芙蓉菊多糖体外抗氧化活性研究

目的研究芙蓉菊多糖的体外抗氧化活性。方法采用1,1-二苯基苦基苯肼(DPPH)自由基、还原力、超氧阴离子、羟自由基4种体外抗氧化模型研究芙蓉菊多糖的抗氧化活性,用维生素C作对照。结果芙蓉菊粗多糖对DPPH自由基、还原力、超氧阴离子、羟自由基均有明显的清除能力,其中DPPH、超氧阴离子、羟自由基的EC50值分别为0.273、0.669、0.594mg/mL,对羟自由基清除能力强于维生素C。芙蓉菊多糖对自由基清除率与其质量浓度存在着明显的量效关系。结论芙蓉菊多糖具有良好的体外抗氧化活性,作为天然抗氧化剂和自由基清除剂有进一步研究的价值。     

阿魏酸及其类似物的合成及其清除自由基活性研究

目的:合成阿魏酸及其类似物并研究其清除1,1-二苯基苦基苯肼自由基(DPPH·)的能力。方法:不同对羟基苯甲醛衍生物和丙二酸进行Knoevenagel缩合反应,得到阿魏酸及其类似物;用体外清除DPPH·测定法检测其清除自由基的能力。结果:合成了9个化合物,其中7个为新报道化合物;在体外清除DPPH·测定中,这些化合物对DPPH·的清除率有较大差异。结论:阿魏酸及其类似物苯环上3,5位取代基可以明显地影响此类化合物清除DPPH·的能力。甲氧基和乙氧基可明显提高活性,溴次之,硝基则降低活性。     

何首乌炮制前后及其主要成分体外抗氧化活性研究

目的：研究何首乌生品、炮制品及其主要成分的体外抗氧化活性,探讨何首乌的炮制机理及其抗氧化作用物质基础。方法：采用2,2-二苯基-1-苦肼基（DPPH）自由基清除实验及铁离子还原（FRAP）法抗氧化能力检测方法评价何首乌炮制前后及其主要化学成分的体外抗氧化活性。结果：DPPH自由基清除实验中,何首乌生品（S）,随着乙醇浓度的增加,对DPPH自由基的清除率也增加,制品（Q/H/Z）中,以90%乙醇提取所得样品的平均清除率为最高,其次是水、70%乙醇和50%乙醇提取物;FRAP法检测结果显示何首乌生品（S）、黑豆汁制品（H）、清蒸制品（Q）及市售制品（Z）的FRAP值范围分别为2.23~9.27 mmol·L^-1,5.94~9.66 mmol·L^-1,5.74~10.49 mmol·L^-1,3.99~10.40 mmol·L^-1 FeSO₄,不同溶剂提取物的FRAP值由大到小为70%醇 > 50%醇 > 水 > 90%醇;何首乌的组成成分中虎杖苷、白藜芦醇、槲皮苷、槲皮素、芦丁、儿茶素、金丝桃苷、二苯乙烯苷和没食子酸有明显的清除DPPH自由基的作用,没食子酸、槲皮素、槲皮苷、儿茶素、芦丁和白藜芦醇的FRAP值较高,具有较强的抗氧化作用。结论：何首乌炮制前后均有较强的抗氧化作用,虎杖苷、白藜芦醇、槲皮苷、槲皮素、芦丁、儿茶素、金丝桃苷、二苯乙烯苷和没食子酸对何首乌的抗氧化活性有一定的贡献作用。     

木薯叶不同溶剂提取物中芦丁含量测定及抗氧化活性研究

目的 该实验对木薯叶分别用不同溶剂进行萃取,并对不同溶剂提取物中芦丁的含量和抗氧化活性进行比较分析。方法 对木薯叶分别进行水提、95%乙醇醇提,旋蒸浓缩出2种提取物;分别用水和95%乙醇加热回流后得到两种提取液,对两种提取液采用系统溶剂法分别按照石油醚、氯仿、乙酸乙酯、正丁醇的顺序进行萃取,旋蒸浓缩得到8种溶剂提取物,测定出10种提取物中芦丁含量,并采用DPPH自由基体系法对10种提取物进行抗氧化活性比较。结果 不同提取方法提取出的物质中芦丁含量有所差异性,且在相同质量浓度比较下,抗氧化活性顺序为：醇提正丁醇萃取物>醇提乙酸乙酯萃取物>水提乙酸乙酯萃取物>水提正丁醇萃取物>水提物质>水提氯仿萃取物>醇提氯仿萃取物>醇提物质>水提石油醚萃取物>醇提石油醚萃取物。结论 木薯叶不同溶剂提取物中95%乙醇醇提物质中芦丁含量最高,不同溶剂提取物均有具有不同程度的抗氧化活性,其中醇提正丁醇萃取物的抗氧化活性最高,本实验研究可以为天然抗氧化剂的开发利用提供相关的理论依据。     

