Antioxidants in dermocosmetology: from the laboratory to clinical application

Half-Preparative Scale Synthesis of (S)-1-Phenylethane-1,2-Diol as a Result of 2-Phenylethanol Hydroxylation with Aspergillus niger (IAFB 2301) Assistance

Aspergillus niger (IAFB 2301) was employed for bioconversions of 2-phenylethanol as an immobilized or free mycelium and also as a spore suspension. Experiments were conducted on laboratory and half-preparative scale (bioreactor New Brunswick Scientific, BioFlo Model C32). Thus, A. niger applied as free mycelium, depending on the outcome, supported formation of the mixture of 4-hydroxyphenylacetic acid and hydroxytyrosol (final concentration of 13.8 mg/L and 3.7% efficiency) or 4-hydroxyphenylacetic acid, as single product (final concentration of 140 mg/L and 18% efficiency). In case of scaling experiments conducted with flow and batch reactors, accordingly, the following results were achieved: 1. mixture of antioxidants 4-hydroxyphenylacetic acid and hydroxytyrosol formed with final concentration of 76 mg/L and 10% efficiency (simplified flow system and immobilized mycelium); 2. (S)-1-phenylethane-1,2-diol synthesized with a final concentration of 447 mg/L and 65% (1.3 L batch reactor).

Topical application of a commercially available formulation of vitamin C stabilized by vitamin E and ferulic acid reduces tissue viability and protein synthesis in ex vivo human normal skin

BACKGROUND

Aqueous formulations of vitamin C stabilized by vitamin E and ferulic acid at low pH effectively protect skin against reactive oxygen species-induced damage. However, the effects of these formulations on human skin have not clearly been described. The aim of this study was to investigate whether topical application of two commercially available formulations of vitamin C alter human skin using an ex vivo model.

METHODS

Human skin explants were topically treated on alternate days with commercially available formulation 1 (15% vitamin C) at 100% (without dilution), 50%, or 10% diluted in saline or formulation 2 (20% vitamin C) at 100% (without dilution), 50%, or 10% diluted in saline. Only saline was applied to control skin explants.

RESULTS

Topical formulation 1 at 100%, 50%, or 10%, but not formulation 2 at 100%, 50%, or 10%, reduced the viability of ex vivo human skin compared to the control after 7, 10, and 13 days. In addition, compared to the control, ex vivo human skin treated with formulation 1 at 50%, but not formulation 2 at 50%, also decreased mRNA levels of actin and ribosomal protein L10 and gene expression of extracellular matrix components after 10 days. Furthermore, after 10 days, topical application of formulation 1 at 50%, but not formulation 2 at 50%, decreased the protein expression of proliferating cellular nuclear antigen, lysyl oxidase, β-actin, and glyceraldehyde-3-phosphate dehydrogenase compared to the control.

CONCLUSIONS

Topical formulation 1, but not formulation 2, may reduce the viability of and protein synthesis in ex vivo human skin. Those effects might be due to action of vehicle of formulation 1 on ex vivo human skin.

Carotenoids from UV-resistant Antarctic Microbacterium sp. LEMMJ01

The Microbacterium sp. LEMMJ01 isolated from Antarctic soil does not belong to any of the nearest species identified in the RDP database. Under UV radiation (A, B and C wavebands) the survival fractions of Microbacterium sp. cells were much higher compared with wild-type E. coli K12A15. Especially remarkable for an Antarctic bacterium, an expressive resistance against high UV-B doses was observed. The increased survival of DNA repair-proficient E. coli grown overnight added of 0.1 mg/ml or 1 mg/ml of the whole pigment extract produced by Microbacterium sp. revealed that part of the resistance of Microbacterium sp. against UV-B radiation seems to be connected with photoprotection by its pigments. Scanning electron microscopy revealed that UV-A and UV-B ensued membrane alterations only in E. coli. The APCI-MS fingerprints revealed the diagnostic ions for neurosporene (m/z 580, 566, 522, 538, and 524) synergism for the first time in this bacterium by HPLC-MS/MS analysis. Carotenoids also were devoid of phototoxicity and cytotoxicity effects in mouse cells and in human keratinocytes and fibroblasts.

Propofol protects human keratinocytes from oxidative stress via autophagy expression

Background

The skin consists of tightly connected keratinocytes, and prevents extensive water loss while simultaneously protecting against the entry of microbial pathogens. Excessive cellular levels of reactive oxygen species can induce cell apoptosis and also damage skin integrity. Propofol (2,6-diisopropylphenol) has antioxidant properties. In this study, we investigated how propofol influences intracellular autophagy and apoptotic cell death induced by oxidative stress in human keratinocytes.

