Renata M. Martinez

Efficacy of topical formulations containing Pimenta pseudocaryophyllus extract against UVB-induced oxidative stress and inflammation in hairless mice.

Plants rich in antioxidant substances may be a promising strategy for preventing UV-induced oxidative and inflammatory damage of the skin. Pimenta pseudocaryophyllus is native to Brazil and presents flavonoids and other polyphenolic compounds in high concentration. Thus, the present study evaluated the possible effects of topical formulations containing P. pseudocaryophyllus ethanolic extract (PPE) at inhibiting UV-B irradiation-induced oxidative stress and inflammation. PPE was administered on the dorsal skin of hairless mice using two formulations: F1 (non-ionic emulsion with high lipid content) and F2 (anionic emulsion with low lipid content) before and after UV-B irradiation. The following parameters were evaluated in skin samples: edema, myeloperoxidase activity, cytokines levels, matrix metalloprotease-9 (MMP-9) secretion/activity, reduced glutathione (GSH), superoxide anion and lipid peroxidation levels, and mRNA expression for glutathione reductase and gp91phox. The UV-B irradiation increased all parameters, except for IL-10 levels and glutathione reductase mRNA expression, which were not altered, and GSH levels, which were reduced by exposure to UV-B light. Treatments with F1 and F2 containing PPE inhibited UV-B-induced edema formation (89% and 86%), myeloperoxidase activity (85% and 81%), IL-1β production (62% and 82%), MMP-9 activity (71% and 74%), GSH depletion (73% and 85%), superoxide anion (83% and 66%) and TBARS (100% and 100%) levels, increased glutathione reductase (2.54 and 2.55-fold) and reduced gp91phox (67% and 100%) mRNA expression, respectively. F2 containing PPE also increased IL-10 levels. Therefore, this study demonstrates the effectiveness of topical formulations containing PPE in inhibiting UV-B irradiation-induced inflammation and oxidative stress of the skin.

Topical Formulation Containing Naringenin: Efficacy against Ultraviolet B Irradiation-Induced Skin Inflammation and Oxidative Stress in Mice.

Naringenin (NGN) exhibits anti-inflammatory and antioxidant activities, but it remains undetermined its topical actions against ultraviolet B (UVB)-induced inflammation and oxidative stress in vivo. The purpose of this study was to evaluate the physicochemical and functional antioxidant stability of NGN containing formulations, and the effects of selected NGN containing formulation on UVB irradiation-induced skin inflammation and oxidative damage in hairless mice. NGN presented ferric reducing power, ability to scavenge 2,2′-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and hydroxyl radical, and inhibited iron-independent and dependent lipid peroxidation. Among the three formulations containing NGN, only the F3 kept its physicochemical and functional stability over 180 days. Topical application of F3 in mice protected from UVB-induced skin damage by inhibiting edema and cytokine production (TNF-α, IL-1β, IL-6, and IL-10). Furthermore, F3 inhibited superoxide anion and lipid hydroperoxides production and maintained ferric reducing and ABTS scavenging abilities, catalase activity, and reduced glutathione levels. In addition, F3 maintained mRNA expression of cellular antioxidants glutathione peroxidase 1, glutathione reductase and transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), and induced mRNA expression of heme oxygenase-1. In conclusion, a formulation containing NGN may be a promising approach to protecting the skin from the deleterious effects of UVB irradiation.

Trans-chalcone added in topical formulation inhibits skin inflammation and oxidative stress in a model of ultraviolet B radiation skin damage in hairless mice

Trans-chalcone (TC) is a common precursor of flavonoids. However, the pharmacological properties of TC remain to be fully understood. The present study investigated whether topical formulation containing TC (TFcTC) presents therapeutic effect in UVB radiation-induced skin damage using disease, enzyme activity, antioxidant activity, protein and mRNA parameters. Control topical formulation (CTF) and TFcTC were applied in hairless mice before and after exposure to UVB radiation. Dorsal skin samples were collected after UVB exposure to evaluate: i) skin edema (weight) was measured by punch biopsy; ii) spectrophotometric assays were used to measure myeloperoxidase (MPO) and catalase activities, ferric (FRAP) and ABTS cation reducing antioxidant power, superoxide anion production and levels of reduced glutathione (GSH); iii) enzymography was used to measure matrix metalloproteinase-9 (MMP-9) activity; iv) chemiluminescence was used to measure the lipid peroxidation (LPO); v) enzyme-linked immunosorbent assay (ELISA) was used to measure tumor necrosis factor alpha (TNF-α) levels; vi) reverse transcription quantitative PCR (RT-qPCR) was used to measure cyclooxygenase-2 (COX-2), gp91phox (NADPH oxidase sub-unity), glutathione peroxidase-1 (Gpx1), glutathione reductase (Gr), nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) mRNA expression. TFcTC inhibited UVB-induced skin edema, MPO activity, MMP-9 activity, TNF-α production, and COX-2 mRNA expression. TFcTC inhibited UVB-induced LPO, down-regulated superoxide anion levels and gp91phox mRNA expression, and improved antioxidant potential and GSH skin levels. The mRNA expression of detoxification systems such as Nrf2, HO-1, Gpx1 and Gr, and catalase activity were also enhanced by treatment with TFcTC. In conclusion, TFcTC protects mice skin from UVB radiation by inhibiting inflammation, and improving antioxidant and detoxification systems. Therefore, topical treatment with TC is a novel therapeutic approach for the treatment of UVB radiation skin damages, which merits further pre-clinical and clinical investigation.

