水栀子化学成分的研究

目的对水栀子Gardenia jasminoides var.radicans的化学成分进行研究。方法采用色谱技术进行分离,通过NMR等波谱方法鉴定化合物结构。结果分离并鉴定了12个化合物,其中3个为环烯醚萜苷类化合物,分别为京尼平苷(1)、去乙酰车叶草苷酸甲酯(2)、6′-O-sinapoylgeniposide(3);4个为二萜类化合物,分别为西红花苷-1(4)、西红花酸(5)、西红花苷-2(6)、西红花苷-3(7);4个为黄酮类化合物,分别为芦丁(8)、5,7,3′,5′-四羟基-6,4′-二甲氧基黄酮(9)、5-羟基-7,3′,4′,5′-四甲氧基黄酮(10)、麦黄酮(11);1个三萜类化合物为熊果酸(12)。结论化合物2、3、5～12为首次从该植物中分离得到;化合物9和11为首次从该属植物中分离得到。     

栀子化学成分研究

目的：研究栀子的化学成分。方法：用各种现代色谱方法分离栀子化学成分,用波谱技术(IR,UV,MS,1D和2D-NMR)鉴定结构。结果：从焦栀子中分离得到9个化合物,分别鉴定为欧前胡素(imperatorin,1),异欧前胡素(isoimperatorin,2),藏红花酸(crocetin,3),5-羟基-7,3′,4′,5′-四甲氧基黄酮(5-hydroxy-7,3′,4′,5′-tetramethoxyflavone,4),2-甲基-3,5-二羟基色原酮(2-methyl-3,5-dihydroxychromone,5),苏丹Ⅲ(sudanⅢ,6),京尼平苷(geniposide,7),藏红花素(crocin,8),藏红花酸糖苷-3(crocin-3,9)。结论：其中化合物1～6为首次从该植物中分离。     

Gusanlungionosides A-D, potential tyrosinase inhibitors from Arcangelisia gusanlung

Four new megastigmane glycosides, named gusanlungionosides A-D (1-4), together with 10 known compounds (5-14), were isolated from the stems of Arcangelisia gusanlung. The structures and absolute configurations of 1-4 were elucidated by comprehensive analysis of their NMR and CD data. Compounds 1-4 exhibited strong inhibitory effects not only on the mushroom tyrosinase activity in vitro but also on melanogenesis in cells.     

Prenylated flavanones with anti-tyrosinase activity from Dalea boliviana

Three new prenylated flavanones, (2S)-5,7,2'-trihydroxy-5'-(1',1'-dimethylallyl)-8-prenylflavanone (1), (2S)-5,7,2'-trihydroxy-8,3'-diprenylflavanone (2), and (2S)-5,2'-dihydroxy-6',6'-dimethylchromeno-(7,8:2',3')-3'-prenylflavanone (3), and a known chromeno (dimethylpyrano) flavanone, obovatin (4), were isolated from the n-hexane extract of Dalea boliviana roots. The compounds were evaluated in vitro in relation to their inhibitory effect on the tyrosinase activity by using a spectrophotometric method.     

Biphenyl glycosides from the fruit of Pyracantha fortuneana

Five new biphenyl glycosides, fortuneanosides A (1), B (2), C (3), D (4), and E (5), were isolated from the fruit of Pyracantha fortuneana. Their structures were established as 3,3'-dihydroxy-5'-methoxy-(1,1'-biphenyl)-4-O-beta-d-glucoside, 4'-hydroxy-2,3',5'-trimethoxy-(1,1'-biphenyl)-2'-O-beta-d-glucoside, 4'-hydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-2-O-beta-d-glucoside, 2,4'-dihydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-3-O-beta-d-glucoside, and 3,4'-dihydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-4-O-beta-d-glucoside by spectroscopic analysis. All compounds were evaluated for inhibitory activity against tyrosinase. Compared with arbutin (IC(50) = 0.23 mM), fortuneanoside D possessed more potency, with an IC(50) value of 0.07 mM.     

Tyrosinase inhibitory constituents from the stems of Maackia fauriei

Bioassay‐guided investigation of the stems of Maackia fauriei led to the isolation of seven flavonoid constituents, formononetin (1), genistein (2), daidzein (3), texasin (4), tectorigenin (5), odoratin (6) and mirkoin (7). Their structures were elucidated on the basis of spectral studies as well as by comparison with literature data. Tyrosinase inhibition activities were carried out on the isolated compounds. Among these, mirkoin (7) was identified as a potent tyrosinase inhibitor. It inhibited mushroom tyrosinase with an IC₅₀ value of 0.005 mm , which is ten times more active than kojic acid (IC₅₀ = 0.045 mm ). The inhibition kinetics, analysed by Lineweaver‐Burk plots, indicated mirkoin (7) to be a competitive inhibitor of tyrosinase when l ‐tyrosinase was used as a substrate. The results suggest that hydroxyl groups at C‐4′ in the B ring of flavonoids play an important role in the tyrosinase inhibition activities. Interestingly, compounds 4–7 were isolated for the first time from this plant. Copyright © 2009 John Wiley & Sons, Ltd.     

