%0 Journal Article
%T An evaluation of antibacterial activities of Psidium guajava (L.)
%A Sanches
%A Neviton Rog¨¦rio
%A Garcia Cortez
%A Di¨®genes Apar¨ªcio
%A Schiavini
%A Michelle Simone
%A Nakamura
%A Celso Vataru
%A Dias Filho
%A Benedito Prado
%J Brazilian Archives of Biology and Technology
%D 2005
%I Tecpar
%R 10.1590/S1516-89132005000300014
%X the present study was designated to evaluate the antibacterial activities of aqueous and ethanol:water extracts from leaves, roots and stem bark of psidium guajava l. the antibacterial activities of the extracts against bacteria were tested by using both microdilution assay. the aqueous extracts of p. guajava leaves, roots and stem bark were active against the gram-positive bacteria staphylococcus aureus (mics=500, 125 and 250 ¦Ìg/ml, respectively) and bacillus subtilis (mics=500 ¦Ìg/ml), and virtually inactive against the gram-negative bacteria escherichia coli and pseudomonas aeruginosa (mics >1000 ¦Ìg/ml). the ethanol:water extracts showed higher antimicrobial activity as compared to aqueous extracts. based on this finding, the ethanol:water extract of p. guajava leaves was fractionated on silica gel column chromatography in a bioassay-guided fractionation affording flavonoid mixture, triterpenes (a- and b-amyrin) and sterol (b-sitosterol). flavonoid mixture showed good activity on s. aureus with mic of 25 ¦Ìg/ml. b-sitosterol was inactive for all the bacteria tested.
%K psidium guajava
%K antibacterial activities
%K flavonoids
%K a- and b-amyrin
%K b-sitosterol.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1516-89132005000300014&lng=en&nrm=iso&tlng=en