Abstract

Lagerstroemia speciosa bark extract was investigated for its pharmacokinetic and pharmacodynamic parameters against two selected pathogenic bacteria by the time-kill curves assay. The brine shrimp lethality test was carried out to determine the toxic level of the extract towards the eukaryotic cells. The extract showed a concentration-dependent killing effect for both B. spizizenii ATCC 6633 and A. anitratus. The number of bacteria was significantly reduced when they were exposed to 2MIC (minimum inhibition concentration) level. Bacteria B. spizizenii ATCC 6633 was more susceptible to the extract as compared to A. anitratus. The extract was found to be nontoxic during the short term (acute) exposure but it was toxic during the prolonged time (chronic) exposure. The LC50 for acute test and chronic test were 3422.68 and 35.30 µg/ml, respectively. This study indicated that the methanol extract of L. speciosa is a promising candidate for the search of natural antimicrobial and anticancer drugs.