Extraction and Purification Process Optimization and Antioxidant Activity in vitro of Flavonoids in Amaranthus caudatus L.

[Objectives]To explore the optimal extraction and purification process of the flavonoids in Amaranthus caudatus L.and to study the antioxidant activity in vitro of the flavonoids in A.caudatus.[Methods]Taking A.caudatus as the raw material,flavonoids were extracted by alcohol extraction method,and AB-8 macroporous adsorption resin was selected for purification.The hydroxyl radical scavenging ability,DPPH radical scavenging ability,and O^2-radical scavenging ability were used as evaluation indicators,to explore the antioxidant activity in vitro of the flavonoids in A.caudatus.[Results]The optimal extraction process conditions of flavonoids in A.caudatus are:liquid-to-material ratio 40:1,extraction temperature 60℃,ethanol concentration 60%,ultrasonic power 320 W,extraction time 50 min.Under these conditions,the extraction yield of flavonoids in A.caudatus is(1.35±0.01)%.The optimal purification process conditions of flavonoids in A.caudatus are 2.5 g AB-8 macroporous adsorption resin,sample volume 5 mL,mass concentration of adsorption solution 1.60 mg/mL,pH value of adsorption solution 3.0,sample flow rate 3 BV/h,ethanol concentration in desorption process is 70%and the desorption flow rate is 3 BV/h.Under these conditions,the recovery rate reaches 88.35%±0.68%.[Conclusions]A.caudatus has a high content of flavonoids and has excellent free radical scavenging ability in vitro.This study is intended to provide important technical support for the research of flavonoid activity of A.caudatus and the development of functional products.

Isolation,Purification and Immunomodifying Activity of Polysaccharides from Phellinus igniarius

Phellinus igniarius polysaccharides were obtained by hot water extraction of mushroom fruit bodies followed by ethanol precipitation,and further purified by anion exchange and gel filtration chromatography.Immuno-enhancing activity was evaluated by determining the effect of different polysaccharide fractions on mouse spleen lymphocyte proliferation in vitro.Three crude polysaccharide preparations,designated PIP30,PIP60 and PIP80 according to the percentage concentration of ethanol required for precipitation from hot aqueous extracts,promoted lymphocyte proliferation to varying degrees.Purification of polysaccharide present in PIP30 and PIP60 was carried out using anion exchange chromatography.Proliferation rates in samples treated with 200 μg/mL of fractions P30U,P30W and P30S1(obtained following anion exchange chromatography of PIP30) were approximately 5-,4-,and 3.5-fold higher,respectively compared with negative controls.Similarly,marked increases(3.4-and 2.8-fold) in cell proliferation rates compared with negative controls were observed with 200 μg/mL concentrations of P60W and P60S2(obtained following anion exchange chromatography of PIP60),respectively.Two purified polysaccharide preparations,P60W1-1 and P60S1-1,were obtained following gel filtation chromatography of fractions P60W1 and P0S1,respectively.Fraction P60W1-1(10-100 g/mL) enhanced splenocyte proliferation 0.5-1.4-fold compared with negative controls,whereas no effects were observed with P60S1-1.

Purification and characterization of novel antioxidant peptides of different molecular weights from mackerel Pneumatophorus japonicus protein hydrolysate

Mackerel （Pneumatophorus japonicus） proteins were hydrolyzed by five proteases： trypsin, papain, neutrase, acid protease, and flavourzyme. The hydrolysate treated by neutrase exhibited the highest antioxidant activity. Response surface methodology （RSM） was employed to optimize the hydrolysis conditions in an effort to obtain a mackerel protein hydrolysate （MPH） with the highest DPPH radical scavenging activity. The MPH was fractioned using a series of ultrafiltration membranes and five fractions, namely, MPH-I （〉10 kDa）, MPH-II （10-2.5 kDa）, MPH-III （1-2.5 kDa）, MPH-IV （0.4-1 kDa）, and MPH-V （below 0.4 kDa）, were obtained. DPPH radical scavenging activity, reducing power, hydroxyl radical scavenging activity, and the lipid peroxidation inhibition capability of these fractions were evaluated. The fractions in molecular weights 〈2.5 kDa （MPH-III, MPH-IV, and MPH-V）, which occupied 93.4% of the total fractions, showed the strongest antioxidant activity; and the antioxidant activities of the three fractions are similar to each other. Using SP Sephadex C-25 and Sephadex G-25 columns, eight fractions were obtained from the MPH （〈2.5 kDa）. The isolated peptide I （1 664 kDa） displayed the highest DPPH radical scavenging activity. Therefore, MPH is a potential source of antioxidant peptides.

