New Polyoxygenated Briarane Diterpenoids, Briaexcavatolides O−R, from the Gorgonian <i>Briareum excavatum</i>

Wu, Shwu-Li; Sung, Ping‐Jyun; Chiang, Michael Y.; Wu, Jing‐Yun; Sheu, Jyh‐Horng

doi:10.1021/np010253l

Cited by 44 publications

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References 12 publications

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“…The molecular formula of C 28 Tables 1, 2) and 2D-NMR (Fig. 7, Table 3) data of 4 were similar to those of a known briarane derivative, briaexcavatolide P (7), 33) except that the signals corresponding to a butyryloxy group in 7 were replaced by signals for an acetoxy group in 4. The correlations from a NOESY experiment of 4 ( Fig.…”

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confidence: 56%

“…Thus, the remaining hydroxy groups had to be positioned at C-12 and C-14 by the key 1 H-1 H COSY correlations and characteristic NMR signal analysis. The relative stereochemistry of 3 was confirmed as being similar to that of a known metabolite, briaexcavatolide P (7), 33) by comparison of the NMR chemical shifts and coupling constant analysis for the chiral centers. In the NOESY experiment of 3 (Fig.…”

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confidence: 76%

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Briaexcavatins M-P, Four New Briarane-Related Diterpenoids from Cultured Octocoral Briareum excavatum (Briareidae)

et al. 2008

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Gorgonian corals are recognized as rich sources of diterpenoid derivatives with the well-known briarane carbon skeleton, a group of diterpenoids having a highly oxidized bicyclo [8.4.0] system with a g-lactone group. Compounds of this type exist only in marine organisms, particularly in octocorals.1,2) In our screening for novel natural products from the marine invertebrates collected in Taiwanese waters, we have discovered a series of terpenoid and steroid metabolites from the octocorals Alcyonium sp., 3,4) Briareum sp., 5)Briareum excavatum, 6-10) Ellisella robusta, [11][12][13][14] Junceella fragilis, 10,[15][16][17][18][19][20][21][22] Junceella juncea, 17,23) Rumphella antipathies, [24][25][26][27][28] and the tunicate Eudistoma sp. 29); and some of these metabolites have been reported to exhibit interesting biological activity such as anti-inflammatory, 8,9,20,22) cytotoxicity, 8,29) and antibacterial activity. 11,24,26,27) In this paper, we describe the isolation and structure determination of four new briarane-type diterpenoids, briaexcavatins M-P (1-4), from the cultured octocoral Briareum excavatum (Briareidae). The structures of briaranes 1-4 were established by spectroscopic methods. Results and DiscussionSpecimens of the octocoral B. excavatum, collected from the culturing tank in the National Museum of Marine Biology and Aquarium (NMMBA), Taiwan, were minced and extracted with a mixture of MeOH and CH 2 Cl 2 (1 : 1). The extract was further partitioned with EtOAc and H 2 O. The EtOAc layer was successively subjected to silica gel gravity column chromatography and re-purified by normal phase HPLC guided by the signals for the interesting structures found in the proton NMR experiments to afford briaranes 1-4 (see Experimental).Briaexcavatin M (1) . Thus, from the above NMR data, six degrees of unsaturation were accounted for, and compound 1 must be tetracyclic. The presence of a tetrasubstituted epoxide containing a methyl substituent was elucidated from the signals of two oxygenated quaternary carbons at d C 68.2 (s, C-8) and 63.1 (s, C-17), and further confirmed by the proton signal of a methyl singlet resonating at d H 1.57 (3H, s, H 3 -18) ( Four new briarane-related diterpenoids, designated as briaexcavatins M-P (1-4), were isolated from the cultured octocoral Briareum excavatum. The structures, including the relative configurations of natural products 1-4 were established on the basis of extensive spectral data analysis and by comparison with the spectral data from other known metabolites featuring a briarane carbon skeleton.

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Briaexcavatins M-P, Four New Briarane-Related Diterpenoids from Cultured Octocoral Briareum excavatum (Briareidae)

et al. 2008

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“…1), the cembrane group (Fig. 2), as well as some meroditerpenoid-related metabolites (275)(276)(277)(278)(279)(280)(281)(282)(283) from Nephthea chabroli [138]. Dolabellane diterpenoids were discovered in two species of the genus Clavularia.…”

Section: Coelenteratesmentioning

confidence: 99%

“…Five briarane analogues, brianthein W (627), 9-deacetylbriareolide H (628), 2β-acetoxy-2-(debutyryloxy) stecholide E (629), 9-deacetylstylatulide lactone (630), and 4β-acetoxy-9-deacetylstylatulide lactone (631) [274], were isolated from an unidentified species of the genus Briareum which is known for generating the first briarane diterpenoid, briarein A [275]. Extensive chemical investigation on B. excavatum resulted in the isolation of a large group of briaranes, namely the excavatolides A-M (632-644) [276,277] and U-Z (645-650) [278], the briaexcavatolides A-Z (651-676) [279][280][281][282][283][284], as well as the brianolides 677 and 678 [276,280]. The natural briarane diterpenoids are commonly cytotoxic compounds.…”

