Cytotoxic and antioxidant activities of alkylated benzoquinones from Maesa lanceolata

The natural and semi-synthetic analogs of substituted 1,4-benzoquinones were evaluated for in vitro cytotoxic and antioxidant activities. Maesanin, dihydromaesanin, maesanin dimethyl ether and isomeric mixtures of 3-[(Z)-10'-pentadecenyl]-benzoquinone derivatives exhibited cytotoxic activity against HL-60 cell line (IC50 values 4.5, 2.2, 0.43 and 2.8 microg/mL, respectively), while it was found to be inactive against ROS (Reactive Oxygen Species) generation in HL-60. In contrast, the isomeric acylated benzoquinones with shorter alkyl substituents, namely, 2-acetoxy-5-hydoxy-6-methyl-3-tridecyl-1,4-benzoquinone and 2-hydoxy-5-acetoxy-6-methyl-3-tridecyl-1,4-benzoquinone showed most prominent antioxidant and antiproliferative effect on HL-60 (IC50 values 6.2 and 2.2 microg/mL, respectively), as well as cytotoxicities against SK-MEL, KB, BT-549 and SK-OV-3 carcinomas (IC50 values <1.1-4.2 microg/mL). All benzoquinones were found to be inactive against cell aggregation and cell adhesion assays, thus showing no effect on immune responses and inflammation.     

血党化学成分的研究

目的:研究血党Ardisia punctata的化学成分。方法:采用反复硅胶柱色谱和制备高效液相色谱进行分离纯化,根据理化性质和光谱数据进行结构鉴定。结果:得到12个化合物,鉴定为3-羟基-5-十三烷基-苯甲醚(1),5-十五烷基-1,3-间苯二酚(2),2-甲氧基-6-十三烷基-1,4-苯醌(3),2-甲氧基-6-十五烷基-1,4-苯醌(4),glutinol(5),ar-disicrenoside A(6),ardisiacrispin B(7),24-乙基-Δ7,22-胆甾二烯-3-酮(8),24-乙基-Δ7,22-胆甾二烯-3-醇(9),胡萝卜苷(10),香草酸(11),正三十四烷酸(12)。结论:所有化合物均为首次从该植物中获得。     

Terphenylquinone inhibitors of the src protein tyrosine kinase from Stilbella sp

Three new secondary metabolites, 2,5-dihydroxy-3-(3,4-dihydroxyphenyl)-6-phenyl-1,4-benzoquinone (3), 2,5-dihydroxy-3-phenyl-6-(3,4,5-trihydroxyphenyl)-1,4-benzoquinone (4), and 2,7,8-trihydroxy-3-phenyl-1,4-dibenzofurandione (5), as well as two known natural products were isolated from the fungus Stilbella sp. strain 1586. The structures of these compounds were established by spectroscopic and chemical methods. The terphenylquinones 3-5 exhibited significant activity against human src protein tyrosine kinase.     

Cytotoxic flavonol glycosides from Triplaris cumingiana

Three new compounds, 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-oxo-4H-chromen-3-yl-4,6-bis-O-beta-D-(3,4,5-trihydroxybenzoyl)glucopyranoside (1), 5,7-dihydroxy-2-(4-hydroxyphenyl)-4-oxo-4H-chromen-3-yl-5-O-alpha-L-(3,4,5-trihydroxybenzoyl)arabinofuranoside (2), and 2-hydroxy-4-O-alpha-L-(3,5,7-trihydroxy-4-oxo-4H-chromen-2-yl)phenylarabinofuranoside (3), were isolated from the young leaves of Triplaris cumingiana, together with two known compounds, quercetin 3-O-alpha-L-(5"-O-galloyl)arabinofuranoside (4) and quercetin 3-O-beta-D-(6"-O-galloyl)glucopyranoside (5). The structures of 1-3 were established by spectroscopic methods. Compounds 1-5 were evaluated for their cytotoxic activities against the MCF-7, H-460, and SF-268 human cancer cell lines.     