甘草饮片中抗氧化活性成分的快速筛选及鉴定

目的:建立在线检测甘草饮片中抗氧化活性成分的方法,并对其进行鉴定.方法:通过检测1,1-二苯基-2-三硝基苯肼(DPPH)清除率来评价甘草饮片的抗氧化活性;采用在线高效液相色谱-紫外-1,1-二苯基-2-三硝基苯肼法(HPLC-UV-DPPH)筛选甘草饮片中的抗氧化活性成分;采用高效液相色谱-飞行时间高分辨质谱法(HP...     

7株海洋来源真菌Penicillium spp.菌体丙酮提取物的抗氧化活性和挥发性成分分析

目的分析分离自中国东海的7株海洋来源真菌Penicillium sPp.菌体丙酮提取物的抗氧化活性和挥发性成分,以期寻找海洋真菌的活性天然产物。方法人工海水GYT培养基发酵,离心后菌体部分经冷冻干燥后用丙酮处理制备浸膏。抗氧化活性采用2,2-二苯基-1-苦肼基自由基(DPPH)清除方法进行测试;其挥发性成分采用GC-MS方法检测。结果与结论7株海洋来源真菌的抗氧化活性强弱顺序为708>703>709>707>704>701和705,但其挥发性成分相似,主要为甲苯和乙酸丁酯,这表明非挥发性成分为其主要抗氧化活性部位。     

猫眼草的抗氧化活性成分的分离鉴定与活性测定

目的研究猫眼草(Euphorbia lunulataBge.)全草抗氧化活性成分。方法以抗氧化活性为指标,运用多种柱色谱等现代分离手段对体积分数60%乙醇提取物进行活性追踪分离;根据理化性质和谱学技术分析确定化合物的化学结构;采用DPPH自由基清除法对提取物、各流份及分离得到的化合物进行体外抗氧化活性评价。结果从猫眼草体积分数60%乙醇提取物的乙酸乙酯萃取层(活性部位)中分离得到8个化合物。分别鉴定为东莨菪素(scopoletin,1)、异嗪皮啶(isofraxi-din,2)、金丝桃苷(hyperin,3)、柚皮素-7-O-β-D-葡萄糖苷(naringenin-7-O-β-D-glucopyranoside,4)、quercetin-3-O-(6″-galloyl)-β-D-galactopyranoside(5)、quercetin-3-O-(2″-galloyl)-β-D-galactopyrano-side(6)、槲皮素(quercetin,7)、芹菜素-7-O-β-D-葡萄糖苷(apigenin-7-O-β-D-glucopyranoside,8)。结论化合物1~5首次从猫眼草中分离得到;化合物8首次从大戟属植物中分离得到。化合物3、5、6、7具有较强的抗氧化活性。     

UPLC快速测定石崖茶中5个黄酮类化合物含量及其体外抗氧化活性评价

目的:建立石崖茶中山茶苷A、山茶苷B、表儿茶素、槲皮苷和芹菜素5个黄酮类成分超高效液相色谱(UPLC)测定方法,初步评价石崖茶的体外抗氧化活性。方法:采用Waters Acquity BEH(2.1 mm×100 mm,1.7μm)色谱柱,水-乙腈作流动相,梯度洗脱,流速0.35 mL.min-1,检测波长280 nm(0～1.5 min)用于检测表儿茶素,330 nm(1.5～2.5 min和3.0～7.0min)检测山茶苷A、山茶苷B和芹菜素,254 nm(2.5～3.0 min)检测槲皮苷,柱温40℃,分析时间7 min。采用1,1-二苯基-2-苦基苯肼(DPPH)和2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二氨盐(ABTS)法测定石崖茶63%乙醇提取物的抗氧化活性。结果:山茶苷A、山茶苷B、表儿茶素、槲皮苷和芹菜素的线性范围分别为120.0～600.0,2.5～18.0,50.0～480.0,1.0～3.5,1.5～7.5 ng(r≥0.9996);平均加样回收率分别为98.03%,98.26%,100.8%,98.48%,100.2%;精密度、重复性和稳定性良好,RSD均小于2%。石崖茶抗氧化活性较维生素C弱,抗氧化活性与含测指标成分不呈相关性。结论:石崖茶具有一定抗氧化活性。该UPLC方法操作简便,检测结果准确,可为石崖茶的质量标准研究提供依据。     

