Evaluation of extracts and essential oil from Callistemon viminalis leaves:Antibacterial and antioxidant activities,total phenolic and flavonoid contents

Objective:To investigate antioxidant and antibacterial activities of Callistemon viminalis(C.viminalis)leaves.Methods:The essential oil of C.viminalis leaves obtained by hydrodistillation was analyzed by GC/MS.Different extracts were tested for total phenolic and flavonoid contents and in vitro antioxidant(DPPH assay)and antibacterial(agar disc diffusion and 96-well micro-plates methods)actives.Results:Fourteen components were identified in the essential oil,representing 98.94%of the total oil.The major components were 1,8-cineole(64.53%)andα-pinene(9.69%).Leaf essential oil exhibited the highest antioxidant activity of(88.60±1.51)%comparable to gallic acid,a standard compound[(80.00±2.12)%].Additionally,the biggest zone of inhibitions against the studied bacterial strains was observed by the essential oil when compared to the standard antibiotic(tetracycline).The crude methanol extract and ethyl acetate fraction had a significant antibacterial activity against the tested bacterial strains.Conclusions:It can be suggested that C.viminalis is a great potential source of antibacterial and antioxidant compounds useful for new antimicrobial drugs from the natural basis.The present study revealed that the essential oil as well as the methanol extracts and ethyl acetate fraction of C.viminalis leaves exhibited highly significant antibacterial activity against the tested bacterial strains.

Total phenolic, flavonoid content, and antioxidant activity of flour, noodles, and steamed bread made from different colored wheat grains by three milling methods

The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health.

GC-MS analysis,determination of total phenolics,flavonoid content and free radical scavenging activities of various crude extracts of Moringa peregrina(Forssk.) Fiori leaves

Objective:To perform phytochemical screening,estimate total phenolics,flavonoids and to evaluate antioxidant potential of Moringa peregrina(M.peregrina) leaves.Methods:The dried powdered leaves of M.peregrina(150 g) were extracted exhaustively by Soxhlet with ethanol and then fractionated into hexane,chloroform,ethy alacetate and methanol.All the prepared extracts were also analyzed by gas chromatography-mass spectrometry to identify and characterize the chemical compounds present in the crude extracts.Folin- Ciocalteu reagent and aluminium chloride colorimetric methods were used to estimate total phenolic and flavonoid content of extracts.Hydrogen peroxide and 1,1 diphenyl-2-picrylhydrazyl were used to determine in vitro antioxidant activity.Results:Phytochemical analysis of ethanol extract showed presence of major classes of phytochemicals.Gas chromatography-mass spectrometry results revealed presence of 19 phytoconstituents in hexane extract,6 in ethyl acetate and 7 compounds in methanolic extract.Methanol extract was found to contain the highest phenolic content and flavonoids.In vitro antioxidant activities of all crude extracts were significant and comparable with the standard ascorbic acid.Conclusions:Results of this study show that the leaves of M.peregrina are the rich source of phenolic compounds that can play an important role in preventing the progression of many diseases.

Study of total phenol,flavonoids contents and phytochemical screening of various leaves crude extracts of locally grown Thymus vulgaris

Objective:To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol,flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al Jabal Al Akhdar,Nizwa.Sultanate of Oman.Methods:The leave sample was extracted with methanol and evaporated.Then it was defatted with water and extracted with different polarities organic solvents with increasing polarities.The prepare hexane,chloroform,ethyl acetate,hutanol and methanol crude extracts were used for their evaluation of total phenol,flavonoids contents and phytochemical screening study.The established conventional metliods were used for quantitative determination of total phenol,flavonoids contents and phytochemical screening.Results:Phytochemical screening for various crude extracts were tested and shown positive result for flavonoids,saponins and steroids compounds.The result for total phenol content was the highest in hutanol and the lowest in methanol crude extract whereas the total flavonoids contents was the highest in methanol and the lowest hexane crude extract.Conclusions:The crude extracts from locally grown Thymus vulgaris showed high concentration of flavonoids and it could be used as antibiotics for different curable and uncurable diseases.

