In vitro evaluation of the efficacy of commercial green tea extracts in UV protection.

Plants with antioxidant properties are beneficial for preventing the ageing events evoked by UV light, and numerous products based on Camellila sinensis (green tea) are commercially available, many of which claiming to contain bioactive compounds that would prevent UV-induced skin damage. In this study, we tested the efficacy of five commercial green tea extracts used to enrich cosmetic formulations for protecting human and mouse fibroblasts against UV radiation effects and compared with a fluid one prepared according to the Brazilian Pharmacopoeia recommendations. Taking into consideration that the ageing process can be accelerated by solar radiation by excessive free radical generation, leading to depletion of skin antioxidant defences, and its collapse caused by disruption of the metalloproteinase metabolism, we have used their individual (-)-epigallocathechin-3-gallate (EGCG) content, the catalase and SOD status and the matrix-degrading metalloproteases (MMP)-1, MMP-9 and MMP-13 levels as comparative parameters. The EGCG content of the commercial products showed wide variability, ranging from undetectable levels to 58.65 ± 1.12 µg mL(-1) , in contrast with the fluid extract (87.82 ± 1.35 µg mL(-1) ). Moreover, only the pharmacopoeic extract was able to significantly reduce MMP degradation while enhancing the levels of SOD and catalase. These results indicate, for the first time, that the methodologies for preparing herbal mixtures can interfere significantly with compounds endowed with photoprotective effects, and the efficacy of products containing C. sinensis extracts thought to act against effects of solar radiation can be compromised.

Influência de extratos hidroetanólicos de plantas medicinais sobre a quimiotaxia de leucócitos humanos / Influence of some medicinal plant hydroethanolic extracts on human leukocyte chemotaxis

Vários métodos in vitro têm sido empregados para a investigação das atividades biológicas de plantas usadas na medicina popular para o tratamento de processos inflamatórios. Neste trabalho, investigou-se a influência dos extratos hidroetanólicos de Rauvolfia sellowii Muell. Arg, Hybanthus bigibbosus (St.-Hil) Hassler e Anchieta pyrifolia (Mart.) G. Don, conhecidas popularmente como pau-pra-tudo, canela-de-veado e cipó-suma, respectivamente, sobre a quimiotaxia de leucócitos humanos, estimulados a migrar contra um gradiente de caseína, utilizando-se o método de Boyden. A dexametasona foi utilizada como substância de referência da inibição da quimiotaxia leucocitária. Os resultados demonstraram efeito inibitório significativo de todos os extratos das plantas testadas, sobre a migração de polimorfonucleares, induzida por caseína. Entretanto, essa atividade variou de intensidade conforme a concentração e a espécie estudada. Efeitos máximos foram observados, nas concentrações de 1000, 10 e 1µg/ml com os extratos de pau-pra-tudo, canela-de-veado e cipó-suma, respectivamente, com migração de 81,6±3,9 por cento; 85,4±2,4 por cento e 91,7±2,2 por cento dos polimorfonucleares, enquanto que, com a dexametasona, este efeito foi de 70,3±5,9 por cento. Embora estudos mais aprofundados sejam necessários, os resultados apresentados podem servir como base preliminar de dados, contribuindo para esclarecer o mecanismo da atividade antiinflamatória atribuída às essas plantas na medicina caseira.

Several in vitro methods have been used for the investigation of the biological activities of plants used in folk medicine for the treatment of inflammatory conditions. In this study, we have investigated the ability of the hydroethanolic extracts from Rauvolfia sellowii Muell. Arg, Hybanthus bigibbosus (St.-Hil) Hassler, and Anchieta pyrifolia (Mart.) G. Don, locally known as pau-pra-tudo, canela-de-veado, and cipó-suma, respectively, in interfering with the human leukocytes migration induced by casein, using the Boyden chamber method. Dexamethasone has been used as a positive control for leukocyte inhibition in the same experimental approach. The data herein presented showed a significant inhibition of the casein-induced polymorphonuclear leukocytes migration for all plants studied. However, the intensity of such activity was variable according to the dose and plant tested. For pau-pra-tudo, canela-de-veado, and cipó-suma extracts the average number of migrated polymorphonuclear leukocytes was 81.6±3.9 percent, 85.4±2.4 percent and 91.7±2.2 percent of the input for the doses of 1000, 10, and 1mg/ml, respectively, while for dexamethasone, the value found was 70.3±5.9 percent. Although further studies are needed, the results presented in this study may be useful to clarify the anti-inflammatory properties of these herbal medicines, supporting their ethnobothanical use for the treatment of inflammatory diseases.