Antifungal and larvicidal compounds from the root bark of Cordia alliodora

Two new natural products, a phenylpropanoid derivative characterized as 1-(3'-methoxypropanoyl)-2,4,5-trimethoxybenzene (1) and a prenylated hydroquinone, 2-(2Z)-(3-hydroxy-3,7-dimethylocta-2, 6-dienyl)-1,4-benzenediol (2), have been isolated from the root bark of Cordia alliodora. Both compounds exhibited antifungal properties against the phytopathogenic mold Cladosporium cucumerinum. The phenylpropanoid derivative (1), whose structure is closely related to beta-asarone, also demonstrated a marked activity against larvae of the yellow-fever-transmitting mosquito Aedes aegypti.     

Phytotoxic compounds from Prionosciadium watsoni

Bioassay-guided fractionation of a phytotoxic extract of Prionosciadium watsoni led to the isolation of three new pyranocoumarins and two pyranochromones. The new compounds were characterized as propionic acid (9R,10R)-9-acetoxy-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (1), isobutyric acid (9R,10R)-9-hydroxy-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (2), isobutyric acid (9R)-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-9-yl ester (10), 2-methylbut-(2Z)-enoic acid (3R)-5-methoxy-3,4-dihydro-2,2,8-trimethyl-6-oxo-2H,6H-benzo[1,2-b:5,4-b']dipyran-3-yl ester (11), and isobutyric acid (3R)- 5-methoxy-3,4-dihydro-2,2,8-trimethyl-6-oxo-2H,6H-benzo[1,2-b:5,4-b']dipyran-3-yl ester (12) by spectroscopic and chemical methods. The stereochemistry at the stereogenic centers was established by applying the Mosher ester methodology. The structures of 1 and 2 were corroborated by single-crystal X-ray diffraction studies. The phytotoxic activity of the isolated compounds was assessed on Amaranthus hypochondriacus, Echinochloa crus-galli, and Lemna pausicostata. The phytotoxins also modified the electrophoretic mobility of calmodulin from both bovine-brain and spinach.     

New phenolic glucosides from the leaves of Eurya tigang.

Three new compounds, 6'-O-coumaroyl-1'-O-[2-(4-hydroxyphenyl)ethyl]-beta-D-glucopyra nos ide [1] (eutigoside A), 6'-O-coumaroyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1- yl)ethyl]-beta-D-glucopyranoside [2] (eutigoside B), and 6'-O-cinnamoyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1-yl)eth yl]- beta-D-glucopyranoside [3] (eutigoside C) have been isolated from the leaves of Eurya tigang, along with other known compounds (afzelin, quercitrin, p-coumaric acid, methyl-alpha-D-fructofuranoside, isorengyol, and euryanoside). Their structures were determined by chemical and spectroscopic methods (uv, ir, ms, 1H-1H COSY, and 1H-13C COSY).     

狗牙根化学成分的研究

目的研究狗牙根的化学成分。方法狗牙根95%乙醇提取物正丁醇部位采用MCI、Rp-C18、半制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到13个化合物,分别鉴定为monocerin (1)、绿原酸甲酯(2)、4-O-香豆酰基奎宁酸甲酯(3)、5-O-阿魏酰奎宁酸(4)、异血红酸(5)、麦芽酚-β-D-吡喃葡萄糖苷(6)、1, 4-二甲氧基吩嗪(7)、19α-羟基齐墩果酮酸(8)、3-羟基-1-(4-羟基-3,5-二甲氧基苯基)-2-[4-(3-羟基-1-(E)-丙烯基)-2,6-二甲氧基苯氧基]丙基-β-D-吡喃葡萄糖苷(9)、4,5-二咖啡酰基奎宁酸甲酯(10)、苯甲酸(11)、4-羟基-邻茴香醛(12)、阿替匹林C(13)。结论所有化合物均为首次从该植物中分离得到。     

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.     

Antibacterial activity of Tabebuia impetiginosa Martius ex DC (Taheebo) against Helicobacter pylori

