Antifouling activity of sponge-derived polybrominated diphenyl ethers and synthetic analogues

The antifouling (AF) activity of 2-hydroxy-4-(3-hydroxy-5-methylphenoxy)- 6-methylbenozoic acid methyl ester (1), 3,5-dibromo-2-(2',4'-dibromophenoxy)phenol (2); 3,4,5-tribromo-2-(2',4'-dibromophenoxy)phenol (3), 3,4,5-tribromo-2-(2'-bromophenoxy)phenol (4), 3,5-dibromo-2(2',4'-dibromophenoxy)phenol (5), 3,4,5,6-tetrabromo-2-(2'-bromophenoxy)phenol (6); 4-phenoxyphenol (7), 4-phenoxyaniline (9), 1-chloro-4-phenoxybenzene (10); 1-bromo-4-phenoxybenzene (13) was investigated against marine bacteria, a diatom, barnacle larvae and mussel juveniles. The naturally occurring compound 2 showed the strongest AF activity in all bioassays but lacked toxicity. It inhibited the growth of all tested bacterial strains (MIC = 0.02 - 1.52 microM) and its 50% effective concentrations (EC(50)) were 0.24 microM (diatom test), 0.66 microM (mussel test) and 1.26 microM (barnacle test). Among the commercially available derivates, compound 7 was the most active in bacterial and diatom bioassays but its activity was lower than that of compound 2. Overall, the naturally occurring compounds showed stronger activity than the commercially available analogues and could be possible future non-toxic AF candidates.     

地菍的化学成分(英文)

为了研究野牡丹科药用植物地菍(Melastoma dodecandrum)的化学成分,采用柱层析方法分离鉴定了15个化合物,通过波谱分析及对比文献等方法鉴定为4-O-β-D-吡喃葡萄糖基-3,3',4'-三甲氧基鞣花酸(1),槲皮素3-O-刺槐二糖苷(2),8-C-吡喃葡萄糖基-5,7,3',4'-四羟基黄酮(3),3-O-β-D-吡喃葡萄糖基-4',5,7-三羟基黄酮(4),6-C-吡喃葡萄糖基-4',5,7-三羟基黄酮(5),3-hydroxy-22(29)-hopen-23-oic acid(6),2,3-dihydroxy-9(11)-fernen-23-oic acid(7),3β-sitosterol laminaribioside(8),姜糖酯B(9),3-O-β-D-galactopyranoside-glycerol1-alkanoates(10),胡萝卜苷(11),β-谷甾醇(12),二十八烷醇(13),二十四烷酸(14)以及三十四烷(15)化合物结构。所有化合物均为首次从该植物中分离得到。     

Osteoblast differentiation stimulating activity of biflavonoids from Cephalotaxus koreana

Six amentoflavone-type biflavonoids, bilobetin (1), ginkgetin (2), 4',7'-di-O-methyl-amentoflavone (3), 7-O-methyl-isoginkgetin (4), sciadopitysin (5), and 7,4',7',4'-O-methyl-amentoflavone (6), were isolated from the EtOAc fraction of Cephalotaxus koreana Nakai (Cephalotaxaceae) by bioactivity-guided fractionation technique using primary cultures of mouse osteoblasts as an in vitro assay system. Among the six biflavonoids isolated, bilobetin (1), sciadopitysin (5), and 7,4',7',4'-O-methyl-amentoflavone (6) significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity, collagen synthesis, and mineralization. Considering structure-activity relationship, methoxyl groups at 4' and 4' in the B rings in amentoflavone-type biflavonoid might be important in osteoblast differentiation. Taken together, our present study suggests therapeutic potential of biflavonoids against bone diseases such as osteoporosis.     

