刺桑皮正丁醇部位化学成分研究

为研究刺桑(Taxotrophis ilicifolia)皮正丁醇部位的化学成分，该研究采用硅胶、ODS、Sephadex LH-20、反相半制备高效液相等色谱法对刺桑皮正丁醇萃取部位进行分离纯化，并综合理化性质及波谱数据鉴定其化合物的结构。结果表明：从刺桑皮正丁醇萃取物中分离得到16个化合物，分别鉴定为icariside E5 (1)、裂环异落叶松脂醇-9-O-β-吡喃葡萄糖苷(2)、2,4,6-三甲氧基苯酚-1-O-β-D-葡萄糖苷(3)、9-O-β-glucopyranosyl trans-cinnamyl alcohol (4)、3,4,5-三甲氧基苯酚-1-O-β-呋喃芹糖基-(1″→6′)-β-吡喃葡萄糖苷(5)、3-羟基-4,5-二甲氧基苯酚-β-D-吡喃葡萄糖苷(6)、2,6-二甲氧基-4-羟基苯酚-1-O-β-D-吡喃葡萄糖苷(7)、isotachioside (8)、ficuscarpanoside A (9)、uridine (10)、methyl syringate 4-O-β-D-glucopyranoside (11)、3,4,5-三甲氧基苯酚-β-D-吡喃...     

山楂核干馏油GC-MS主要成分分析及含量测定

本研究目的在于建立气相色谱-质谱联用法(GC-MS)分析山楂核干馏油中挥发油、脂溶性成分以及气相色谱法(GC-FID)同时测定山楂核干馏油中活性成分的定量分析方法。采用GC-MS法对山楂核干馏油化学成分进行分析,共分析出62种化学成分,用峰面积归一化法测定各成分的相对百分含量,含量最高的化合物为醛类,占总量的55.96%。以GC-FID法同时测定山楂核干馏油中的主要成分的含量(糠醛、愈创木酚、2,6-二甲基苯酚、2-甲基苯酚、苯酚、2-甲氧基-4-甲基苯酚、2,6-二甲氧基苯酚、四氯愈创木酚、1,2,3-三甲氧基苯、3,4,5-三甲氧基甲苯),测得加样回收率范围为100.06%~102.44%,RSD范围为2.98%~4.57%。本方法准确、简便、重复性好,为山楂核干馏油制剂的内在质量控制及提升废弃物山楂核循环利用价值提供依据。     

桑白皮化学成分的研究

从桑白皮(Cortex Mori)的水提液中分离得到5个化学成分,通过波谱数据结合理化性质分别鉴定为4,4’-二苯甲烷二氨基甲酸甲酯(4,4’-diphenylmethane-bis(methyl)carbamates,1),东莨菪内酯(seopoletin,2),伞形花内酯(umbelliferone,3),3,4,5-三甲氧基苯酚(3,4,5-trimethoxyphenol,4),对羟基苯甲酸乙酯(4-hydroxy ethyl-benzoate,5)。其中,化合物1为新的天然化合物,4和5为首次从该植物中分得。     

重唇石斛地上部分化学成分及其生物活性研究

为了解重唇石斛(Dendrobium hercoglossum)的化学成分,利用硅胶、Sephadex LH-20柱色谱和半制备高效液相色谱等方法,从其地上部分分离了14个化合物,经波谱分析,其结构分别鉴定为：3,4,5-三甲氧基苯酚(1)、3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-propan-1-one (2)、methyl 3-(p-hydroxyphenyl) propionate (3)、justiciresinol (4)、榕醛(5)、异落叶松脂素(6)、threo-2,3-bis-(4-hydroxy-3-methoxyphenyl)-3-methoxypropanol (7)、(+)-松脂素(8)、aloifolⅠ(9)、dendrocandin T (10)、3-甲氧基-4-羟基苯丙酮(11)、1,3,5-三甲氧基苯酚(12)、香草醇(13)和丁香脂素(14),其中化合物1～12,14均为首次从重唇石斛中分离得到,化合物7、10和14为首次从石斛属植物中分离得到。化合物4、8和10具有显著的酪氨酸酶抑制活性,IC_...     

