柬埔寨柯拉斯那沉香的化学成分研究

该文采用ODS、硅胶、Sephadex LH-20等柱色谱技术,对柬埔寨野生柯拉斯那沉香(Aquilaria crassna)进行了研究。结果表明:从柬埔寨柯拉斯那所产沉香的乙醇提取物中进行分离共得到了10个化合物,包括一对对映异构体(9a/9b)。经波谱解析分别鉴定为6-甲氧基-2-[2-(3-羟基-4-甲氧基苯)乙基]色酮(1)、6-甲氧基-2-[2-(3-甲氧基-4-羟基苯)乙基]色酮(2)、6,7-二甲氧基-2-(2-苯乙基)色酮(3)、6-羟基-2-(2-苯乙基)色酮(4)、6-羟基-2-[2-(4-甲氧基苯)乙基]色酮(5)、8-氯-6-羟基-2-[2-(3-羟基-4-甲氧基苯)乙基]色酮(6)、8-氯-6-羟基-2-[2-(4-甲氧基苯)乙基]色酮(7)、oxidoagarochromone B(8)、4'-demethoxyaqusisnenone D(9)。其中,化合物6、7和9均为首次从柯拉斯那沉香中分离得到。活性测试结果显示,化合物1和2对乙酰胆碱脂酶具有一定的抑制活性,化合物2对人慢性髓原白血病细胞K562具有较弱的抑制作用。     

Diarylpropanes from the wood of Iryanthera grandis

Trunk wood of Iryanthera grandis contains 1(2′-hydroxy-4′,6′-dimethoxyphenyl)-3-(3″,4″-methylenedioxyphenyl)-propane and 1(2′-hydroxy-4′,6′-dimethoxyphenyl)-3-(3″-methoxy-4″-hydroxyphenyl)-propane, as well as three additional known diarylpropanes, a new flavan (±)-5,7-dimethoxy-4′-hydroxyflavan and the known (±)-7,4′-dihydroxy-3′-methoxyflavan.     

Ferulic acid dehydrodimers from wheat bran: isolation,purification and antioxidant properties of 8-0-4-diferulic acid

Summary

Wheat bran contains several ester-linked dehydrodimers of ferulic acid, which were detected and quantified after sequential alkaline hydrolysis. The major dimers released were: trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxy-phenyl)-7-methoxy-2,3-dihydrobenzofuran-3-carboxylic acid (5–8-BendiFA), (Z)-β-(4-[(E)-2-carboxyvinyl]-2-methoxy-phenoxy)-4-hydroxy-3-methoxycinnamic acid (8-O-4-diFA) and (E,E)-4,4′-dihydroxy-5,5′-dimethoxy-3,3′-bicinnamic acid (5–5-diFA). trans-7-hydroxy-1-(4-hydroxy-3methoxyphenyl)-6-methoxy-1,2-dihydro-naphthalene-2,3-dicarboxylic acid (8–8-diFA cyclic form) and 4,4′-dihydroxy-3,3′-dimethoxy-β,β'-bicinnamic acid (8–8-diFA non cyclic form) were not detected. One of the most abundant dimers, 8-O-4-diFA, was purified from de-starched wheat bran after alkaline hydrolysis and preparative HPLC. The resultant product was identical to the chemically synthesised 8-O-4-dimer by TLC and HPLC as confirmed by ¹H-NMR and mass spectrometry. The absorption maxima and absorption coefficients for the synthetic compound in ethanol were: λ_max: 323 nm, λ_min: 258 nm, ε_λmax (M^?1cm^?1): 24800 ± 2100 and ε₂₈₀ (M^?1cm^?1): 19700 ± 1100. The antioxidant properties of 8-O-4-diFA were assessed using: (a) inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine liposomes and; (b) scavenging of the radical cation of 2,2′-azinobis (3-ethyl-benzothiazoline-6-sulphonate) (ABTS) relative to the water-soluble vitamin E analogue, Trolox C. The 8-O-4-diFA was a better antioxidant than ferulic acid in both lipid and aqueous phases. This is the first report of the antioxidant activity of a natural diferulate obtained from a plant.     