Geranylated phenolic constituents from the fruits of Artocarpus nobilis

Chemical investigation of the combined dichloromethane and ethyl acetate extracts of the fruits of Artocarpus nobilis, furnished four new geranylated phenolic constituents, 2,4,4'-trihydroxy-3-[(2E)-5-methoxy-3,7-dimethylocta-2,6-dienyl]chalcone (4), 1-(3,4-dihydro-3,5-dihydroxy-2-methyl-2-(3-methyl-2-butenyl)-2H-1-benzopyran-6-yl-3-(4-hydroxyphenyl)-2(E)-propen-1-one (5), 8-geranyl-3',4',7-trihydroxyflavone (8), 3'-geranyl-4',5,7-trihydroxyflavanone (9), together with known related compounds, xanthoangelol (1), xanthoangelol B (2), 3-geranyl-2,3',4,4'-tetrahydroxychalcone (3), lespeol (6), 8-geranyl-4',7-dihydroxyflavanone (7), and isonymphaeol-B (10). Compounds 3, 8 and 10 showed strong antioxidant activity against DPPH radical by spectrophotometric method.     

Prolyl endopeptidase inhibitors from Syzygium samarangense (Blume) Merr. & L. M. Perry

Compounds isolated from the hexane extract of the leaves of Syzygium samarangense (Blume) Merr. & L. M. Perry were tested for inhibitory activity against the following serine proteases: trypsin, thrombin and prolyl endopeptidase. The compounds were identified as an intractable mixture of alpha-carotene and beta-carotene (1), lupeol (2), betulin (3), epi-betulinic acid (4), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (5), 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (6), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (7), 2',4'-dihydroxy-6'-methoxy-3'-methyldihydrochalcone (8) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (9). Hydrogenation of compounds 5, 6 and 7 yielded compound 8, 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (10) and 2',4'-dihydroxy-6'-methoxy-3',5'-dimethyldihydrochalcone (11), respectively. The hydrogenated products of compounds 6 and 7 were also tested for enzyme inhibitory activity. In addition, beta-sitosterol (12) and beta-D-sitosterylglucoside (13) were also isolated. This is the first report of the isolation of compounds 1-6, 8 and 13 from this plant. Compounds 3-8 and 10 exhibited significant and selective inhibition against prolyl endopeptidase among three serine proteases. This is the first report of this kind of activity for all these compounds.     

Rare biscoumarins and a chlorogenic acid derivative from Erycibe obtusifolia

Three coumarins, 7,7'-dihydroxy-6,6'-dimethoxy-3,3'-biscoumarin (1), 7,7'-dihydroxy-6,6'-dimethoxy-8,8'-biscoumarin (2) and 7-O-[4'-O-(3',4'-dihydroxycinnamyl)-beta-d-glucopyranosyl]-6-methoxycoumarin (3), and a chlorogenic acid derivative, methyl-3-O-(4'-hydroxy-3',5'-dimethoxybenzoyl)-chlorogenate (4) were isolated from the roots of Erycibe obtusifolia along with four known coumarins, scopoletin (5), scopolin (6), cleomiscosin A (7) and cleomiscosin B (8). Their structures were elucidated by spectroscopic methods. Among them, compounds (1) and (2) are rare carbon-carbon linked symmetrical biscoumarins.     

凹叶瑞香的化学成分研究(英文)

从凹叶瑞香的乙酸乙酯部位分离得到14个化合物,经理化性质及波谱数据分析分别鉴定为瑞香黄烷A(1),瑞香黄烷B(2),瑞香黄烷C(3),瑞香黄烷E(4),瑞香黄烷F(5),芫花素(6),芫根苷(7),4,′5-二羟基-3,′7-二甲氧基黄酮(8),瑞香新素(9),5′′-去甲氧基瑞香新素(10),左旋松脂酚(11),瑞香醇酮(12),紫丁香苷(13)和丁香醛(14)。化合物1～14均为首次从该植物中分离得到。     

DPPH free radical scavenger components from the fruits of Alpinia rafflesiana Wall. ex. Bak. (Zingiberaceae)

The methanol extract of the dried ripe fruits of Alpinia rafflesiana was investigated for its DPPH free radical scavenger constituents. 2',3',4',6'-Tetrahydroxychalcone (7), which has never been isolated from natural sources was found to be most active as a DPPH free radical scavenger with the IC50 value of 55 microM. Other known compounds isolated from this species include 5,6-dehydrokawain (1), flavokawin B (2). 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4), cardamonin (5) and (-)-pinostrobin (6). The DPPH free radical scavenger compounds were detected using TLC autographic analysis. The percentage inhibition of DPPH free radical scavenging activity was measured on isolates (5-7) using colorimetric analysis.     