Isolation and Identification of Antioxidative Active Component from Total Flavonoids of Mimenghua

In this study, bioassay-guided isolation, identification and biological evaluation of antioxidant components from total flavonoids of Chinese herbal plant Mimenghua were performed. 1, 1-Diphenyl-2-picrylhydrazyl(DPPH) radical scavenging test was adopted as the bioassay-guided method, Sephadex LH-20 column chromatography and high performance liquid chromatography were used as the purification tools for the acquisition of antioxidant components. One compound was obtained and identified as acteoside by its physicochemical properties and spectral characteristics. Antioxidant activity in vitro of acteoside was determined by evaluation of the scavenging activity on DPPH radical and hydroxyl radical, reducing power and total antioxidant capability.The results showed that acteoside had significant antioxidative activity and possessed higher activity with the increase of concentration, which provides the potential application of acteoside in food, pharmaceutical and cosmetic industries.

Elucidation of the structure, antioxidant, and interfacial properties of flaxseed proteins tailored by microwave treatment

The microwave treatment is commonly applied to flaxseed to release nutrients, inactivate enzymes, remove cyanogens,and intensify flavors. The current study aimed to explore the influences of microwave exposure on the antioxidant and interfacial properties of flaxseed protein isolates(FPI), focusing on the altering composition and molecular structure.The results showed that after microwave exposure(700 W, 1–5 min), more compact assembly of storage proteins and subsequent permeation by membrane fragments of oil bodies occurred for cold-pressing flaxseed flours. Moreover, the particle sizes of FPI was progressively reduced with the decrement ranged from 37.84 to 60.66%(P<0.05), whereas the zeta potential values initially decreased and then substantially recovered during 1–5 min of microwave exposure. The conformation unfolding, chain cross-linking, and depolymerization were sequentially induced for FPI based on the analysis of fluorescence emission spectra, secondary structure, and protein subunit profiles, thereby affecting the dispersion or aggregation properties between albumin and globulin fractions in FPI. Microwave exposure retained specific phenolic acids and superior in vitro antioxidant activities of FPI. The inferior gas–water interface absorption and the loose/porous assembly structure were observed for the foams prepared by FPI, concurrent with obviously shrinking foaming properties upon microwave exposure. Improving oil–water interface activities of FPI produced the emulsion droplets with descending sizes and dense interface coating, which were then mildly destabilized due to the lipid leakage and weakened rheological behavior with microwave exposure extended to 5 min. Our findings elucidated that microwave treatment could tailor the application functionality of protein fractions in flaxseed based on their in situ structural remodeling.

Antarctic krill antioxidant peptides show inferior IgE-binding ability and RBL-2H3 cell degranulation

Enzymatic hydrolysis,isolation,and purification might make a great deal of difference in antioxidant activity and antigenicity of peptide components.This study aimed to isolate and purify antioxidant peptide components from Antarctic krill and evaluate their allergenicity of them.Electron paramagnetic resonance(EPR)spectroscopy results indicated 3-10 kDa Antarctic krill hydrolysates(AKHs)had higher DPPH and·OH radical scavenging rates.And the second component(N2-2)purified 3-10 kDa hydrolysate showed better ability to scavenge DPPH and·OH radicals(P<0.05),which were(47.43±2.18)%and(34.33±1.25)%,respectively.Additionally,indirect-ELISA results revealed that N2-1 had a weaker ability to bind specific IgE and that N2-2 had a lower binding capability to specific IgG1(P<0.05).And N2-2 had a higher EC50 value of(5.29±0.95)ng/mL(P<0.05)in cell degranulation assay,which was about 13.80 times that of Antarctic krill.Therefore,N2-2 might be the potential source of the antioxidant peptides with lower allergenicity.

