高速逆流色谱分离与鉴定鹿药中黄酮类化合物

采用高速逆流色谱(HSCCC)与其它色谱联用的方法分离纯化鹿药中的化学成分,得到5个黄酮类化合物: 5,7,3′,4′-四羟基-3-甲氧基-8-甲基黄酮(1)、 8-甲基木犀草素(2)、 3′-甲氧基木犀草素(3)、 木犀草素(4)和槲皮素(5),它们均为首次自该种及该属植物中分离得到.HSCCC以V(氯仿)∶ V(甲醇)∶ V(水)=4∶ 3∶ 2混合液为溶剂,上相为固定相,下相为流动相, 分离纯化得到3个分别含化合物1, 4和5的主要部分,经HPLC检验纯度分别为98.3%, 96.7%和95.3%;还有1个含有化合物2和3的较纯部分,通过Sephadex LH-20柱色谱,以V(甲醇)∶ V(水)=1∶ 1混合液洗脱将二者分离.通过理化性质及紫外、红外、质谱、核磁等波谱分析确定化合物结构.     

A New Flavonol Glycoside from Anaphalis sinica Hance

ＩｎｔｒｏｄｕｃｔｉｏｎＳｅｖｅｒａｌｐｌａｎｔｓｏｆｇｅｎｕｓＡｎａｐｈａｌｉｓ(Ｃｏｍｐｏｓｉｔａｅ)ｈａｖｅｂｅｅｎｐｈｙｔｏｃｈｅｍｉｃａｌｌｙｓｔｕｄｉｅｄ ,ｆｒｏｍｗｈｉｃｈｆｌａｖａｎｏｉｄｓ[1,2 ] ,ｈｅｌｉｐｙｒｏｎｅ[3] ,ｃｈｌｏｒｏａｃｅｔｙｌｅｎｉｃｃｏｍｐｏｕｎｄｓｗｉｔｈａｄｉｈｙｄｒｏｐｙｒａｎｏｒｆｕｒａｎｒｉｎｇ[4] ａｎｄｐｈｔｈａｌｉｄｅｓｈａｖｅｂｅｅｎｒｅｐｏｒｔｅｄ[5 ] .Ａ .ｓｉｎｉｃａＨａｎｃｅ ,ｄｉｓｔｒｉｂｕｔｅｄｉｎＣｈｉｎａａｎｄａｌｓｏｆｏｕｎｄ…     

Studies in polyphenol chemistry and bioactivity. 4.(1) Synthesis of trimeric,tetrameric, pentameric,and higher oligomeric epicatechin-derived procyanidins having all-4beta,8-interflavan connectivity and their inhibition of cancer cell growth through cell cycle arrest

We report an improved synthesis of bis(5,7,3',4'-tetra-O-benzyl)epicatechin 4beta,8-dimer (3) from 5,7,3',4'-tetra-O-benzylepicatechin (1) and 5,7,3',4'-tetra-O-benzyl-4-(2-hydroxyethoxy)epicatechin (2) by replacing the previously employed Lewis acid, titanium tetrachloride, with the clay mineral Bentonite K-10. Under the same conditions, the benzyl-protected all-4beta,8-trimer, -tetramer, and -pentamer were obtained regioselectively from their lower homologues, albeit in rapidly decreasing yields. Reaction of 2 with an organoaluminum thiolate generated from 2-mercaptobenzothiazole and trimethylaluminum followed by acetylation produced 3-O-acetyl-4-[(2-benzothiazolyl)thio]-5,7,3',4'-tetra-O-benzylepicatechin (12). Medium-sized protected oligomers with 4beta,8-interflavan linkages are obtained in improved yields by using this compound as the electrophile and silver tetrafluoroborate as activator and are isolated by reversed-phase HPLC. Their deprotection by ester saponification followed by hydrogenolysis yielded the free procyanidins, which were characterized as their peracetates. The synthetic procyanidins are identical by normal-phase HPLC with fractions isolated from cocoa. The principle of chain extension by two members was demonstrated using a dimeric electrophile obtained by self-condensation of compound 12. Both the synthetic and natural pentamer 32 inhibit the growth of several breast cancer cell lines. Using the MDA MB 231 line, it was established that this outcome is based on the induction of cell cycle arrest in the G0/G1 phase. Subsequent cell death is more likely necrotic rather than apoptotic. Control experiments demonstrate that the polyphenol itself, rather than hydrogen peroxide potentially formed by its autoxidation, is the causative agent.     