Synthesis and antibacterial activity of egonol derivatives

Synthesis of egonol derivatives, 5-(3'-chloropropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran 1, 5-(3'-bromopropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran 2, 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propanal 3, 5-(3'-iodopropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran 4, 5-[3-(3'-bromopropyloxy) propyl]-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran 5, 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propylmethanoate 6, 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propyloleate 7, 5-[3'-hydroxypropyl]-6-bromo-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran 8, 4-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]butanenitrile 9, 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propylbenzoate 10, 5-[3'-hydroxypropyl]-7-methoxy-3-nitro-2-(3',4'-methylenedioxyphenyl)benzofuran 11 and their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli are reported. The starting material egonol 5-[3'-(hydroxy)propyl]-7-methoxy-2-(3', 4'methylenedioxyphenyl)benzofuran was isolated from seeds of Styrax officinalis L. The structural elucidication of these compounds (1-11) was established using 1D ((1)H, (13)C), 2D NMR (HMBC, HMQC, COSY) and LCMS spectroscopic data. While egonol and some synthesised new compounds show similar antibacterial activity and MIC values against S. aureus, B. subtilis, C. albicans and E. coli, other new derivatives show different activity against S. aureus, B. subtilis, C. albicans and E. coli.     

Flavonoids, including an unusual flavonoid-Mg2+ salt, from roots of Cudrania cochinchinensis

Four flavonoids with 2',4'-di-oxygenated B-rings, cochinchinol A (1), cochinchinol B (2), (2R,3R)-4',7-dihydroxy-2',5-dimethoxydihydroflavonol (3), 4',7-dihydroxy-2',5-dimethoxyflavonol (4), along with 11 known compounds, were isolated from an ethanolic extract of the roots of Cudrania cochinchinensis. Their structures were elucidated by chemical and spectroscopic methods. Cochinchinol A (1) and cochinchinol B (2) have two hitherto unprecedented flavonol salt structures in natural product chemistry. Cytotoxic activities were evaluated against several different cell lines.     

艾纳香黄酮类化学成分的研究(英文)

从艾纳香(Blumea balsamiferaDC.)的地上部分中分离得到13个黄酮类化合物,经鉴定分别为5,7-二羟基-3,3′,4′-三甲氧基黄酮(1),3,5,3′,4′-四羟基-7-甲氧基黄酮(2),4,2′,4′-三羟基双氢查尔酮(3),儿茶素(4),阿亚黄素(5),davidioside(6),二氢槲皮素-7,4′-二甲醚(7),艾纳香素(8),二氢槲皮素-4′-甲醚(9),3,5,3′-三羟基-7,4′-二甲氧基黄酮(10),5,7,3′,5′-四羟基二氢黄酮(11),木犀草素(12),槲皮素(13)。其中化合物1和3~6为首次从该植物中分离得到。     

Effects of hydroxylated polychlorinated biphenyls on mouse liver mitochondrial oxidative phosphorylation.

The effects of three tetrachlorobiphenylols [2',3',4',5'-tetrachloro-2-biphenylol (1); 2',3',4',5'-tetrachloro-4- biphenylol (2); and 2',3',4',5'-tetrachloro-3-biphenylol (3)]; three monochlorobiphenylols [5-chloro-2-biphenylol (5), 3-chloro-2-biphenylol (6); and 2-chloro-4-biphenylol (7)] and a tetrachlorobiphenyldiol [3,3',5,5'-tetrachloro-4,4'-biphenyldiol (4) on respiration, adenosine triphosphatase (ATPase) activity, and swelling in isolated mouse liver mitochondria have been investigated. Tetrachlorobiphenylols (1-3) and the tetrachlorobiphenyldiol (4) inhibited state-3 respiration in a concentration-dependent manner with succinate as substrate (flavin adenine dinucleotide [FAD]-linked) and the tetrachlorobiphenyldiol (4) caused a more pronounced inhibitory effect on state-3 respiration than the other congeners. The monochlorobiphenylols 5-7 were less active as inhibitors of state-3 mitochondrial respiration and significant effects were observed only at higher concentration (greater than or equal to 0.4 microM). However, in the presence of the nicotinamide adenine dinucleotide (NAD)-linked substrates (glutamate plus malate), hydroxylated PCBs (1-7) significantly inhibited mitochondrial state-3 respiration in a concentration-dependent manner. Compounds 5, 6, and 7 uncoupled mitochondrial oxidative phosphorylation only in the presence of FAD-linked substrate as evidenced by increased oxygen consumption during state-4 respiratory transition, stimulating ATPase activity, releasing oligomycin-inhibited respiration, and inducing mitochondrial swelling (5, 6, and 7). Tetrachlorobiphenylols 1, 2, and 3 had no effect on mitochondrial ATPase activity while the tetrachlorobiphenyldiol, 4, decreased the enzyme activity. The possible inhibitory site of electron transport by these compounds and their toxicologic significance is discussed.     