Chemical components from Crotalaria pallida Ait. and their antioxidant activities

Nine compounds were isolated from the 95%ethanol extract of the dried seeds of Crotalaria pallida.The structures of all compounds were identified through the analysis of spectral data.All compounds were isolated for the first time from Crotalaria genus.Compounds 1-5 were evaluated for their antioxidant abilities by ABTS,DPPH and FRAP assays.Results showed that compounds 1-5 had moderate antioxidant activities。

Isolation and identification of chemical constituents from the vinegar-prepared Corydalis yanhusuo

Phytochemical investigation of the vinegar-prepared Corydalis yanhusuo led to the isolation of one aristolactam derivative,1,2,8,9-tetramethoxy-5-methyldibenzo[cd,f]indol-4-(5H)-one(1),and seven aporphine alkaloids,including 2,9,10-trimethoxydibenz[de,g]quinolin-7-one(2),1-hydroxy-2,9,10-trimethoxy-7H-dibenzo(de,g)quinoline-7-one(3),oxoglaucine(4),N-methyloxoglaucine trifluoroacetate trifluoroacetate(5),corunine acetate(6),pontevedrine(7),and oxoglaucidaline trifluoroacetate(8).The structures of the isolated compounds were elucidated by extensive spectroscopic data analysis and comparison with the previous reports.Among them,compounds 1 and 2 were obtained as natural products for the first time,and their NMR data were unambiguously assigned.In addition,compound 1 exhibited moderate cytotoxic activity against HepG2 cells with an IC50 value of 16.0±6.4μM.

荞麦蜂花粉多糖的纯化、表征及其在体外消化过程中抗氧化活性的变化

本论文旨在研究荞麦蜂花粉多糖(BWPP)在模拟体外胃肠消化过程中的抗氧化活性。采用DEAE-52纤维素柱对粗多糖进行分级纯化,经体外模拟胃、肠消化研究其在体外消化过程中的抗氧化活性的变化规律。结果表明经DEAE-52纤维素柱层析洗脱纯化后得到总糖含量最高组分BWPP-1,其主要由Glc、Xyl、Ara等组成,且红外光谱显示BWPP-1具有明显的多糖特征吸收峰。BWPP和BWPP-1在进行体外模拟胃肠消化时,模拟胃液消化60 min时,BWPP和BWPP-1的ABTS^(+)·清除率均达到最大值,分别为86.39%±1.28%、90.38%±2.78%,与其他消化时间的存在显著差异(P<0.05);60 min时对DPPH·清除率达到最大值,分别为86.86%±0.11%、89.58%±1.67%,且二者差异不显著(P>0.05);模拟肠液消化时,BWPP和BWPP-1对ABTS^(+)·清除率在60 min时达到最大值为88.67%±0.40%和91.82%±2.77%,且二者差异不显著(P>0.05);对DPPH·清除率在240 min时达到最大值57.11%±0.06%和65.67%±3.67%,二者差异显著(P<0.05);而在消化过程中,对铁离子还原能力均较弱。由此可得,BWPP和BWPP-1具有较好的ABTS^(+)·和DPPH·清除能力,且胃液消化时DPPH·清除能力略高于肠液消化,而肠液消化时的ABTS^(+)·清除能力略高于胃液消化。本研究为以荞麦蜂花粉为基料的功能性产品的开发提供理论依据。

两种不同产地锁阳多糖组分的结构解析及体外抗氧化活性对比研究

研究两种不同产地锁阳多糖的组成及初级结构,并探讨体外抗氧化活性。利用水提醇沉法提取粗多糖,采用红外分光光度法、离子色谱法、高效凝胶色谱法等对样品进行初级结构解析、单糖组成及分子量的测定;并测定其体外抗氧化活性。结果显示,苏尼特粗多糖中总糖含量(49.65%)比阿拉善粗多糖中总糖含量(35.44%)略高。苏尼特右旗锁阳TCA法脱蛋白多糖及阿拉善锁阳TCA法脱蛋白多糖的重均分子量分别为56.131、50.696kDa,两种脱蛋白多糖中单糖组成没有明显区别。在一定浓度范围之内均有一定的体外抗氧化活性,并呈质量浓度依赖关系。研究发现,苏尼特右旗产锁阳中多糖含量比阿拉善产锁阳高,分子量、单糖组成及抗氧化活性等方面没有明显差异。本研究可为锁阳及其它类似药材中多糖的提取、纯化及药理活性研究提供参考。

