In Vitro Antimicrobial Activities of the Plants Belonging to Family Myrtaceae

Present study was undertaken to find out in vitro antibacterial and antifungal activities of methanolic extracts of Psidium guajava, Syzygium cumini, Eucalyptu srudis and Callistemon rigidus belonging to family Myrtaceae, against Gram-positive bacteria (Bacillus subtilis NCLM-2063 and Staphylococcus aureus NCLM-2098), Gram-negative bacteria (Escherichia coli NCLM-2112 and Pseudomonas syringae p.v. pisi NCLM-2204), and plant pathogenic fungi (Aspergillus flavus, Penicillium chrysogenum, Helminthosporium gramineum, and Mucor plumbeus).. For these studies leaves, stem and fruits of the plants were used, while agar well diffusion method was employed. The results demonstrated concentration-dependent antimicrobial activity of almost all extracts., Methanolic extracts of Eucalyptus rudis leaves (ERL) and Callistemon rigidus Stem (CRS) exhibited comparatively higher antibacterial activity, particularly against Pseudomonas syringae and Bacillus subtilis, while, moderate inhibition was also observed against Escherichia coli and Staphylococcus aureus. Similarly inhibitory effects were also recorded against Penicillium chrysogenum and Aspergillus flavus. The Eucalyptus rudis leaves extract demonstrated strong antifungal activity against Helminthosporium gramineum. The findings thus indicated that plant extracts of suitable species possess broad-spectrum antimicrobial properties.