Isolation of novel phenolic compounds with multidrug resistance (MDR) reversal properties from Onychium japonicum

We isolated seven novel compounds, namely, 3',4',6-trihydroxy-2,4-dimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (1), 3',6-dihydroxy-2,4,4'-trimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (2), α,β-dihydro-3',6-dihydroxy-2,4,6'-trimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (3), 3',4,4'-trihydroxy-2,6-dimethoxychalcone (4), 4',5,7-trihydroxy-6-(3″,4″-dihydroxybenzyl)flavone (5), 3-(3',4'-dihydroxybenzyl)-6,7-dihydroxycoumarin (6), 3-(3',4'-dihydroxyphenyl)-3,4-dihydroisocoumarin (7), as well as a known compound, 3',4',7-trihydroxy-5-methoxyflavanone (8) from the whole grass of Onychium japonicum, and elucidated their structures by spectroscopic methods. Compounds 1-3 exhibited significant multidrug resistance (MDR) reversal effects on MCF-7/ADR and Bel-7402/5-Fu cell lines.     

Geranylated flavanones from the secretion on the surface of the immature fruits of Paulownia tomentosa

Chemical investigation of the methanol extract of the viscous secretion on the surface of immature fruits of Paulownia tomentosa furnished nine geranylated flavanones, 6-geranyl-5,7-dihydroxy-3',4'-dimethoxyflavanone (1), 6-geranyl-3',5,7-trihydroxy-4'-methoxyflavanone (2), 6-geranyl-4',5,7-trihydroxy-3',5'-dimethoxyflavanone (3), 6-geranyl-4',5,5',7-tetrahydroxy-3'-methoxyflavanone (4), 6-geranyl-3,3',5,7-tetrahydroxy-4'-methoxyflavanone (5), 4',5,5',7-tetrahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]-3'-methoxyflavanone (6), 3,3',4',5,7-pentahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]flavanone (7), 3,3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (8), and 3,4',5,5',7-pentahydroxy-3'-methoxy-6-(3-methyl-2-butenyl)flavanone (9), along with six known geranylated flavanones. Among these, compounds 4, 6-9 and the known 6-geranyl-3',4',5,7-tetraahydroxyflavanone (diplacone), 6-geranyl-3,3',4',5,7-pentahydroxyflavanone (diplacol) and 3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone showed potent radical scavenging effects towards DPPH radicals.     

A benzil and isoflavone from Iris tenuifolia

Two compounds, tenuifodione (1) and tenuifone (2), and 12 known compounds, izalpinin (3), alpinone (4), arborinone (5), irilin B (6), irisone A (7), irisone B (8), betavulgarin (9), beta-sitosterol (10), 5,7-dihydroxy-2',6-dimethoxyisoflavone (11), 2',5-dihdroxy-6,7-methylenedioxy flavanone (12), irisoid A (13) and ethyl-beta-d-glucopyranoside (14) were isolated from the whole plant of Iris tenuifolia Pall. All compounds, except 12, were isolated for the first time from this plant. Compounds 2, 3 and 11 have shown a considerable DPPH radical scavenging activity. Structures of these compounds were identified on the basis of spectroscopic techniques, including 2D NMR. Compounds 3, 5 and 7 were also subjected to single-crystal X-ray diffraction analysis and their structures were unambiguously deduced.     