An Evaluation on Antioxidant Activity, Total Phenolic and Total Flavaonoid Contents of Extracts from <i>Adina cordifolia</i>(Roxb.)

In this study, in vitro antioxidant activity, total phenolic content and concentration of flavonoids of four different extracts of Adina cordifolia (Roxb.) were determined using spectrophotometric methods. Antioxidant activity of extracts was expressed as percentage of DPPH radicals’ inhibition and IC50 values (μg/ml). IC50 values ranged from 20.39 to 38.96 μg/ml. The total phenolic content ranged from 17.48 to 20.83 mg/g of dry weight of extract, expressed as gallic acid equivalents. The total flavonoid concentrations varied from 17.49 to 22.48 mg/g, expressed as quercetin equivalents. The significant linear correlation was confirmed between the values for the total phenolic content and antioxidant activity of plant extracts. Adina cordifolia (Roxb.) can be regarded as promising candidates for natural plant sources of antioxidants with high value.

大黄不同极性部位成分分析及抗氧化和抑菌活性研究

[目的]探究大黄不同极性部位有效成分含量与体外抗氧化和抑菌活性的相关性。[方法]采用90%乙醇回流提取大黄,采用氯仿、乙酸乙酯和正丁醇依次分级萃取,得到不同极性部位;以高效液相色谱(high performance liquid chromatography,HPLC)法测定其蒽醌类物质,以紫外分光度法测定总酚和总黄酮含量;以1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)法、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS]法和总还原力法测定抗氧化活性,采用抑菌圈直径和生长曲线测定法探究大黄不同极性部位对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的影响。[结果]正丁醇部位芦荟大黄素-8-O-葡萄糖苷和大黄酸-8-O-葡萄糖苷含量最多,峰面积分别为(2.72±0.07)mAU*min和(2.59±0.06)mAU*min,总酚和总黄酮含量最高,分别为(29.95±4.95)mg·g^(-1)和(35.71±3.26)mg·g^(-1);正丁醇部位的抗氧化活性和抑菌活性最强;芦荟大黄素-8-O-葡萄糖苷、大黄酸-8-O-葡萄糖苷、总酚和总黄酮含量与抗氧化活性正相关(P<0.05)。[结论]大黄总提物正丁醇部位的抗氧化和抑菌活性最强,可能与芦荟大黄素-8-O-葡萄糖苷、大黄酸-8-O-葡萄糖苷等成分有关,该结果对后续的深入研究具有指导意义。

Diversity of Antioxidant Content and Its Relationship to Grain Color and Morphological Characteristics in Winter Wheat Grains

The current interest in the health beneifts of whole wheat grain has prompted breeders to further increase the concentration of antioxidants in wheat. The objective of this study was to investigate the variation in antioxidant content among Chinese wheat grains and the relationship between antioxidants and grain color and morphological characteristics. A wide variation was observed in the total phenolic, carotenoid and lfavonoid contents, as well as the antioxidant activity （AOA）, of Chinese wheat varieties. Black wheat had the highest mean total phenolic, carotenoid and lfavonoid contents and the highest AOA, followed by red and white wheats. The grain color parameters were signiifcantly negatively correlated with total phenolic, carotenoid and lfavonoid contents and AOA among all of the wheat varieties examined, and grain weight was also signiifcantly negatively correlated with these traits. The same correlation between grain weight and antioxidant traits was also observed within individual groups of wheat, which indicates that grain weight may be used as an index for selecting wheat varieties with high AOA. Landraces had signiifcantly higher lfavonoid content than commercial wheat varieties. The results of this study may be useful for breeding nutrient-rich wheat varieties.

