百香果果皮的微波预处理-超声波提取工艺及其抗氧化活性研究

研究了百香果果皮提取物的微波预处理-超声波提取工艺及其抗氧化活性。以黄酮得率、多酚得率、花色苷得率、ABTS自由基清除能力为考核指标,采用总评归一值法,结合正交实验设计,优选百香果果皮的微波预处理-超声波提取工艺,并对不同提取方法所制备的百香果果皮提取物进行有效成分得率和抗氧化活性的对比分析。优选的微波预处理-超声波提取工艺条件为:超声时间25min、微波时间90s、乙醇浓度70%、料液比1∶50、解吸剂比1∶7。百香果果皮提取物具有一定的体外抗氧化活性,微波预处理-超声波提取法的有效成分含量和抗氧化活性,均优于超声波提取法和直接水浴提取法,具有效率高、操作简便和成本低等优点,可作为百香果果皮有效物提取的新方法。     

五指毛桃抗氧化活性研究

对客家常用中草药五指毛桃进行提取并研究其抗氧化活性,为利用五指毛桃开发天然抗氧化剂提供依据。采用9种溶剂(甲醇、60%乙醇、80%乙醇、95%乙醇、异丙醇、正丁醇、三氯甲烷、乙酸乙酯、蒸馏水)结合超声波辅助提取法及传统煎煮法分别提取五指毛桃活性成分,用亚硝酸钠-硝酸铝-氢氧化钠分光光度法、福林-酚法、二苯代苦味酰基自由基(DPPH)法分别测定提取液的总黄酮含量、总酚含量、自由基清除活性。结果表明,以五指毛桃干粉重计,乙酸乙酯提取物的总黄酮含量最大,甲醇提取物的总酚含量最大;在超声波辅助提取法中60%乙醇、95%乙醇、蒸馏水三种提取物和传统煎煮法的提取物DPPH自由基清除率大于15%,其余均小于15%。     

龙眼叶乙醇提取物自由基清除活性研究

采用二苯基苦味肼基自由基体系,研究龙眼叶乙醇冷浸法提取物对抗自由基的能力,并测定其总黄酮含量,探讨自由基清除活性和总黄酮含量之间的关系。结果表明,龙眼叶乙醇提取物在非常低的浓度即表现出很强的自由基的清除能力。龙眼叶乙醇提取物浓度增加后DPPH自由基清除活性迅速增加。此外,龙眼叶乙醇提取物的自由基清除率和作用时间的关系变化不明显。     

ABTS法测定龙眼叶乙醇提取物抗氧化活性

本论文采用ABTS和还原能力法考察龙眼叶乙醇提取物的抗氧化能力。对于龙眼叶乙醇提取物,其ABTS自由基清除能力在非常低的浓度下就达到了不错的效果。药液浓度提高,龙眼叶乙醇提取物对ABTS自由基清除率超过60%。当作用时间增长,龙眼叶乙醇提取物对ABTS自由基展现了更强的清除率。     

三白草提取物对自由基的清除作用研究

考察了三白草乙醇提取物经不同溶剂萃取所得的各部分对1,1-二苯基-2-三硝基苯肼(DPPH)自由基、羟基自由基和超氧自由基的清除能力。以2,6-二叔丁基-4-甲基苯酚(BHT)为参考。结果表明,三白草乙醇提取物经不同溶剂萃取所得的各部分对DPPH自由基、羟基自由基和超氧自由基都具有清除能力,且随着提取物浓度的增加,清除能力逐渐增高;其中乙酸乙酯部分对DPPH自由基、羟基自由基和超氧自由基的清除作用最强。     

银杏叶总黄酮的提取及其抗氧化性的研究

采取微波辅助乙醇法提取银杏叶总黄酮,探讨最佳提取条件及产品的抗氧化性活性。研究表明,提取的影响因素顺序为乙醇浓度>固液比>微波时间>微波功率,最佳工艺条件为:乙醇浓度90%,固液比1∶40(g/mL),微波时间20 min,微波功率600 W。抗氧化的实验表明,银杏叶黄酮提取物对超氧阴离子、羟自由基和DPPH自由基均有较强的清除作用,且随着添加量的增大而增强。同浓度的银杏提取物比同浓度的Vc溶液清除效果好。     

巨尾桉叶中原花色素提取工艺比较及不同溶剂萃取物生物活性的研究

通过正交试验探讨了巨尾桉叶中原花色素的3种提取方法的最佳提取工艺条件,并进行了对比。结果显示,传统溶剂提取法的最优工艺为:60%乙醇、80 ℃、100 min、料液比1:14(g:mL,下同),原花色素得率5.95%;微波辅助提取法的最优工艺为:50%乙醇、微波功率200 W、微波时间4 min、料液比为1:20,得率5.48%;超声波辅助提取法的最优工艺为:60%乙醇、60 ℃、超声波时间25 min、料液比为1:14,得率为6.07%。超声波辅助提取法效果最好,时间短,得率高。实验对超声波提取物的不同溶剂萃取物体外抗氧化性和抗肿瘤活性进行了研究,结果表明,乙酸乙酯萃取物抗氧化作用较强,当质量浓度为1.2 g/L时,对DPPH自由基清除率达到96.33%;乙酸乙酯萃取物质量浓度为2 g/L时,对于人肝癌细胞Bel-7404具有很强的抗肿瘤活性,抑制率为56.37%。     