金属离子对西红花苷稳定性的影响

目的考察金属离子对西红花苷稳定性的影响。方法采用HPLC法测定在Fe^3+、Fe^2+、Al^3+、Cu^2+、Na^+、K^+、Ca^2+、Mg^2+作用下,西红花苷-Ⅰ和西红花苷-Ⅱ在24 h内的浓度变化,以及不同温度、浓度Fe^3+和Na^+对西红花苷-Ⅰ和西红花苷-Ⅱ降解的影响。结果 Fe^3+和Fe^2+对西红花苷-Ⅰ和西红花苷-Ⅱ降解有较强的促进作用,而Na^+和K^+则有明显的抑制作用。不同温度下Fe^3+均能显著促进西红花苷-Ⅰ和西红花苷-Ⅱ的降解。随着Fe^3+浓度的升高,西红花苷-Ⅰ和西红花苷-Ⅱ降解速率加快。Na^+在温度为4~20℃,浓度为0.001~0.01 mol/L时减缓西红花苷-Ⅰ和西红花苷-Ⅱ降解的作用最强。结论西红花苷类化合物对部分金属离子较为敏感,西红花苷类成分在工业生产以及用药过程中应注意金属离子对稳定性的影响。     

Pyronane monoterpenoids from the fruit of Gardenia jasminoides

Five new pyronane-type monocyclic monoterpenoids, jasminodiol (1), jasminoside H (6), 6'-O-sinapoyljasminoside A (7), 6'-O-sinapoyljasminoside C (8), and jasminoside I (9), together with four known analogues, were isolated from the fruit of Gardenia jasminoides. The structures of the new metabolites were characterized using spectroscopic data, and the absolute configurations of 1, 6, and 7 were established using circular dichroism (CD) analysis. Compound 1 showed tyrosinase inhibitory activity (IC 50 2.2 mM).     

Chalcones and other compounds from the exudates of Angelica keiskei and their cancer chemopreventive effects

Three new chalcones, xanthoangelol I (1), xanthoangelol J (2), and deoxydihydroxanthoangelol H (3), were isolated from an ethyl acetate-soluble fraction of exudates of the stems of Angelica keiskei, and their structures were established on the basis of spectroscopic methods. Nine aromatic compounds of known structure, 4-12, and a diacetylene, 13, were also isolated and identified from this same fraction. On evaluation of these compounds for their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, 1, 2, 4, and 9-12 showed potent inhibitory effects on EBV-EA induction. In addition, upon evaluation of the inhibitory effects against activation of (+/-)-(E)-methyl-2[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexemide (NOR 1), a nitrogen oxide (NO) donor, six compounds, namely, 1, 2, 4, 9, 11, and 12, exhibited potent inhibitory effects. Further, isobavachalcone (4) exhibited inhibitory effects on skin tumor promotion in an in vivo two-stage mouse skin carcinogenesis test using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter.     

Inhibition of respiratory burst in human neutrophils and lipoxygenase enzyme by compounds from Haloxylon griffithii

Secondary metabolites, ferulic acid (1), 2,6-dimethoxy-4-hydroxy acetophenone (2), herniarin (3), p-hydroxy acetophenone (4), methyl 3,4-dihydroxycinnamate (5), and methyl 4-hydroxy-3-methoxycinnamate (6) were isolated from Haloxylon griffithii, a member of the family Chenopodiaceae. The structures of compounds 1-6 were identified with the help of spectroscopic techniques. These compounds were isolated for the first time from this plant. The lipoxygenase and respiratory burst inhibitory activities were determined. Compound 5 was found to be the most potent inhibitory activity against respiratory burst in human neutrophils among all the compounds as well as exhibited moderate lipoxygenase inhibitory activity from this plant.     

Tyrosinase inhibitory pentacyclic triterpenes and analgesic and spasmolytic activities of methanol extracts of Rhododendron collettianum

During the course of screening of medicinal plants of Pakistan for the isolation and structure elucidation of bioactive natural products, it was found that the methanol extract of the Rhododendron collettianum showed analgesic and spasmolytic activities. The methanol extract was then extracted with chloroform. Nine pentacyclic triterpenes were isolated from the chloroform extract and their structures were elucidated as erythrodiol (1), betulinic acid (2), maslinic acid (3), 2alpha,3alpha,23-trihydroxyolean-12-en-28-oic acid (4), bayogenin (5), arjunilic acid (6), methyl arjunolate (7), arjungenin (8) and 3beta, 23, 24-trihydroxyolean-12-en-28-oic acid (9). Among the triterpenes (1-9) tested, arjunilic acid (6) was found to be most potent. Their structure-activity relationship (SAR) showed that if the configuration of the -OH group at C-2 is changed from alpha to beta the potency is decreased. In most of the compounds the position and configuration of the -OH group was found to be important for the inhibitory potency against the enzyme tyrosinase. For the comparison, the standard tyrosinase inhibitors kojic acid (IC50=16.67 microm) and L-mimosine (IC50=3.68 microm) were used as controls.     

