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Studies on the Secondary Metabolites from the Soft Corals Nephthea erecta, Lobophytum durum, and Sarcophyton ehrenbergi

by Cheng, Shi-Yie

Abstract (Summary)
In order to search for novel bioactive compounds, we have investigated the secondary metabolites of the soft corals Nephthea erecta, Lobophytum durum, and Sarcophyton ehrenbergi. Chemical examinations on the organic extracts of N. erecta, have resulted in the isolation of six new sesquiterpenoids (1-6), a new calamenene-type sesquiterpene with a mercaptan group, erectathiol (7), a new tri-nor-eudesmadienone (8), two known sesquiterpenoids (9 and 10), one novel seco-germacrane sesquiterpene (11), three unexpected artificial 19-oxygenated steroids (12-14), as well as twelve new polyhydroxylated steroids (15-26). Furthermore, twelve new cembranolids, durumolides A-L (27-38), three unprecedented hemiketal cembranoids, durumhemiketalolides A-C (39-41), six previously described cembranolids (42-47), together with one known metabolite, peridinin (48), were isolated from the acetone extracts of L. durum. Chemical investigation of S. ehrenbergi, has led to the isolation of a known ceramide (49), two new cerebrosides, sarcoehrenosides A (50) and B (51), along with three previously characterized cerebrosides (52-54). The structures of the isolated metabolites were elucidated through extensive spectroscopic analyses, while the relative stereochemistry of 10 and 44 were further confirmed by X-ray diffraction analyses. Moreover, the absolute configurations of 24, 25, 29, 34, 38, and 43-45 were established by application of modified Mosher¡¦s method. The cytotoxicities, antibacterial activities, anti-inflammatory effects, and inhibition assay of HCMV (human cytomegalovirus) endonuclease activities of these isolated metabolites were evaluated in vitro.
Bibliographical Information:

Advisor:Ian-Lih Tsai; Ling-Ching Chen; Jyh-Horng Sheu; Ping-Jyun Sung; Chun-Nan Lin; Chang-Yih Duh

School:National Sun Yat-Sen University

School Location:China - Taiwan

Source Type:Master's Thesis

Keywords:nephthea erecta lobophytum durum sarcophyton ehrenbergi

ISBN:

Date of Publication:03/02/2009

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