The first 5,6-dihydroxyindole tetramer by oxidation of 5,5',6,6'-tetrahydroxy- 2,4'-biindolyl and an unexpected issue of positional reactivity en route to eumelanin-related polymers

[structure: see text]. The first tetramer of the eumelanin precursor 5,6-dihydroxyindole has been obtained, as the acetyl derivative, by peroxidase/H2O2-induced oxidative coupling of 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (2) in the presence of Zn2+ ions. The tetramer, 5,5',5',5',6,6',6',6'-octaacetoxy-2,4':2',3':2',4'-tetraindolyl (acetylated 7), incorporates an unprecedented 2,3'-biindolyl substructure suggestive of a different positional reactivity of the 5,6-dihydroxyindole system when framed into a dimeric scaffold.     

Preparative isolation and separation of a novel and two known flavonoids from Patrinia villosa Juss by high-speed counter-current chromatography

Preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and separation three flavonoids including bolusanthol B, a novel compound named 5,7,2',6'-tetrahydroxy-6,8-di(gamma,gamma-dimethylallyl) flavanone and tetrapterol I from Patrinia villosa Juss using two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at the volume ratio of 10:11:11:8 (v/v). A total of 25.4 mg bolusanthol B, 52.5 mg 5,7,2',6'-tetrahydroxy-6,8-di(gamma,gamma-dimethylallyl) flavanone and 50.2 mg tetrapterol I were obtained from 250 mg crude extract with purities of 96.8%, 99.2% and 99.3%, respectively determined by HPLC in one single operation and less than 5 h. The structure identification was performed by UV, IR, MS, 1H NMR, 13C NMR and 2D NMR. Among then, bolusanthol B and tetrapterol I were obtained from the plant of Patrinia genius for the first time, and 5,7,2',6'-tetrahydroxy-6,8-di(gamma,gamma-dimethylallyl) flavanone was a novel prenylated flavonoid and discovered from nature for the first time.     

The enantioselective metabolism of p-cymene in rabbits.

p-Cymene (1) was metabolized in rabbits and the following four optically active metabolites, 2-(p-tolyl)-1-propanol (3': R/S = 65:35), 2-(p-tolyl)propanoic acid (5': R/S = 0:100), p-(2-hydroxy-1-methylethyl)benzoic acid (6': R/S = 91:9) and p-(1-carboxyethyl)benzoic acid (8': R/S = 30:70), were isolated in addition to three optically inactive metabolites, 2-(p-tolyl)-2-propanol (2), p-isopropylbenzoic acid (4'), and p-(1-hydroxy-1-methylethyl)benzoic acid (7'). The presumed metabolic pathways of p-cymene in rabbits were confirmed by the administration of the intermediate metabolites (2, 3', 4', and 5'). The enantiomeric ratios of the metabolites, 3' and 6', suggested that omega-hydroxylations of the isopropyl group in 1 and 4' occurred preferentially at the pro-S methyl group. In the metabolism of 1, the S-isomers are predominant in the propanoic acid derivatives, but the R-isomers are rich in the propanol derivatives. It is of interest that the metabolism of 4', however, produced predominantly the corresponding propanol derivative (6'; R/S = 91:9) and propanoic acid derivative (8'; R/S = 80:20) possessing the same R-configuration. Some optically active p-cymene derivatives were also synthesized as standard compounds.     

Two new flavanone glycosides of Jasminum lanceolarium and their anti-oxidant activities

Two new flavanone glucosides, (2S)-5,7,3',5'-tetrahydroxy-flavanone 7-O-beta-D-allopyranoside (1) and (2S)-5,7,3',5'-tetrahydroxy-flavanone 7-O-beta-D-glucopyranosie (2) were isolated from the stems and leaves of Jasminum lanceolarium, along with five known compounds: Betulinaldehyde (3), betulinic acid (4), betulin (5), syringin (6) and Liriodendrin (7). Their structures were determined on the basis of spectroscopic and chemical methods. The isolated compounds were screened for their in vitro antioxidant activity through DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. Compounds 2 demonstrated significant radical scavenging activity.     