澳洲坚果抗氧化肽的分离纯化及肽段鉴定

为研究澳洲坚果抗氧化肽的抗氧化活性和氨基酸组成,以复配蛋白酶水解澳洲坚果粕制备粗多肽,利用超滤、大孔树脂纯化技术制备了抗氧化活性最佳的分子量小于1000 Da的多肽,采用Sephadex G-15凝胶对其分离并评价各组分对DPPH、羟基、ABTS+自由基的清除能力与还原能力,筛选出抗氧化活性最强组分,利用液相色谱-串联质谱技术(liquid chromatography and tandem mass spectrometry,LC-MS/MS)进行鉴定并分析。结果表明,葡聚糖凝胶柱层析分离出G1、G2、G3组分,其中G3具有最佳的抗氧化活性,其羟基自由基清除能力半抑制浓度(half maximal inhibitory concentration,IC_(50))6.18 mg/mL与还原能力IC_(50)2.19 mg/mL优于谷胱甘肽,DPPH自由基清除能力IC_(50)0.50 mg/mL,ABTS+自由基清除能力IC_(50)0.02 mg/mL;通过液相色谱-串联质谱鉴定G3含有46个肽段,肽段长度均小于10个氨基酸,匹配得分大于200分的9条肽段分子量为631~920 Da,均无毒性;筛选获得高抗氧化活性肽HLLPK、KEFFP、KEFFPA,其分子量分别为606.84、666.83、737.92 Da。本研究初步揭示了澳洲坚果抗氧化肽组成,深化了澳洲坚果抗氧化肽的研究,为澳洲坚果抗氧化肽的开发利用提供了理论参考。

酱渣大豆异黄酮大孔树脂纯化工艺及其抗氧化活性研究

研究酱渣大豆异黄酮的纯化工艺及其抗氧化活性。选用5种树脂(AB-8、HPD300、ADS-7、DM301、D101)进行静态吸附试验,筛选吸附效果最好的树脂,再以动态吸附试验筛选最佳纯化工艺,最后研究纯化后酱渣大豆异黄酮的抗氧化活性。结果表明,AB-8树脂的吸附效果最好,在流速1.5 mL/min、pH 3的条件下吸附0.6 mg/mL的样品溶液75 mL,再用100 mL 60%乙醇溶液解吸,样品纯度可由11.37%提升到55.84%;纯化后的酱渣大豆异黄酮具有较好的抗氧化活性,其浓度为0.07 mg/mL时,对DPPH自由基和ABTS自由基的清除率分别为93.35%和98.67%。AB-8树脂可用于酱渣大豆异黄酮的分离纯化且效果较好,酱渣大豆异黄酮具有较强的抗氧化活性。