红树林植物瓶花木中的细胞毒活性成分

从红树林植物瓶花木(Scyphiphora hydrophyllacea Gaertn. F.)的乙醇提取物中分离得到6个化合物,经波谱分析及与文献数据对照确定其结构分别为:betulone(1)、3,4,5-三甲氧基苯酚-β-D-吡喃葡萄糖苷(2)、α-香树脂醇(3)、β-香树脂醇(4)、β-谷甾醇(5)和豆甾醇(6)。经MTT法活性测定,结果表明化合物1对肝癌细胞SMMC-7721的增殖显示生长抑制活性,其IC50值为12.5μgml-1。     

海绵Dysideidae sp.中的两个溴代酚类化合物

利用各种层析手段,从海绵Dysideidae sp.的正丁醇部分纯化了两个溴代酚类化合物,通过各种波谱数据鉴定为3,4,5-三溴-2-(2,′4′-二溴-苯氧基)-苯酚(1)和3,4,5,6-四溴-2-(2,′4′-二溴-苯氧基)-苯酚(2)。     

花锚的三个新(口山)酮

从花锚(Halenia elliptica D.Don)中又得到三种新的(Ⅵ、Ⅶ、Ⅹ)和两种已知的(Ⅷ、Ⅸ)(口山)酮成分。根据化学反应、光谱数据及其相应衍生物与已知化合物比较,三种新(口山)酮的结构分别确定为1,7-二羟基-2,3,4,5-四甲氧基(口山)酮(Ⅵ),1,5-二羟基-2,3,7-三甲氧基(口山)酮(Ⅶ)及1,2-二羟基-3,4,5-三甲氧基(口山)酮(X)。两种已知(口山)酮分別为1,5-二羟基-2,3-二甲氧基(口山)酮(Ⅷ)和1,7-二羟基-2,3-二甲氧基(口山)酮(Ⅸ)。     

三丫苦的化学成分研究

采用硅胶柱层析从三丫苦的乙酸乙酯萃取物中分离得到6种化合物,经波谱分析鉴定为4,7-二甲氧基呋喃喹啉生物碱(1)、顺式-3,4,5-三羟基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(2)、3-羟基-4-乙氧基-5,7-二甲氧基-6-乙酰-2,2-二甲基色烷(3)、3,5-二羟基-4-乙氧基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(4)、异吴茱萸酮酚(5)和异吴茱萸酮酚甲醚(6)。所有化合物均首次从该植物的根部分离得到。     

α-O-4型木质素二聚体模型物热解解聚机理

为了解木质素α-O-4连接部分的热解机理,以4-(3-羟基-1-苯氧基丙基)-苯酚为α-O-4型木质素二聚体模型化合物,采用密度泛函理论M06-2X/6-31+G(d,p)方法,对该二聚体热解过程中的反应物、中间产物、过渡态、产物进行几何结构的完全优化,通过计算各可能路径的反应能垒,确定了该模型化合物主要通过Cα-O键的均裂和协同断裂的方式发生裂解反应,主要生成苯酚、4-甲基苯酚、4-乙烯基苯酚和香豆醇等酚类产物以及乙醇、甲醇、甲醛等小分子物质,由此首次从理论上揭示了该模型化合物的详细热解解聚过程。     

紫红獐牙菜中的酮类成分及其细胞毒活性

采用色谱分离手段对紫红獐牙菜Swertia punicea的乙醇提取物中乙酸乙酯和石油醚萃取部分进行分离纯化,运用1H NMR、13C NMR、HSQC、HMBC和ESI-MS等波谱方法和文献数据对比鉴定化合物结构,从紫红獐牙菜全草中得到8个口山酮类化合物,分别鉴定为1-羟基-2,3,5,7-四甲氧基口山酮(1)、1,2,3,4,5-五甲氧基口山酮(2)、1-羟基-2,3,4,7-四甲氧基口山酮(3)、1-羟基-2,3,5-三甲氧基口山酮(4)、dulcisxanthone C(5)、1-羟基-2,3,7-三甲氧基口山酮(6)、1,5-二羟基-2,3-二甲氧基口山酮(7)、1-羟基-3,4,5-三甲氧基口山酮(8),所有化合物均为首次从该植物中分离得到,化合物1、4、5、7对Hep G-2显现了很好的细胞毒活性。     

Antioxidant flavonoids from leaves of Polygonum hydropiper L

Ten flavonoid compounds were isolated from the dried leaves of Polygonum hydropiper L. (Laksa leaves), and identified as 3-O-alpha-L-rhamnopyranosyloxy-3',4',5,7-tetrahydroxyflavone; 3-O-beta-D-glucopyranosyloxy-4',5,7-trihydroxyflavone; 6-hydroxyapigenin; 6"-O-(3,4,5-trihydroxybenzoyl) 3-O-beta-D-glucopyranosyloxy-3', 4', 5, 7-tetrahydroxyflavone; scutillarein; 6-hydroxyluteolin; 3',4',5,6,7-pentahydroxyflavone; 6-hydroxyluteolin-7-O-beta-D-glucopyranoside; quercetin 3-O-beta-D-glucuronide; 2"-O-(3,4,5-trihydroxybenzoyl) quercitrin; quercetin. Evaluation of the antioxidative activity, conducted in vitro, by using electron spin resonance (ESR) and ultraviolet visible (UV-vis) spectrophotometric assays, showed that these isolated flavonoids possess strong antioxidative capabilities. Measurement of the Trolox equivalent antioxidant capacity (TEAC) values, against ABTS (2,2'-azinobis(3-ethyl-benzo-thiazoline-6-sulphonic acid) radicals and phenyl-tert-butyl nitrone (PBN) azo initiator (AI) also showed strong anti-oxidative activity. The most powerful of the antioxidants was 2"-O-(3,4,5-trihydroxybenzoyl) quercitrin (galloyl quercitrin). A combination of two flavonoid compounds was tested for synergistic anti-oxidative capacity, but no significant improvement was observed.     

