Molecular structures of the briantheins, new insecticidal diterpenes from Briareum polyanthes

Grode, Stephen H.; James, Thomas R.; Cardellina, John H.; Onan, Kay D.

doi:10.1021/jo00174a010

Cited by 70 publications

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“…These are data derived from comparing peak retention times on an HPLC. With the exception of the briarane diterpenoid brianthein Y (Grode et al 1983), the major metabolites observed were unreported briarane, asbestinane and in one case, A-4, eunicellane diterpenoids. For the purpose of this study it was impractical to comprehensively assign the structures of all metabolites observed.…”

Section: Resultsmentioning

confidence: 84%

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Local and geographic variation in the defensive chemistry of a West Indian gorgonian coral (Briareum asbestinum)

Harvell¹,

Fenical²,

Roussis³

et al. 1993

Mar. Ecol. Prog. Ser.

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We sampled the between-colony and between-habitat variation in defensive chemistry of colonies of Briareum asbestinum, one of the most ubiquitous and chemically deterrent of the West Indian gorgonians. The basis of deterrence appears to reside in a diverse complement of 5 to 15 briarane and asbestinane diterpenoids found in individual colonies. Variation in chemistry of colonies is extensive throughout the Bahamas and the Virgin Islands: the complement of compounds is slightly different a t each site in the Bahamas and colonies from all the Bahamian sites are distinct from those a t the St. Croix (US Virgin Islands) site. St. Croix colonies not only differ in their composition of compounds, but also have fewer major diterpenoids than colonies from shallow water sites in the Bahamas. The shallow St. Croix extracts also differ in being dominated by asbestinanes instead of briaranes as in the Bahamas. The qualitative chemistry of colonies also vanes locally between depths near San Salvador and Chub Cay, 2 islands in the Bahamas. At both sites, the ratio of briarane to asbestinane diterpenoids was higher in shallow (1 to 12 m) water colonles than In deeper ones (25 to 40 m). To determine whether the qualitative differences in chemistry between depths could be induced or were fixed, colonies were transplanted from shallow to deep reefs in San Salvador. After 7 mo, newly grown tlssue from transplanted colonies still retained the same shallow water diterpenes. This experiment suggests that the qualitative differences in chemistry observed with depth are fixed in adult colon~es. We also sampled quantitative variation in colonies from St. Croix and the Bahamas. Although we expected higher levels of compounds in shallow colonies because both productivity and numbers of predators are higher in shallow waters, at both sites levels of compounds were higher in deeper waters Briareum asbestinum is unusual in being heavily invested with a diversity of extremely deterrent diterpenoids. The outstanding feature of this chemical defense system is the qualitative variation In the chen~lstry of colonies from different habitats, which appears to be genetically fixed, raising the question of what selective agents maintain the variation in chemistry among different habitats

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Section: Resultsmentioning

confidence: 84%

“…The structure assignments of the purified briarane and asbestinane diterpenoids were accomplished by combined spectral methods involving mainly 'H and I3C NMR methods. In one case, a major compound was Identified as brianthein Y by comparison of NMR spectral data with those appearing in the literature (Grode et al 1983).…”

Section: Methodsmentioning

confidence: 99%

Local and geographic variation in the defensive chemistry of a West Indian gorgonian coral (Briareum asbestinum)

Harvell¹,

Fenical²,

Roussis³

et al. 1993

Mar. Ecol. Prog. Ser.

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“…The freeze-dried sample was kept in the refrigerator at 4°C until needed. About 6 grams of the freeze-dried sample was reserved whilst the remaining was subjected to the solvent partitioning protocol as previously described [8,9]. …”

Section: Methodsmentioning

confidence: 99%

In vitro antimicrobial activity of ethanolic fractions of Cryptolepis sanguinolenta

Mills-Robertson¹,

Tay

Duker-Eshun³

et al. 2012

Ann Clin Microbiol Antimicrob

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BackgroundFollowing claims that some plants have antimicrobial activities against infectious microbes, the in vitro antimicrobial activities of different solvent fractions of ethanolic extract of Cryptolepis sanguinolenta were evaluated against eight standard bacteria and clinical isolates.MethodsThe solvent partitioning protocol involving ethanol, petroleum ether, chloroform, ethyl acetate and water, was used to extract various fractions of dried pulverized Cryptolepis sanguinolenta roots. Qualitative phyto-constituents screening was performed on the ethanol extract, chloroform fraction and the water fraction. The Kirby Bauer disk diffusion method was employed to ascertain the antibiogram of the test organisms while the agar diffusion method was used to investigate the antimicrobial properties of the crude plant extracts. The microplate dilution method aided in finding the MICs while the MBCs were obtained by the method of Nester and friends. The SPSS 16.0 version was used to analyze the percentages of inhibitions and bactericidal activities.ResultsThe phytochemical screening revealed the presence of alkaloids, reducing sugars, polyuronides, anthocyanosides and triterpenes. The ethanol extract inhibited 5 out of 8 (62.5%) of the standard organisms and 6 out of 8 (75%) clinical isolates. The petroleum ether fraction inhibited 4 out of 8 (50%) of the standard microbes and 1 out of 8 (12.5%) clinical isolates. It was also observed that the chloroform fraction inhibited the growth of all the organisms (100%). Average inhibition zones of 14.0 ± 1.0 mm to 24.67 ± 0.58 mm was seen in the ethyl acetate fraction which halted the growth of 3 (37.5%) of the standard organisms. Inhibition of 7 (87.5%) of standard strains and 6 (75%) of clinical isolates were observed in the water fraction. The chloroform fraction exhibited bactericidal activity against all the test organisms while the remaining fractions showed varying degrees of bacteriostatic activity.ConclusionThe study confirmed that fractions of Cryptolepis sanguinolenta have antimicrobial activity. The chloroform fraction had the highest activity, followed by water, ethanol, petroleum ether and ethyl acetate respectively. Only the chloroform fraction exhibited bactericidal activity and further investigations are needed to ascertain its safety and prospects of drug development.

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“…[34][35][36] Our study also showed that the changes in configurations of the 10-membered ring unit will cause the coupling constant between H-9 and H-10 to change significantly, even if the C-11 remains unchanged as the present compound 1 (Jϭ0 Hz). 36) In the biological activity testing, briaexcavatin P (4) was found to show a 14.99% inhibitory effect on superoxide anion generation by human neutrophils at 10 mg/ml.…”

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confidence: 54%

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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Molecular structures of the briantheins, new insecticidal diterpenes from Briareum polyanthes

Cited by 70 publications

References 0 publications

Local and geographic variation in the defensive chemistry of a West Indian gorgonian coral (Briareum asbestinum)

Local and geographic variation in the defensive chemistry of a West Indian gorgonian coral (Briareum asbestinum)

In vitro antimicrobial activity of ethanolic fractions of Cryptolepis sanguinolenta

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

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