Nepalese medicinal plants have been known to relieve various diseases in Ayurveda. The aim of our study was to investigate the in-vitro antimicrobial effect of methanolic extracts of some selected medicinal plants collected from mountain, hills and terai regions of Nepal. Phytochemical screening of the 46 selected medicinal plant extracts was conducted to detect metabolites like flavonoids, terpenoids, tannins, polyphenols, steroids, glycosides, reducing sugars, cardiac glycosides, anthraquinone, carotenoids and saponins. The methanol soluble plant extracts inhibited the growth of gram-positive (Staphylococcus aureus, Bacillus subtilis) and gram-negative bacteria(Salmonella typhi, Escherichia coli). Out of 46 screened medicinal plants, twenty three extracts possessed active antibacterial components against the test microorganisms. Cleistocalyx operculatusextractwas found inhibitory against all the microbes studied in this work. Antibacterial susceptibility test using its extract showed zone of inhibition against Stayphylococcus aureus (18.23 ± 0.15 mm/disc), Bacillus subtilis (18.1 ± 0.2 mm/disc), E. coli (16 ± 0.2 mm/disc) and Salmonella typhi (13.16 ± 0.15 mm/disc) at 10mg/ml concentration.Similarly, the extract ofBridelia retusashowed remarkable antibacterial property against Staphylococcus aureus (13.5 ± 0.2 mm/disc),Bacillus subtilis (11.16 ± 0.1 mm/disc), E. coli (16.23 ± 0.05 mm/disc) and Salmonella typhi (12.33 ± 0.2mm/disc). Our study showed that extracts of Curcuma angustifolia, and Justicia adhatoda, Bauhinia variegate containedbioactiveingredient against these organisms.