响应面法优化管萼山豆根总生物碱提取工艺

采用微波控温辅助超声波的方法提取管萼山豆根茎中总生物碱,通过单因素法和响应面法优化了提取工艺,考察了管萼山豆根茎中总生物碱对1, 1-二苯基-2-三硝基苯肼自由基(DPPH·)、2, 2-联氮-二-3-乙基-苯并噻唑-6-磺酸自由基(ABTS·)和超氧阴离子自由基(O2?·)的清除作用。结果表明,模型优化并修正的最佳工艺条件为:提取时间37.8 min,微波加热温度64.5℃,超声功率575 W,乙醇体积分数95%,在该条件下总生物碱得率为0.5418%,高于不采用微波超声辅助的0.2436%、超声辅助的0.4538%、乙醇回流的0.3884%。管萼山豆根茎中总生物碱在DPPH·、ABTS·、邻苯三酚浓度分别为0.1、7.0、8.0 mmol/L条件下,其半数抑制质量浓度(IC50)分别为0.891、0.552和0.390 g/L。     

龙眼叶乙酸乙酯提取物抗氧化活性研究

采用DPPH自由基和羟自由基体系评测龙眼叶乙酸乙酯提取物抗氧化活性,为龙眼叶的开发与应用提供参考数据。方法:将龙眼叶用乙酸乙酯冷侵提取,旋转蒸发得到龙眼叶乙酸乙酯提取物,采用苯基苦味肼基自由基(DPPH)法与还原能力测定法,对其提取物进行自由基清除能力评定。结果:龙眼叶乙酸乙酯提取物对DPPH自由基与羟自由均具有较强清除能力,其中对DPPH自由基的清除能力可高达46.14%。结论:龙眼叶乙酸乙酯提取物不仅具有一定的抗氧化活性和优异的自由基清除能力,其还原能力与乙酸乙酯提取浓度还存在一定量效关联。     

橄榄黄酮的提取及其抗氧化作用的研究

本文对超声波法提取橄榄中黄酮类化合物的工艺条件进行了研究。通过单因素提取实验和正交实验,结果表明,橄榄黄酮的提取最佳条件为:50 Hz的超声波处理25 min,用40%的乙醇在80℃下提取1 h,黄酮得率为3.84%。同时研究了橄榄黄酮提取物对羟基自由基(.OH)的清除作用和超氧自由基(O2-.)的抑制效果,结果表明,橄榄黄酮对羟基自由基有一定的清除作用,对超氧自由基有很好的抑制效果。     

马占相思树皮中原花色素提取工艺及其生物活性的研究

通过正交试验优化了马占相思树皮中原花色素的3种提取方法的最佳提取工艺条件。结果显示,传统溶剂提取法的最佳工艺为：60%乙醇、70℃、70 min、料液比1∶18（g∶mL,下同）,原花色素得率为7.42%;微波辅助提取法的最佳工艺条件为：60%乙醇、微波功率200 W、微波时间8 min、料液比1∶18,得率为7.05%;超声波辅助提取法的最佳工艺为：70%乙醇、超声波温度50℃、超声波时间50 min、料液比为1∶16,得率为8.57%。超声波辅助提取法效果最好,浸提温度低,得率高。进一步对超声波提取物不同溶剂萃取物的体外抗氧化活性和抗肿瘤活性进行了研究。结果表明,乙酸乙酯萃取物对DPPH·清除效果最好,其半数抑制浓度（IC₅₀）为17.94 mg/L,低于对照样维生素C（Vc）的IC₅₀值;乙酸乙酯萃取物对人肝癌细胞Bel-7404具有明显的抑制效果,IC₅₀值为4.86 mg/L,与抗肿瘤药依托泊苷效果相当。     

甘蔗花与叶抗氧化活性研究

为了探明农作物甘蔗花和甘蔗叶提取物的抗氧化活性。以甲醇和乙醇为溶剂,采用超声提取法对甘蔗花及甘蔗叶进行提取,考察其对DPPH自由基活性的清除能力,并与多种抗氧化剂的清除能力进行比较。甘蔗花和甘蔗叶的提取物与5种标准品的抗氧化能力对比为:没食子酸咖啡酸芦丁甘蔗花甲醇提取物香草酸甘蔗叶甲醇提取物甘蔗花乙醇提取物甘蔗叶乙醇提取物对香豆酸。结果表明,甘蔗花的甲醇提取物抗氧化能力大于香草酸、对香豆酸两种标准品,因此具有一定的抗氧化能力。     

