Evaluation of Antibacterial and Synergistic/Antagonistic Effect of Some Medicinal Plants Extracted by Microwave and Conventional Methods

The purpose of the study was to evaluate the efficiency of the microwave (MW) extraction method by comparing it with a conventional method through evaluation of antimicrobial and synergism/antagonism activity of each aquatic and ethanolic extracts samples, which were extracted from the dried plants (Ficus sycomorus leaves, Lawsonia inermis leaves and Glycerrhiza glabra Linn.). Nine samples of each plant for both solvents were irradiated with MW at several power outputs (180 w, 360 w, and 540 w) in several interval times (1, 2 and 3 minutes). The antibacterial activities of extracts and the synergistic effect between plants and antibiotics were evaluated using disk diffusion method against clinical isolated Staphylococcus aureus and Escherichia coli. The result revealed that the inhibition zone for more than 50% using aquatic and ethanolic samples results (extracted in two minutes and MW power 180 w) had shown the optimum extract and better antibiotic activity for each plant. Also, the results of ethanolic extracts used against selected microorganisms showed antimicrobial and synergistic effect with most antibiotics better than aquatic extracts. Our results indicate the possibility of using MW apparatus as an extractor to obtain bioactive compounds from plants and thus used in the treatment of bacterial infections, and some results of this study were encouraging. However, the antagonistic reactions of some extracts with some antibiotics and their use in combination should be further studied for in vitro activities. It is clearly a need to be furthermore evaluated, to identify the effective components, the mode of action and the possible toxic effect in-vivo of these ingredients.

Synergistic effect of microwave irradiation and CaF2 on vanadium leaching

The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride （CaF2） on the vana- dium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when CaF2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%-15% when 5wt% CaF2 is added; by contrast, in the absence of CaF2, the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation, whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover, a large amount of A1 and V and a small amount of Si are dissolved from samples under microwave heating, as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When CaF2 is present, the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer, resulting in a prominent effect of mi- crowave irradiation.

A Comparative Study of Process Parameter Optimization and Process of Flavonoid in Planted Trollius Chinensis through Backflow Method, Ultrasonic Wave Method and MicrowaveMethod

It takes flavonoid extraction rate as indicator and adopts the method of orthogonal experiment to study process of total flavonoid in Trollius chinensis through ultrasonic wave assisted extraction, microwave assisted extraction and backflow extraction, as well as optimization of process parameter. The result indicates that in terms of extraction efficiency, microwave extraction method is better than ultrasonic radiation extraction method, which is better than backflow extraction method. Optimal process parameter through backflow extraction is： backflow temperature 60℃, fluid material ratio 1：20, ethanol density 65%, backflow time 60min; optimal process parameter through ultrasonic wave assisted extraction is： ultrasonic radiation temperature 70℃, fluid material ratio 1：20, ethanol density 65%, ultrasonic wave radiation time 45rain; optimal process parameter of microwave assisted extraction is： microwave radiation temperature 60℃, fluid material ratio 1：20, ethanol density 75%, microwave radiation time 45min.

Comparison of Different Extraction Approaches for Heavy Metal Partitioning in Sediment Samples

Three extraction methods, ultrasonic assisted extraction (USE), microwave assisted extraction (MSE), and conventional single extraction (CSE), in conjunction with the modified three-stage BCR sequential extraction procedure (SEP) were applied to examine the contents of Cd, Cu, Cr, Ni, Pb and Zn from lake sediment samples, to know whether these techniques can reduce extraction time and improve reproducibility. The SEP and developed alternative single extrac- tion methods were validated by the analysis of certified reference material BCR 601. By the use of optimized sonication and microwave conditions, steps 1, 2 and 3 of the BCR sequential extraction methods (excluding the hydrogen peroxide digestion in step 3, which was not performed with sonication and microwave) could be completed in 15-30 min and 60- 150 s, respectively. The recoveries of total extractable metal contents in BCR 601, obtained by three single extractions ranged from 93.3%-102%, 88.9%-104% and 81.2%-96.2% for CSE, USE and MSE, respectively. The precision of the single extraction methods was found in the range of 3.7%-9.4% for all metals (n = 6).