超高压辅助酶解对汉麻分离蛋白结构和抗氧化活性的影响

本研究以汉麻分离蛋白(Hemp Protein Isolate,HPI)为原料,通过超高压辅助酶解反应对HPI进行改性,测定不同压力下汉麻蛋白酶解产物(hydrolysate of hemp protein isolate,HPIH)的聚丙烯酰胺凝胶电泳(SDS polyacrylamide gelelectrophoresis,SDS-PAGE)电泳特性、表面疏水性、巯基含量、傅立叶红外光谱和内源荧光光谱分析改性前后汉麻分离蛋白的结构变化。结果表明,超高压(ultra-high pressure,UHP)(0.1、100、200、300 MPa)处理对HPI酶解反应具有一定的辅助作用,且随压力的升高酶解反应程度逐渐增大,分子量逐渐降低;HPI经改性后,疏水性基团逐渐暴露,表面疏水性随压力的增大先上升后下降,且变化差异性显著(P<0.05),在200 MPa时表面疏水性达到最大;酶解反应后,HPIH游离巯基含量显著降低(P<0.05),而表面巯基含量随压力增大呈先上升后下降的趋势;通过测定改性前后蛋白质氨基酸组成及含量可知,改性前后HPI氨基酸组成不变,但各氨基酸含量存在不同程度下降;由傅立叶红外光谱图可以看出,与HPI相比,HPIH的吸收峰强度、峰型及峰面积等均发生不同程度变化,说明超高压辅助酶解反应使蛋白质二级结构发生改变;内源荧光光谱显示,HPIH荧光强度增大且最大发射波长发生红移,说明酶解反应改变了HPI的三级结构;抗氧化活性结果表明,适当的压力处理可有效提升酶解产物的抗氧化能力,当压力为200 MPa时,HPIH的DPPH、ABTS^(+)自由基清除能力及还原能力达到最高。综上所述,超高压辅助酶解改性处理能显著改变汉麻分离蛋白的二、三级结构,暴露出疏水基团等活性基团,从而提高其抗氧化性。

刺五加新品种‘紫加1号’多糖分离纯化及抗氧化活性分析

‘紫加1号’为该课题组选育的刺五加(Acanthopanax senticosus)新品种,嫩茎叶灰紫色且味甘。为分离纯化‘紫加1号’嫩茎叶多糖,并测定各组分的单糖组成和分子量大小、评价各组分的抗氧化活性。该研究以‘紫加1号’嫩茎叶为材料,采用水提醇沉工艺,经大孔树脂吸附法除杂脱色得到粗多糖(A.polysaccharides,ASPS);通过DEAE-Cellulose 52离子柱和Sephadex G-100凝胶柱分离纯化得多糖组分;采用离子色谱和凝胶色谱-示差-多角度激光光散射色谱,测定各均一组分的单糖组成和分子量;通过测定均一组分清除羟基自由基(·OH)、超氧阴离子自由基(O_(2)^(-·))、1,1-二苯基-2-三硝基苯肼自由基(DPPH)的能力,分析其体外抗氧化活性强弱。结果表明:ASPS经分离纯化得到4种多糖组分,即酸性多糖ASPA-1-1、ASPA-2-1、ASPA-3-1和中性多糖ASPN-1,其分子量依次为8.10、26.15、0.91、0.89 kDa,主要是由阿拉伯糖、鼠李糖、半乳糖、葡萄糖、木糖、甘露糖、核糖、半乳糖醛酸和葡萄糖醛酸等按不同比例组成的杂多糖。ASPA-1-1、ASPA-2-1、ASPA-3-1、ASPN-1均具有明显的抗氧化活性,其中ASPA-2-1清除·OH、DPPH的能力高于ASPA-1-1、ASPA-3-1、ASPN-1,而ASPA-3-1清除O_(2)^(-·)的能力最强。综上认为,从‘紫加1号’中分离纯化得到的多糖具有较好的抗氧化活性。该研究结果为‘紫加1号’作为天然抗氧化剂的深度研究和进一步开发与利用提供了一定的科学理论依据。

大孔树脂纯化滇黄精黄酮工艺优化及纯化前后抗氧化活性比较

试验研究滇黄精黄酮的纯化工艺及其抗氧化活性。通过单因素试验结合响应面试验,利用超声辅助溶剂提取法对滇黄精黄酮进行提取工艺优化,通过静态和动态试验,考察树脂种类、粗提液浓度、洗脱剂、洗脱流速对滇黄精黄酮吸附解吸性能的影响,确定最佳纯化工艺条件。采用1, 1-二苯基-2-三硝基苯肼(DPPH)自由基和2, 2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基法,比较纯化前后滇黄精黄酮的抗氧化性。结果显示,滇黄精总黄酮的最佳提取工艺参数为乙醇浓度79%、提取温度61℃、提取时间2 h、液料比20 mL/g,提取率达到0.29%。AB-8大孔树脂纯化滇黄精黄酮效果最好,最佳条件为将40 g/L粗提液上柱,用70%乙醇以2.0 g/L速度洗脱,此条件下滇黄精黄酮纯度提高至5.31%,是粗提物浓度的11.8倍。滇黄精黄酮纯化后对DPPH自由基和ABTS自由基清除率为82.44%、86.22%,远高于纯化前。研究表明,AB-8大孔树脂适合分离纯化滇黄精黄酮,且滇黄精黄酮具有抗氧化活性。