Biotransformation of a C-glycosylflavone, abrusin 2''-O-beta-D-apioside, by human intestinal bacteria

After anaerobic incubation of abrusin 2'-O-beta-D-apioside (1) with a human fecal suspension, five metabolites were isolated and identified as abrusin (2), 1-(2',6'-dihydroxy-3',4'-dimethoxyphenyl)-3-(4'-hydroxyphenyl)propan-1- one (5), 5,6-dimethoxybenzene-1,3-diol (6), 3-(4'-hydroxyphenyl)propionic acid (7) and 3-phenylpropionic acid (8). However, methyl ether derivatives of abrusin (4'-O-methylabrusin and 4'-O-, 5-O-dimethylabrusin) resisted degradation under the same conditions.     

Isolation of sesquiterpenoids from sponge Dysidea avara and chemical modification of avarol as potential antitumor agents

The marine sponge Dysidea avara contained avarol (1) and avarone (2). Avarol on acylation yielded 2',5'-O-dibenzoylavarol (3); 2,5'-O-(4-chlorobenzoyl)avarol (4); 2,5'-O-dicinnamoylavarol (5); 2,5'-O-(4-bromobenzoyl)avarol(6); 2',5'-O-dioctanoylavarol (7); 2',5'-O-(4-fluorobenzoyl)avarol (8) and diacetylavarol (9). The structural elucidation of all the compounds 1-9 have been done by spectral analysis. The cytotoxicity of these compounds were also determined and evaluated. Compounds 6 and 9 showed selective cytotoxicity against Hepa (human hepatoma) and KB cell lines respectively.     

Anti-inflammatory activity of a novel flavonol glycoside from the Bauhinia variegata Linn

Bauhinia variegata Linn. (Leguminosae) is commonly known as 'Kachnar' in Hindi. It is distributed almost throught India. Its powdered bark is traditionally used for tonic, astrain, ulcers. It is also useful in skin diseases. The roots are used as antidote to snake poison. The present article deals with the isolation and structural elucidation of a novel flavonol glycoside 5,7,3',4'-tetrahydroxy-3-methoxy-7-O-alpha-L-rhamnopyranosyl(1-->3)-O-beta-galactopyranoside (1) from the roots of Bauhinia Variegata and its structure was identified by spectral analysis and chemical degradations. The novel compound (1) showed anti-inflammatory activity.     

5,6-dihydroxyindole tetramers with "anomalous" interunit bonding patterns by oxidative coupling of 5,5',6,6'-tetrahydroxy-2,7'-biindolyl: emerging complexities on the way toward an improved model of eumelanin buildup

Chemical or enzymatic oxidation of 5,6-dihydroxyindole (1) leads to the rapid deposition of a black solid resembling eumelanin pigments by way of a complex oligomerization/polymerization process that proceeds in the early stages via dimers 2-3 and trimers 5-6 characterized by 2,4'- and 2,7'-couplings. Despite extensive efforts, the structures of the higher oligomers, which define the structural architecture and physicochemical properties of the eumelanin particles, have so far defied elucidation. Using a dimer-dimer coupling strategy that has recently allowed the first successful entry to a tetramer of 1, we report now three additional tetramers obtained by oxidation of 5,5',6,6'-tetrahydroxy-2,7'-biindolyl (3) with the peroxidase/H2O2 system. On the basis of extensive 2D NMR and mass spectrometric analysis, the products were identified as 5,5',5',5',6,6',6',6'-octaacetoxy-7,2':3',3':2',7'-tetraindolyl (acetylated 8, 3%), 5,5',5',5',6,6',6',6' '-octaacetoxy-2,7':4',4':7',2'-tetraindolyl (acetylated 9, 4%), and 5,5',5',5',6,6',6',6'-octaacetoxy-2,7':2',3':2',7'-tetraindolyl (acetylated 10, 5%), in which the inner units are linked through unexpected 3,3'-, 4,4'-, and 2,3'-linkages. If verified in further studies, the newly uncovered coupling patterns would entail important consequences for current models of eumelanin structure based on one-dimensional structural chains with extended pi-electron conjugation or pi-stacked flat oligomer aggregates.     

Novel flavanes from Livistona halongensis

A study of the chemical constituents of a methanolic extract of the roots of Livistona halongensis (Arecaceae) led to the isolation of two new flavanes, 2S,3S-3,5,7,3'-tetrahydroxy-5'-methoxyflavane (1) and 3,7,3'-trihydroxy-5'-methoxyflavane 5-O-beta-glucopyranoside (2), together with trans-3,5,3',5'-tetrahydroxy-4-methoxystilbene, saccharose and beta-sitosterol-3-O-beta-glucopyranoside. The structures of these compounds were elucidated on the basis of spectroscopic data.     

