Avaliação da atividade antimicrobiana, citotóxica e capacidade sequestradora de radicais livres de extratos brutos do Cocos nucifera Linn

Abstract

Cocos nucifera Linn is a tropical palm tree whose fruit is used for alimentary, cosmetics, handmade and medicinal purposes. However the research from other parts of this species is incipient. The researchs about therapeutic activities from plants used by population is encouraged by the Health World Organisation and, in Brazil, fomented by 10 thousand vegetable species cataloged and only 10% evaluated with respect to their biological activities and safety. The resolution No. 197/1997 of the Federal Council of Nursing endorses the use of plants in the practice of nursing care and linked to the need for alternatives against microbial multirresistance and oxidative diseases which are problems contemporaries of humanity. This preclinical experimental research was performed at the Master’s Program in Nursing at the Federal University of Alagoas in order to investigate the antimicrobial activity and cytotoxicity and free radical scavenging capacity of crude ethanol extracts of the leaves, stem and stalk's husk of Cocos nucifera L. (coconut palm) in vitro. It was evaluated the extract's antimicrobial activities against the Gram positive bacteria: S. aureus and Gram negative: E. coli and P. aeruginosa and C. albicans fungus by Àgar diffusion methods and identification of the Minimum Inhibitory Concentrations by microdilution. It was performed cytotoxicity assay in J774 lineage cells by MTT [3 - (4,5-dimethylthiazol-2) -2,5-diphenyltetrazolium bromide] and verification of the antioxidant potential by qualitative and quantitative methods of free radical scavenging ability. The results confirmed the antioxidant potential against the DPPH with CI50 of 135.03 ± 0.04 mg / mL and 179.22 ± 2.1 mg / mL from extracts of stem and leaf respectively while stem and ethanolic and methanolic leaf only showed free radical scavenging capacity in qualitative assay. The extracts of stem and leaves of the Cocos nucifera L. inhibited bacterial growth of S. aureus and P. aeruginosa with lower growth inhibitory concentration of 10mg (5%). There was no growth inhibition of E. coli and C. albicans at a concentration of 1.5 x 106 UFC with extracts by 10%. The crude extracts of Cocos nucifera Linn didn't showed cytotoxicity at concentrations of 200 and 100 mg / mL; crude ethanol extract of the stem did not cause cytotoxicity at concentration of 1000 mg / mL. The DMSO 2% solvent was cytotoxic, making unfeasible analysis of the extracts at 2000μg. The results confirm existence of free radical scavenging and antimicrobial activity and absence of cytotoxicity in some of crude extracts of the leaves, stem and stalk's husk of the Cocos nucifera Linn collected in Alagoas soil