Chemical characterization and biological activities of Himalayan aromatic medicinal plants.

摘要

Nepal is a small country, located between two emerging giants of the Asian continent: India and China. However, like the Himalayan range, Nepal's biodiversity, a mosaic of species, is an unmatched giant in its own right. In coordination with a botanist and a chemist from Tribhuvan University in Nepal and the Natural Products Group at the University of Alabama in Huntsville, around 100 essential oil samples were collected and further analyzed using GC-MS for chemical composition and were tested for biological activity including cytotoxicity, antimicrobial, brine shrimp lethality, allelopathy, larvicidal, and insecticidal activity. In addition, separate testing of essential oil components was conducted to determine if any single component was responsible for the biological activity recorded in our samples. The results could not identify any one compound as being responsible for the observed activities in the samples. Therefore, we conclude the activities to be a result of a synergistic effect amongst the components in the samples. Aside from biological testing, the result of our systematic and detailed analyses about plant chemical composition has revealed new chemotaxonomic divisions for some of the different species. Plant chemotypes are not only dependent on genetic differences between species but vary among geographical and climatic conditions. This was studied in some cases through comparison of oil compositions of the same species that were collected from different locations. In this thesis, out of 100 samples, I am going to present only Acarus calamus, Amomum subulatum, Artemisia dubia, Artemisia indica, Artemisia vulgaris, Cinnamomum camphora, Cinnamomum glaucescens, and Cinnamomum tamala essential oil compositions and their biological activities.;In conclusion, through international collaboration, this project was undertaken with the single goal of identifying potential biologically active essential oils in Nepalese plants. However, our efforts have also translated into a wider understanding of chemodiversity and species differentiation. Through our research, we believe that the Himalayan range has the potential to be one of the most important sources for alternate natural medicine.