Gymnoascolides A-C: aromatic butenolides from an Australian isolate of the soil ascomycete Gymnoascus reessii

Three new aromatic butenolides, gymnoascolides A-C (1-3), have been isolated from the Australian soil ascomycete Gymnoascus reessii and assigned structures on the basis of detailed spectroscopic analysis. The absolute configurations of gymnoascolides B (2) and C (3) at C-5 were solved using a combination of chemical derivatization and quantum chemical simulations.     

New lactone-containing metabolites from a marine-derived bacterium of the genus Streptomyces

Six novel metabolites containing a lactone moiety as a common structural feature, along with the previously described (-)-blastmycinolactol, have been isolated from the cultivation broth of a bacterium of the genus Streptomyces isolated from marine sediment. On the basis of the results of combined spectroscopic analysis, the structures of the new compounds have been determined as butenolides and 3-hydroxy-gamma-butyrolactones.     

New butenolides from two marine streptomycetes

Chemical examination of two marine Streptomycetes has resulted in the isolation of four new butenolides, namely 4, 10-dihydroxy-10-methyl-dodec-2-en-1,4-olide (1), two diastereomeric 4,11-dihydroxy-10-methyl-dodec-2-en-1,4-olides (2/3), and 4-hydroxy-10-methyl-11-oxo-dodec-2-en-1,4-olide (4). The structures were identified by interpretation of the 2D NMR and mass spectral data.     

硬棘软珊瑚醋酸乙酯部位的化学成分研究

目的研究硬棘软珊瑚醋酸乙酯部位的化学成分。方法采用正、反相硅胶柱色谱以及半制备高效液相色谱进行分离,并根据理化性质和波谱数据鉴定化合物的结构。结果分离得到11个化合物,其中3个环丁烯内酯类化合物,分别鉴定为（研-13-（2-羟基-3,4-二甲基-5-氧代-2,5-二氢呋喃。2-基）十三烷酸（1）、（S）-11-（2-羟基-3,4-二甲基-5-氧代-2,5-二氢呋喃-2-基）十一烷酸（2）、羟基二氢博伏内酯（3）;1个嘌呤类化合物,鉴定为1,3-二甲基黄嘌呤（4）;7个甾体类化合物,分别鉴定为孕甾-20-烯-3-酮（5）、孕甾-1,4,20-三烯-3-酮（6）、3β-羟基-孕甾-20-烯（7）、3p-羟基-孕甾-5,20-二烯（8）、20-羟基-孕甾-1,4-二烯-3-酮（9）、20-羟基-孕甾-1-烯-3-酮（10）、1713-羟基一雄甾-1-烯-3-酮（11）。结论环丁烯内酯类化合物是首次从该属软珊瑚中分离得到,其中化合物1和2为新化合物,而硬棘软珊瑚醋酸乙酯部位的化学成分主要为甾体类化合物。     

Eutypoids B-E produced by a Penicillium sp. strain from the North Sea

Crude extracts of the Penicillium sp. strain KF620 isolated from the North Sea showed antimicrobial activities against Xanthomonas campestris and Candida glabrata. Purification of the extracts led to the isolation of the new aromatic butenolides eutypoids B (1), C (2), D (3), and E (4). Their structures were elucidated by NMR spectroscopy and supported by HRESIMS and UV data. The antibacterial activity of the crude extracts was due to the presence of the known diketopiperazine fellutanine (cyclo(Trp-Trp)). The eutypoids were neither cytotoxic nor antibacterial, but inhibited the activity of glycogen synthase kinase-3β.     

Marine sesquiterpenoids that inhibit the lyase activity of DNA polymerase beta

Bioassay-directed fractionation of an extract of the marine species Spongia sp. led to the discovery of the new sesquiterpenoid derivative 17-O-isoprenyldictyoceratin-C (1), the known sesquiterpenoid derivative dictyoceratin-C (2), and the sesquiterpenoid quinone ilimaquinone (3), in addition to the nucleoside 2'-deoxyuridine. The structure of the new compound 1 was determined on the basis of spectroscopic methods and by conversion of dictyoceratin-C (2) to 1.     

Novel meroditerpenoid-related metabolites from the formosan soft coral Nephthea chabrolii

Nine new metabolites, including one novel naphthoquinone derivative, chabrolonaphthoquinone A (1), four tetraprenyltoluquinol-related metabolites, chabrolohydroxybenzoquinones A-D (2-5), and four tetraprenyltoluquinone-related compounds, chabrolobenzoquinones A-D (6-9), were isolated from the organic extract of a Taiwanese soft coral, Nephthea chabrolii. The structures of 1-9 were elucidated on the basis of spectral data.     