四种食药菌固体发酵菌质活性物质及其抗氧化能力研究

以灵芝、猴头菇、平菇、杏鲍菇为出发菌种,研究培养时间和不同食药菌对固体发酵菌质中总黄酮、总酚、DPPH·清除力和总抗氧化力的影响,为产品开发奠定基础。培养时间对菌质的总黄酮、总酚、DPPH·清除力和总抗氧化力的影响不同,且各指标的最大值出现时间各异。培养时间对平菇菌质的总酚及对灵芝、猴头菇和平菇菌质的DPPH·清除力和总抗氧化力产生显著影响,平菇菌质总酚的最大值出现在24 d,灵芝、猴头菇和平菇菌质的DPPH·清除力和总抗氧化力的最大值出现在24 d、14 d和14 d。培养时间对杏鲍菇菌质的总黄酮、总酚、DPPH·清除力和总抗氧化力产生显著影响,总黄酮、总酚和总抗氧化力的最大值出现在19 d,DPPH·清除力的最大值出现在24 d。不同菌种对菌质的总黄酮、总酚、DPPH·清除力和总抗氧化力产生显著影响。灵芝的总黄酮均值最高,猴头菇的总酚、DPPH·清除力和总抗氧化力的均值最高。研究发现菌质的活性物质与总抗氧化力之间的相关性因菌种而各异。综合考虑,猴头菇在固态发酵14 d菌质的各指标表现优异。

额济纳绿洲胡杨(Populus euphratica)酚类物质含量和分布及其与土壤水分的关系

采用分光光度法测定了额济纳绿洲胡杨（Populus euphratica）的披针形叶、卵圆形叶、嫩枝、枝（D〈5mm）、枝（5～10mm）、主干树皮、根（D〈2mm）、根（2～5mm）和根（5～10mm）9类器官中的总酚、黄酮和缩合单宁含量。结果表明，总酚含量较高的器官为皮（27．93mg／g），叶、根、枝中总酚含量分别为17．64mg／g（两类叶均值）、16．72mg／g（三类根均值）、12．19mg／g（三类枝均值）；黄酮含量较高的器官为皮（51．30mg／g），叶、根、枝中黄酮含量分别为28．45mg／g（两类叶均值）、39．99mg／g（三类根均值）、23．67mg／g（三类枝均值）；根中缩合单宁含量较高，三类根均值为22．10mg／g，皮、叶、枝中缩合单宁含量分别为8．41mg／g、4．03mg／g（两类叶均值）、4．47mg／g（三类枝均值）。披针形叶和卵圆形叶中酚类物质含量没有显著性差异（P〉0．05）；随着枝不断成熟，嫩枝、枝（D〈5mm）、枝（5～10mm）中酚类物质逐渐减少；随着根直径减少，根中缩合单宁逐渐增加，细根（D〈2mm）中的缩合单宁含量最高（25．95mg／g）。分析胡杨各器官中酚类物质含量与土壤水分的关系，结果表明卵圆形叶中酚类物质含量与土壤水分含量成显著负相关关系（P〈0．05，总酚：r=-0．949；黄酮：r=-0．923；缩合单宁：r=-0．944）。研究揭示了极端干旱地区胡杨各器官中酚类物质的变化规律，及其与环境因子的相互作用关系。

20种市售凉茶类植物饮料抗氧化性的比较研究

利用DPPH自由基清除实验、ORAC法和Fe3+还原能力实验,考察20种市售凉茶类植物饮料的抗氧化性。结果表明:20种凉茶在不同的抗氧化评价体系中均表现出不同程度的抗氧化能力。运用模糊评价理论建立的抗氧化综合评价模型表明,抗氧化综合评价值最高的5种凉茶类植物饮料皆为传统凉茶铺出售的凉茶。各凉茶试样的抗氧化综合评价值与总酚含量有一定的相关性,但线性关系不显著。

