Methanolic extracts of 41 plant species belonging to 27 families used in the traditional medicine in Nepal have been investigated for in vitro antiviral activity against Herpes simplex virus type 1 (HSV-1) and influenza virus A by dye uptake assay in the systems HSV-1/Vero cells and influenza virus A/MDCK cells. The extracts of Astilbe rivularis, Bergenia ciliata, Cassiope fastigiata and Thymus linearis showed potent anti-herpes viral activity. The extracts of Allium oreoprasum, Androsace strigilosa, Asparagus filicinus, Astilbe rivularis, Bergenia ciliata and Verbascum thapsus exhibited strong anti-influenza viral activity. Only the extracts of A. rivularis and B. ciliata demonstrated remarkable activity against both viruses.

Street dust has been sampled from eight major locations of Kathmandu city. The samples were separated into three particle size fractions (<425, 425-600 and >600 μm) and analyzed for Pb, Cu, Zn and Fe using Atomic Absorption Spectrophotometric method. Results revealed that the bulk samples as well as all particle size fractions under investigation were found to have the metal abundance order as Fe > Zn > Cu > Pb. However, the trace metal concentrations increased with the decrease of dust particle size in all samples. About 35-68% of heavy metals were associated with the small particle size fraction (<425 μm) and this particle size accounted for 64-81% of the total mass of street dust from all locations. The smaller particle size fraction has a higher heavy metal content, low density, high mobility in runoff, and thus is a higher risk for the residents of Kathmandu city. From the present study, we conclude that a monitoring plan and a suitable risk assessment are necessary to evaluate the evolution of metal concentration in dust in order to develop the proper measures for reducing the risk of inhalation and ingestion of dust for humans and environment.

This study attempts to document the lichen species and their distribution in different areas of Kathmandu valley, Nepal. Twenty sampling sites with different degrees of air pollution categorized as disturbed (industrial, heavy traffic and residential areas) and undisturbed areas (clean area) were selected for the study. Sampling was done using the quadrat method. To enumerate the total number of lichen species found in Kathmandu valley, lichen specimens were collected from inside as well as outside the quadrats. A total of 97 species of corticolous lichens belonging to 21 families and 44 genera were recorded from the study sites. Parmeliaceae was the largest family followed by Graphidaceae. The importance value analysis showed that Candelaria concolor (115.2), Dirinaria aegialita, Lepraria sp., Phaeophyscia hispidula var. hispidula and Physcia sorediosa (106.02) are the most common and dominant lichen species in Kathmandu valley. Among the most common and dominant lichen species, Candelaria concolor, Dirinaria aegialita, Phaeophyscia hispidula var. hispidula and Physcia sorediosa were found concentrated in heavy traffic areas whereas Lepraria sp. in the industrial areas. A higher number of lichen species (70%) was recorded in undisturbed areas than in disturbed areas (50%). These study confirm that the distribution of lichen flora is strongly influenced by degrees of pollution. This in turn suggests that lichens can be used as bio indicators of air quality in the Kathmandu valley.

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