Diterpenoid acids from Grindelia nana

Two new norditerpenoid acids of the labdane-type (norgrindelic acids), 4,5-dehydro-6-oxo-18-norgrindelic acid (1) and 4beta-hydroxy-6-oxo-19-norgrindelic acid (2), as well as a new grindelic acid derivative, 18-hydroxy-6-oxogrindelic acid (3), were isolated from the aerial parts of Grindelia nana. In addition, the known compounds, 6-oxogrindelic acid, grindelic acid, methyl grindeloate, 7alpha,8alpha-epoxygrindelic acid, and 4alpha-carboxygrindelic acid were also isolated. The structures of the new compounds were characterized on the basis of spectroscopic analysis.     

Three novel C-glycosidic ellagitannins, rhoipteleanins H, I, and J, from rhoiptelea chiliantha

Three novel C-glycosidic ellagitannins named rhoipteleanins H (1), I (2), and J (3) were isolated from the fruits and bark of Rhoiptelea chiliantha Diels et Hand.-Mazz. (Rhoipteleaceae), and the structures were elucidated on the basis of detailed spectroscopic analysis and chemical evidence. Rhoipteleanin H possesses a unique cyclopentenone carboxyl moiety, which is probably formed by oxidation and subsequent rearrangement of an aromatic ring of a usual C-glycosidic ellagitannin. Rhoipteleanin I is the first ellagitannin having a hydroxynaphthalene glucoside moiety. Rhoipteleanin J is a dimeric ellagitannin generated by dehydrative coupling between two molecules of a monomeric C-glycosidic ellagitannin and subsequent oxidation of an aromatic ring. From a chemotaxonomic viewpoint, presence of these characteristic ellagitannins in this plant provides a further support for the establishment of the order Rhoipteleales comprising Rhoipteleaceae as the only family.     

Sesquiterpenoid derivatives from Gonospermum elegans and their cytotoxic activity for HL-60 human promyelocytic cells

Four new compounds, a sesquiterpene, eleganodiol (1), and three sesquiterpene lactones, eleganolactone A (2), eleganolactone B (3), and elegain (4), were isolated from Gonospermum elegans along with 16 known compounds. The structures of 1, 2, and 4 were determined on the basis of MS and NMR studies of their acetate derivatives (1a, 2a, 4a). The structure of the acetate derivative (3a) of 3 was determined on the basis of spectroscopic data interpretation and by single-crystal X-ray diffraction. Compounds 2a and 3a were used to study their biological activities on the HL-60 human promyelocytic leukemia cell line. These compounds induced morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death.     

Cadinane sesquiterpenes from the leaves of Eupatorium adenophorum

Four new cadinane sesquiterpenes (1- 4), including a dimeric cadinane derivative (2) and a peroxide cadinane analogue (3), have been isolated from the leaves of Eupatorium adenophorum. Their structures including absolute configurations were determined on the basis of spectroscopic data interpretation and single-crystal X-ray crystallography. Compound 4 showed in vitro cytotoxicity against the HCT-8, Bel-7402, and A2780 cancer cell lines.     

Cinnafragrins A-C, dimeric and trimeric drimane sesquiterpenoids from Cinnamosma fragrans, and structure revision of capsicodendrin

Two new dimeric sesquiterpenoids and a new trimeric drimane sesquiterpenoid named cinnafragrins A-C (1-3), together with cinnamodial (4), D-mannitol, capsicodendrin (5), and a vitamin E analogue, delta-tocotrienol, were isolated from Cinnamosma fragrans, a Malagasy medicinal plant. The structures of the new compounds were determined on the basis of physical, chemical, and spectroscopic evidence. Capsicodendrin, previously isolated from Capsicodendron dinisii and tentatively suggested to be a tetramer of cinnamodial, was revised structurally as a mixture of C-12'-epimers of 12'-hydroxycinnafragrin B by extensive 2D NMR analysis and X-ray crystallography of the lactone derivative, cinnafragrolide (6). The chemosystematics of the family Canellaceae are discussed.     

Asmarines A-F, novel cytotoxic compounds from the marine sponge Raspailia species

Three pairs of nitrogen-containing metabolites, asmarines A-F (1-6), were isolated from the Red Sea sponge Raspailia sp., collected in the Dahlak Archipelago, Eritrea. Although the first pair could fully be separated to give compounds 1 and 2, the other two pairs could only be enriched up to about 80% of one isomer. The structures of the new compounds were established by spectroscopic means. Besides the asmarines, methyl 3-oxo-cholan-24-oate (12) was also isolated. The absolute configuration of asmarine A (1) was determined on the basis of CD measurements of its unstable 18-oxo derivative (7) and mainly the Cotton effect of the dicarbonyl derivative (9) of chelodane (8). A O,N(7')-dimethyl derivative (10) and a second, unexpected, methylated product (11) were obtained from 2.     