提取溶剂对青稞提取物总酚、黄酮含量及其抗氧化活性的影响

以3种不同的青稞为原料,采用不同的提取溶剂(水、60%乙醇、60%甲醇、60%丙酮、95%乙醇、100%甲醇、100%丙酮)对青稞进行提取。对各提取物的总酚、总黄酮进行测定,同时采用3种抗氧化方法:二苯代苦味酰自由基(DPPH)、2,2’-联氨-双(3-乙基苯并噻唑啉-6-磺酸)二胺盐自由基(ABTS)和总抗氧化能力(FARP)评价青稞提取物的抗氧化活性。结果表明,95%乙醇和60%丙酮更有利于青稞多酚的提取。藏青2000的各溶剂提取物的总酚、总黄酮及抗氧化活性普遍高于相应溶剂的循化蓝青稞和香格里拉绿青稞。藏青2000的60%丙酮提取物含有最高的总酚含量,达到211.92mg GAE/100g DW;在60%乙醇提取时具有最高的总黄酮含量,达到60.11mg RT/100g DW;在60%乙醇提取时具有最强的DPPH清除能力,达到80.08%;而用60%丙酮提取时,具有最强的ABTS清除能力和总抗氧化能力,分别达到了1.85,9.28 mmol TEAC/100g DW。总酚含量与抗氧化活性均具有显著的相关性,FRAP法与DPPH、ABTS法具有极显著的相关性。综上表明,青稞富含总酚成分,是一种潜在的天然抗氧化剂资源。

不同品种龙眼果肉酚类物质的抗氧化活性比较

为研究不同龙眼品种资源中酚类物质、黄酮类化合物含量及其抗氧化性差异,选取广东省农业科学院果树研究所龙眼资源圃的24个龙眼品种,分析其果肉中游离态和结合态总酚、总黄酮物质的含量,采用DPPH自由基清除能力、ABTS总抗氧化能力、FRAP抗氧化能力和氧自由基吸收能力ORAC四种不同方法评价其体外抗氧化能力差异;不同龙眼品种果肉总酚、总黄酮含量与DPPH、ABTS、FRAP、ORAC四种不同方法测定的抗氧化能力的变幅和变异系数较大,呈现出显著的基因型差异;不同品种龙眼果肉的多酚和黄酮的含量分别与ABTS自由基清除能力、FRAP和ORAC呈极显著(p<0.01)正相关关系,而与DPPH自由基清除能力的EC50值呈极显著负相关关系(p<0.01)。采用快速聚类法将24个不同品种的龙眼聚成多酚及总黄酮含量和抗氧化能力差异显著的三大群类。不同品种龙眼果肉游离态和结合态酚类物质含量与其抗氧化活性均呈显著正相关关系,提示酚类物质是龙眼果肉抗氧化活性的主要成分;酚类物质和黄酮类物质在龙眼果肉中主要以游离态存在,其中结合态平均占总酚含量的17.45%。

22种常见抗肿瘤中草药的抗氧化活性研究

目的:本研究以常见的22种具有抗肿瘤活性的中药材为对象,对其抗氧化活性进行研究。方法:以DPPH自由基清除率为指标,测定各试样的抗氧化活性;通过FRAP法,Folin-Ciocaheu法以及铝盐显色法,比较其总还原力,总酚含量以及黄酮含量。结果:抗氧化活性大于50%的药材占到了90.09%,其中莪术、虎杖、野生黄芩、白芍、凤尾草、丹参、川断、姜黄等8种药材DPPH的清除作用均超过了90%,显示了较强的抗氧化作用,且野生黄芩的IC50最低(IC50=0.05g/L),抗氧化能力最强,与总还原力的实验结果一致,总酚和黄酮含量也在所有测试品中均为最高,分别为5 240μg/L、83 210μg/L。结论:除了薏苡仁和茯苓,各试样都有较强的抗氧化活性,表明天然抗氧化剂与其抑癌作用具有一定的相关性,但其相互作用机制需要进一步的探讨研究,本研究为从广泛的天然抗肿瘤资源中寻找抗氧化物质及开发抗氧化型抗肿瘤药物提供了实验依据。

