Complete 1H and 13C NMR assignments of three new polyhydroxylated sterols from the South China Sea gorgonian Subergorgia suberosa

Three new polyhydroxylated sterols, 3beta,6alpha,11,20beta,24-pentahydroxy- 9,11-seco-5alpha-24-ethylcholest-7,28-diene-9-one (1), 3-(1',2'-ethandiol)-24- methylcholest-8(9),22E-diene-3beta,5alpha,6alpha,7alpha,11alpha-pentaol (2), 24-methylcholest-7,22 E-diene-3beta,5alpha,6beta,25-tetraol (3) together with five known sterols, were isolated from the EtOH/CH2Cl2 extract of the South China Sea gorgonian Subergorgia suberosa. The complete assignments of the 1H and 13C NMR chemical shifts for these new compounds were achieved by means of 1D and 2D NMR techniques, including HSQC, HMBC, 1H--1H COSY, and NOESY spectra.     

Juncenolides F and G, two new briarane diterpenoids from Taiwanese gorgonian Junceella juncea

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.     

Suberoretisteroids A–E,Five New Uncommon Polyoxygenated Steroid 24‐Ketals from the Hainan Gorgonian Suberogorgia reticulata

Five new uncommon polyoxygenated steroids, namely suberoretisteroids A–E ( 1 – 5 ), were isolated from the gorgonian Suberogorgia reticulata, never studied so far. The structures and relative configurations of these new compounds were elucidated on the basis of extensive spectral analysis. This work led to the structural revision of some steroids previously found in the Indian gorgonian Gorgonella umbraculum.     

Junceols D-H, new polyoxygenated briaranes from sea whip gorgonian coral Junceella juncea (Ellisellidae)

Chemical investigations on the sea whip gorgonian coral Junceella juncea have led to the isolation of five new 8-hydroxybriarane diterpenoids, junceols D-H (1-5). The structures of briaranes 1-5 were determined on the basis of spectroscopic methods and the methylenecyclohexane rings were found to exist in boat form in these new diterpenoids. Junceols D (1) and F-H (3-5) exhibited cytotoxicity toward CCRF-CEM and DLD-1 tumor cells and junceols E-H (2-5) displayed weak inhibitory effects on superoxide anion generation by human neutrophils.     

Juncenolides H – K,New Briarane Diterpenoids from Junceella juncea

Chemical investigation of the Taiwanese gorgonian coral Junceella juncea resulted in the isolation of four new briarane‐type diterpenoids, juncenolides H, I, J, and K ( 1 – 4 ). Their structures were determined on the basis of spectroscopic analysis, especially 1‐ and 2D‐NMR. The inhibitory effects of compounds 1 – 4 on superoxide‐anion generation and elastase release by human neutrophils were evaluated.     

Chemical constituents of the Gorgonian Dichotella fragilis (Ridleg) from the South China Sea

Two new steroidal glycosides, fragilioside A (1) and fragilioside B (2), along with five known compounds (3-7) were isolated from the gorgonian Dichotella fragilis (Ridleg) collected from the South China Sea. The structures of the new compounds (1 and 2) were elucidated by comprehensive analysis of spectral data, especially 2D NMR. The brine shrimp lethality and antifouling activity of the isolated compounds were also evaluated.     

Study on the chemical constituents of the South China Sea gorgonian Junceella juncea

A new steroidal glycoside--4'-O-acetyl-3-O-[beta-D-arabino-pyranosyl-oxy]-cholest-5-ene-3beta,19-diol (1), and a new glycerol derivative--1,2-O-[2'-hydroxyoctadecyl]-glycerol (2), along with 16 known compounds were isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian coral Junceella juncea. The structures of 1 and 2 were established by extensive spectroscopic analysis, including 1D and 2D NMR data.     

Rumphellolides A-F, six new caryophyllane-related derivatives from the Formosan Gorgonian coral Rumphella antipathies

Six new caryophyllane-related natural products, including two carboxylated sesquiterpenoids, rumphellolides A (1) and B (2), and four norsesquiterpene alcohols, rumphellolides C-F (3-6), were isolated from the Formosan gorgonian coral Rumphella antipathies. The structures of the above new natural products were established on the basis of extensive spectral data analysis. Rumphellolides A (1), D (4), E (5), and F (6) showed weak antibacterial activity.     

Three New Polyoxygenated Steroids from Two Species of the South China Sea Gorgonian Muricella flexuosa and Menella verrucosa Brundin

Three new polyoxygenated steroids, muricesteroid ( 1 ), and menellsteroids A ( 2 ) and B ( 3 ), were isolated from two species of the South China Sea gorgonian Muricella flexuosa and Menella verrucosa Brundin , respectively. The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis, chemical methods and comparison with known related compounds.     

Junceellonoids A and B,Two New Briarane Diterpenoids from the Chinese Gorgonian Junceella fragilis Ridley

Two new diterpenoids, junceellonoids A and B ( 1 and 2 , resp.), together with the seven known diterpenoids 3 – 9 , all possessing the briarane carbon skeleton, were isolated from the gorgonian Junceella fragilis Ridley , collected in the South Sea of China. The structures and relative configurations of the new metabolites were elucidated based on extensive spectral analysis and by comparison with known spectral data.     

Purine and pyrimidine derivatives from the South China Sea gorgonian Subergorgia suberosa

Three new purine derivatives, namely, 4-caryboxy-5,6-dihydro-4H,8H-pyrimido[1,2,3-cd]purine-8,10(9H)-dione (1), 7,9-dihydro-1-(3-oxobutyl)-1H-purine-6,8-dione (2), and 7-hydro-9-(3-oxobutyl)-1H-purine-6,8-dione (3) together with six known purine and pyrimidine derivatives were isolated from the EtOH/CH(2)Cl(2) extracts of the South China Sea gorgonian Subergorgia suberosa. The structures of 1-3 were determined on the bases of extensive spectroscopic analysis, including 1D and 2D NMR data.     

