In vitro anti leptospiral activity of chloroform extract of Piper betle L

Abstract

The chloroform extract of the leaf of Piper betle L., (Piperceae) was investigated for its antileptospiral activity against 10 serovars of selected Leptospira. The leaves of this plant have been long in use tropical countries for the preparation of traditional herbal remedies. The minimum inhibitory concentration (MIC and minimum leptospiricidal concentration (MLC) of the chloroform extract were determined by using broth microdilution method. Time kill curve studies, post antileptospiral effects and mutation prevention concentrations were determined against L. australis and L. patoc. The membrane permeability was measured by the uptake of propidium iodide.  The extract exhibited the inhibitory effect on leptospiral serovars of clinical significance, with the MIC ranging from 17.5 to 500µg/ml for the serovars whereas the MLCs were found to be similar or two fold greater than the MICs. There was concentration dependent killing of leptospires. There was increased uptake of propidium iodide by leptospires cells when exposed to chloroform extract thus indicating that the membrane disruption could be the probable mode of action of the chloroform extract of Piper betle. The antileptospiral activity exhibited by this extract warrants its use as a potent antileptospiral agent particularly for liver disorder and dysfunction.