超声波处理对红葡萄酒总酚、总黄酮含量及自由基清除活性的影响

应用超声波处理红葡萄酒,探讨超声因素(超声频率,超声功率,超声处理温度,超声时间)对红葡萄酒中总酚、总黄酮含量及自由基清除活性的影响。结果表明超声处理会使红葡萄酒总酚含量、总黄酮含量与自由基清除活性显著降低(p<0.05)。超声处理红葡萄酒后,其抗氧化活性与其总酚含量呈高度正相关,回归方程为y=0.0270x+38.806(R2=0.9007,p<0.01);其抗氧化活性与其总黄酮含量亦存在一定线性关系,回归方程为y=0.0592x+37.357(R^2=0.4970,p<0.05)。在本文实验条件下根据实验结果可以推知,超声处理后红葡萄酒自由基清除活性的降低,部分是由于总酚含量和总黄酮含量降低所引起的。

白花菜子不同溶剂提取物总多酚、总黄酮含量及抗氧化活性测定

测定了白花菜子四种不同溶剂提取物的总多酚含量、总黄酮含量和体外抗氧化活性。以没食子酸为对照品,采用福林-酚试剂法测定白花菜子提取物中总多酚的含量;以芦丁为对照品,采用可见-紫外分光光度法测定白花菜子提取物中总黄酮的含量。通过测定DPPH自由基清除率、氢氧基清除率和还原能力来评价白花菜子提取物的抗氧化活性。在四种白花菜子不同溶剂提取物中,总黄酮含量从高到低的顺序为乙酸乙酯提取物(CAEE)>甲醇提取物(CME)>石油醚提取物(CPEE)>二氯甲烷提取物(CCE);总多酚含量从高到低的顺序为CME>CAEE>CPEE>CCE。白花菜子提取物各种方法抗氧化活性从高到低的顺序为CME>CAEE>CPEE>CCE,与总多酚含量顺序一致。结果表明白花菜子乙酸乙酯提取物总黄酮含量最高,白花菜子甲醇提取物总多酚含量最高,且甲醇提取物具有很强的抗氧化活性,可以用作抗氧化药物或食品添加剂,因此有必要对白花菜子的化学成分、体内抗氧化活性和机理进行深一步的研究。

暗紫贝母内生真菌Fusarium sp.A14次生代谢产物抗氧化活性研究

本文采用石油醚(30~60℃)、乙酸乙酯、二氯甲烷、正丁醇和乙醇5种溶剂依次对暗紫贝母内生真菌Fusarium sp.A14发酵液进行提取,获得5种不同极性馏分。用DPPH·、ABTS^+·清除活性和FRAP活性对其进行了抗氧化活性评价,用福林酚法和NaNO_2-Al(NO_3)_3-Na OH比色法测定了各馏分中总多酚含量(TPC)和总黄酮含量(TFC),最后用TLC自显影法和HPLC法分析抗氧化活性成分。抗氧化活性及TPC和TFC测定结果表明,后四种溶剂提取馏分具良好的抗氧化活性,以乙酸乙酯和正丁醇提取馏分活性最强,且抗氧化活性与TPC和TFC存在明显相关性。此外,TLC自显影分析结果表明抗氧化活性成分具有多样性;HPLC分析结果表明乙酸乙酯和二氯甲烷中馏分中有多种具较强抗氧化活性的酚酸类物质,如儿茶素、咖啡酸、木樨草素和阿魏酸。本研究表明:暗紫贝母内生真菌Fusarium sp.A14具有能够生产已知或者未知抗氧化活性物质的潜力,其在医药健康领域具有重要应用价值。本试验为其进一步开发和利用奠定了基础。