A new sphingolipid from the gorgonian Junceella juncea of the Indian Ocean

A new sphingolipid, (2S,3R,4E)-1,3-dihydroxy-2-[(nonadecanoyl) amino]-octadec-4-ene (1) along with ubiquitous batyl alcohol is isolated from the gorgonian, Junceella juncea Pallas (Gorgonaceae) of the Indian Ocean. The structure of 1 is determined on the basis of 1H- and 13C-NMR, COSY, FABMS, and GC-EIMS experiments.     

Cyclobutenbriarein A,the first diterpene with a tricyclo[8.4.0.0(3,6)]tetradec-4-ene ring system isolated from the Gorgonian Briareum asbestinum

Cyclobutenbriarein A (2), a novel class of C20-rearranged diterpene briarane possessing an unprecedented tricyclo[8.4.0.0(3,6)]tetradec-4-ene ring system was isolated, along with five new briarane diterpenoids (1 and 3-6), from the organic extracts of the Bahamian gorgonian Briareum asbestinum. The structures of these secondary metabolites were established on the basis of extensive NMR studies and accurate mass measurements (HRFABMS).     

Abietanes and a Novel 20‐Norabietanoid from Plectranthus cyaneus (Lamiaceae)

Antioxidative‐activity‐guided fractionation of extracts of the aerial parts of the title plant yielded the two novel abietanoid diterpenoids 11,20‐dihydroxysugiol (=11,12,20‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 3 ) and 1,11‐epoxy‐6,12‐dihydroxy‐20‐norabieta‐1(10),5,8,11,13‐pentaen‐7‐one ( 4 ) in addition to 11‐hydroxysugiol (=12‐O‐demethylcryptojaponol=11,12‐dihydroxyabieta‐8,11,13‐trien‐7‐one; 2 ) and the main constituent carnosolon (=6,20‐epoxy‐6,11,12‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 1 ). The structures were established on the basis of spectroscopic, chiroptic, and X‐ray crystallographic evidence.     

Briarane derivatives from the gorgonian coral Junceella fragilis

A new trihydroxyl briarane-type diterpenoid, junceellolide H (1), along with two known compounds, praelolide (2) and junceellin (3), have been isolated from the gorgonian coral Junceella fragilis. The structure, including the relative configuration of the new diterpenoid 1, was elucidated by extensive spectroscopic methods.     

Complete 1H and 13C NMR assignments of four new steroidal glycosides from a gorgonian coral Junceella juncea

Four new cholest-type steroidal glycosides, junceellosides A-D, isolated from the EtOH/CH(2)Cl(2) extracts of the South China Sea gorgonian coral Junceella juncea, were identified. Complete assignments of the (1)H and (13)C NMR chemical shifts for these compounds were achieved by means of one- and two-dimensional NMR techniques, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectra.     

Antifouling and antibacterial compounds from the gorgonians Subergorgia suberosa and Scripearia gracillis

In this study, we investigated the potential antilarval and antibacterial activity of secondary metabolites of the gorgonians Subergorgia suberosa and Scripearia gracillis from the South China Sea. Fresh specimens of these two gorgonian corals were collected from a shallow reef in Sanya Bay of Hainan Island and extracted with different solvents. Antilarval activity of the chemical extracts and pure compounds was evaluated in settlement inhibition assays with laboratory-reared Balanus amphitrite and Bugula neritina larvae, while antibacterial activity was assessed with disc diffusion bioassay on growth inhibition of 15 marine bacterial species. Using bioassay-guided procedures, we purified and identified nine compounds. The most potent metabolites produced by these gorgonian corals were subergorgic acid and pregn-4-ene-3, 20-dione extracted from S. suberosa. Our results show that the gorgonian coral S. suberosa and S. gracillis can produce potent anti-fouling compounds that deserve further exploration.     

Models for Taxol Biosynthesis: SeO2 Oxidation of Taxadiene

Together with the expected mono‐oxidized taxa‐4(20),11(12)‐diene‐5‐ol (1) and taxa‐4(5),11,20‐diene‐20‐ol (2), a new taxane skeleton, 3,12‐cyclotaxane (3), was obtained from chemical oxidation of taxadiene by selenium dioxide/t‐butylhydroperoxide.     

Subergane‐Type Sesquiterpenes from Gorgonian Coral Subergorgia suberosa with Antibacterial Activities

A new subergane‐type sesquiterpene, named epoxysubergorgic acid ( 1 ), along with seven known sesquiterpenes, were isolated from the gorgonian coral Subergorgia suberosa. The structure of the new compound was determined by extensive spectroscopic analyses. The previously uncertain absolute configuration of the known analogues 2 – 6 was determined on the basis of CD, Mosher's method, and through chemical conversions. All compounds were evaluated for antibacterial activities.     

南海中华小尖柳珊瑚Muricella sinensis化学成分的研究

从采自中国南海的中华小尖柳珊瑚(Muricella sinensis)中分离得到了1个新的Eunicellane型二萜, 命名为sinensin (1), 和6个已知化合物: 13-去乙酰氧基calicophirin B (2), calicophirin B (3), calicophirin C (4), astrogorgin (5), calicoferol E (6)和calicoferol B (7), 这些化合物的结构是经波谱学实验(1H NMR, 13C NMR, HMQC, HMBC, COSY和NOESY)并与文献报道的数据对照而确定的.