Screening of plant species for inhibition of bacterial population of raw water

Seven plant species i.e., Adhatoda vasica, Andrographis paniculata, Azadira chta indica, Lawsonia inermis, Moringa oleifera, Ocimum sanctum and Trigone lla foenum-graecum have been screened out systematically for their effectiv eness in inhibition of bacterial population of raw water (in vitro) at vari able pH level i.e., 6.0, 6.5, 7.0, 7.5 and 8.0. Maximum percentage inhibiti on was observed in three plant species at 6.5 pH level while in four plant species at 7.0 pH level. Among all the studied plants, maximum inhibition w as recorded in case oft. inermis (93.97%) which was followed by M. oleifera (89.72%) and A. vasica (81.75%). In order of maximum to minimum inhibition , individual plant species depicted their effectiveness in the following ma nner : L. inermis > M. oleifera > A. vasica > A. indica > O. sanctum > A. p aniculata > T. foenum-graecum. Besides, MPN coliform and E. coli were also inhibited maximum at 7.0 pH level by the extract of L. inermis which was fo llowed by A. vasica and M. oleifera at 6.5 pH level. Hence, these plant spe cies may be used for elimination of bacterial contaminants of raw drinking water obtained directly from the sources to reduce the occurrence of differ ent water borne diseases.