The growth-inhibiting activity of Tabebuia impetiginosa Martius ex DC dried inner bark-derived constituents against Helicobacter pylori ATCC 43504 was examined using paper disc diffusion and minimum inhibitory concentration (MIC) bioassays. The activity of the isolated compounds was compared to that of the commercially available anti-Helicobacter pylori agents, amoxicillin, metronidazole, and tetracycline. The biologically active components of Tabebuia impetiginosa dried inner bark (taheebo) were characterized by spectroscopic analysis as 2-(hydroxymethyl)anthraquinone, anthraquinone-2-carboxylic acid, and 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone (lapachol). With the paper disc diffusion assay 2-(hydroxymethyl)anthraquinone exhibited strong activity against Helicobacter pylori ATCC 43504 at 0.01 mg/disc. Anthraquinone-2-carboxylic acid, lapachol and metronidazole were less effective, exhibiting moderate anti-Helicobacter pylori activity at 0.1 mg/disc. Amoxicillin and tetracycline were the most potent compounds tested, displaying very strong activity at 0.005 mg/disc. 2-(Hydroxymethyl)anthraquinone exhibited moderate activity at this dose. Tetracycline still had strong activity at 0.001 mg/disc while amoxicillin had little activity at this dose. In the MIC bioassay, 2-(hydroxymethyl)anthraquinone (2 microg/mL), anthraquinone-2-carboxylic acid (8 microg/mL), and lapachol (4 microg/mL) were more active than metronidazole (32 microg/mL) but less effective than amoxicillin (0.063 microg/mL) and tetracycline (0.5 microg/mL). The anti-Helicobacter pylori activity of seven 1,4-naphthoquinone derivatives (structurally related to lapachol), 1,4-naphthoquinone, 5,8-dihydroxy-1,4-naphthoquinone (naphthazarin), 2-methyl-1,4-naphthoquinone (menadione), 2-hydroxy-1,4-naphthoquinone (lawsone), 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin), 5-hydroxy-1,4-naphthoquinone (juglone), and 2,3-dichloro-1,4-naphthoquinone (dichlone) was also evaluated using the paper disc assay. Menadione and plumbagin were the most potent compounds tested with the later still exhibiting very strong activity at 0.001 mg/disc. Menadione, juglone and tetracycline had strong activity at this low dose while the latter two compounds and amoxicillin had very strong activity at 0.005 mg/disc. Lawsone was unusual in that it had very strong activity at 0.1 and 0.05 mg/disc but weak activity at doses of 0.01 mg/disc and lower. Naphthazalin, lapachol and dichlone had similar activities while metronidazole had the lowest activity of all compounds tested. These results may be an indication of at least one of the pharmacological actions of taheebo. The Tabebuia impetiginosa dried inner bark-derived materials, particularly 2-(hydroxymethyl)anthraquinone, merit further study as potential Helicobacter pylori eradicating agents or lead compounds.     

Phenolic compounds from tournefortia sarmentosa

Three new isoprenylbenzenes, tournefolins A (1), B (2), and C (3), and two new 2-ethoxy-4,5-dihydroxybenzoyl compounds, 4 and 5, together with the known compounds, salicylic acid and allantoin, were isolated from the stems of Tournefortia sarmentosa. The structures of new compounds were elucidated as 2-(4beta-methyltetrahydrofuran-2alpha-yl)-5-(4beta-methyltetrahydrofu ran-2beta-yl)-1,4-dihydroxybenzene (1), methyl 5-(5-hydroxy-2-methoxyphenyl)-3-furoate (2), methyl 5-(2, 5-dihydroxyphenyl)-3-furoate (3), 2-ethoxy-4,5-dihydroxybenzaldehyde (4), and 2-ethoxy-4,5-dihydroxybenzoic acid (5), on the basis of spectral and chemical methods. The relative configuration of 1 was determined by single-crystal X-ray crystallography.     

Isolation, synthesis, and structure-activity relationships of bioactive benzoquinones from Miconia lepidota from the Suriname rainforest

Bioactivity-directed fractionation of an EtOAc extract from the leaves of Miconia lepidota afforded the two benzoquinones 2-methoxy-6-heptyl-1,4-benzoquinone (1) and 2-methoxy-6-pentyl-1,4-benzoquinone (primin) (2). This is the first reported isolation of 1. Both quinones 1 and 2 exhibited activity toward mutant yeast strains based on Saccharomyces cerevisiae, indicative of their cytotoxicity and potential anticancer activity. A number of previously synthesized and new analogues were prepared and tested in the same strains. Compounds 1, 2, 2-methoxy-6-butyl-1,4-benzoquinone (5), and 2-methoxy-6-decyl-1,4-benzoquinone (6) were tested in two cytotoxicity assays. In the M109 tumor cell lines, quinones 1, 2, and 6 had an IC(50) value of 10 microg/mL. In the A2780 cell line, compounds 1, 2 and 5 had IC(50) values of 7.9, 2.9, and 3.2 microg/mL, respectively.     

