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Background: Among solar radiation, ultraviolet light is the most harmful for the skin, because of intracellular reactive oxygen species formation, leading to oxidative stress, cell damage and apoptosis. Crucial role in skin protection against oxidative stress play antioxidant enzymes regulated by Nrf2 transcription factor. Some plant-derived polyphenols are known to protect skin fibroblasts against UV through induction of Nrf2-dependent antioxidant genes expression.Purpose: We previously found out that water extracts from Galinsoga sp. herb protected human dermal fibroblasts against UVA-induced oxidative stress and apoptosis. However, which compounds were responsible for such protective action remained unclear. Here, we investigated photoprotective potential and mechanism of action of two main isolated compounds, 2,3,5(2,4,5)-tricaffeoylaltraric acid and 2,4(3,5)-dicaffeoylglucaric acid, on human dermal fibroblasts (NHDF).Study Design/methods: NHDF cells were pretreated with tested compounds (6.25-50 µM) and irradiated with UVA (25 J/cm2). Intracellular ROS and GSH level, cell viability, cell membrane integrity and apoptosis were measured. HO-1 protein expression and Nrf2 transcription factor activation were also assessed.Results: Cells pretreated with tested compounds prior to UVA showed inhibition of intracellular ROS formation and increase of GSH level. Significant increase of cell viability was also observed, as well as decrease of LDH release and a the rate of apoptotic cells in comparison to untreated cells. Furthermore, tested compounds increased HO-1 expression and activated the Nrf2 transcription factor in NHDF cells.Conclusion: Present study demonstrated that caffeic acid derivatives present in Galinsoga parviflora herb, in particular tricaffeoylaltraric acid may protect dermal fibroblasts against UVA-induced oxidative stress through activation of intracellular antioxidative system. Such caffeic acid derivatives are bioactive compounds which might prevent UV-induced photoageing and photocarcinogenesis. [ABSTRACT FROM AUTHOR]

Four new caffeoyl -glucaric and -altraric acid derivatives along with eleven known compounds were isolated from aerial parts of Galinsonga parviflora . Their structures were elucidated by high-resolution spectroscopic studies. The four new compounds were determined as being 2,3,4,5-tetracaffeoylglucaric acid ( 1 ), 2,4,5-tricaffeoylglucaric acid ( 2 ), 2,3,4- or 3,4,5-tricaffeoylaltraric acid ( 3 ) and 2,3(4,5)-dicaffeoylaltraric acid ( 4 ). A reliable criterion for the determination of the linkage position of caffeic acids moieties in glucaric acid derivatives has been proposed, on the basis of detailed analysis of the respective J -couplings, including substitution and solvent influence on the observed values. All hexaric acids derivatives appeared as inhibitors of reactive oxygen species production by stimulated neutrophils. [ABSTRACT FROM AUTHOR]

Galinsoga parviflora Cav. and Fumaria officinalis L. are well known to have many therapeutic applications based also on their antioxidant activity. Because the antioxidative potential of plant materials is related to the presence of phenolic compounds, we determined their content in both herb extracts. Then the antioxidant potency of the extracts was estimated by measuring ABTS scavenging activity and by Saccharomyces cerevisiae cell assays, including the estimation of viability, respiration coupling and protein carbonylation for the yeast Δ sod1 mutant. This mutant undergoes oxidative stress because of the depletion of the superoxide dismutase form encoded by the SOD1 gene (CuZnSOD). We demonstrated that the antioxidative activities of G. parviflora and F. officinalis extracts coincide with the content of phenolic compounds, namely, phenolic acids. Moreover, we observed a relationship between the extract activities and their effects on the Δ sod1 cell status of energy coupling and protein carbonylation, as well as cell viability. These findings provide new data regarding the mechanism of antioxidative activity of plant phenolic compounds and the potential of the studied herb for application as a functional food ingredient. [ABSTRACT FROM AUTHOR]