Screening of selected aromatic plants belonging to Labiateae and Verbenaceae family for their antimicrobial activity

The present study aimed that 17 plant species belonging to Lamiaceae and Verbenaceae families were screened for their antimicrobial activity. The crude extracts of root, stem, leaf, inflorescence and whole plant were prepared in n-Hexane, ethyl acetate, methanol and D/W and tested against six gram positive and six gram negative bacteria by agar well diffusion method and the zone of inhibition was measured. The MIC value was examined by the twofold serial broth dilution method. The results showed that Bacillus cereus, Klebsiella pneumoniae, Serratia marcescens and Enterococcus faecalis were found to be most susceptible organism. The n-hexane crude extracts inhibited the growth of Klebsiella pneumonia (91.17%), Bacillus cereus and Serratia marcescens (88.23%), ethyl acetate extract Enterococcus faecalis (85.29%), Bacillus cereus (82.35%) while methanolic extract found to inhibit the growth of Bacillus cereus (76.47%). Least to no activity was found in D/W extract. Salmonella paratyphi, Escherichia coli, Micrococcus luteus were found to most resistant organism for all tested crude plant extracts. The MIC values were observed in the range of >8 mg/ml to 0.25 mg/ml of selected crude plant extracts against tested organisms. HPTLC finger printing and TLC-bioautography of certain active extracts demonstrated the presence of common phytochemical compound in plant extracts. The results obtained in present study suggested that these plant extracts can be a source of active principle for antibacterial activity