The air quality of the Kathmandu valley is highly degraded by pollution from motor vehicles. Planting green vegetation along roadsides has been shown to reduce air pollutants. Different leaf parameters like pH, relative water content, chlorophyll content, and ascorbic acid content, that comprise the Air pollution tolerance index (APTI), were used to test the susceptibility of plants to air pollution. APTI values of ≤11, 12–16, and ≥17 categorised the plant species under sensitive, moderate, and tolerant species, respectively. In the present study, all the plant species had APTI less than 11. The highest APTI value was for Mangifera indica (10.62) and the lowest for Buddleia asiatica (6.92). Therefore, based on the findings of the present study, planting trees with high APTI value alongside the roads may help reduce air pollution as these trees are resistant to high pollution levels.

Ethnobotany is the study of ethnic plants of particular people living in particular place. It accommodates list, details and description of all those studied plants regarding with their various uses. Tharu people belong to one of the indigenous communities especially in Terai region of Nepal. Tharu people have been using these plant resources since 18th century. This study aims to identify ethnic plants of Tharu community of eastern Nepal and their uses in their daily lives. Enumeration of useful plants from Tharu ethnic community was conducted in four villages of Ramdhuni municipality of Sunsari district. Participatory Rural Appraisal (PRA) and household sampling technique were used for data collection. Plant specimens were collected and information regarding it was obtained from local Dhamis, Jhankris, farmers and old age people. This study reported thirty-seven useful plant species under 25 families. In total 37 species, 25 were recorded as medicinal plant, used to treat pneumonia, menstrual disorder, stones, piles, skin disease etc. Other plant species were used for food, fodder, timber, fiber and ceremonial/ religious activities. Most plant species (78.3%) were having multiple use value, and kept under more than one use category and few species (21.7%) with single use category. Trees (27.02%) and herbs (27.02%), both were dominant over grass, shrubs, climbers and creepers. This study has revealed that many plants species are being used by Tharu community of Eastern Nepal as their ethnic plants for medicine, food, fodder, ornament, material etc which needs to be more explored. Int. J. Appl. Sci. Biotechnol. Vol 8(2): 223-230

Essential oils are volatile, natural, complex compounds which are produced as secondary metabolites by plants for their protection against various microorganisms as well as pests. A wide range of plants have been explored for their essential oils in the past few decades. The study was conducted to determine the antibacterial activity of essential oils against human pathogenic bacteria which were gram positive (Staphylococcus aureus and Streptococcus pyogenes) as well as gram negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Shigella sonnei). Five ml of three different oils, i.e. clove oil, castor oil, and ginger oil, were taken in a test tube so that each oil had four different concentrations. Four concentrations of (0, 25, 50 and 75) μL of oils were mixed with 1000, 975, 950 and 925 μL of DMSO respectively to make it a volume of 1ml. It was observed that clove oil was effective against the entire gram positive as well as gram negative bacteria that were used. The inhibition zone was greatest in the case of clove oil at 75 μL against P. aeruginosa (23 mm) and the smallest zone of inhibition was shown by castor oil against K. pneumoniae (12 mm). Other oils were sensitive as well as resistant to the bacteria. Hence, it is found that different oils have shown inhibitory activity towards different pathogens to a variable extent. However, clove oil was inhibitory to all the bacteria in all concentrations. Int. J. Appl. Sci. Biotechnol. Vol 9(4): 250-255