Lipoxin A4 inhibits UV radiation-induced skin inflammation and oxidative stress in mice

BACKGROUND Lipoxin A4 (LXA4) is a metabolic product of arachidonic acid. Despite potent anti-inflammatory and pro-resolution activities, it remains to be determined if LXA4 has effect on ultraviolet (UV) radiation-induced skin inflammation. OBJECTIVE To investigate the effects of systemic administration with LXA4 on UV radiation-induced inflammation and oxidative damage in the skin of mice. METHODS Varied parameters of inflammation and oxidative stress in the skin of mice were evaluated after UV radiation (4.14 J/cm2). RESULTS Pretreatment with LXA4 significantly inhibited UV radiation-induced skin edema and myeloperoxidase activity. LXA4 efficacy was enhanced by increasing the time of pre-treatment to up to 72 h. LXA4 reduced UV radiation-induced skin edema, neutrophil recruitment (myeloperoxidase activity and LysM-eGFP+ cells), MMP-9 activity, deposition of collagen fibers, epidermal thickness, sunburn cell counts, and production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-33). Depending on the time point, LXA4 increased the levels of anti-inflammatory cytokines (TGF-β and IL-10). LXA4 significantly attenuated UV radiation-induced oxidative damage returning the oxidative status to baseline levels in parameters such as ferric reducing ability, scavenging of free radicals, GSH levels, catalase activity and superoxide anion production. LXA4 also reduced UV radiation-induced gp91phox [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) subunit] mRNA expression and enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target enzyme nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (Nqo1) mRNA expression. CONCLUSION LXA4 inhibited UV radiation-induced skin inflammation by diminishing pro-inflammatory cytokine production and oxidative stress as well as inducing anti-inflammatory cytokines and Nrf2.

Topical emulsion containing pyrrolidine dithiocarbamate: effectiveness against ultraviolet B irradiation-induced injury of hairless mouse skin

To evaluate the effects of a topical emulsion containing pyrrolidine dithiocarbamate (PDTC) (EcPDTC) in skin oxidative stress and inflammation triggered by ultraviolet B (UVB) irradiation (dose of 4.14 J/cm2).

Formulação Tópica Contendo Naringenina ou Hesperidina Metil Chalcona Reduz os Danos Cutâneos Foto-oxidativos em Camundongos sem Pelo

Introducao: A exposicao cutânea a radiacao ultravioleta (UV) induz a producao de especies reativas de oxigenio, o que leva a reducao dos antioxidantes endogenos. Este desequilibrio, denominado estresse oxidativo, pode ser prevenido e/ou tratado com a utilizacao de antioxidantes exogenos, como os flavonoides. Neste contexto, o presente trabalho teve como objetivo avaliar os efeitos terapeuticos e mecanismos de acao dos flavonoides naringenina (NGN) e hesperidina metil chalcona (HMC) quando veiculados em formulacao topica, nos danos cutâneos oxidativos induzidos pela radiacao UVB em camundongos sem pelo. Metodos: Este estudo foi aprovado pela CEUA da UEL (Processo no. 19972.2013.46). Os animais foram tratados com as formulacoes topicas contendo NGN (0,5%) ou HMC (1%) por 12 horas, 6 horas, 5 minutos antes da radiacao e 6 horas apos o inicio da radiacao. Amostras de pele foram coletadas 2, 4 e 12 horas apos o termino da exposicao a radiacao (4,14 J/cm). Foram utilizados cinco animais em cada grupo e os dados foram analisados por ANOVA seguido do pos-teste de Tukey. Resultados: Os tratamentos com as formulacoes topicas contendo NGN ou HMC protegeram a pele dos danos oxidativos induzidos pela radiacao UVB por manter a expressao de RNAm dos componentes antioxidantes celulares glutationa redutase (100 e 100% respectivamente) e glutationa peroxidase-1 (100 e 100% respectivamente), o que resultou na melhora da capacidade antioxidante da pele pela manutencao dos niveis de glutationa reduzida (67 e 90% respectivamente) e atividade da catalase (77 e 91% respectivamente), do poder em reduzir o ferro (89 e 100% respectivamente) e o radical ABTS (53 e 100% respectivamente), e na reducao da producao de hidroperoxidos lipidicos (89 e 93% respectivamente). Conclusoes: Os resultados demonstraram que os flavonoides NGN e HMC veiculados topicamente atuaram na diminuicao dos danos foto-oxidativos cutâneos. Desta forma, sugere-se a utilizacao destas substâncias como possivel abordagem terapeutica em doencas cutâneas relacionadas com a exposicao a radiacao UVB. Agencias de Fomento: Capes, CNPq e Fundacao Araucaria.