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Studies on Secondary Metabolites from Soft Coral Lobophytum crassumLin, Shih-tseng 23 August 2010 (has links)
We have investigated the chemical constituents of the organic extracts of soft
coral Lobophytum crassum, collected at Dongsha Atoll. This study has led to the
isolation of eight new compounds, including six cembrane-type diterpenoids 1-6
and two a-tocopherol-type compounds 7 and 8 The chemical structures of
compounds 1-8 were elucidated by extensive analysis of 1D, 2D NMR
spectroscopic data (1H and 13C NMR¡B1H-1H COSY¡BHSQC¡BHMBC¡BNOESY),
UV, IR, CD and MS. Compounds 1 and 6 possess unprecedented diterpenoid
skeletons. The absolute configurations of compound 1 were determined using a
modified Mosher¡¦s method.
Compounds 1-8 were tested against A-549 (human lung epithelial
carcinoma)¡BHT-29 (human colon adenocarcinoma)¡BP-388 (mouse lymphocytic
leukemia) tumor cell lines. Compounds 1, 7, and 8 displayed modest cytotoxicity
against P-388 cell line with ED50 values of 3.2, 3.2, and 2.7 £gg/mL, respectively.
Compound 8 exhibited marginal cytotoxicity against H-29 cell line with an ED50
value of 3.9 £gg/mL.
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Studies on the Natural Products from the Soft Corals Sinularia lochmodes¡BSinularia nanolobata¡BSinularia grandilobata¡BSinularia depressa and Lobophytum crassumTseng, Yen-Ju 07 September 2010 (has links)
In order to search for bioactive compounds, we have studied the chemical constituents from the organic extracts of five soft corals including Sinularia lochmodes, Sinularia nanolobata, Sinularia grandilobata, Sinularia depressa and Lobophytum crassum. This study had led to the isolation of eighteen natural compounds 1¡Ð18, including seven new compounds, lochmolins A ¡Ð G (1 ¡Ð 7) from S. lochmodes, a new compound nanolobatolide (8) featuring with a new carbon skeleton from S. nanolobata, two new compounds grandilobatin G (9) and sinugrandisterol E (10) from S. grandilobata, a new compound depressoloide A (11) and a known compound sarcophytol L (12) from S.depressa, and three new compounds crassumolides G¡ÐI (13¡Ð15) along with three known compounds durmolides B and C (16 and 17) and
sinularolide C (18) from L. crassum. The structures of compounds 1¡Ð18 were established by detailed spectral data analysis (IR, MS, 1D & 2D NMR) and by comparison with the spectral data of the related known compounds. The relative stereochemistries of compound 8 was further confirmed by X-ray single-crystal diffraction analysis.
Among them, compounds 13¡Ð15 and 16¡Ð17 were found to show significant activity against the accumulation of the pro-inflammatory iNOS and COX-2 proteins at 10 £gM.
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Studies on the Secondary Metabolites from the Soft Corals Nephthea erecta, Lobophytum durum, and Sarcophyton ehrenbergiCheng, Shi-Yie 02 March 2009 (has links)
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.
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Isolation and Biological Activities of Secondary Metabolities from the Soft Coral Lobophytum sarcophytoidesLin, You-Cheng 08 September 2009 (has links)
Investigation on the chemical constituents of the EtOH extract of the soft coral Lobophytum sarcophytoides, collected off the coast of Dongsha Atoll, Taiwan, has led to the isolation of ten natural compounds 1¡V10, including four new cembrane-type diterpenoids, Sarcophytolins A¡VD (1¡V4) and one new polyhydroxylated steroid 23, 24-Dimethyl-cholesta-5, 16-diene-3£], 20£\-diol (5) along with five know compounds 6¡V10¡CThe structure of compounds 1¡V10 were established by detailed spectral data analysis (IR, MS, 1D, 2D NMR) and by comparison of the spectral data with those of the related known compounds. The relative stereochemistries of compound 5 was further confirmed by X-ray single-crystal diffraction analysis.
The cytotoxicity of compounds 1¡V10 against the Daoy (human medulloblastoma), Hep-2 (human laryngeal carcinoma), MCF-7 (human breast adenocarcinoma), CCRF-CEM (human T-cell acute lymphoblastic leukemia), and DLD-1/WiDr (human colon adenocarcinoma) tumor cell lines were determined. Compounds 6, 8, 9, and 10 exhibited moderate cytotoxicities against the tested tumor cells. Furthermore, compounds 1, 2, 4, 6, and 10 were found to show significant activity against the accumulation of the pro-inflammatory iNOS protein at 10 £gM.
