Phytochemical Screening and Antibacterial Properties of Croton hirtus L’Her. Plant Against Some Important Pathogenic Bacteria

The present study is aimed at evaluating the in vitro antimicrobial activity of different solvent extracts of Croton hirtus L'Her. against ten medically important bacterial strains namely Escherichia coli, Enterococcus sp., Salmonella typhi, Salmonella paratyphi, Bacillus thuringiensis, Bacillus subtili, Staphylococcus aureus, Pseudomonas fluorescens, Proteus sp. and Klebsiella pneumoniae. Phytochemical analysis and antimicrobial properties of shoot, ischolar_main and whole plant extracts of C. hirtus were investigated separately in methanol, ethanol, chloroform, acetone and water. Phytochemical screening reveals the presence of alkaloids, tannins, flavonoids, steroids, phenols, glycosides, terpenoids, anthroquinone, saponins and cardiac glycosides. The methanol extract exhibited higher and wider range of activity against majority of the test organisms. The shoot methanol extracts recorded highest activity against Bacillus thuringiensis (13.67 mm ZOI and MIC of 600μg/mL), Bacillus subtili (13.83 mm ZOI and MIC of 600μg/mL) and Salmonella paratyphi (12.5 mm ZOI and MIC of 800μg/mL). The methanol whole plant extracts demonstrated highest activity against Salmonella typhi (13.33 mm ZOI and MIC of 700μg/mL) whereas methanol ischolar_main extracts demonstrated highest against Klebsiella pneumoniae (13.33 mm ZOI and MIC of 800μg/mL) and Enterococcus sp. (10.5 mm ZOI and MIC of 1000μg/mL). The performance of methanol extracts was followed by chloroform extracts. The chloroform whole plant extracts showed the highest activity against Escherichia coli (14.67 mm ZOI and MIC of 400μg/mL) and Staphylococcus aureus (12.67 mm ZOI and MIC of 800 μg/mL), whereas chloroform shoots extracts against Pseudomonas fluorescens (12.33 mm ZOI and MIC of 900μg/mL). The highest activity against Proteus sp. was recorded in shoot acetone extracts (10.67 mm ZOI and MIC of 1000μg/mL). Water and ethanol extracts demonstrated the least activity against the test bacteria.