不同商品等级枸杞子的抗氧化活性比较及其生物效价检测

目的:针对枸杞子的抗氧化作用,尝试建立基于清除有机自由基1,1-二苯基苦基苯肼(DPPH)的枸杞子质量控制方法。方法:通过正交试验,优选枸杞子样品提取方法;通过单因素考察确定枸杞子与DPPH溶液的最佳反应条件。结果:固液比1∶10,50%乙醇超声提取20 min时自由基清除率最高;DPPH浓度0.05 mg.mL-1,样品浓度100 mg.mL-1,室温反应90 min为最适反应条件。不同商品等级的枸杞子自由基清除率不同。结论:文中建立的抗氧化生物效价检测法,以枸杞子对DPPH系统自由基清除率为评价指标,可以客观反映枸杞子抗氧化活性的差异,适用于枸杞子药材质量控制,对其他具有抗氧化作用中药的质量控制以及高通量活性筛选也具有一定的参考价值。     

女贞子三萜类化学成分及其体外抗氧化活性的研究

目的研究女贞子中三萜类成分及体外抗氧化活性。方法用甲醇浸提,反复硅胶柱色谱分离,并测定DPPH自由基的清除率。结果分离鉴定了4个三萜类化合物:3-乙酰齐敦果酸、19α-羟基-3-乙酰熊果酸、齐墩果酸、熊果酸,均具有清除DPPH自由基的能力。结论抗氧化活性为19α-羟基-3-乙酰熊果酸>3-乙酰齐敦果酸>熊果酸>齐墩果酸。     

Antioxidant constituents from the stem ofSorghum bicolor

The EtOAc soluble fraction from the stem of Sorghum bicolor showed a strong free radical scavenging activity. Five major compounds were isolated from this fraction. They were identified by spectral data as methyl ferulate (1), methyl p-hydroxycinnamate (2), p-hydroxybenzaldehyde (3), tricin (4), and quercetin 3,4'-dimethyl ether (5). Among these compounds, 1 exhibited a strong, free radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) with an IC50 value of 0.7 microM. We further studied the effects of these isolated compounds on the lipid peroxidation in rat liver microsomes induced by non-enzymatic method. All five compounds showed anti-lipid peroxidation activity (IC50 values of 0.5, 0.4, 0.3 and 0.3 microM, respectively).     

Antioxidant constituents from Setaria viridis

The EtOAc and n-BuOH soluble fractions from the aerial part of Setaria vindis showed a strong free radical scavenging activity. Six major compounds were isolated from these fractions. They were identified by spectral data as tricin (1), p-hydroxycinnamic acid (2), vitexin 2'-O-xyloside (3), orientin 2'-O-xyloside (4), tricin-7-O-beta-D-glucoside (5) and vitexin 2"-O-glucoside (6). Among these compounds, 4 and 5 exhibited strong free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH). We further studied the effects of these isolated compounds on the lipid peroxidation in rat liver microsomes induced by non-enzymatic method. As expected, 4 and 5 exhibited significant inhibition on ascorbic/Fe2+ induced lipid peroxidation in rat liver microsomes.     

Antitumor and antioxidant activity of protocatechualdehyde produced from Streptomyces lincolnensis M-20

We characterized the biological functions of protocatechualdehyde (PA) isolated from the butanol extract of culture supernatant from Streptomyces lincolnensis M-20. Following butanol extraction, it was purified by silica gel and Sephadex LH-20 column chromatography. PA was analyzed by Furier Transform Infrared Spectroscopy (FT-IR), Gas chromatograph-Mass Spectrometer (GC-MS), and Nuclear Magnetic Resonance (NMR). PA had potent antioxidant activity, as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Antitumor activity against MCF-7 human breast cancer cells was evaluated by the 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium-bromide (MTT) assay. PA treatment (0∼150 μM) dose-dependently blocked apoptosis, as shown by improved cell viability and inter-nucleosomal DNA fragmentation. Our findings suggest that Streptomyces lincolnensis M-20, a lincomycin producer, also produces protocatechualdehyde.     

