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ABSTRACT

The ultraviolet (UV) protective effects of aqueous herb extracts from Latin America such as Yerba Mate (Ilex paraguariensis), Chancapiedra (Phyllanthus niruri L.) and Huacatay (Tagetes minuta) were assessed by using the UV light-induced cell death in Saccharomyces cerevisiae yeast model. UV radiation–mediated oxidative stress promoted cell death of S. cerevisiae by inducing breakdown of its energy metabolism. The addition of high-phenolic herb extracts (61–103 mg gallic acid equivalents/g dw) prior to UV treatment protected yeast from UV-induced oxidative stress and delayed death. This effect appeared to be related with the high free radical scavenging activities shown by all extracts (91%). Insights into the UV protective mechanisms of Yerba Mate extract in yeast model indicated that protection was achieved by maintaining the growth-supporting tricarboxylic acid cycle/NADH–linked system and the proline-linked mitochondrial oxidative phosphorylation coupled to pentose phosphate pathway. Therefore, studied herb extracts show potential protective properties against UV radiation–induced yeast death.

PRACTICAL APPLICATIONS

Yerba Mate (Ilex paraguariensis), Chancapiedra (Phyllanthus niruri L.) and Huacatay (Tagetes minuta) have been traditionally consumed in Latin American countries because of their potential health benefits. Results from this study using the UV-induced cell death in Saccharomyces cerevisiae yeast model indicate that such high-phenolic herbs (61–103 mg gallic acid equivalents/g dw) would have potential applications as beneficial dietary supplements for protecting eukaryotic cells against UV-induced free radical–mediated damage with potential implications in the dietary management of oxidation-linked diseases in humans. Furthermore, the model for the UV-protective effect of external phenolic phytochemicals in eukaryotic cellular systems proposed by our laboratory was investigated, and according to results from this study, this model could provide a sound rationale for understanding the mechanism of action of phenolic phytochemicals from dietary or medicinal plants in cellular systems and help screen diverse relevant extracts influencing endogenous enzyme response more rapidly.