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Studies on the Secondary Metabolites from the Soft Coral Lobophytum durumChen, Hwa-Pyng 21 June 2011 (has links)
Soft corals of the genus Lobophytum (Alcyoniidae) have been well recognized as a rich source of various secondary metabolites that have attracted much interest for the natural products chemists due to their structural complexity and remarkable pharmacological activities such as cytotoxicity, antibacterial activities, anti-inflammatory properties, and antiviral activity. Twelve cembrane diterpenes including six new secondary metabolites 1−6 were isolated organic extracts of soft coral Lobophytum durum collected at Dongsha Atolls. The structures of these six new cembranolides were determined by 1H, 13C, DEPT, COSY, HMBC, HSQC, NOESY, IR and Mass spectra. Furthermore, these six new secondary metabolites 1−6 were evaluated in vitro for the cytotoxicity against A-459 (human lung carcinoma), HT-29 (human colon adenocarcinoma), and P-388 (mouse lymphocytic leukemia) cancer cell lines, and antiviral activity against HCMV (human cytomegalovirus) cells.
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Study on the Natural Products from Two Formosan Soft Corals Lobophytum crassum and Dendronephthya griffini and the Chemical Modifications of LobohedleolideChao, Chih-Hua 25 August 2007 (has links)
Marine invertebrate have been found to be a rich source of bioactive secondary metabolites. During the course of our investigation on the bioactive chemical constituents from marine invertebrates, twenty-eight metabolites have been isolated from two soft coral Lobophytum crassum and Dendronephthya griffini. Investigation on L. crassum has led to the isolation of fourteen compounds, including seven new cembranoids, crassumolides A¡VG (1¡V7), and three new glycolipids (2R)-1-hydroxy -3-hexadecyloxy-propyl-£]-D-arabinopyranoside (8), (2R)-1-hydroxy-3- octadecyloxy-propyl-£]-D-arabinopyranoside (9), and (2R)-1-acetoxy-3- hexadecyloxy-propyl-£]-D-arabino-pyranoside (10), coupled with four known compounds, lobohedleolide (11), 17-dimethylaminolobohedleolide (12), sinulariol A (13), and denticulatolide (14). Ten new steroids, griffinisterones A¡VJ (15¡V24), were isolated from the soft coral D. griffini, while a known, 15-chlorogriffinsulfate (25), and three new polychlorinated acyclic compounds¡Agriffinsulfate (26), 15-chlorogriffinol (27), and griffinol (28), were also purified from the same organism. Structures of these metabolites were identified as new natural products by extensive spectroscopic methods. Except for the use of 2D NMR, the 24-epimers of 15 and 16 were identified by a single-crystal X-ray crystallography on 15.
Lobohedleolide (11), obtained in large quantity in L. crassum, has also been modified to 29¡V34 by chemical conversion. Oxidation with meta-chloro-peroxybenzoic acid (MCPBA) afforded compounds 29 and 30, and with selenium dioxide led to the formation of 31. Compound 34 is the product of O-coupling reaction of 11 with 1-hydroxybenzotriazole (HOBt). Over 99¢Mdiastereoselectivity was observed in the process of Henbest hydroxyl-directed epoxidation on 11 to yield 32. EDC-coupling with an aid of HCl salt of DMAP afforded methylester 33 in high yield, and proved the absolute stereochemistry of 3. The cytotoxicity and anti-inflammatory activities of the natural and modified compounds were also discussed herein.
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Genomic Analyses of the Complete Mitochondrial DNA Sequences of Five Alcyonacea CoralsChen, Chun-ting 29 August 2007 (has links)
Corals are the dominant species of the coral reefs. The diversity of species is classified by traditional morphological traits, especially relied on the calcious deposits-sclerites. The formation of sclerites may be affected by the environmental conditions; therefore, some controversies may exist. The ambiguities may be clarified with molecular approaches. Five soft coral species, Lobophytum pauciflorum, Sinularia leptoclado, Sinularia flexibilis, Sarcophyton sp., Nephthea erecta were chosen for this study. The total mitochondrial DNA sequences were determined by PCR and primer walking. The genome contains 18562 bp, 18732 bp, 18752 bp, 18806 bp, 18716 bp separately, which harbors 14 protein-coding genes (ATP6¡BATP8¡BCOI¡BCOII¡BCOIIII¡BCYTB¡BND1¡BND2¡BND3¡BND4¡BND4L¡BND5¡BND6¡BMSH), 2 rRNA and only 1 tRNA genes. The phylogenetic relationship of alcyonacea corals were analyzed and compared with published sequences. The possibility of using a short ¡§DNA bar-code sequence¡¨ of the mitochondria as an alternative for species identification may be feasible. We found the short DNA signature sequences for these five corals. They may speed up the identification of corals in the long run.
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