花生仁中抗氧化成分的研究与分析

采用恒温水浴法﹑回流提取法﹑微波提取法﹑超声波提取法探讨花生仁的抗氧化性,通过对羟自由基的清除作用比较各种方法的优缺点。结果表明：以氢氧化钠作溶剂,采用恒温水浴法的提取效果较佳,其最佳工艺条件为：以0.1 mol/L氢氧化钠溶液为溶剂,温度为37℃,时间为60 min。     

Comparative study on the antioxidant and nitrite scavenging activity of fruiting body and mycelium extract from Pleurotus ferulae

We investigated the effects of the antioxidant and the nitrite scavenging activities of the extracts from Pleurotus ferulae fruiting body grown on the solid state using corn cob and activated bleaching earth (CCABE media) and its mycelium grown in the liquid state. The total phenol and polysaccharide concentrations in hot water extract of fruiting body were approximately 3.6- and 4.3-fold higher than those of the mycelium. Using the hot water extract of fruiting body, the maximum DPPH radical scavenging activity at 9 mg/mL, hydroxyl radical scavenging activity at 12mg/mL, reducing power at 12 mg/mL, and chelating ability at 12 mg/mL were obtained, 80.5%, 72.4%, 0.99 OD (700 nm), and 77.0%, respectively. However, in the case of hydrogen peroxide scavenging activity, the ethanol extract was the highest, 78.7% at 12 mg/mL. The maximum nitrite scavenging activity was obtained, 89.7% at 6 mg/mL of hot water extract from fruiting body. Hot water extracts were more effective than ethanol extracts in scavenging activity on DPPH radicals and hydroxyl radical scavenging, reducing power, and chelating activity of ferrous, whereas ethanol extracts were more effective in hydrogen peroxide scavenging activity as evidenced by their lower EC₅₀ values. These results indicate that the hot water extract of P. ferulae fruiting body using CCABE media has good potential to be used as a source of materials or additives for oxidation suppressant in food, cosmetics and drug compositions.     

Evaluation of Antioxidant and Antiproliferative Properties of Three Actinidia (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) Extracts in Vitro

The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O(2) (-)·radical, DPPH, and the ABTS(+) radical scavenging activity assays were used to identify the antioxidant activities of Actinidia extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the Actinidia kolomikta extract had a higher antioxidant activity than the other two Actinidia extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (R(2) ≥ 0.712, p < 0.05). The Actinidia arguta extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that Actinidia extracts can potentially have health benefits.     

Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O(2) (-)) and hydrogen peroxide (H(2)O(2)) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.     

溪黄草黄酮的超声波法提取与活性研究

采用超声波法提取溪黄草中的总黄酮,用正交法确定了最佳提取工艺,并与常规回流提取法作了比较研究。超声波法的最佳提取条件为:使用60%乙醇作溶剂,在温度60℃,料液比为1∶40条件下超声波辅助提取20 min,连续提取2次,黄酮的总提取率可达99.81%。研究了黄酮提取物对羟自由基的抑制作用及体外抑菌作用,结果表明,溪黄草黄酮提取物对羟自由基有抑制作用,对金黄色葡萄球菌和枯草杆菌有一定的抑菌效果。     

不同提取工艺的马尾松松针提取物抗氧化性能研究

研究超临界二氧化碳萃取、内置超声提取、外置超声提取、普通醇提4种不同提取工艺制备的马尾松松针提取物（SCDEP、IUEP、OUEP,EEP）,分析4种提取物内总酚和总黄酮含量差异;同时研究4种松针提取物的抗氧化性能。结果表明：SCDEP提取物中总酚与总黄酮含量分别为22．18％和4．96％,含量最高;而EEP中总酚和总黄酮含量最低,分别为13．47％和2．98％。4种提取物具有较强抗氧化能力,SCDEP、IUEP、OUEP清除DPPH自由基和还原三价铁能力均强于丁基羟基甲苯（BHT）,而EEP还原三价铁能力弱于BHT。马尾松松针提取物中总酚及总黄酮含量与抗氧化性具有明显的量效关系。     

Antiradical activity of extracts of almond and its by-products

Antioxidant activities of ethanolic extracts of whole almond seed, brown skin, and green shell cover were evaluated using different free radical trapping assays. Trolox equivalent antioxidant capacity assay revealed that the total antioxidant capacities of brown skin and green shell cover extracts were 13 and 10 times greater than that of the whole seed extract at the same extract concentration. The free radical-scavenging activity of extracts of brown skin and green shell cover also exceeded that of the whole seed. The scavenging activity of superoxide radical by different almond extracts ranged from 76 to 97% at 100 ppm and 85 to 99% at 200 ppm. The corresponding reduction of hydrogen peroxide concentration was 59–66% (100 ppm) and 86–91% (200 ppm). The hydroxyl radical-scavenging capacities at 100 and 200 ppm were 16 and 42% for whole seed, 57 and 100% for brown skin, and 40 and 56% for green shell extracts, respectively. A 100% scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was observed for brown skin and green shell extracts at 100 and 200 ppm concentrations, respectively, and whole seed extracts scavenged 21 (at 100 ppm) and 73% (at 200 ppm) of the DPPH radical.