1-Methoxy-, 1-deoxy-11-hydroxy- and 11-Hydroxy-1-methoxy-Δ-tetrahydrocannabinols: new selective ligands for the CB2 receptor

Three series of new cannabinoids were prepared and their affinities for the CB₁ and CB₂ cannabinoid recptors were determined. These are the 1-methoxy-3-(1′,1′-dimethylalkyl)-, 1-deoxy-11-hydroxy-3-(1′,1′-dimethylalkyl)- and 11-hydroxy-1-methoxy-3-(1′,1′-dimethylalkyl)-Δ⁸-tetrahydrocannabinols, which contain alkyl chains from dimethylethyl to dimethylheptyl appended to C-3 of the cannabinoid. All of these compounds have greater affinity for the CB₂ receptor than for the CB₁ receptor, however only 1-methoxy-3-(1′,1′-dimethylhexyl)-Δ⁸-THC (JWH-229, 6e) has effectively no affinity for the CB₁ receptor (K_i=3134±110 nM) and high affinity for CB₂ (K_i=18±2 nM).     

Degradation of 3,9-dimethoxypterocarpan and medicarpin by Fusarium fungi

Fusarium sporotrichioides and Gibberella saubinetti O-demethylate 3,9-dimethoxypterocarpan to 3-methoxy-9-hydroxypterocarpan and then 3,9-dihydroxypterocarpan. F. anguioides Sherb., F. avenaceum and F. graminearum convert the same substrate to a mixture of 3-methoxy-9-hydroxypterocarpan and 3-hydroxy-9-methoxypterocarpan. Induction of pterocarpan degradation by pisatin in F. avenaceum leads to preferential conversion of 3,9-dimethoxypterocarpan to 3-hydroxy-9-methoxypterocarpan (medicarpin) and the isoflavan vestitol. The data are discussed with respect to phytoalexin degradation by phytopathogenic Fusarium fungi.Dedicated to Prof. Dr. H. Holzer, Freiburg, at the occasion of his 60th birthday     

Pterocarpans from Dalbergia spruceana

The wood of Dalbergia spruceana contains, besides O-acetyloleanolic acid, elemicin and 3,4,5-trimethoxy-cinnamaldehyde; the neoflavonoids (S)-4-methoxydalbergione and dalbergin; the isoflavones biochanin-A, formononetin, pseudobaptigenin and caviunin; and the pterocarpans (±)-medicarpin, (±)-maackiain, as well as the 3,4-dihydroxy-, 3-hydroxy-4-methoxy- and 4-hydroxy-3-methoxy-derivatives of (6aR,11aR)-8,9-methylenedioxypterocarpan. The constitutions of the three last named compounds were deduced by spectra and confirmed by synthesis of (±)-4-hydroxy-3-methoxy-8,9-methylenedioxypterocarpan.     

Selective cleavage of 10-methyl benzo[b]naphtho[2,1-d]thiophene by recombinant Mycobacterium sp. strain

Recombinant Mycobacterium sp. strain MR65 carrying dszABCD genes was used for desulfurization of 10-methylbenzo[b]naphtho[2,1-d]thiophene (10-methyl BNT) in the hexadecane phase. The specific activity was 25% of that of dibenzothiophene (DBT). One of two major metabolites of 10-methyl BNT produced by strain MR65 was identified as 1-methoxy-2-(3-methylphenyl)naphthalene by ¹H and ¹³C NMR. The other major metabolite and two minor metabolites were determined as 1-hydroxy-2-(3-methylphenyl)naphthalene, 2-(2-methoxy-3-methylphenyl)naphthalene and 2-(2-hydroxy-3-methylphenyl)naphthalene, respectively, by HPLC and GC-MS. The production ratio of the two desulfurization metabolite isomers was 0.99:0.01, calculated on the basis of peak GC areas. These results indicated that the C-S bond adjacent to the naphthalene skeleton was selectively cleaved to form the two major compounds.     

Anti-mosquito and antimicrobial nor-halimanoids, isocoumarins and an anilinoid from Tessmannia densiflora

The nor-halimane diterpenoid tessmannic acid and its methyl, 2-methylisopropyl and 1-methylbutyl esters, the unusual isocoumarins 8-hydroxy-6-methoxy-3-pentylisocoumarin and 7-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin, and 5-pentyl-3-methoxy-N-butylaniline were isolated from the stem and root bark extracts of Tessmannia densiflora Harms (Caesalpiniaceae) that showed mosquito larvicidal activity. The structures were determined on interpretation of spectroscopic data. Tessmannic acid and its methyl ester exhibited antibacterial and antifungal activity. The compounds also caused high larvae and adult Anopheles gambiae mosquitoe mortality effects, and stronger mosquito repellency than that shown by the standard repellent DEET, hence indicating Tessmannia species to be potential sources of bioactive natural products.     