超声波-微波联合辅助提取澳洲坚果青皮多糖工艺优化及其抗氧化活性

为了开发澳洲坚果青皮多糖产品,促进澳洲坚果青皮的综合利用,我们以澳洲坚果青皮为试材,比较澳洲坚果果实不同部位的多糖提取率,并采用超声波-微波联合辅助法,运用单因素与正交试验比较微波功率、提取时间、料液比、超声温度4个因素对多糖提取率的影响,研究其最优提取条件。以维生素C为对照,测定澳洲坚果青皮多糖清除1,1-二苯基-2-三硝基苯肼(DPPH)、羟基自由基的能力与还原力,评价其抗氧化活性。结果表明,澳洲坚果果实不同部位中,青皮多糖提取率最高。青皮多糖超声波-微波联合辅助提取工艺中各因素对提取率的影响力从高到低依次为提取时间>料液比>超声温度>微波功率,且均达到极显著水平(p<0.01),最佳提取工艺条件为提取时间90 min、超声温度65℃、料液比(1∶25)g/mL、微波功率400 W,此条件下提取率达到1.96%。澳洲坚果青皮多糖的抗氧化活性与质量浓度呈极显著正相关(p<0.01),相关系数R分别为0.9707、0.9813、0.9912,具有较强的DPPH、羟基自由基清除能力和较高的还原力,其半抑制浓度(IC 50)分别为38.55、20.38、41.51μg/mL,相同浓度下略低于维生素C。

超声波微波协同浸提工艺优化及速溶红茶产品品质分析

为提高速溶红茶品质,研究超声波微波协同浸提工艺,考察不同因素(超声时间、超声功率、微波时间、微波功率、微波温度)对茶黄素总量及其单体组分含量的影响,并通过响应面优化条件。在此基础上对速溶红茶产品进行感官审评和主要理化指标的测定。结果表明:最优工艺条件为超声时间31 min、超声功率360 W、微波时间9 min、微波温度52℃、微波功率203 W。在该工艺条件下,速溶红茶的汤色红亮,香气醇厚,感官审评总分为91.73,其中香气90.00、汤色91.80、组织形态92.40、滋味94.20;茶黄素总含量高达3.74%,茶多酚含量为24.11%。

协同微波法提取香蕉皮果胶的工艺研究

以本地香蕉皮为原料,采用不同提取剂协同微波法提取果胶,分析果胶的产率及理化性质,结果显示六偏磷酸钠协同微波法来制备皮果胶得率和品质较好。以六偏磷酸钠提取剂协同微波提取香蕉皮果胶,通过单因素试验和正交法优选,确定了香蕉皮果胶提取的最优工艺条件。结果表明:加入0.6%含量的六偏磷酸钠螯合剂辅助微波法提取果胶的最佳工艺参数为:料液比为1∶12 g/mL、pH值为2、微波功率为800 W、微波时间为3 min,果胶提取率达10.15%。

超声微波协同提取药桑叶生物碱及其保肝活性研究

本研究以药桑叶为原料,采用单因素结合响应面法优化了药桑叶生物碱的超声微波协同提取工艺,并采用四氯化碳致小鼠急性肝损伤模型评价了药桑叶提取物(MNLE)的保肝活性。结果表明药桑叶生物碱的最佳提取工艺为:料液比1∶54 g/mL,乙醇浓度79%,微波功率300~0 W(0~7 min),超声功率493 W,提取时间29 min,提取温度70℃,在此条件下生物碱提取率可达11.325 mg/g。药效学试验结果显示,与模型组相比,MNLE能明显降低血清谷丙转氨酶(ALT)、谷草转氨酶(AST)水平以及肝组织丙二醛(MDA)和一氧化氮(NO)水平(P<0.05或P<0.01),升高肝组织超氧化物歧化酶(SOD)和谷胱甘肽(GSH)水平(P<0.05或P<0.01),肝组织病理学变化也得到了明显改善。结果表明MNLE具有较好的保肝作用,其作用机制与其抗氧化活性相关。

