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Investigations On Bioactive Constituents From Three Marine Organisms And One Terrestrial Higher Plant

Posted on:2006-06-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:S W YinFull Text:PDF
GTID:1100360182472445Subject:Marine biology
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This dissertation describes the isolation, structure elucidation, and bioactivity evaluation of chemical constituents isolated from three marine organisms and one terrestrial higher plant species, that is, soft coral Lobophytum crassum Von Marenzeller, green alga Codium fragile (Suringar) Hariot, red alga Chondria crassicaulis Harv., and higher plant Garuga forrestii W. W. Smith. L. crassum was collected from the coast of Sanya, Hainan province, China. Codium fragile and Chondria crassicaulis were collected along the coast of Qingdao, Shandong province, China, while Garuga forrestii were collected from Yunan province, China. Whole specimen was air-dried, powdered and extracted with EtOH for three times at room temperature (one week for each time). The resulting extractive solution was filtered and evaporated at reduced pressure to give a crude residue, which was then successively partitioned between petroleum ether and methanol, between ethyl acetate and water, and between n-butanol (water saturated) and water, to afford petroleum ether-, EtOAc-, and n-butanol-soluble fractions, respectively. The compounds were isolated by repeated column chromatography (CC) on silica gel, RP-18, and Sephadex LH-20, as well as by preparative thin layer chromatography (PTLC) and recrystallization. The structures of these compounds were elucidated by means of spectroscopic methods including IR, UV, EI-MS, FAB-MS, HR-ESI-MS, 1D-NMR (1H-NMR, 13C-NMR, DEPT and NOEDS) and 2D-NMR (1H-1H COSY, HMBC, HMQC and NOESY). From marine soft coral Lobophytum crassum, thirty compounds were isolated and nineteen of them were structurally elucidated, including a new hydroperoxyl substituted cembranolide diterpene, namely, 2-hydroperoxysarcophine, and two cembranolide diterpene that obtained as natural products for the first time. From Codium fragile, seven compounds including a new clerosterol derivative, trans-phytol, and related metabolites were isolated. From Chondria crassicaulis, ten compounds were isolated, of which one of them are new, and, finally, from Garuga forrestii, a new euphane triterpenoid, a new acylglycosyl steroid, and other ten related chemical constituents were isolated. The cytotoxic and antibacteria bioactivities of some isolated compounds and subfractions were studied. Compounds LC4, LC5, LC6 isolated from L. crassum exhibit cytotoxic activities against SMMC-7721, HMEC, NIH3T3 and A-549 cells. Subfractions C2 from petroleum ether-soluble fractions of Codium fragile showed antibacterial activities against Bacillus subtilis, however, the compound phytyl acetate obtained from the subfractions C2 exhibit no antibacterial activities against Bacillus subtilis at all.
Keywords/Search Tags:Lobophytum crassum, Codium fragile, Chondria crassicaulis, Garuga forrestii, Bioactivity, Chemical constituents, Structure clucidation
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