Identification of flavonoids in the stems and leaves of Scutellaria baicalensis Georgi

Scutellaria baicalensis Georgi (S. baicalensis), a perennial herb of the Labiatae family, is a well-known traditional Chinese medicine. In the present study, a comprehensive qualitative analysis of flavonoids in the stems and leaves of S. baicalensis was performed. Under the optimized experimental conditions, 21 flavonoids were clearly detected. 17 of them were successfully identified based on the on-line UV and MS(n) data and were sequentially confirmed by the literature search. The rest 4 flavonones, which were not on-line identified, were successfully isolated and were identified by 1D and 2D NMR. One of them, 5,6,7,3',4'-pentahydroxy flavanone-7-O-glucuronide (2) is a new compound.     

Effects of two hexachlorobiphenyl isomers on ornithine decarboxylase induction: inhibitory effects correlate with aryl hydrocarbon hydroxylase activity

The effects of 2,2',4,4',5,5'-hexachlorobiphenyl (2,4,5-HCB) or 3,3',4,4',5,5'-hexachlorobiphenyl (3,4,5-HCB) on hepatic ornithine decarboxylase (ODC) induction by dexamethasone were investigated. At one week after a single i.p. dose of corn oil or 2,4,5,-HCB and 4 h after administration of dexamethasone, rats exhibited 50- to 60-fold increases of ODC activity. However, rats that had received 3,4,5-HCB in place of 2,4,5-HCB exhibited only a 8-fold increase in ODC activity in response to dexamethasone administration. 2,4,5-HCB administration resulted in increased hepatic aryl hydrocarbon hydroxylase (AHH) activity. Administration of 3,4,5-HCB produced increased AHH activity and decreased N-demethylase activity. It is suggested that the ODC-inhibitory effects may have resulted from Ah-receptor-mediated events.     

DPPH radical scavenging reaction of hydroxy- and methoxychalcones

The DPPH radical scavenging activity of 2',4',6'-trihydroxy- and 2'-hydroxy-4',6'-dimethoxychalcones carrying a 2,3- and 3,4-dihydroxylated, and 3,4,5-trihydroxylated B-ring was evaluated in alcoholic and non-alcoholic solvents. All test compounds scavenged more than two equivalent of radicals by a possible conversion to the corresponding B-ring quinones and in most cases subsequently underwent cyclization to aurones and flavanones, these being identified in the reaction solutions by an in situ NMR analysis. Interestingly, the reaction between 2',3,4-trihydroxy-4',6'-dimethoxychalcone and the DPPH radical was significantly affected by the solvent used, which might be accounted for by the difference in readiness for cyclization to an aurone.     

Influence of chlorine substituents on rates of oxidation of chlorinated biphenyls by the biphenyl dioxygenase of Burkholderia sp. strain LB400

Biphenyl dioxygenase from Burkholderia (Pseudomonas) sp. strain LB400 catalyzes the first reaction of a pathway for the degradation of biphenyl and a broad range of chlorinated biphenyls (CBs). The effect of chlorine substituents on catalysis was determined by measuring the specific activity of the enzyme with biphenyl and 18 congeners. The catalytic oxygenase component was purified and incubated with individual CBs in the presence of electron transport proteins and cofactors that were required for enzyme activity. The rate of depletion of biphenyl from the assay mixture and the rate of formation of cis-biphenyl 2,3-dihydrodiol, the oxidation product, were almost equal, indicating that the assay accurately measured enzyme-specific activity. Four classes of CBs were defined based on their oxidation rates. Class I contained 3-CB and 2,5-CB, which gave rates that were approximately twice that of biphenyl. Class II contained 2,5,3',4'-CB, 2,3,2',5'-CB, 2,3,4,5-CB, 2,3,2',3'-CB, 2,4, 5,2',5'-CB, 2,5,3'-CB, 2,5,4'-CB, 2-CB, and 3,4,5-CB, which gave rates that ranged from 97 to 35% of the biphenyl rate. Class III contained only 2,3,4,2',5'-CB, which gave a rate that was 4% of the biphenyl rate. Class IV contained 2,4,4'-CB, 2,4,2',4'-CB, 3,4,5, 2'-CB, 3,4,5,3'-CB, 3,5,3',5'-CB, and 3,4,5,2',5'-CB, which showed no detectable depletion. Rates were not significantly correlated with the aqueous solubilities of the CBs or the number of chlorine substituents on the rings. Oxidation products were detected for all class I, II, and III congeners and were identified as chlorinated cis-dihydrodiols for classes I and II. The specificity of biphenyl dioxygenase for the CBs examined in this study was determined by the relative positions of the chlorine substituents on the aromatic rings rather than the number of chlorine substituents on the rings.     