Anthraquinones from Polygonum cuspidatum as tyrosinase inhibitors for dermal use

Four anthraquinones, physcion (1), emodin (2), citreorosein (3) and anthraglycoside B (6), and two stilbenes, resveratrol (4), and piceid (5), were isolated previously from the root of Polygonum cuspidatum. These bioactive compounds were examined for their antityrosinase potency. No antityrosinase activity was detected with treatment using stilbenes. On the other hand, the anthraquinones showed moderate to strong inhibition of tyrosinase. Physcion exhibited the most potent tyrosinase inhibition among the four anthraquinones examined, which was comparable to kojic acid. The ability of anthraquinones to permeate the skin was also examined. Based on the same thermodynamic activity, physcion showed a higher permeation compared with emodin (48-fold), suggesting it as a potent candidate for dermal use. As naturally occurring tyrosinase inhibitors, anthraquinones from P. cuspidatum may be useful as skin-whitening agents to inhibit tyrosinase for dermal use.     

Compounds with tyrosinase inhibition, elastase inhibition and DPPH radical scavenging activities from the branches of Distylium racemosum Sieb. et Zucc

Twenty compounds were isolated from the ethanol extract of Distylium racemosum branches and their inhibitory activities on tyrosinase, elastase and free radicals evaluated. The isolated compounds were identified as dibenzofurans (1–4), abscisic acid (5), 6′‐O‐galloylsalidroside (6), catechin derivatives (7–11), gallic acid derivatives (12–14), tyrosol (15), flavonoids (16–18), lupeol (19) and 1,2,3,6‐tetragalloylglucose (20). For study of tyrosinase inhibition activities, when compared with arbutin (IC₅₀ 48.8 μg/mL), four compounds (8, 11, 13, 17) showed higher activities, with IC₅₀ values of 4.8, 30.2, 40.5 and 37.7 μg/mL, respectively. For the elastase inhibition test, dibenzofuran 1 showed greater activity than the positive control, oleanolic acid (IC₅₀ 9.7 μg/mL), with an IC₅₀ of 7.7 μg/mL. In the studies on DPPH radical scavenging activities, five compounds (11, 12, 13, 14, 15) showed higher activities than ascorbic acid (IC₅₀ 5.0 μg/mL), with IC₅₀ values of 4.6, 3.9, 2.9, 3.8 and 4.7 μg/mL, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Antityrosinase and antioxidant effects of ent-kaurane diterpenes from leaves of Broussonetia papyrifera

Three new ent-kaurane type diterpenes, broussonetones A-C (1-3), were isolated from leaves of Broussonetia papyrifera, together with seven known compounds, and their structures determined by 1D and 2D NMR and MS methods. Compounds 1-3 were marginal inhibitors of tyrosinase. Antioxidant assays showed them also to be inhibitors of xanthine oxidase. The mild inhibition of tyrosinase and significant inhibition of xanthine oxidase suggests that 1-3 could be useful ingredients in the development of skin-protecting cosmetics.     

Triterpenoids and a sterol from the stem-bark of Styrax japonica and their protein tyrosine phosphatase 1B inhibitory activities

Five pentacyclic triterpenoids (1-5) and a sterol (6) were isolated from the stem-bark of Styrax japonica. The six compounds, 1-6, were determined to be 3beta-acetoxy-28-hydroxyolean-12-ene (1), 3beta-acetoxyolean-12-en-28-acid (2), 3beta-acetoxyolean-12-en-28-aldehyde (3), 3beta-acetoxy-17beta-hydroxy-28-norolean-12-ene (4), taraxerol (5) and stigmasterol (6), respectively, by spectroscopic means, including the 2D-NMR technique. Compound 4 is a newly discovered natural compound. The protein tyrosine phosphatase 1B (PTP1B) inhibitory activities of the isolated compounds (1-6) were determined in vitro. Among the isolated compounds, 3beta-acetoxyolean-12-en-28-acid (2) and 3beta-acetoxyolean-12-en-28-aldehyde (3) had the most potent inhibitory PTP1B activity, with IC50 values of 7.8 and 9.3 microm, respectively.     