Iridoid glucosides and flavones from the aerial parts of Avicennia marina

Two new iridoid glucosides, namely, 2'-O-[(2E,4E)-5-phenylpenta-2,4-dienoyl]mussaenosidic acid (1; mussaenosidic acid = [1S-(1alpha,4aalpha,7alpha,7aalpha)]-1-(beta-D-glucopyranosyloxy)-1,4a,5,6,7,7a-hexahydro-7-hydroxy-7-methylcyclopenta[c]pyran-4-carboxylic acid) and 2'-O-(4-methoxycinnamoyl)mussaenosidic acid (2), were isolated from the aerial parts of the mangrove plant Avicennia marina. Beside that, one known iridoid glucoside, 2'-O-coumaroylmussaenosidic acid (3) and four known flavones (flavone = 2-phenyl-4H-1-benzopyran-4-one) including 4',5-dihydroxy-3',7-dimethoxyflavone (4), 4',5-dihydroxy-3',5',7-trimethoxyflavone (5), 4',5,7-trihydroxyflavone (6), and 3',4',5-trihydroxy-7-methoxyflavone (7) were also isolated and identified. The structures of these compounds were elucidated by NMR spectroscopy and by low- and high-resolution mass spectrometry. The chemotaxonomic significance of these findings was discussed. In addition, each isolated compound was evaluated for the ability of alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical-scavenging activity.     

Non-alkaloid Constituents of Buxus sinica (Buxaceae)

From the aerial parts of Buxus sinica, ten non- alkaloid compounds were isolated and identified as cleomiscosin A ( 1 ), 3, 5-dihydroxyl-4', 6, 7-trimethyl flavone-3′- O-β- D-glucopyranoside ( 2 ), 3, 5, 3', 4′tetrahydroxyl-3, 6, 7-trimethyl flavone (3 ) , cleomiscosin A-4′- O-β- D-gluco-pyranoside (4 ), 3, 5-dimethoxybenzoicacid-4- O-β- D-glucopyranoside (5 ), 4′, 5-dihydroxyl-3, 6, 7-trimethyl flavone (6), lupine (7), ( + )-pinoresinol- O-β- D-glucopyranoside (8 ), β-sitosterol (9), and daucosterol (10). Their structures were identified by spectral evidence.     

Natural PTP1B inhibitors from Broussonetia papyrifera

Two new compounds, 8-(1,1-dimethylallyl)-5'-(3-methylbut-2-enyl)-3',4',5,7-tetrahydroxyflanvonol (1), 3'-(3-methylbut-2-enyl)-3',4',7-trihydroxyflavane (2) and three known compounds 3,3',4',5,7-pentahydroxyflavone (3), uralenol (4), broussochalcone A (5) were isolated from the roots of Broussonetia papyrifera, and their structures determined by spectroscopic methods. Compounds 1, 3, 4 and 5 significantly show the inhibitory activities against the PTP1B enzyme.     

An lonone Derivative from Isodon leucophyllus

A new ionone derivative and six known flavonoids were isolated from the aerial parts of Isodon leucophyllus (Dunn) Kudo. Their structures were respectively elucidated as 13-carboxy-blumenol C (1), 5, 7, 3', 4'-tetramethoxyflavone (2), cirsiliol (3), 5-hydroxy-6, 7, 3', 4'-tetramethoxyflavone (4), 3'-hydroxy-5, 7, 8, 4'-tetramethoxyflavone (5), isosinensetin (6) and isoquercetrin (7), based on their spectra analysis. All of the six flavonoids were reported firstly from this plant.     

Effect of the azetidine and azocine rings of okaramine B on insecticidal activity

Four degraded okaramine B (2) products, 4',5'-dihydrookaramine B (3), two azetidine ring-opened compounds (4 and 5) and 1',2',4',5'-tetrahydrookaramine B (6), were prepared and their insecticidal activity was examined. Neither compounds 4 nor 5 showed such activity against silkworms, indicating that the azetidine ring moiety played an important role in the insecticidal activity. Moreover, both compounds 3 and 6 exhibited lower activity than 2, which means that the azocine ring moiety was indispensable to form the active conformation.