Bioassay‐Guided Isolation and Structural Modification of the Anti‐TB Resorcinols from Ardisia gigantifolia

Tuberculosis (TB) is a highly contagious disease mainly caused by Mycobacterium tuberculosis H₃₇R_V. Antitubercular (anti‐TB) bioassay‐guided isolation of the CHCl₃ extract of the leaves and stems of the medicinal plant Ardisia gigantifolia led to the isolation of two anti‐TB 5‐alkylresorcinols, 5‐(8Z‐heptadecenyl) resorcinol ( 1 ) and 5‐(8Z‐pentadecenyl) resorcinol ( 2 ). We further synthesized 15 derivatives based on these two natural products. These compounds (natural and synthetic) were evaluated for their anti‐TB activity against Mycobacterium tuberculosis H₃₇R_V. Resorcinols 1 and 2 exhibited anti‐TB activity with MIC values at 34.4 and 79.2 μm in MABA assay, respectively, and 91.7 and 168.3 μm in LORA assay, respectively. Among these derivatives, compound 8 was found to show improved anti‐TB activity than its synthetic precursor ( 2 ) with MIC values at 42.0 μm in MABA assay and 100.2 μm in LORA assay. The active compounds should be regarded as new hits for further study as a novel class of anti‐TB agents. The distinct structure–activity correlations of the parent compound were elucidated based on these derivatives.     

Antidepressant-like activity of the phenylpiperazine pyrrolidin-2-one derivatives in mice

The present study was designed to investigate the central nervous system activity of 23 novel phenylpiperazine pyrrolidin-2-one derivatives. These compounds had marked antiarrhythmic and hypotensive activities and revealed affinity for α1- and α2-adrenoceptors. These effects may be related to their α-adrenolytic properties. We assessed their antidepressant-like effect in the forced swimming test, influence of spontaneous locomotor activities and binding to 5-HT1A and 5-HT2 receptors. Our study demonstrated the strong antidepressant-like activity of compound EP-65 in the forced swimming test. The effect of EP-65 was stronger than results obtained with the classical antidepressants imipramine and mianserin. Other compounds, EP-41, EP-42, EP-44, EP-47, EP-48, EP-49, EP-50, EP-62, EP-66, EP-70, EP-75 and EP-76, showed significantly weaker activities in this test. Compound EP-42 showed the strongest affinity for 5-HT1A (Ki=24.5 nM), and compound EP-50 showed the strongest affinity for the 5-HT2 receptor (Ki=109.1 nM). All tested compounds significantly suppressed the spontaneous locomotor activity of mice. Currently, it is not possible to determine which mechanisms are involved in the witnessed antidepressant-like activity of novel phenylpiperazine pyrrolidin-2-one derivatives.     

Norlignan derivatives from <Emphasis Type="Italic">Curculigo crassifolia</Emphasis> and their DPPH radical scavenging activity

A novel norlignan derivative, crassifogenin C (1), and a known compound, curcapital (2), were isolated from the ethanolic extract of the rhizomes of Curculigo crassifolia. Their structures were elucidated on the basis of spectroscopic evidence and comparisons with literature data. Curcapital (2) was isolated from this plant for the first time. The free radical scavenging activity of the isolated compounds along with crassifoside E (3) and crassifoside F (4), which were reported previously, was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. All compounds showed strong radical scavenging activity. The primary structure-activity relationship is also discussed.     

Flavonoids from the flower ofRhododendron yedoense var.Poukhanense and their antioxidant activities

Antioxidant flavonoids have been isolated from the flower of Rhododendron yedoense var. poukhanense. One new flavonoid and three known flavonoids, quercetin-5-O-beta-D-glucopyranoside (1), quercetin (3), and quercitrin (4), were isolated from the butanol and ethyl acetate extracts of the plant. The new flavonoid was identified as myricitrin-5-methyl ether (2). The isolation of these flavonoids from this plant, for the first time, is a valuable finding. The flavonoids were evaluated for their antioxidant activities using 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH), TBARS (thiobarbituric acid reactive substance) and superoxide anion radical (O2-) in the xanthine/xanthine oxidase assay system. In the DPPH scavenging assay, the IC50 values were 4.5 +/- 0.48 microM for compound 2 and 9.7 +/- 0.29 microM for compound 3, which showed an antioxidant activity approximately 1.5-2 times higher than the antioxidant activity of alpha-tocopherol (9.8 +/- 0.94 microM). Additionally, the antioxidant activities of myricitrin-5-methyl ether (2) (IC50 = 1.7 +/- 0.22 microM) and quercetrin (4) (IC50 = 1.9 +/- 0.63 microM) were higher than that of L-ascorbic acid (IC50 = 7.4 +/- 0.63 microM) when evaluated using a TBARS assay. Compound 2 showed high activity in both the inhibition of xanthine oxidase (1.1 +/- 0.21 mM) and in the activation of superoxide scavenging.     