Phenolic glycosides from the stem bark of Caryocar villosum and C. glabrum

Mushroom tyrosinase inhibitory activity of methanol extracts and polar fractions of the stem bark of Caryocar villosum and C. glabrum has been assessed. Seven new phenolic glycosides (1-7) were isolated from the most active fractions, along with 15 known compounds (8-22). The structures of these compounds were established on the basis of spectroscopic methods including 1D and 2D NMR analysis, HRESIMS, and comparison with literature experimental data for known compounds.     

小黄皮茎的化学成分及生物活性研究

目的研究小黄皮Clausenaemarginata茎的化学成分及其保肝活性。方法采用硅藻土、硅胶等多种柱色谱、中压制备液相色谱(MPLC)及制备型HPLC等方法对小黄皮茎的化学成分进行分离纯化,根据化合物理化性质结合现代波谱学方法鉴定化合物结构;并测试其对DL-半乳糖胺诱导肝细胞损伤的保护活性及其对脂多糖(LPS)诱导小鼠小胶质BV2细胞产生一氧化氮(NO)的抑制活性。结果从小黄皮茎的95%乙醇提取物的氯仿部位分离得到11个化合物,分别鉴定为nordentatin(1)、oxanordentatin(2)、5′-羟基葡萄内酯(3)、7-[(E)-7′-羟基-3′,7′-二甲基-2′,5′-二烯]-香豆素(4)、7-羟基香豆素(5)、claulamine A(6)、γ-崖椒碱(7)、开环异落叶松脂素(8)、2-{4-[(1E)-3-hydroxyprop-1-en-1-yl]-2,6-dimethoxyphenoxy}propane-1,3-diol(9)、2-[4-(3-hydroxy-1-propenyl)-2-methoxyphenoxy]-1,3-propanediol(10)、甲基-2-O-β-D-吡喃葡萄糖基苯甲酸(11)。其中,化合物1~5为香豆素类化合物,6为咔唑生物碱,7为呋喃喹啉类生物碱,8为木脂素类化合物,9、10为苯丙素类化合物,11为酚酸类化合物。结论化合物2~4、7~11为首次从该植物中分离得到,化合物5和7对DL-半乳糖胺诱导的肝细胞损伤具有一定的保护活性,化合物11对LPS诱导BV2细胞产生NO具有一定的抑制作用。     

Antimycobacterial triterpenes from Melia volkensii

In a bioassay-guided search for antimycobacterial compounds from higher plants, we have chemically investigated methanolic extracts of seeds of Melia volkensii. Chromatographic fractions provided two new euphane (20R)-type triterpenoids. The structures of the new compounds, 12beta-hydroxykulactone (1) and 6beta-hydroxykulactone (2), were elucidated by 1D and 2D NMR (13C, 1H, 1H-1H COSY, HMQC, HMBC, and NOESY spectra) and FABMS studies and shown to be hydroxyl derivatives of kulactone (3). Also isolated was the known kulonate (4). In a radiorespirometric bioassay against Mycobacterium tuberculosis, compounds 1, 2, and 4 exhibited minimum inhibitory concentrations of 16, 4, and 16 microg/mL, respectively.     

Vitexin, orientin and other flavonoids from Spirodela polyrhiza inhibit adipogenesis in 3T3-L1 cells

To investigate the adipogenesis inhibitory effect on lipid accumulation, 3T3-L1 cells were treated with fractions and isolated flavonoids of Spirodela polyrhiza. An ethanol extract of S. polyrhiza was fractionated into three fractions. The butanol soluble fraction (SPB) exhibited potent antiadipogenesis activity and decreased C/EBPα and PPARγ protein expression level in 3T3-L1 cells without significant cytotoxicity. The flavonoids were isolated from SPB and their chemical structures were identified as chrysoeriol (1), apigenin (2), luteolin (3), vitexin (4), cosmosin (5), orientin (6) and luteolin-7-O-β-d-glucoside (7) by spectroscopic analysis. Studies on the adipogenesis and intracellular triglyceride accumulation inhibitory effect showed that compounds 4 and 6 had the highest activity and decreased C/EBPα and PPARγ protein expression level in 3T3-L1 cells. These results suggest that the flavonoids isolated from SPB, especially compounds 4 and 6, contribute to the inhibitory activity of S. polyrhiza in 3T3-L1 cells.     

Inhibitory phenolic amides on lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells from Beta vulgaris var. cicla seeds

Four phenolic compounds were isolated from Beta vulgaris L. var. cicla L. (Chenopodiaceae). These isolated compounds were identified as N-cis-feruloyl 3-O-methyldopamine (1), N-cis-feruloyl tyramine (2), N-trans-feruloyl 3-O-methyldopamine (3), N-trans-feruloyl tyramine (4), respectively, by spectroscopic analysis. The phenolic amides 1-4 exhibited modest inhibitory activity on LPS-activated nitric oxide production dose-dependently in RAW 264.7 cells.