管萼山豆根总黄酮的提取工艺优化及其抗氧化活性研究

以管萼山豆根的叶为原料,采用微波-超声波辅助低共熔溶剂(DES)提取总黄酮,筛选出较优的DES体系,在单因素试验的基础上,运用Plackett-Burman和响应面试验优化其提取工艺;并考察了最佳提取工艺下总黄酮对DPPH·、·ABTS^(+)和·OH的清除作用。研究结果表明:较优的DES溶剂体系为n(氯化胆碱)∶n(三乙二醇)=1∶3,总黄酮的最佳提取工艺条件为提取时间45 min、提取温度74℃、料液比1∶45(g∶mL)、微波功率300 W、DES含水量25%、超声波功率300 W,在该条件下叶中总黄酮得率为3.460%;分别采用乙酸乙酯、热乙酸乙酯(50±1)℃、大孔吸附树脂AB-8、NKA-9和D101分离总黄酮,其回收率分别为23.40%、28.09%、88.66%、71.55%和41.86%;AB-8大孔树脂分离所得总黄酮对DPPH·、·ABTS^(+)与·OH的半数抑制质量浓度(IC_(50))值分别为0.01705、0.01835和0.12330 g/L;总黄酮对DPPH·、·ABTS^(+)的清除率显著高于维生素C(V_(c)),而对·OH的清除率略低于V_(c)。进一步分析发现:优化条件下叶总黄酮得率(3.460%)高于茎(2.059%)和根(1.875%),高于单一微波提取(3.377%)和超声波提取(3.390%),低于加热回流提取(3.635%),但所需时间仅为加热回流提取的1/4。

豆腐柴叶果胶提取工艺优化

研究不同提取方法、影响因素和提取工艺参数对豆腐柴叶果胶品质的影响,建立模型并进行优化,以期得到品质好的果胶提取方法及工艺参数。采用5种不同方法提取豆腐柴叶果胶,通过综合比较果胶得率、半乳糖醛酸含量和酯化度确定最适提取方法;利用Plackett-Burman试验对超声微波串联提取果胶工艺中的超声时间、超声功率、超声温度、料液比、微波时间和微波温度6个影响因素进行关键因素筛选,采用Box-Behnken响应面试验对提取工艺参数进行优化,得出最佳参数并加以验证。结果表明豆腐柴叶果胶最适提取方法为超声微波串联辅助盐酸法;影响超声微波串联辅助盐酸法提取豆腐柴叶果胶的关键因素为微波时间、超声温度和微波温度;建立的豆腐柴叶果胶提取工艺参数与果胶得率、半乳糖醛酸含量和酯化度的回归模型显著(P<0.05),最佳提取工艺参数为:料液比1∶20、超声时间10 min、超声温度30℃、超声功率600 W、微波时间30 min、微波温度88℃,该条件下,豆腐柴叶果胶得率为15.68%,半乳糖醛酸含量为83.24%,酯化度为70.25%。研究为提升豆腐柴叶果胶资源的开发利用价值提供了参考依据。

大麦芽碱的提纯工艺优化及其结构鉴定研究

以大麦芽为原料,优化提纯工艺,获得大麦芽碱并鉴定其结构。通过超声微波协同提取法进行正交试验,优化大麦芽碱提取工艺,采用响应面优化分析法探究大孔树脂纯化大麦芽碱的最佳工艺条件,利用高效液相质谱进行结构鉴定。大麦芽碱提取最佳工艺是液料比45∶1,温度60℃,微波时间40 min,微波功率400 W,提取含量2.74 mg·g^(-1),此条件下得率为82.64%;大麦芽碱纯化最佳工艺是吸附流速193.00 BV·h^(-1),pH 6.21,洗脱流速1.57 mL·min^(-1),洗脱乙醇浓度84.60%,质谱分析提取物为纯度90%的大麦芽碱。综上,研究为大麦芽的机理研究及产品开发提供了理论依据。

超声-酸性乙醇协同提取荷叶生物碱的工艺优化

在单因素实验的基础上,通过正交实验考察了pH值、料液比、超声时间、乙醇体积分数对荷叶生物碱提取率的影响。确定超声-酸性乙醇协同提取荷叶生物碱的最佳工艺为:pH值2、料液比1∶18(g∶mL)、超声时间40 min、乙醇体积分数70%,在此条件下,荷叶生物碱提取率可达3.22%。该工艺具有操作简便、提取率高、耗时短等优点,可应用于荷叶生物碱的提取。