6-Alkyl-3,4-dihydro-2H-pyrans: chemical secretion compounds in neotropical harvestmen

The defensive secretions of five neotropical species of harvestmen (Opiliones: Gonyleptidae) from the Brazilian Atlantic Forest were analyzed and chemically characterized by GC-MS and NMR methods. Three of the species, Cobania picea, Roweria virescens, and Serracutisoma proximum, secrete a mixture of 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone. The secretions produced by the other two species, Iporangaia pustulosa and Neosadocus maximus, contain 1-hepten-3-one, 5-methyl-1-hexen-3-one, and 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) as major components, as well as 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone as minor constituents. The dihydropyran 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) is a new natural product, composed of two 1-hepten-3-one subunits formally linked in a hetero-Diels-Alder reaction. The natural product was proven to be racemic, and its biogenetic origin is discussed.     

Structural revision of aspernigrin A, reisolated from Cladosporium herbarum IFB-E002

Aspernigrin A was reisolated as a secondary metabolite of the Cynodon dactylon-associated endophytic fungus Cladosporium herbarum IFB-E002 coproducing rubrofusarin B, fonsecinone A, 7-hydroxy-4-methoxy-5-methylcoumarin, orlandin, kotanin, and 3beta,5alpha,6beta-trihydroxyergosta-7,22-diene. The structure of aspernigrin A, previously elucidated to be 4-benzyl-6-oxo-1,6-dihydropyridine-3-carboxamide (1), was revised as 6-benzyl-4-oxo-1,4-dihydropyridine-3-carboxamide (2) on the basis of its additional NMR spectroscopic data and the X-ray crystallographic analysis.     

5-hydroxytryptamine-derived alkaloids from two marine sponges of the genus Hyrtios

Indonesian specimens of the marine sponges Hyrtios erectus and H. reticulatus were found to contain 5-hydroxytryptamine-derived alkaloids. Their structures were determined on the basis of their spectral properties. H. erectus contained hyrtiosulawesine (4), a new beta-carboline alkaloid, together with the already known alkaloids 5-hydroxyindole-3-carbaldehyde (1), hyrtiosin B (2), and 5-hydroxy-3-(2-hydroxyethyl)indole (3). H. reticulatus contained the novel derivative 1,6-dihydroxy-1,2,3,4-tetrahydro-beta-carboline (11) together with serotonin (5), 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (7), and 6-hydroxy-3,4-dihydro-1-oxo-beta-carboline (9).     

麻叶千里光抗菌化学成分的研究(Ⅱ)

目的研究麻叶千里光S enecio cannabif olius抗菌活性成分。方法以革兰氏阳性菌金黄色葡萄球菌S taphy lococcus aureus、枯草芽孢杆菌B acillus subtilis和阴性菌大肠杆菌E scherich ia coli为受试菌,采用体外抑菌圈法追踪抗菌活性部分,利用各种色谱技术进行分离纯化,根据理化性质和谱学数据进行结构鉴定。结果从麻叶千里光中分离得到5个化合物,分别鉴定为5-羟基吡啶-2-甲酸甲酯(E-13)、6-羟基-7,7a-二氢-2-(6H)-苯骈呋喃酮(E-14)、2-(1,4-二羟基环己烷基)-乙酸(E-16)、3-羟基环己酸(E-17)、4-羟基苯甲醛(B-14)。结论它们均为从千里光属植物中首次分到。     

冬凌草中的一个新生物碱

目的:研究冬凌草(Rabdosia rubescens (Hemls.) Hara)地上部分的化学成分。方法:利用大孔吸附树脂色谱进行分离纯化,根据化合物的理化性质和光谱数据鉴定结构。结果:从冬凌草地上部分分离得到7个化合物,分别为:冬凌草碱(1),黄嘌呤(2),芹菜素-6,8-二-C-β-D-葡萄糖苷(3),7-羟基-4(1H)-喹啉酮(4),1,5-二-(3,4-二羟基苯基)-乙烯醚(5),3-(3,4-二羟基苯基)-2-异丙氧基-丙酸(6),邻苯二甲酸双-(2-乙基己基)酯(7)。结论:化合物1为新化合物,其余化合物均为首次从该属植物中分离得到。     

