Studies on the Steroidal Natural Products from Formosan Gorgonian Isis hippuris
Several terpenoids isolated from a Formosan gorgonian coral Isis hippuris have shown significant cytotoxic activity against various cancer cell lines. In our studies, the EtOAc and n-Hexane extracts showed potent cytotoxic response toward P-388, A549 and HT-29 cancer cell lines. In order to search other active components, we have studied the chemical constituents of I. hippuris from a Green Island specimen. Thus, the investigation on the chemical content of this extract was carried out.
After our hard working, we haved isolated eleven new steroids (1- 11) , A-nor-2-carboxy-22-epi-hippurin-1 (1)¡B2a-acetoxy-3a-hydroxy- 11b-hydroxy-24-methyl-22,25-epoxy-5a-furostan-18,20b-lactone (2)¡B2a,3a-dihydroxy-11b-hydroxy-24-methyl-22,25-epoxy-5a-furostan-18,20b-lactone (3)¡B2a-hydroxy-3a-acetoxy-11b-hydroxy-24-methyl-22, 25-epoxy-5a-furostan-18,20b-lactone (4)¡B2a-hydroxy-3a-acetoxy-24- methyl-11b,18;18,20b;22,25-triepoxy-5a-furostane (5)¡B2a-acetoxy- 3a-hydroxy-24-methyl-11b,18;18,20b;22,25-triepoxy-5a-furostane (6)¡Bhippuristerone K (7)¡Bhippuristerone L (8)¡B hippuristerol F (9)¡B1a, 3b,5b,11a-tetrahydroxy gorgostan-6-one (10)¡B22-epi-hippuristan-11-one (11). We also isolated two known compounds, 22-epi- hippuristanol (19)¡B 2-desacetyl-22-epi-hippurin-1 (25).
The structures of new compounds (1-11) were elucidated by spectroscopic evidences (IR, MS, 1D NMR, 2D NMR) and the comparison of literature. Among those, the stereochemistry of compound 1, with a new skeleton, were confirmed by single-crystal X-ray diffraction analyses. Unfortunately, because of the poor yield, the cytotoxicity test can not be carry out. But now, we try to get enough by semisynthesis.
Advisor:Jyh-Horng Sheu; Yang-Chang Wu; Chang-Yih Duh
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:spiroketal steroids isis hippuris new skeleton steroid
Date of Publication:07/23/2003