Antioxidant activity of a new capsaicin derivative from Capsicum annuum

A new capsaicin derivative, 6' ',7' '-dihydro-5',5' "-dicapsaicin (1), and a known capsaicin metabolite, omega-hydroxycapsaicin (2),(1) were isolated from the fruit of Capsicum annuum. Their structures were established on the basis of spectroscopic evidence. Compound 1 showed almost the same antioxidant activity as capsaicin, but did not have a pungent taste.     

一个从急性子中分离得到的新的具有细胞毒活性的双萘呋喃-7,12-酮类衍生物(英文)

目的:研究急性子的化学成分。方法:采用硅胶、反相材料、凝胶柱色谱等方法分离化合物,用波谱方法结合理化性质鉴定其结构;采用体外活性筛选技术研究化合物抑制肿瘤细胞增殖的活性。结果:从急性子中分离得到3个双萘呋喃-7,12-酮类衍生物:balsaminone C(1)、balsaminone A(2)、balsaminone B(3)。结论:化合物balsaminone C为一新化合物。化合物1～3均具有抑制肿瘤细胞A549、Bel-7402、Hela增殖的活性。     

A chemical study of cyclic depsipeptides produced by a sponge-derived fungus

Two novel cyclic depsipeptides, guangomides A (1) and B (2), together with a new destruxin derivative (3) were isolated from the cytotoxic extract obtained from the saltwater culture of an unidentifiable sponge-derived fungus. The new structures were elucidated on the basis of analysis of extensive 1D and 2D NMR data sets, and the absolute configurations of 2S, 9S, 13S, 19S, 24R, 28R of 1 were determined on the basis of the combined X-ray and Marfey's method structure analysis. Identical absolute configurations were assumed for 2. The cytotoxicity of the extract was found to be due to brefeldin A, while 1 and 2 showed weak antibacterial activity against Staphylococcus epidermidis and Enterococcus durans.     

Antifungal azaphilones from the fungus Chaetomium cupreum CC3003

Three new azaphilones named rotiorinols A-C (1-3), two new stereoisomers, (-)-rotiorin (4) and epi-isochromophilone II (5), and a known compound, rubrorotiorin (6), were isolated from the fungus Chaetomium cupreum CC3003. Structures were established on the basis of spectroscopic evidence. The absolute configuration of 1 was determined by the modified Mosher's method along with an X-ray analysis of its acetate derivative, as well as by chemical transformation. Compounds 1, 3, 4, and 6 exhibited antifungal activity against Candida albicans with IC50 values of 10.5, 16.7, 24.3, and 0.6 microg/mL, respectively.     

Meroditerpenoids from a Formosan soft coral Nephthea chabrolii

Eight new meroditerpenoid-related metabolites, including one naphthoquinone derivative, chabrolonaphthoquinone B (1), four tetraprenyltoluquinone-related compounds, chabrolobenzoquinones E-H (2-5), and three tetraprenyltoluquinol-related metabolites, chabrolohydroxybenzoquinones E-G (6-8), were isolated from the organic extract of a Taiwanese soft coral Nephthea chabrolii. The structures of 1-8 were elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of the related metabolites. Cytotoxic activity of metabolites 1-3 and 5-8 against a limited panel of cancer cell lines is also described.     

Kahalalide derivatives from the Indian sacoglossan mollusk Elysia grandifolia

Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known congeners, kahalalides F (3) and D (4), were isolated from the Indian sacoglossan mollusk Elysia grandifolia. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, HMBC) and mass spectrometric (FABMS, ESIMS, MALDI-TOF/PSD) data, which also included Marfey amino acid analyses. The new derivative kahalalide R was found to exert comparable or even higher cytotoxicity than the potential drug candidate kahalalide F toward the MCF7 human mammary carcinoma cell line.     

Sesquiterpene benzoxazoles and sesquiterpene quinones from the marine sponge Dactylospongia elegans

A new sesquiterpene benzoxazole, nakijinol B (3), its acetylated derivative, nakijinol B diacetate (6), and two new sesquiterpene quinones, smenospongines B (4) and C (5), were isolated from the methanol extract of the marine sponge Dactylospongia elegans. Also isolated were the known compounds dactyloquinone B and a 1:1 mixture of ilimaquinone and 5-epi-ilimaquinone. Their structures were determined on the basis of spectroscopic analyses and comparison with literature data. The isolated compounds were assessed for their cytotoxicity against a panel of human tumor cell lines (SF-268, H460, MCF-7, and HT-29) and a normal mammalian cell line (CHO-K1). All compounds were found to have activities in the range 1.8-46 μM and lacked selectivity for tumor versus normal cell lines.