Perfil químico e avaliação da atividade antioxidante de extratos da polpa dos frutos de Garcinia cochinchinensis

Abstract

Garcinia cochinchinensis (Clusiaceae), popular name false mangosteen, is a poorly studied species among the species of this genus, in folk medicine the bark is used to treat skin diseases and the threat of abortion. Other species of this genus have antioxidant activity, antiglycemic, anticancer and other activities. Plant species provide organic compounds that have antioxidant ability, such as phenolic compounds, flavonoids and xanthones, where species of the genus Garcinia (Clusiaceae) are a relevant source of these metabolites. Oxidative stress occurs when there is an imbalance between oxidant species and antioxidant species in favor of the former. This phenomenon is related to several diseases, such as diabetes mellitus, neurodegenerative diseases such as Alzheimer's and Parkinson's and others. The present work aimed to evaluate the antioxidant activity of extracts from the fruits of Garcinia cochinchinensis. The extraction of pulp from the fruit was carried out by means of ultrasound-assisted extraction and the classic method of fractional solvent extraction. After obtaining the extracts, the content of total phenolics and total flavonoids was determined using the Folin-Ciocalteau reagent and aluminum complexation methods, respectively. The extracts A12A and AM12A were analyzed by Gas Chromatography coupled to a Mass Spectrometer (GC-MS), making it possible to identify and quantify the volatile compounds present. The antioxidant activity of all extracts was evaluated by DPPH• and ABTS radical capture methods, as well as by iron chelation and reducing power assays. The extracts obtained with ethyl acetate at pH 8 in the three fractionations showed the highest content of phenolic compounds and flavonoids compared to the others (p > 0.05). The yield of ultrasound extraction was higher than that of classical extraction. The pH variation to 8 in the extractions was the optimal value for the extraction of phenolic compounds and thus obtaining better antioxidant activity. The A8C (90.6%) and AM8C (91%) extracts showed the highest iron chelation capacity compared to the other extracts (p > 0.05). As for the antioxidant activity of capturing DPPH• and ABTS radicals, the extracts obtained with ethyl acetate at pH 8 and 4 showed excellent inhibition values for these radicals. The results showed good antioxidant activity of the extracts obtained by different extraction methods. Therefore, extracts of G. cochinchinensis may be submitted to further investigations about the antioxidant activity in vivo and related mechanisms to verify its possible usefulness as a source of active principles to be applied in the prevention and treatment of diseases whose pathophysiology is related to oxidative stress.