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.     

Inhibitory effects of polymethoxy flavones isolated from Citrus reticulate on degranulation in rat basophilic leukemia RBL-2H3: enhanced inhibition by their combination

Polymethoxy flavones (PMFs) are present in fruit tissues of Citrus species. It has been reported that flavonoids isolated from several Citrus have been shown to suppress the degranulation as inferred by histamine release in rat basophilic leukemia RBL-2H3 cells. In this study, we examined the effect of PMFs (PMF-1: 6,7,4',5'-tetramethoxy-5-monohydroxyflavone, PMF-2: 5,6,8,3',6'-pentamethoxy flavone, PMF-3: 5,6,7,3',4',5'-hexamethoxy flavone) on the degranulation in RBL-2H3 cells. All the PMFs suppressed the degranulation from Ag-stimulated RBL-2H3 cells. Interestingly, PMF-combination (PMF-1+PMF-2; PMF-1+PMF-3) treatment enhanced the inhibition of degranulation compared with PMF-single treatment. In order to clarify the inhibitory mechanism of degranulation by PMFs, we examined the activation of intracellular signaling molecules such as Lyn, Syk, and PLCgammas. All the PMFs significantly suppressed the activation of Syk and PLCgammas. In Ag-mediated activation of Fc epsilonRI on mast cells, three major subfamilies of mitogen-activated protein kinases, especially ERK44/42, were activated. These PMFs reduced the level of phospho-ERKs. The intracellular free Ca(2+) concentration ([Ca(2+)]i) was elevated by Fc epsilonRI activation, and PMF treatment reduced the elevation of [Ca(2+)]i by suppressing Ca(2+) influx. Thus, it was suggested that the suppression of Ag-stimulated degranulation by these PMFs mainly is due to the Syk/PLCgammas/PKC pathway and Ca(2+) influx. Furthermore, to be noted in the PMF-combination treatment, inactivation of Syk was enhanced compared with PMF-single treatment. But the inhibitory effect of degranulation by PMF-combination treatment was not associated with the suppression of Ca(2+) influx.     

Acylated flavone glycosides from Veronica

A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two unusual allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-rhamnopyranosyl(1"'-->2")[6"-O-acetyl-beta-glucopyranoside] and 6-hydroxyluteolin 7-O-(6"-O-(E)-caffeoyl)-beta-glucopyranoside, respectively. Isoscutellarein 7-O-(6"'-O-acetyl)-beta-allopyranosyl(1"'-->2")-beta-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete 1H and 13C NMR spectral assignments are presented for both isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens.     

Anti-leishmanial activity of neolignans from Virola species and synthetic analogues

Surinamensin, a neolignan isolated from Virola surinamensis, 3,4,5-trimethoxy-8-[2',6'-dimethoxy-4'-(E)-propenylphenoxy]-phenylpropane, a neolignan isolated from Virola pavonis, and 25 of its synthetic analogues or correlated substances with ether linkages and their corresponding C-8 sulphur and nitrogen analogues, were tested for activity against Leishmania donovani amastigotes and promastigotes in vitro. Some were active against L. donovani promastigotes at 30 microM but inactive against intracellular amastigotes. The natural neolignan from V. pavonis was active against promastigotes at 100 microM. The highest selective activity was found in those compounds with sulphur bridges. The beta-ketosulfide (3,4-dimethoxy)-8-(4'-methylthiophenoxy)-propiophenone produced 42% inhibition of L. donovani amastigotes in the liver of BALB/c mice at 100 mg/kg given once daily for five consecutive days (P>0.05).     

粗糙肉齿菌子实体化学成分研究

利用硅胶柱层析、RP-8层析及Sephadex LH-20分离的方法,从高等真菌粗糙肉齿菌(Sarcodon scabrosus)干燥子实体的甲醇提取物中分离并鉴定了8个化合物,经现代光谱技术鉴定分别为苯甲酸(1)、麦角甾-5,7,22-三烯-3β-醇(2)、2',3'-二乙酰基-3,4,5',6',4″-五羟基-对联三苯(3)和1-乙基-β-D-吡喃葡萄糖苷(4)、对羟基苯甲酸(5)、丁二酸(6)、腺嘌呤(7)、腺嘌呤核苷(8).以上化合物均为首次从粗糙肉齿菌中获得.