A new depside and two new diphenyl ether compounds from the lichen Ramalina farinacea (L.) Ach

The chemical investigation of the Vietnamese lichen Ramalina farinacea (L.) Ach. led to the isolation and the structure elucidation of eight compounds (1–8), including one new depside, formulated as methyl homosekikate (1) and two new diphenyl ethers, 3-(2-carboxy-5-methoxy-3-propylphenoxy)-2-hydroxy-4-methoxy-6-propylbenzoic acid, namely ramalinic acid A (2), and 3-(2-carboxy-5-methoxy-3-propylphenoxy)-2-hydroxy-4-methoxy-6-pentylbenzoic acid, namely ramalinic acid B (3). Their chemical structures were unambiguously determined by analysis of 1D and 2D NMR and high resolution ESI mass spectroscopic data, as well as by comparison with literature data. We also proposed a possible biosynthetic route for the formation of the two new diphenyl ethers (2) and (3) via an enzymatically induced intramolecular Smiles rearrangement of the depsides sekikaic acid and homosekikaic acid, respectively.     

人工诱导海南龙血竭的化学成分研究

为了解人工诱导海南龙血树(Dracaena cambodiana)所产血竭的化学成分,从其乙醇提取物中分离得到10个化合物,经波谱分析分别鉴定为socotrin-4?-ol(1)、homoisosocotrin-4?-ol(2)、(E)-3-(3,4-dihydroxybenzylidene)-7-hydroxy-chroman-4-one(3)、5-hydroxy-7-methoxy-3-(4?-hydroxybenzyl)-4-chromanone (4)、3-去氧苏木查耳酮(5)、苏木查耳酮(6)、7,4?-二羟基黄酮(7)、7,4?-二羟基-8-甲基黄酮(8)、丁香树脂醇(9)和邻苯二甲酸二(2-乙基己基)酯(10)。化合物1～10均为首次从人工诱导海南龙血树所产血竭中分离得到,其中化合物8为新天然产物,化合物3～6为首次从血竭中分离得到。化合物7和8对耐甲氧西林金黄色葡萄球菌具有生长抑制作用。     

Bioconversion of substituted naphthalenes to the corresponding salicylic acids

The Pseudomonas fluorescens N3 was isolated from soil for its ability to utilize naphthalene as a carbon source. The strain transforms 2,3-dimethyl-, 2-methoxy-, 1- and 2-ethylnaphthalenes to the corresponding salicylic acids competitively with chemical synthesis. The identification of 2-hydroxy-2-carboxy-7-ethylchromane by biotransformation of 2-ethylnaphthalene, contributes to elucidating the steps involved in the catabolic pathways of naphthalenes to salicylaldehydes. Correspondence to: F. Pelizzoni     

Isolation and characterization of substituted 4-hydroxy-cyclohex-2-enones as metabolites of 3,4-dimethoxybenzyl alcohol and its methyl ether in ligninolytic cultures of Phanerochaete chrysosporium

The metabolism of quinones formed in the enzymatic oxidation of veratryl alcohol (3,4-dimethoxybenzyl alcohol) (Ia) and its methyl ether Ib in ligninolytic cultures of Phanerochaete chrysosporium was studied. A metabolite of 2-hydroxymethyl-5-methoxy-2,5-cyclohexadiene-1,4-dione (IIa, formed from Ia by oxidation) was isolated and identified as cis-4-hydroxy-6-hydroxymethyl-3-methoxy-cyclohex-2-en-one (IVa), formally the reduced hydroquinone IIIa. The formation of IVa was also observed when both veratryl alcohol Ia or 2,5-dihydroxy-4-methoxybenzyl alcohol (IIIa), the hydroquinone of IIa, were used as substrates. Analogously, cis-4-hydroxy-3-methoxy-6-methoxymethyl-cyclohex-2-en-one (IVc) was isolated and identified as a metabolite from either 3,4-dimethoxybenzyl methyl ether (Ib) or from its oxidation product 5-methoxy-2-methoxymethyl-2,5-cyclohexadiene-1,4-dione (IIb) as well as from the corresponding hydroquinone 2,5-dihydroxy-4-methoxybenzyl methyl ether (IIIc). The physiological role of these unprecedented conversions is discussed. Correspondence to: H. E. Schoemaker     

A chromene an isoprenylated methyl hydroxybenzoate and a C-methyl flavanone from the bark of Piper hostmannianum

In addition to sitosterol, linalool, 5-hydroxy-7-methoxy-6,8-dimethylflavanone and 5,7-dihydroxyflavanone, two new natural products were isolated from Piper hostmannianum and characterized as methyl 2,2-dimethyl-2H-1-benzopyran-6-carboxylate and methyl 4-hydroxy-3-(2′-hydroxy-3′-methylbut-3′-enyl)-benzoate on the basis of spectroscopic data and chemical derivatization.     