Two new xanthones from the pericarp of Garcinia mangostana

Two new xanthones, 3-hydroxy-6-methoxy-5'-isopropyl-4',5'-dihydrofuro[2',3'?:?7, 8]-6″,6″-dimethyl-4″,5″-dihydropyrano[2″,3″?:?1,2]xanthone (1) and 1,6-dihydroxy-7-methoxy-8-(3-methylbut-3-enyl)-6',6'-dimethyl-4',5'-dihydropyrano[2'3'?:?3,2]xanthone (2), were isolated from the pericarp of Garcinia mangostana. Their structures were elucidated by spectral means (1-D and 2-D NMR, MS).     

冠醚环化二硫烯双核Au(I)配合物的合成、结构及电化学性质

合成了含有冠醚环化二硫烯的双核Au(I)配合物[(30-C2S4)Au2(PPh3):](1),[(40-C2S4)Au2·(PPh3)2](2),[(30一C6-S8)Au2(Pph3)2](3)和[(40-C6-S8)Au2(PPh3)2](4)以及富硫配合物[(btdt)Au2·(PPh3)2](5).通过x射线...     

Short-lived quinonoid species from 5,6-dihydroxyindole dimers en route to eumelanin polymers: integrated chemical, pulse radiolytic, and quantum mechanical investigation

The transient species formed by oxidation of three dimers of 5,6-dihydroxyindole (1), a major building block of the natural biopolymer eumelanin, have been investigated. Pulse radiolytic oxidation of 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (3) and 5,5',6,6'-tetrahydroxy-2,7'-biindolyl (4) led to semiquinones absorbing around 450 nm, which decayed with second-order kinetics (2k=2.8x10(9) and 1.4x10(9) M-1 s-1, respectively) to give the corresponding quinones (500-550 nm). 5,5',6, 6'-Tetrahydroxy-2,2'-biindolyl (2), on the other hand, furnished a semiquinone (lamdamax=480 nm) which disproportionated at a comparable rate (2k=3x10(9) M-1 s-1) to give a relatively stable quinone (lamdamax=570 nm). A quantum mechanical investigation of o-quinone, quinonimine, and quinone methide structures of 2-4 suggested that oxidized 2-4 exist mainly as 2-substituted extended quinone methide tautomers. Finally, an oxidation product of 3 was isolated for the first time and was formulated as the hydroxylated derivative 5 arising conceivably by the addition of water to the quinone methide intermediate predicted by theoretical analysis. Overall, these results suggest that the oxidation chemistry of biindolyls 2-4 differs significantly from that of the parent 1, whereby caution must be exercised before concepts that apply strictly to the mode of coupling of 1 are extended to higher oligomers.     

重氮萘酮在环醚中热解反应研究

三种带有不同取代基的重氮萘酮(la～1c)在THF和二氧六环中加热分解给出不同的产物。1-重氮-4-萘酮(1a)的热解产物主要是重氮萘酮热解后产生的烯酮卡宾(2a)与环醚开环后形成的聚合物;3-甲基-1-重氮-4-萘酮(1b)的热解产物比较复杂,除冠醚类产物之外,还有烯酮卡宾对四氢呋喃和二氧六环的C-H键的插入反应产物、螺环化合物、2-甲基萘酚以及难以分离的聚合物;3-硝基-1-重氮-4-萘酮(1c)的热解产物主要是聚合物,此外还有少量C－H键的插入反应产物和2-硝基萘酚。对重氮萘酮热解反应的机理作了讨论。     

A novel nitroimidazole compound formed during the reaction of peroxynitrite with 2',3',5'-tri-O-acetyl-guanosine.

