10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 3 2012 (July - September) lessThan i greaterThan Lobelia inflata lessThan /i greaterThan L. is a medicinally important herb used in the treatment of respiratory problems. The objectives of this present study were phytochemical screening and evaluation of antimicrobial activities of aqueous, ethanolic and methanolic extracts of different parts of the plant such as leaf, root, stem and inflorescence. Extracts of lessThan i greaterThan in vitro lessThan /i greaterThan grown callus of the leaf, obtained after 4 weeks of incubation on 1X MS medium containing 1mg/ml 2, 4-D and 1mg/ml Kinetin were also screened. Fifteen extracts revealed the presence of phytochemicals such as alkaloids, carbohydrates and phytosterols. The methonolic extracts of root showed alkaloid (0.50 mg/ml) and stem showed carbohydrate (1.76 mg/ml). The ethanolic leaf extract showed phytosterols (3.68 mg/ml). Antimicrobial activities revealed that among all the extracts, the highest sensitivity was recorded for the methanolic and ethanolic extract of inflorescence against lessThan i greaterThan Klebsiella pneumonia lessThan /i greaterThan and lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan respectively. The ethanolic extract of root and stem showed the highest zone of inhibition against lessThan i greaterThan Serratia marcescens. lessThan /i greaterThan None of the aqueous extracts exhibited any antimicrobial activity. The methanolic extract of the callus was found to inhibit lessThan i greaterThan Cryptococcus neoformans lessThan /i greaterThan among the various fungal pathogens. This study may provide the scientific basis for the use of this plant for various therapeutic purposes. . Nagananda G.S, Aarthi Krishnamoorthy, Arijit Das And Sourav Bhattacharya Lobelia inflata L., phytochemical screening, antimicrobial activities, callus, extracts, pathogens. 433-442