Method

The following groups were used for experimentation: control, cells were incubated under normoxia (5% CO₂, 21% O₂, and 74% N₂) without propofol; hydrogen peroxide (H₂O₂), cells were exposed to H₂O₂ (300 µM) for 2 h; propofol preconditioning (PPC)/H₂O₂, cells pretreated with propofol (100 µM) for 2 h were exposed to H₂O₂; and 3-methyladenine (3-MA)/PPC/H₂O₂, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to H₂O₂. Cell viability, apoptosis, and migration capability were evaluated. Relation to autophagy was detected by western blot analysis.

Results

Cell viability decreased significantly in the H₂O₂ group compared to that in the control group and was improved by propofol preconditioning. Propofol preconditioning effectively decreased H₂O₂-induced cell apoptosis and increased cell migration. However, pretreatment with 3-MA inhibited the protective effect of propofol on cell apoptosis. Autophagy was activated in the PPC/H₂O₂ group compared to that in the H₂O₂ group as demonstrated by western blot analysis and autophagosome staining.

Conclusion

The results suggest that propofol preconditioning induces an endogenous cellular protective effect in human keratinocytes against oxidative stress through the activation of signaling pathways related to autophagy.

The Effect of Lycopene Preexposure on UV-B-Irradiated Human Keratinocytes

Lycopene has been reported as the antioxidant most quickly depleted in skin upon UV irradiation, and thus it might play a protective role. Our goal was to investigate the effects of preexposure to lycopene on UV-B-irradiated skin cells. Cells were exposed for 24 h to 10 M lycopene, and subsequently irradiated and left to recover for another 24 h period. Thereafter, several parameters were analyzed by FCM and

RT-PCR

genotoxicity/clastogenicity by assessing the cell cycle distribution; apoptosis by performing the Annexin-V assay and analyzing gene expression of apoptosis biomarkers; and oxidative stress by ROS quantification. Lycopene did not significantly affect the profile of apoptotic, necrotic and viable cells in nonirradiated cells neither showed cytostatic effects. However, irradiated cells previously treated with lycopene showed an increase in both dead and viable subpopulations compared to nonexposed irradiated cells. In irradiated cells, lycopene preexposure resulted in overexpression of BAX gene compared to nonexposed irradiated cells. This was accompanied by a cell cycle delay at S-phase transition and consequent decrease of cells in G0/G1 phase. Thus, lycopene seems to play a corrective role in irradiated cells depending on the level of photodamage. Thus, our findings may have implications for the management of skin cancer.

Skin improvement and stability of Echinacea purpurea dermatological formulations

Echinacea purpurea contains many beneficial constituents for protection of skin from oxidative stress and for improving hydration of skin. This study aimed to investigate the stability and dermatological efficacy of E. purpurea cream and gel. Echinacea purpurea extract was incorporated into suitable cream and gel bases. Stability of the extract in the formulations was investigated by determining its residual total phenolic content and antioxidant activity after storage at 4°C, 30°C and 40°C for 6 months. The effect of those formulations on skin irritation, hydration level and wrinkle reduction was evaluated in 10 healthy volunteers, aged 25-40 years. The shelf lives of E. purpurea cream and gel in terms of total phenolic content and antioxidant activity were only 2 and 4 months respectively at 4°C and could be extended up to 7 months by incorporation of α-tocopherol or disodium editate. The corneometer hydration indices increased up to 10.6 AU and 11.4 AU, and the wrinkles decreased 9.47% and 14.92% because of the application of E. purpurea cream and gel for 1 month. Both formulations showed no irritation to skin. Echinacea purpurea cream and gel developed in this study were effective in improving skin hydration and reducing wrinkle, but showed low storage stability.

Ellagic acid protects human keratinocyte (HaCaT) cells against UVA-induced oxidative stress and apoptosis through the upregulation of the HO-1 and Nrf-2 antioxidant genes

UV radiation from the sun is a potent environmental risk factor in the pathogenesis of skin damage. Much of the skin damage caused by ultraviolet A (UVA) irradiation from the sun is associated with oxidative stress. The aim of this study was to investigate the protective role of ellagic acid (25-75 μM), a natural antioxidant, against UVA (5-20 J/cm(2))-induced oxidative stress and apoptosis in human keratinocyte (HaCaT) cells and to reveal the possible mechanisms underlying this protective efficacy. Ellagic acid pre-treatment markedly increased HaCaT cell viability and suppressed UVA-induced ROS generation and MDA formation. Moreover, ellagic acid pre-treatment prevented UVA-induced DNA damage as evaluated by the comet assay. Ellagic acid treatment also significantly inhibited the UVA-induced apoptosis of HaCaT cells, as measured by a reduction of DNA fragmentation, mitochondria dysfunction, ER stress, caspase-3 activation, and Bcl-2/Bax deregulation. Notably, the antioxidant potential of ellagic acid was directly correlated with the increased expression of HO-1 and SOD, which was followed by the downregulation of Keap1 and the augmented nuclear translocation and transcriptional activation of Nrf2 with or without UVA irradiation. Nrf2 knockdown diminished the protective effects of ellagic acid. Therefore, ellagic acid may be useful for the treatment of UVA-induced skin damage.