against ultraviolet-light-induced damage and hyperpigmentation in a safe way. The anti-melanogenic effect of herbal extracts seems to be related to their antioxidant activity and their polyphenolic content. In this study, the skin-whitening effect of some Mediterranean species, already known for their strong antioxidant and radical scavenger activity, has been evaluated by in vitro and in vivo models. The results obtained showed that herbal extracts possessed an inhibitory effect on tyrosinase enzyme. Each extract showed a similar inhibiting activity even though it was less intensive than kojic acid and hydroquinone. Otherwise, a significant higher activity than kojic acid and hydroquinone was observed when the herbal extracts were combined. Furthermore, the anti-melanogenic activity and an evaluation of skin tolerance were affected by in vivo methods.

Gelatin tannate reduces the proinflammatory effects of lipopolysaccharide in human intestinal epithelial cells.

BACKGROUND: Gelatin tannate is a mixture of tannic acid and gelatin. Tannic acid has astringent properties, due to its capacity to form protein-macromolecular complexes, as well as antibacterial and antioxidant properties. However, little is known about its anti-inflammatory properties. PURPOSE: To evaluate the anti-inflammatory activity of gelatin tannate by quantifying the suppression of key molecules produced during inflammatory events in lipopolysaccharide (LPS)-stimulated human intestinal cells. METHODS: Intercellular adhesion molecule-1 (ICAM-1) expression was determined by Western blot analysis; interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) concentrations were measured by enzyme-linked immunosorbent assays in Caco-2 cells 24 hours after treatment with LPS (1 µg/mL) in presence of different concentrations of gelatin tannate. RESULTS: ICAM-1 is induced on a wide variety of cells by inflammatory stimuli such as LPS. Our results have shown gelatin tannate as a potent inhibitor of ICAM-1 expression in LPS-stimulated Caco-2 cells. IL-8 and TNF-α are important inflammatory mediators, recruiting neutrophils and T-lymphocytes. Together with LPS, adding gelatin tannate at different concentrations induced a dose-dependent inhibition of IL-8 and TNF-α released by Caco-2 cells. CONCLUSION: These results suggest that gelatin tannate exerts anti-inflammatory effects by inhibiting the specific cytokines and adhesion molecules involved in several inflammatory disorders.

Comparative in vivo study of the efficacy and tolerance of exfoliating agents using reflectance spectrophotometric methods.

The aim of the present study was to compare the effectiveness and the safety of different topical agents (glycolic acid, mandelic acid, and grape juice acid mixture) in skin exfoliation by objective instrumental methods. To evaluate the exfoliating effects of these substances, a new experimental in vivo protocol based on DHA (dihydroxyacetone)-induced skin pigmentation was used. Skin acceptability towards acid application was investigated by the evaluation of skin erythema induced by topical application of these substances at increased concentrations. Furthermore, their photosensitizing effects were evaluated by determining the increase in sensitivity to UV-light exposure in cutaneous sites previously treated with acids. These in vivo evaluations were monitored by reflectance spectophotometry. From the results obtained, we observed the differing capacities of the tested acids to increase the rate of skin regeneration, with a significant reduction in the time required to obtain skin renewal. The study pointed out that glycolic acid (10% w/w) induced a faster skin exfoliation, a more intense erythema, and a higher photosensitizing effect in comparison with the mandelic acid and grape juice acid mixtures. Further evidence showed that the mandelic acid and grape juice acid mixtures were able to induce a slower and safer peeling action in comparison with glycolic acid. Finally, our results suggest that the methodologies and protocols used in this study may help in choosing the most appropriate topical agents for skin exfoliating treatments.