Cytotoxic tirucallane C26 triterpenoids from the stem barks of Aphanamixis grandifolia

Five tirucallane type C₂₆ triterpenoids, accompanied by two known compounds, 3α-hydroxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone and 3-oxo-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, were isolated from the stem barks of Aphanamixis grandifolia. Their structures were established mainly by means of a combination of 1D and 2D NMR spectroscopic and mass spectrometry techniques as 3α-hydroxyl-21α-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3α-hydroxy-21β-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3-oxo-21α-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3-oxo-21β-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, and 3-oxo-21α-ethoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone. All isolates were in vitro evaluated for their cytotoxic activities against five tumor cell lines (MCF-7, HeLa, HepG2, SGC-7901 and BGC-823).     

Lignans from machilus thunbergii

Five new lignans, machilin A[(2S,3R)-2,3-dimethyl-1,4-dipiperonyl-butane], machilin B [(2S,3S)-2,3-dihydro-7-methoxy-3-methyl-2-piperon threo-2-(2-methoxy-4-trans-propenylphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol], machilin E (erythro-1-acetoxy-2-(2-methoxy-4-trans-(3-hydroxy-1-propenyl)phenoxy]-l-piperonylpropane) were isolated from the bark of Machilus thunbergii and their structures were characterized.     

Tetronic acid and diarylpropanes from Iryanthera elliptica

The trunk wood of Iryanthera elliptica Ducke (Myristicaceae) contains, besides 2-(ω-piperonyltridecyl) -4-methylidenetetronic acid (iryelliptin), three biogenetically related compounds: (±)-7,4′-dihydroxy-3′-methoxyflavan, 1-(4′-hydroxy-2′-methoxyphenyl)- 3-(4″-hydroxy-3″-methoxyphenyl)-propane and spiro-[3-methoxy-2,5-cyclohexadien-1.1′-6′,7′- dihydroxy-5′-methoxy-1′,2′,3′,4′-tetrahydronaphthalen]-4-one-(spiroelliptin). Spiroelliptin rearranges upon methylation to 2,2′-trimethylene-3,4,5,4′,5′-penta-methoxybiphenyl.     

Synthesis of (±)-licarin-B

The synthesis of (±)-licarin-B, a neolignan of Licaria aritu Ducke (Lauraceae), was achieved by pyrolysis of 3-hydroxy-3-piperonyl-1-propyl-2-methoxy-4-(E)-propenylphenyl ethers.     

Chiral synthesis via organoboranes. 41. The utility of B-chlorodiisopinocampheylborane for a general synthesis of enantiomerically pure drugs

A general approach to the synthesis of enantiomerically pure α-phenyl amino alcohols via the asymmetric reduction of α-phenyl haloalkyl ketones or α-phenyl aminoalkyl ketones with B-chlorodiisopinocampheylborane is described. Using this approach, an improved synthesis of a potential antipsychotic, α-(4-fluorophenyl)-4-(2-pyrimidinyl)-1-piperazinebutanol in ⩾98% ee, and the broncholdilator 1-(2-methoxy-2-phenethyl)-4-(3-hydroxy-3-phenylpropyl)piperazine (eprozinol) in ⩾99% ee is achieved. © 1995 Wiley-Liss, Inc.     

Isolation and Some Properties of Anti-proteolytic Polypeptides from Potato

A new nematicidal alkaloid, peniprequinolone (1), together with the known alkaloids penigequinolones A and B (2a, 2b), 3-methoxy-4-hydroxy-4-(4′-methoxyphenyl)quinolinone (3), and 3-methoxy-4,6-dihydroxy-4-(4′-methoxyphenyl)quinolinone (4), were isolated from Penicillium cf. simplicissimum (Oudemans) Thom. Cyclopenin (5) and a compound (6a/6b) structurally related to cyclopenin also were isolated from the fungus, and their structures were established by spectroscopic analysis. The biological activities of 1, 2, 3, 4, and 5 were examined by a bioassay with root-lesion nematodes.