Resumo

NEIRA GONZALEZ, Adriana María; RAMIREZ GONZALEZ, Martha Beatriz  e  SANCHEZ PINTO, Nidia Lizbeth. Phytochemical study and antibacterial activity of Psidium guíneense Sw (choba) against Streptococcus mutans, causal agent of dental caries. Rev Cubana Plant Med [online]. 2005, vol.10, n.3-4, pp. 0-0. ISSN 1028-4796.

The antibacterial potentialities of the ethanol extract and its petroleum ether, dicloromethane, ethyl acetate, and aqueous fractions obtained from the peel and pulp of Psidium guineense Sw ( choba) against the Gram positive Streptococcus mutants ATCC 31089 and a strain of the same germ isolated from a patient, were proved . S. Mutans is recognized as the causal agent of dental caries. The content of secondary metabolites in the crude ethanol extracts and in its respective fractions were proved by staining and thin layer chromatography. The antibacterial tests were made by means of the gel perforation technique and using McFarland's 0.5 scale at 108 ufc/mL. Blood base agar was utilized and 50 mL of the ethanol extracts from the peel and pulp of P. guineense diluted in DMSO at concentrations of 400 and 0.4 mg/mL were applied. According to the highest percentages of inhibition obtained from these extracts, the fractions were taken in concentrations between 25 and 100 mg/ mL and from 400 and 200 mg/mL for the S. mutans strain isolated from a patient. The crude ethanol extracts showed activity against these bacteria. The fractions with the greatest activity were the so-called M1FA (fraction of acetate of choba fruit's dry green peel) and M3FA (fraction of acetate of choba fruit's dry green pulp). The antimicrobial activity of the P. guineense species may be attributed to secondary metabolites, taninns, flavonoids, terpenes and aldehydes present in the fruit of this species.

Palavras-chave : Psidium guineense Sw; fractions; Streptococcus mutans; antibacterial activity.

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