隐甲藻藻渣醇水提取物的抗氧化活性研究

本研究采用总抗氧化能力、DPPH自由基清除能力、亚铁离子螯合能力及总还原力等抗氧化指标评价隐甲藻(Crypthecodinium cohnii)藻渣醇水提取物不同极性萃取物的抗氧化能力,采用分光光度法测定样品中总酚和总黄酮含量。结果表明隐甲藻渣不同极性萃取物均具有一定的抗氧化能力,其中乙酸乙酯相和石油醚相总抗氧化能力和亚铁离子螯合能力较高,水相和正丁醇相的DPPH自由基清除能力和总还原能力较高,且在一定质量浓度范围内存在量效关系。相关性分析结果显示,不同极性萃取物的总多酚含量与DPPH自由基清除能力和总还原能力显著正相关,而总黄酮仅与总抗氧化能力和金属离子螯合能力呈正相关关系,提示除酚类和黄酮类化合物外,可能还含有其他抗氧化成分。本研究表明隐甲藻藻渣具有较好地抗氧化活性,有待合理开发利用,其可能存在的其他抗氧化活性成分也有待于进一步明确。

红豆越橘果酒发酵过程总酚及总黄酮含量的变化

利用红豆越橘浆果发酵生产红豆越橘果酒,采用Folin-酚法对不同发酵时间红豆越橘果酒中的总酚含量进行检测;采用以Na NO2-Al(NO3)3-Na OH为显色剂的分光光度法对红豆越橘果酒中的总黄酮含量进行检测。结果表明,红豆越橘果酒在酿造过程中,原汁总酚含量为2235.1 mg/L,发酵15 d时,下降到2057.2 mg/L,发酵15 d后总酚含量下降的速率十分缓慢。原汁中的黄酮含量为761.7 mg/L,发酵20 d时下降到670.3 mg/L,发酵20 d后总酚含量下降趋于缓慢。发酵15 d后和发酵20 d后的红豆越橘果酒均达到国标要求。感官评定结果:发酵15 d时,红豆越橘果酒的感官评定得分为92.8分;发酵20 d时,红豆越橘果酒的感官评定得分为90.0分。

豆奶甲醇提取物中抗氧化活性物质的鉴定

本文主要在研究了豆奶甲醇提取物有无抗氧化活性的基础上,分析鉴定了其可能存在的抗氧化物质,为相关研究提供理论依据。测定抗氧化能力的方法包括1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl radical,DPPH)法和铁离子还原能力(Ferricreducing antioxidant power,FRAP)法。比色法测定总酚含量和总黄酮含量。通过超高效液相-四极杆飞行时间串联质谱(Ultra-highperformance liquid chromatography-quadruple time-of-flight-mass spectrometry,UHPLC-QTOF-MS)测定豆奶甲醇提取液中活性成分的种类和含量。实验表明,豆奶甲醇提取液具有一定的抗氧化性,且DPPH法和FRAP法测定豆奶抗氧化值不存在显著性差异。豆奶甲醇提取物的总酚含量(285.77±2.93μg/mL)远高于总黄酮含量(11.27±0.51μg/mL)。鉴定出5种化合物,其中只有6,7,4'-三羟基黄酮和Rha-Ara-GlcA-SoyB与抗氧化值存在正相关性。异黄素和大豆甙元两种异黄酮与抗氧化值存在着负相关,6,7,4'-三羟基黄酮可能是主要的抗氧化物质。

超高效液相色谱-串联质谱法同时测定蒲公英根和 蒲公英叶中4种指标性成分的含量

目的建立超高效液相色谱-串联质谱法同时测定蒲公英根和蒲公英叶中4种指标性成分的含量。方法采用Dikma Endeavorsil C 18色谱柱(100 mm×2.1 mm,1.8μm);流动相:0.1%甲酸溶液(A)-甲醇(B),梯度洗脱;流速:0.2 mL·min^-1;柱温:35℃;ESI离子源,正离子扫描,多反应监测模式。结果对香豆酸、咖啡酸、木犀草素、木犀草苷在选定的浓度范围内线性关系良好,其相关系数均>0.9991,加样回收率为98.60%~100.34%,RSD为0.44%~1.62%,重复性、稳定性、精密度良好。结论所建立的含量测定方法快速、简便、准确度高且重复性好,可用于蒲公英根与蒲公英叶样品的质量控制。