UBC Theses and Dissertations
Biologically active natural products from terrestrial and marine environments Wang, Meng
Natural products are one of the most important resources for the discovery and development of new pharmaceuticals. Organisms from different terrestrial and marine environments produce secondary metabolites with unique biological activities that could be utilized by humans medicinally and in other ways. In an effort to search for new potential lead compounds, we use bioassay-guided fractionation and structure elucidation tools to identify new biologically active natural products. The work presented in Chapters 2 and 3 is in an effort to search for new small molecules that activate HIV-1 provirus expression. Novel sesterterpenoids alotaketals C−E (3.7−3.9), phorbadione (3.10), ansellones D−N (3.11−3.21), anvilones A and B (3.22 and 3.23) and phorone C (3.24), along with the known sesterterpenoids ansellones A−C (2.86−2.88), were isolated from a Phorbas sp. sponge collected in Howe Sound, British Columbia. The isolation and structure elucidations of these novel sesterterpenoids are presented. These compounds are a family of highly functionalized sesterterpenoids that have the alotane, ansellane, anvilane and phorane carbon skeletons. The unique ansellane and anvilane carbon skeletons have so far only been found in this particular sponge Phorbas sp. Several classes of natural products produced by this genus of sponge are reviewed. These sesterterpenoids are able to activate HIV-1 provirus expression. The most active analog, alotaketal C (3.9) showed 13.8 % activation of HIV-1 provirus expression at a concentration of 30 μM. Chapter 4 describes the identification of two anti-onchocerciasis natural products isolated from the extracts of traditional medicinal plants. Lantadene A (4.4) and morindicinone (4.5) were isolated from the extracts of Lantata camara and Morinda lucida, respectively. The filaricidal properties of lantadene A (4.4) and morindicinone (4.5) were investigated using an in vitro anti-Onchocerca assay.
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