Acerola fruits (Malpighia emarginata DC.) from the central region of Cuba were analyzed to determine their chemical composition and protective capacity against oxidative damage using an in vitro human dermal fibroblast (HDFa) model. The chemical composition analyses showed a high content of vitamin C, total polyphenols, β-carotene and folates in the acerola fruit. From the HPLC-DAD/ESI-MS analyses, two anthocyanins (cyanidin 3-O-rhamnoside and pelargonidin 3-O-rhamnoside), three hydroxycinnamoyl derivatives (caffeoyl hexoside, dihydrocaffeoylquinic acid and coumaroyl hexoside) and fifteen flavonols (mostly glycosylated forms of quercetin and kaempferol) were detected. HDFa were pre-incubated with an acerola crude extract (ACExt) and subsequently subjected to oxidative stress induced by AAPH. Apoptosis, intracellular ROS and the biomarkers of lipid and protein oxidation significantly increased after inducing stress, while the activities of the antioxidant enzyme catalase and superoxide dismutase and mitochondrial functionality were markedly affected. However, ACExt was able to protect against oxidative damage through decreasing apoptosis, intracellular ROS levels and lipid and protein damage, besides improving antioxidant enzyme activities and mitochondrial functionality. The obtained results support acerola fruits as relevant sources of functional compounds with promising effects on human health.

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Soil salinity is one of the most devastating problems which reduces crop production and increases desertification. New approaches to overcome the negative effect of salinity on plants include the use of plant biostimulants, such as Xyloglucan oligosaccharides (XGOs) derived from the breakdown of xyloglucans from plant cell walls. The present study aimed at verifying the influence of exogenous XGOs derived from Tamarindus indica L. cell walls, on Arabidopsis thaliana's tolerance to salt stress by understanding the gene expression, enzymatic and metabolic changes resulting from its application. A. thaliana plants were grown in liquid media and after 15 days they were treated by a salt shock with 100 mM of sodium chloride, with or without XGOs at 0.1 mg L -1 . Gene expression of four oxidative stress markers as well as catalase and peroxidase activities and content of glutathione, total carbonyl, polyphenolics and chlorophyll were quantified. Bioinformatic models were used to obtain the co-expression network of the four oxidative stress response gene markers from microarray data of Arabidopsis under salt stress. Results showed that in saline conditions, XGOs dramatically increased catalase gene expression and enzymatic activity, peroxidase activity, and chlorophyll a/b ratio, while reducing protein oxidation and total polyphenols. Thus, XGOs may act to counteract negative effects of oxidative stress under saline conditions.

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