Section: Gorgoniansmentioning

confidence: 99%

Secondary Metabolites from the South China Sea Invertebrates: Chemistry and Biological Activity

Zhang

Guo²,

Gu³

2006

CMC

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The increasing demand for new lead compounds in the pharmaceutical and agrochemical industries has driven scientists to search for new sources of bioactive natural products. Marine invertebrates are a rich source of novel, bioactive secondary metabolites and they have attracted a great deal of attention from scientists in the fields of chemistry, pharmacology, ecology, and molecular biology. During the past 25 years, many complex and structurally unique secondary metabolites have been isolated from the invertebrates inhabiting the South China Sea. These metabolites are responsible for various bioactivities such as anti-tumor, anti-inflammation and antioxidant activities, and/or they act on the cardiovascular system. This review will focus on the marine natural product chemistry of invertebrates from the South China Sea, aiming to give the reader a brief view of the compounds isolated from these invertebrates, as well as their biological activities. The article covers the literature published during the period from the beginning of 1980 to the end of 2005, with 340 citations and 811 compounds from invertebrates from the South China Sea, including sponges, coelenterates, molluscs and echinoderms.

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“…1,2) The majority of these compounds are endowed with biological activities that ranges from cytotoxic [3][4][5] to anti-inflammatory, 6,7) immunomodulatory, 8) antiviral, 9) and insecticidal 10,11) actions. In continuation of our interest in the chemistry and potential medicinal importance of briaranes, [12][13][14] we investigated the gorgonian octocoral Junceella juncea collected in Taiwan.…”

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Juncenolides F and G, Two New Briarane Diterpenoids from Taiwanese Gorgonian Junceella juncea

Lin

Huang

Khalil

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Briaranes are diterpenoid g-lactones of highly substituted bicyclic six-and ten-membered rings that are extensively produced by marine octocorals including gorgonians.1,2) The majority of these compounds are endowed with biological activities that ranges from cytotoxic [3][4][5] to anti-inflammatory, 6,7) immunomodulatory, 8) antiviral, 9) and insecticidal 10,11) actions. In continuation of our interest in the chemistry and potential medicinal importance of briaranes, [12][13][14] we investigated the gorgonian octocoral Junceella juncea collected in Taiwan. Several juncins, 15,16) gemmacolides, 16) junceelolides 13) and juncenolides 12,14) have been reported from this species. The current study resulted in the isolation of the two novel briarane-type diterpenoidal compounds, juncenolides F (1) and G (2) from the acetone extract of Junceella juncea. The structures were defined on the basis of spectral studies, especially 1D and 2D NMR.The HR-ESI-MS of 1 revealed a quasi-molecular ion peak at m/z 693 [MϩNa] ϩ consistent with the molecular formula C 33 H 47 O 12 Cl and ten degrees of unsaturation. The IR spectrum displayed absorption bands diagnostic of hydroxyl, 5-membered lactone and ester groups. Both 1 H-and 13 C-NMR spectral data (Table 1 15,16) Besides the previous four ester carbonyls, the carbon signal at d 174.5 was assigned to a 5-membered lactone ring together with the oxygenated methine at d 81.2 (C-7). The two proton singlets at d 5.81 and 5.52 along with the CH 2 signal at d 121.2 were ascribed to an exocyclic methylene group. The 1 H-NMR spectrum contained two mutually coupled signals at d 2.82, 2.35 (each 1H, d, Jϭ4.0 Hz) together with the corresponding d C 50.5 (t) and d C 57.4 (s) that were appropriate for an exocyclic epoxide. The two remaining degrees of unsaturation required a bicyclic carbon skeleton which fits a briarane diterpene. ϩ were strong evidence of the presence of a chlorine atom in 1.7) Consequently, the CH signal at d 51.7 was confidently assigned to a chlorinated carbon (C-6) that was correlated to d (Fig. 1). On the other hand, the HMBC displayed correlations between H-10/C-8, C-20; H-7/C-5; H- * To whom correspondence should be addressed. Chemical investigation of the gorgonian coral Junceella juncea collected in Taiwan has resulted in the isolation of the two novel briarane-type diterpenoid compounds, juncenolides F (1) and G (2). The structures were determined on the basis of spectral studies, especially 1D and 2D NMR.

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New Polyoxygenated Briarane Diterpenoids, Briaexcavatolides O−R, from the Gorgonian Briareum excavatum

Cited by 44 publications

References 12 publications

Briaexcavatins M-P, Four New Briarane-Related Diterpenoids from Cultured Octocoral Briareum excavatum (Briareidae)

Briaexcavatins M-P, Four New Briarane-Related Diterpenoids from Cultured Octocoral Briareum excavatum (Briareidae)

Secondary Metabolites from the South China Sea Invertebrates: Chemistry and Biological Activity

Juncenolides F and G, Two New Briarane Diterpenoids from Taiwanese Gorgonian Junceella juncea

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