Abstract:
Plants have been one of the important sources of medicines even since the dawn of human civilization. Various medicinal plants are common in use in Nepal for the treatment of different diseases. Nowadays, drug resistance has emerged as a major problem for various infections, in such case plants can be used as alternative for the production of new antimicrobial agents. Thuja is a small evergreen genus of the Cupressaceae family. This species is widely cultivated as a common ornamental plant in Nepal and India. This study examined and documented the antibacterial activity of Thuja leaves extract on both gram positive i.e. Staphylococcus aureus and Streptococcus sp. and gram negative bacteria i.e. E. coli and Pseudomonas aeruginosa. Thuja leaves were collected from different localities of Dharan and dried under shade for 10 days. They were then grinded using mechanical grinder. Leaf extract was obtained by soxhlet extraction technique using mixture of Ethyl acetate, Ethanol and chloroform in the ratio 40:30:30 as the solvent. The antibacterial activity of Thuja oleoresin was tested using both Agar well diffusion as well as disc diffusion technique. MIC was also determined by agar well diffusion on MHA plates. Thuja oleoresin showed distinct antibacterial activity towards all four isolates on both agar well and disc diffusion methods. MIC for Pseudomonas aeruginosa and Streptococcus sp. was found to be 12.5µl whereas E. coli and Staphylococcus aureus have a MIC of 25µl. Thus from the result it is concluded that Thuja leaves have medicinal values and can be a potential source for production of antibacterial drugs.