超声微波协同提升贡柑片热风干燥效率的研究

借助动力学、热力学等方法,研究不同热风干燥温度下贡柑片在干燥过程中的干燥规律、动力学模型、水分迁移、热力学参数等,解析超声微波协同预处理对热风干燥贡柑片干燥效率的影响。结果表明:贡柑片的干燥过程遵循Two term exponential模型,干燥速率与干燥温度有关,且当干燥温度为80℃时,干燥速率最快;超声微波协同预处理可有效缩短贡柑片的干燥时间(缩短了0.5~1.5 h),并显著降低其水分扩散的活化能(降低了1.620 kJ/mol);同一热风干燥温度下,超声微波协同预处理组的ΔH^(≠)、ΔS^(≠)和ΔG^(≠)均低于对照组;超声微波协同预处理可提高贡柑片的水分扩散有效系数(4.333×10^(-7)~8.967×10^(-7)),使其表面形成更多孔道。因此,超声微波协同预处理可有效提高贡柑片的热风干燥效率。

铁皮石斛多糖超声-微波协同提取条件优化及其抗氧化活性

以铁皮石斛为原料,采用超声-微波协同法提取铁皮石斛多糖。选择液料比、微波时间、微波功率、超声时间为单因素,以铁皮石斛多糖提取率为评价指标,通过响应面试验对超声-微波协同法提取铁皮石斛多糖进行优化。确定最佳工艺参数为液料比50∶1(mL/g)、微波时间120 s、微波功率370 W、超声时间30 min,在此条件下铁皮石斛多糖提取率为30.56%。根据体外抗氧化活性评价表明,铁皮石斛多糖对羟自由基的清除能力低于维生素C,对α-葡萄糖苷酶表现出明显的抑制能力,具有较好的体外降血糖作用;另外,铁皮石斛多糖对α-淀粉酶也有一定的抑制作用。

超声-微波辅助提取酸浆宿萼多糖及其体外降糖活性

该文以酸浆宿萼为试材,研究料液比、超声功率、微波功率、协同时间对酸浆宿萼多糖提取量的影响,在单因素试验的基础上,采用四因素三水平的响应面法优选提取工艺参数,通过对α-葡萄糖苷酶、α-淀粉酶抑制能力测定检测酸浆宿萼多糖体外降糖活性。结果表明:最佳提取工艺为料液比1∶17(g/mL)、超声功率160 W、微波功率320 W、协同时间4 min;在该条件下,酸浆宿萼多糖提取量为(26.13±0.11)mg/g;体外降糖试验表明,酸浆宿萼多糖有降糖活性。

蒲公英中黄酮的响应面法优化提取和同步荧光法检测研究

本试验应用响应面法优化超声-微波协同萃取蒲公英中黄酮的提取工艺,并建立测定黄酮含量的同步荧光法。在单因素试验结果的基础上,以提取溶剂乙醇浓度、微波功率、萃取时间和料液比为自变量,提取液的荧光强度为响应值,设计4因素3水平响应面试验,优化蒲公英中黄酮的提取工艺;单因素试验确定同步荧光法的测定条件。结果表明:1)判定系数R^(2)=0.9648,说明模型与实际结果拟合程度好,所得模型能解释96.48%的响应值改变,校正判定系数(R_(Adj)^(2)=0.9295)与预测判定系数(R_(Pred)^(2)=0.8860)接近。2)响应面法优化超声-微波协同萃取技术提取蒲公英中的黄酮,其最佳提取条件为乙醇浓度50%,微波功率250 W,萃取时间30 min,料液比1∶30(g∶mL)。3)同步荧光法的最佳测定条件为波长差值(Δλ)=55 nm,Al(NO_(3))_(3)浓度0.2%,加入pH=6的醋酸-醋酸钠缓冲液1 mL,室温条件下反应50 min。在最佳测定条件下,测得蒲公英中黄酮的含量为3.52 mg/g。由此可见,响应面法优化提取工艺能较好地用于蒲公英中黄酮的提取,同步荧光法测定黄酮含量的方法干扰少、准确度高。