Peroxynitrite reacts with 2',3',5'-tri-O-acetyl-guanosine to yield a novel compound identified as 1-(2,3,5-tri-O-acetyl-beta-D-erythro-pentofuranosyl)-5-guanidino-4-nitroimidazole (6). This characterization was achieved using a combination of UV/vis spectroscopy and ESI-MS. Additionally, 1-(beta-D-erythro-pentofuranosyl)-5-guanidino-4-nitroimidazole (6a) was synthesized by an independent route, characterized by UV/vis spectroscopy, ESI-MS, and (1)H- and (13)C NMR, and shown to be identical to deacetylated 6. This product is extremely stable in aqueous solution at both pH extremes and is formed in significant yields. These characteristics suggest that this lesion may be useful as a specific biomarker of peroxynitrite-induced DNA damage. We also observed formation of 2',3',5'-tri-O-acetyl-8-nitroguanosine (2',3',5'-tri-O-acetyl-8-NO(2)()Guo), 2-amino-5-[(2,3,5-tri-O-acetyl-beta-D-erythro-pentofuranosyl)amino]-4H-imidazol-4-one (2',3',5'-tri-O-acetyl-Iz), and the peroxynitrite-induced oxidation products of 2',3',5'-tri-O-acetyl-8-oxoGuo. The formation of 6 and 2',3',5'-tri-O-acetyl-8-NO(2)()Guo was rationalized by a mechanism invoking formation of the guanine radical.     

A predictive tool for assessing (13)C NMR chemical shifts of flavonoids

Herein are presented the (1)H and (13)C NMR data for seven monohydroxyflavones (3-, 5-, 6-, 7-, 2'-, 3'-, and 4'-hydroxyflavone), five dihydroxyflavones (3,2'-, 3,3'-, 3,4'-, 3,6-, 2',3'-dihydroxyflavone), a trihydroxyflavone (apigenin; 5,7,4'-trihydroxyflavone), a tetrahydroxyflavone (luteolin; 5,7,3',4'-tetrahydroxyflavone), and three glycosylated hydroxyflavones (orientin; luteolin-6C-beta-D-glucoside, homoorientin; luteolin-8C-beta-D-glucoside, vitexin; apigenin-8C-beta-D-glucoside). When these NMR spectra are compared, it is possible to assess the impact of flavone modification and to elucidate detailed structural and electronic information for these flavonoids. A simple predictive tool for assigning flavonoid (13)C chemical shifts, which is based on the cumulative differences between the monohydroxyflavones and flavone (13)C chemical shifts, is demonstrated. The tool can be used to accurately predict (13)C flavonoid chemical shifts and it is expected to be useful for rapid assessment of flavonoid (13)C NMR spectra and for assigning substitution patterns in newly isolated flavonoids.     

Human urinary metabolite profile of tea polyphenols analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry with data-dependent acquisition

Tea is rich in polyphenols and has a variety of biological activities. In order to better understand the biological effects of tea constituents on human health, markers for their exposure and their metabolic fates are needed. Previously, we have characterized several catechin metabolites in the blood and urine, but more information on the metabolite profile of tea polyphenols is needed. In the present study, the human urinary metabolite profile of tea polyphenols was investigated using liquid chromatography/electrospray ionization tandem mass spectrometry with data-dependent acquisition. With data-dependent MS/MS analysis by collecting the MS2 and MS3 spectra of the most intense ions in the sample, we identified more than twenty metabolites of tea polyphenols from human urine samples. (-)-Epigallocatechin (EGC) glucuronide, methylated EGC glucuronide, methylated EGC sulfate, (-)-epicatechin (EC) glucruronide, EC sulfate, methylated EC sulfate, as well as the glucuronide and sulfate metabolites of the ring-fission metabolites of tea catechins, 5-(3',4',5'-trihydroxyphenyl)-gamma-valerolactone (M4), 5-(3',4'-dihydroxyphenyl)-gamma-valerolactone (M6) and 5-(3',5'-dihydroxyphenyl)-gamma-valerolactone (M6'), were the major human urinary metabolites of tea polyphenols. To our knowledge, this is the first report of the direct simultaneous analysis of the human urinary metabolite profile of tea polyphenols using single sample analysis. This method can also be used for thorough investigations of the metabolite profiles of many other dietary constituents.     

Studies on the metabolism of gomisin A (TJN-101). II. Structure determination of biliary and urinary metabolites in rat

After oral administration of gomisin A (1) to rats, the bile and urine were collected and treated with beta-glucuronidase and arylsulfatase. Seven metabolites, met B (2), met A-III (3), met E (4), met D (5), met F (6), met G (7), and met H (8) were isolated from the bile treated with the enzymes. Eight metabolites 2-8, and met A-II (9) were isolated from the urine treated with the enzymes. A major metabolite 2, and two minor metabolites 3 and 9 were identified as met B, met A-III, and met A-II, respectively, which are oxidative products of 1 formed by rat liver S9 mix. The structures of five new metabolites 4-7, and 8 were determined on the basis of chemical and spectral studies.