Antibacterial activity of Nepalese medicinal plants against different bacterial isolates

Antimicrobial resistance becomes a widespread issue. With this, more studies concentrating on medicinal plants are being conducted in an effort to uncover their full therapeutic potential. This study was conducted to evaluate the antibacterial activities of eight medicinal plants (Azadirachta indica, Mentha spicata, Terminalia chebula, Terminalia bellirica, Acorus calamus, Tinospora sinensis, Ocimum tenuiflorum, Aloe vera) in the Med-micro Research Laboratory, Babarmahal from January to July 2022. These plants were collected and using the maceration method, their extracts were made separately in distilled water, 95% ethanol, and 1% chloroform. The plant extracts were prepared using Dimethyl sulfoxide (DMSO) in two different concentrations (10% and 1%). The agar well diffusion method was used to measure the antibacterial activity of a total of 48 extracts against four bacterial isolates, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In contrast to gram negative bacteria, the majority of plant extracts had significant antibacterial activity against Staphylococcus aureus, a gram positive bacterium. The ethanolic extract of Terminalia chebula at a 10% concentration exhibited the largest zone of inhibition (26mm) against Staphylococcus aureus. The most potent extracts were found to be those of ethanolic extract of Terminalia chebula and Terminalia bellirica, followed by those of Acorus calamus and Ocimum tenuiflorum. Our results provide additional evidence that these plants hold potential as a natural antibacterial agent, hence can be used in treatment of various infectious diseases.