Estudo do potencial antioxidante da espécie Caryocar coriaceum Wittm. em modelos experimentais in vitro e in vivo

Abstract

Despite the diversity of species found in the National Araripe Forest, Ceará Cariri, there are few studies with Caryocar coriaceumWittm (C. coriaceum), a plant that produces a highly consumed fruit in regional cuisine. The oil extracted from the pulp is also widely used in popular medicine for the treatment of respiratory infections and joint diseases. Studies with oil pulp have consolidated therapeutic properties of species. However, this is the first study with plant leaf extracts and oil from the fruit pulp that assesses markers of oxidative stress and gene expression of antioxidant enzymes in vivo using Drosophila melanogaster. The antioxidant activity of leaf and fruit peel extracts was evaluated in vitro. The major phenolic compounds from extracts, identified by HPLC-DAD, were quercetin, chlorogenic acid and ellagic. In in vitro tests, the extracts exhibited similar and significant DPPH● and OH● scavenging activity, were effective in reducing and chelating iron as well as decreasing lipid peroxidation and production of reactive oxygen species induced by iron and calcium, respectively, in liver homogenate. The extracts did not change the levels O2•– in mitochondria treated with antimycin A. In in vivo study, flies were pretreated with a diet containing aqueous leaf extract (AEL) (1 and 5 mg/g diet) and/or pequi pulp oil (PPO) (1, 5 and 10mg/g diet) for 7 days followed by exposure to paraquat (PQ) (10mM) for 24 hours. A third treatment was performed concomitantly with AEL and PQ (1mM) for 5 days. The analysis of the negative geotaxia was performed to evaluate locomotor ability of flies. Flies homogenate was used to analyze oxidative stress markers specifically activity of catalase (CAT) and glutathione-s-transferase (GST), levels of ROS and peroxidation lipid by levels of TBARS. We evaluated the mRNA expression of antioxidant enzyme genes CAT, superoxide dismutase (SOD), Thioredoxin reductase-1 (Trx R-1), Thioredoxin T (Trx T) and Keap 1 protein by qRT-PCR. Flies exposed to PQ showed a significant impairment in locomotor activity, increase in oxidative stress markers and gene expression of CAT, SOD, Trx R-1, Trx T and Keap 1. The concentrations AEL and OPP, in all treatments, reduced significantly lipid peroxidation levels and reversed locomotor changes induced by exposure to PQ. In both AEL treatments, flies exposed to PQ had a reduction in ROS levels and CAT and GST activities. Flies concomitantly treated with AEL and PQ exhibited a significant decrease in expression of Trx R-1 and Trx T genes, which were increased in the PQ group. Pre-treatment with PPO of 10mg/g diet, we verified a decrease the expression of genes CAT, SOD, Keap 1 and Trx T, which were increased in the group exposed to PQ alone. The data obtained in this study show that the treatment with AEL and PPO reduced oxidative stress markers induced by PQ and suggest that this effect may be related, at least in part, to the antioxidant system modulation. Moreover, these results will collaborate to extend the knowledge about the scientific properties of C. coriaceum as well as point it as a promissing functional food.