淡竹叶多酚的提取纯化工艺优化、组分分析及体外抗氧化活性研究

目的确定淡竹叶多酚提取纯化工艺,分析主要成分及体外抗氧化活性。方法采用超声辅助提取淡竹叶多酚,通过响应面实验确定最佳提取条件。选取适合淡竹叶多酚纯化的大孔树脂,对纯化工艺参数进行优化。通过高效液相色谱-质谱法(high performance liquid chromatography-mass spectrometry,HPLC-MS)鉴定淡竹叶多酚的主要成分,并评价其体外抗氧化活性。结果淡竹叶多酚的最佳提取工艺参数为:乙醇体积分数60%、超声功率500 W、料液比1:25(g/mL)、超声时间24 min及超声温度59℃,该条件下淡竹叶多酚提取量为8.01 mg/g。淡竹叶多酚纯化工艺参数为:上样质量浓度6 mg/mL、pH 4、流速2 mL/min、解吸液为70%乙醇、解吸体积90 mL,纯化后的淡竹叶多酚纯度由12.86%提高到76.18%。通过HPLC-MS鉴定出16种酚类成分,且纯化后多酚有较高的抗氧化活性。结论本研究得到了淡竹叶多酚提取纯化工艺,得到的多酚纯化物有明显的抗氧化活性。

蛇含委陵菜的木脂素类成分及其细胞毒活性研究

为了研究蛇含委陵菜(Potentilla kleiniana)的化学成分及其肿瘤细胞毒活性,该研究综合运用D-101大孔树脂、硅胶、Sephadex LH-20、Toyopearl HW-40F及半制备高效液相等现代色谱分离技术对蛇含委陵菜60%乙醇提取物进行分离纯化,根据化合物的理化性质结合核磁共振波谱(NMR)、高分辨质谱(HR-ESI-MS)鉴定化合物的结构,并采用MTT法测定各化合物对人宫颈癌细胞株Hela的细胞毒活性。结果表明:(1)从蛇含委陵菜中分离鉴定了13个木脂素类化合物,分别为(+)-松脂素(1)、(+)-8-羟基松脂素(2)、(+)-丁香脂素(3)、(+)-杜仲树脂酚(4)、(+)-松脂素-4-O-β-D-吡喃葡萄糖苷(5)、(+)-8′-羟基松脂素-4-O-β-D-吡喃葡萄糖苷(6)、(+)-8′-羟基松脂素-4′-O-β-D-吡喃葡萄糖苷(7)、(+)-松脂素-8′-O-β-D-吡喃葡萄糖苷(8)、schilignan F(9)、(+)-松脂素-4,4′-O-双吡喃葡萄糖苷(10)、(+)-落叶松脂素-4′-O-β-D-吡喃葡萄糖苷(11)、neoolivil-4-O-β-D-glucopyranoside(12)、3,3′-bis[3,4-dihydro-4-hydroxy-6-methoxy-2 H-1-benzopyran](13)。其中,化合物1-4、7、8、10、12、13为首次从委陵菜属植物中分离得到,化合物5、6、9、11为首次从蛇含委陵菜中分离得到。(2)细胞毒试验结果显示,化合物1、3、4对Hela细胞具有较好的抑制活性,其半数抑制浓度IC_(50)值分别为(69.94±1.89)、(66.25±2.11)、(59.81±1.73)μmol·L-1。该研究结果进一步丰富了蛇含委陵菜的化学成分,为抗宫颈癌药物的研发提供物质基础。