2-取代亚肼基-1,3-二硫杂环戊烷类化合物的合成及抗菌活性

目的为了寻找高效、低毒的农用杀菌剂,用超声波法合成新型的2-取代亚肼基-1,3-二硫杂环戊烷类化合物。方法以CS2、NH2NH2·H2O、BrCH2CH2Br为原料,在超声波辐射下合成中间体1,3-二硫杂环戊烷,然后再和取代芳香醛缩合得到3种未见文献报道的新化合物。结果总收率在60%以上。结构经IR,MS,1HNMR和元素分析所确证。结论该类化合物合成方法简单。初步的生物活性实验表明,这3种化合物对大肠杆菌、肺炎克雷伯氏菌、草绿色链球菌等有较好的抑杀作用。     

The effect of complexation with cyclodextrins on the antioxidant and antimicrobial activity of ellagic acid

Purpose: The aim of the paper was to develop the simple procedures for preparation of inclusion complexes of ellagic acid (EA) with cyclodextrins (CDs) and to investigate their antioxidant and antimicrobial activity.

Methods: The structural characterization was carried out using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) methods. The phase solubility technique was used to investigate the interactions between ‘host’ and ‘guest’ molecules and to estimate the molar ratio between them. The antioxidant and antimicrobial activity of EA and inclusion complexes were determined.

Results: The apparent stability constants were found to be 117?dm³ mol^?1 for the complex with β-CD and 161?dm³ mol^?1 for the complex with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD). The results of phase-solubility studies showed that EA formed the inclusion complexes with CDs in the molar ratio of 1:1. The calculated half-maximal inhibitory concentration was 41.18?μg cm^?3 for butyl hydroxy toluene, 1.96?μg cm^?3 for EA, 0.88?μg cm^?3 for inclusion complex with HP-β-CD, and 1.27?μg cm^?3 for inclusion complex with β-CD.

Conclusion: The stability constants indicated the rapid release of EA from the inclusion complexes in the aqueous medium at 25?°C. The antioxidant activity of EA was increased, while the antimicrobial activity was preserved after complexation with CDs.     

Mechanism of action of 2-haloethylnitrosoureas on deoxyribonucleic acid. Nature of the intermediates from nitrosourea decomposition.

Direct current (DC) and differential pulse polarographic analyses were used to measure the rates of decomposition of a series of 2-haloethylnitrosoureas in aqueous solution. Measured by these methods, the rates of the first and rate-determining step which show a marked pH and solvent dependence agree with the overall rate of decomposition measured by gas evolution. In the 1,3-bis(haloethyl)-1-nitrosourea series, changing the nature of the halogen X has a small effect on the rate of decomposition. In the 3-cyclohexyl-1-(2-haloethyl)-1-nitrosourea series, changing X for OH or OCH₃ results in the rate of hydrolysis being reduced considerably. A free—NH₂ group in the nitrosourea structure as in CNU, MNU, ENU, CPNU, 4-CBNU and 5-CPNU accelerates considerably the rate of decomposition relative to the BCNU and CCNU series. Arrhenius parameters for the decomposition in aqueous pH 7.1 solution in the temperature range 28–47° were obtained for BFNU, BCNU and BBNU: log A, ?20.1± 1.4,?21.6± 0.7 and ?22.3±1.6; E_a, 24.4 ± 2.0, 26.5± 1.0 and 27.2 m 2.3 kcal/mole. The corresponding values for BINU were estimated as log A,?23.3± 3.0; E_a, 28.0± 3.0 kcal/mole. Examination of the decomposition products of 1,3-bis(2-chloropropyl)-1-nitrosourea (BCNU-β-Me) and 1,3-bisl 1-(chloromethyl)ethyl]-1-nitrosourea (BCNU-α-Me) favors decomposition pathway B via the diazohydroxide and cyclic chloronium ion for BCNU-β-Me and via the diazohydroxide and/or 2-chloro-1-methylethyl carbonium ion for BCNU-α-Me. While there is no evidence for the contribution of pathway A via a 2-imino-N-nitrosooxazolidinone for these compounds, consideration of product type and yields implicates a third decomposition pathway, via a 1,2,3-oxadiazoline intermediate. Additional evidence for an oxadiazoline intermediate is obtained by the isolation of 2-bromoethanol when BCNU is decomposed in the presence of a high concentration of sodium bromide.