In Vitro Antimicrobial Screening of Four Reputed Bangladeshi Medicinal Plants

The antimicrobial activity of extractives of different plants has been recognized for many years. In present study the crude methanolic extracts and their kupchan partitioning fractions of four medicinal plants of Bangladesh namely, Sansevieria trifasciata (Fam: Asparagaceae), Justicia gendarussa (Fam: Acanthaceae), Hydnocarpus kurzii (Fam: Achariaceae) and Kigelia pinnata (Fam: Bignoniaceae) were investigated for their in vitro antimicrobial properties. All fractions were tested against 11 different gram positive and gram negative bacteria by the disc diffusion technique for bacteria, where kanamycin (30 µg/disc) disk used as standard. Among the extractives, the methanol extract and their pet-ether, carbon tetrachloride and chloroform soluble kupchan fractions of leaf extract of H. kurzii, and the aerial part extract of S. trifasciata showed significant antibacterial activity, where as chloroform soluble extracts of leaves of H. kurzii revealed highest activity against Vibrio mimicus (15.00 mm) and the methnol extract of whole plant of S. trifasciata demonstrated highest activity against V. mimicus (14.67 mm). The chloroform soluble fractions of J. gendarussa also showed mild to moderate antimicrobial activity with zone of inhibition ranging from 8.33-13.00 mm, in which highest activity was seen against Shigella boydii (13.00 mm). All the extractives of K. pinnata, on the other hand, demonstrated mild antimicrobial activity, where highest zone of inhibition was displayed by the chloroform soluble extract against S. boydii (11.00 mm) and Pseudomonas aeruginosa (11.00 mm).