酶辅助超声微波协同提取桑黄黄酮及其抗氧化活性研究

采用纤维素酶辅助超声微波协同提取桑黄黄酮。以黄酮得率为指标,在单因素试验的基础上通过响应面法优化提取工艺,并分析桑黄黄酮的抗氧化活性。结果表明:最优提取工艺为纤维素酶添加量1.5%(以桑黄粉质量为基准)、液料比22∶1(mL/g)、提取温度50℃、提取时间39 min,在此条件下,桑黄黄酮得率为4.55%±0.23%。抗氧化活性试验结果显示,桑黄黄酮清除DPPH·、·OH和ABTS^(+)·的IC_(50)分别为0.046、0.056、0.115 mg/mL,表明桑黄黄酮具有较好的抗氧化活性。

高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用测定富硒小麦中硒代氨基酸

为科学补硒和促进富硒小麦的种植推广,用蛋白酶XIV辅助微波振荡提取富硒小麦中硒代氨基酸,采用C18分离柱分离,以磷酸氢二铵(30.0 mmol/L)+甲醇(1.0%)+四丁基溴化铵溶液(2.0 mmol/L,pH=6.5)为流动相,能在10 min内实现5种硒代氨基酸的分离。在高能氦气模式(HEHe)下,用^(78)Se的色谱峰面积积分作为定量依据,建立了高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)检测富硒小麦中硒代氨基酸的方法。5种硒代氨基酸在1.0~200.0μg/L线性相关性良好,检出限在0.11~0.29μg/L。以富硒小麦为基体进行加标回收,除硒代胱氨酸(SeCys_(2))可能不稳定,易分解造成回收率偏低外,其他4种硒代氨基酸的加标回收率在92.3%~102%,相对标准偏差为1.6%~4.2%(n=7)。用所建立的方法测定农业科技工作者种植推广的富硒小麦,结果发现小麦中的硒赋存形态多为硒代蛋氨酸(SeMet),此外,小麦中还含有少量硒代胱氨酸(SeCys_(2))、硒代半胱氨酸(SeCys)、甲基硒代半胱氨酸(MeSeCys)和硒代乙硫氨酸(SeEt)。方法具有良好的精密度和准确度,适用于富硒小麦中硒代氨基酸的形态分析。

不同消解方法对电感耦合等离子体质谱法检测PM_(2.5)中金属元素的影响

目的:比较不同消解方法对电感耦合等离子体质谱法检测PM_(2.5)中主要金属元素的影响。方法:分别采用水浴超声提取法和微波消解法对空气PM_(2.5)滤膜样品进行消解,再用电感耦合等离子体质谱法(ICP-MS)测定铅、铝、镉、砷、铬、镍、锑、铍、锰、铊、硒、汞等12种金属元素的含量。结论:12种金属元素的相关系数都在0.999以上,精密度RSD在1.2﹪~2.2﹪,检测限在0.08~2.0μg·L~(-1),定量限在0.27~6.7μg·L^(-1)。通过比较两种消解方法对12种金属元素的回收率的影响,发现两种消解方法均具适用于PM_(2.5)滤膜样品中金属元素的消解。

蓝莓花青素的提取及其抗氧化活性和稳定性

该文采用4种不同溶剂(无水乙醇、70%乙醇、50%乙醇、甲醇)提取蓝莓花青素,选取最佳溶剂,探究超声辅助、微波辅助和超声-微波辅助技术对蓝莓花青素含量的影响,并对3种方法提取的花青素分别进行稳定性和抗氧化性分析。结果表明:无水乙醇的提取效果最好,超声-微波相对于单独采用超声或微波提取花青素的效率更高,花青素的最高提取含量为0.846 mg/g。抗氧化性分析结果表明:超声-微波协同提取的花青素对ABTS+自由基清除能力、对DPPH自由基清除率以及FRAP抗氧化能力略低于微波提取的花青素。稳定性分析结果表明:温度越高花青素的稳定性越差;pH值在3~6范围内,花青素稳定性随pH值的增大而减少。微波提取与超声-微波提取的花青素稳定性相对较好,更适合长时间保存。