Atividade antioxidante e citotóxica dos extratos das folhas de myrciaria dubia, coletadas em itacoatiara-Am

Abstract

Myrciaria dubia is also popularly known as camu-camu”, “caçari’, “araçá d’água” or “sarão” and belongs to the Myrtaceae family and can be found in igapós, lakes and floodplains on the Amazon River. Several studies with camu-camu fruits and seeds report cytotoxic and antioxidant properties. However, there are still no reports of studies with extracts from the leaves of this species. Therefore, the objective of this work is to evaluate the chemical composition, antioxidant and cytotoxic activity of extracts from M. dubia leaves, collected in Itacoatiara- Am. Initially, the leaves were collected and dried, then they were crushed and extracted with ethanol 70 %, obtaining the hydroalcoholic extract that was rotary evaporated to remove all the ethanol to obtain the aqueous extract, one part was left to dry and the other part was fractionated using solvents in order of increasing polarity. The chemical responses in test tubes obtained the following results: The crude extract indicated the presence of flavanones, phenols, chalcones and aurones, while the butanolic, ethyl acetate and hydroalcoholic tannin flababenic fractions, flavanones and flavones. The presence of free steroids was evident in the crude extract and in the precipitate fraction, in the pentacyclic triterpenoid chloroform and hexane fractions. The hydroalcoholic fraction and the crude extract are composed of triterpene saponins and the butanolic and ethyl acetate fractions are steroidal saponins. Alkaloids were evident in the crude extract and in the ethyl acetate, butanolic and hydroalcoholic fractions. Thin layer chromatography indicated the presence of terpenes in the crude extract and in the precipitated, chloroform, hexane, butanolic and hydroalcoholic fractions and the presence of flavonoids in the crude extract and in the precipitated and ethyl acetate fractions. The antioxidant activity revealed that the crude extract and the ethyl acetate and hydroalcoholic fractions indicated high antioxidant activity in M. dubia leaves. The cytotoxic assay revealed that the chloroform and precipitate fraction had a cytotoxic effect on cells of the colorectal carcinoma (HCT116) and promyelocytic leukemia (HL60) lineages, especially the precipitate fraction, the chloroform fraction showed selectivity towards cells of the colorectal carcinoma lineage (HCT116) and promyelocytic leukemia (HL60).