香菇中麦角甾醇的提取纯化、表征及其抗氧化活性

为建立一种香菇中麦角甾醇检测的三波长分光光度法,通过单因素试验和响应面试验获得最佳提取条件,并利用溶剂提取法、重结晶法及制备型高效液相法纯化香菇麦角甾醇,对其进行表征及抗氧化活性研究。结果表明,三波长分光光度法可以有效消除杂质和其他背景因素带来的影响,精确测定香菇中麦角甾醇的含量。香菇麦角甾醇的最佳提取条件为超声时间90 min、料液比1∶59(g/mL)、提取温度69℃,麦角甾醇含量的预测值为3.868 78 mg/g,实测值为3.781 4 mg/g。纯化后单体麦角甾醇的纯度可达96%以上,清除DPPH自由基、ABTS+自由基的半数抑制浓度IC_(50)分别为(0.72±0.06)、(0.17±0.01)mg/mL。所建立的方法重复性、稳定性、精密度良好,是一种快速准确测定香菇麦角甾醇的检测方法,且纯化的麦角甾醇具有良好的抗氧化活性。

Isolation of bioactive antioxidant compounds from the aerial parts of Allium roseum var.grandiflorum subvar.typicum Regel.

Objective:To assess the antioxidant activity of aerial parts of Allium roseum var.grandiflorum subvar.typicum Regel.(A.roseum var.grandiflorum subvar.typicum Regel.)for the first time,as well as to isolate the main bioactive compounds.Methods:The chloroformic extract of Allium roseum(A.roseum)and their fractions obtained by subjection to a chromatographic study were tested for their antioxidant activities by using 2,2-diphenyl-2-picrylhydrazyl and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)assays.An activity-guided purification was conducted to isolate five compounds in pure form where their structures were identified by means of nuclear magnetic resonance analyses,including 1D and 2D nuclear magnetic resonance experiments.Results:The evaluation of the antioxidant activity of chloroformic extract and their fractions from A.roseum var.grandiflorum subvar.typicum Regel.showed interesting results.The active chloroformic extract afforded five isolated compounds where their structures were identified as β-sitosterol(1),chrysoeriol(2),luteolin(3),apigenin(4),andβ-sitosterol 3-O-β-D-glucoside(5).All the compounds were isolated for the first time from the A.roseum var.grandiflorum subvar.typicum Regel.The three flavonoids(2–4)exhibited the highest antioxidant activity with IC_(50) values of 62.28,21.26 and 513.42μg/mL,respectively(2,2-diphenyl-2-picrylhydrazyl assay)and 218.00,73.50 and 877.66μg/mL,respectively[2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)assay].An important value of trolox equivalent antioxidant capacity(2.10 mmol/L)was reported for luteolin(3).Conclusions:These results may suggest that the A.roseum var.grandiflorum subvar.typicum Regel.have great potential as a source of a natural preservative ingredient in beneficial for natural health products.

海洋真菌Aspergillus sp.LW152抗细菌活性代谢产物研究

目的对海洋真菌Aspergillus sp.LW152发酵提取物的抗细菌成分进行研究。方法利用硅胶柱层析、葡聚糖凝胶Sephadex LH-20柱层析、半制备高效液相色谱等方法,对该菌株发酵提取物进行分离纯化;化合物结构通过核磁共振波谱(NMR)、质谱(MS)等数据并与文献数据对比进行确定;采用微量肉汤稀释法对化合物抗菌活性进行体外评价。结果从真菌LW152发酵的乙酸乙酯提取物中分离得到了7个化合物,其结构分别鉴定为7-脱氧-7,14-二脱氢水杨酸(1)、7-脱氧-7,8-二脱氢水杨酸(2)、pseudaboydin B(3)、(Z)-5-(羟甲基)-2-(6'-甲基庚-2'-烯-2'-基)苯酚(4)、aspergillusene A(5)、2,4-二羟基-6-甲基苯甲酸甲酯(6)和1-亚油酸单甘油酯(7)。结论海洋真菌Aspergillussp.LW152能产生具有抗细菌活性的次级代谢产物,其中化合物4和5对6种致病细菌的生长均具有一定的抑制作用,化合物7对青枯雷尔菌的生长具有抑制作用。