秦岭冷杉茎叶的化学成分研究

目的研究秦岭冷杉Abies chensiensis茎叶的化学成分。方法利用大孔吸附树脂、葡聚糖凝胶、硅胶柱色谱、半制备高效液相色谱等多种色谱方法分离纯化,根据理化性质及波谱数据对化合物进行结构鉴定。结果从秦岭冷杉95%乙醇提取物中分离得到24个化合物,分别鉴定为7,14,24-mariesatrien-26,23-olide-3α,23-diol(1)、(23R)-3α-hydroxy-9,19-cyclo-9β-lanost-24-en-26,23-olide(2)、7-oxocallitrisicacid(3)、23-hydroxy-3-oxomariesia-8(9),14,24-trien-26,23-olide(4)、紫果冷杉三萜E(5)、3-oxo-9β-lanosta-7,24-dien-26,23R-olide(6)、7,14,22Z,24-mariesatetraen-26,23-olide-3-one(7)、(+)-rel-3α-hydroxy-23-oxocycloart-25 (27)-en-26-oic acid(8)、cycloart-25-en-3β,24-diol(9)、紫果冷杉三萜H(10)、3-oxo-24,25,26,27-tetranolanost-8-en-23-oic acid(11)、abiesadine C(12)、13β-epidioxy-8(14)-abieten-18-oic acid(13)、dehydroabietic acid(14)、15-hydroxydehydroabietic acid(15)、methyl 18-methoxydehydroabietate(16)、7β-hydroxy dehydroabietic acid(17)、dehydroabietan-18-ol(18)、centdaroic acid(19)、abietic acid(20)、6,8,11,13-abi-etatrien-18-oic acid(21)、abiesadine B(22)、abiesadine N(23)、12β-hydroxyabietic acid(24)。结论所有化合物均为首次从该植物中分离得到,其中化合物11为属内首次分离得到。     

皮孔葱臭木化学成分的研究

目的对皮孔葱臭木Dysoxylum lenticellatum茎干的化学成分及其细胞毒活性进行研究。方法利用正相硅胶、RP-18柱色谱、葡聚糖凝胶Sephadex LH-20等手段进行分离纯化,根据波谱数据鉴定化合物的结构,采用MTT法进行细胞毒活性测定。结果分离鉴定了12个化合物,分别为β-谷甾醇(1)、豆甾醇(2)、3-oxo-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone(3)、3α-hydroxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone(4)、laxiracemosin H(5)、laxiracemosin B(6)、24,25-epoxy-tirucall-7-ene-3,23-dione(7)、丁酰鲸鱼醇(8)、齐墩果酸(9)、蒲公英赛酮(10)、蒲公英赛醇(11)和8-hydroxy-6-methoxy-3-pentylisocoumarin(12)。结论 12个化合物均为首次从该种植物中分离得到,化合物8、10～12为首次从该属植物中分离得到,化合物5、6是甘遂烷型生物碱,化合物3具有明显体外肿瘤细胞生长抑制活性。     

Chaetopyranin, a benzaldehyde derivative, and other related metabolites from Chaetomium globosum, an endophytic fungus derived from the marine red alga Polysiphonia urceolata

Cultivation of the endophytic fungus Chaetomium globosum, which was isolated from the inner tissue of the marine red alga Polysiphonia urceolata, resulted in the isolation of chaetopyranin (1), a new benzaldehyde secondary metabolite. Ten known compounds were also isolated, including two benzaldehyde congeners, 2-(2',3-epoxy-1',3'-heptadienyl)-6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (2) and isotetrahydroauroglaucin (3), two anthraquinone derivatives, erythroglaucin (4) and parietin (5), five asperentin derivatives including asperentin (6, also known as cladosporin), 5'-hydroxy-asperentin-8-methylether (7), asperentin-8-methyl ether (8), 4'-hydroxyasperentin (9), and 5'-hydroxyasperentin (10), and the prenylated diketopiperazine congener neoechinulin A (11). The structures of these compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as low- and high-resolution mass experiments). To our knowledge, compound 1 represents the first example of a 2H-benzopyran derivative of marine algal-derived fungi as well as of the fungal genus Chaetomium. Each isolate was tested for its DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging property. Compounds 1-4 were found to have moderate activity. Chaetopyranin (1) also exhibited moderate to weak cytotoxic activity toward several tumor cell lines.