Antioxidant power of phytochemicals from<Emphasis Type="Italic">Psidium guajava</Emphasis> leaf

Dried ground leaves ofPsidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1∶10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin-Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3±15.5 and 511.6±6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH') colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH' color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC₅₀ and the time needed to reach the steady state to EC₅₀ concentration (T _{EC 50}) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC₅₀. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.     

Effect of chlorogenic acid on antioxidant activity of <Emphasis Type="Italic">Flos Lonicerae</Emphasis> extracts

Flos Lonicerae is a medically useful traditional Chinese medicine herb. However, little is known about the antioxidant properties ofFlos Lonicerae extracts. Here the antioxidant capacity of water, methanolic and ethanolic extracts prepared from Flos Lonicerae to scavenge 1,1-diphenyl-2-picrylhydrazyl （DPPH） radical and reduce Fe^3＋ to Fe^2＋ is examined. Chlorogenic acid, a major component of Flos Lonicerae, is identified and further purified from 70% ethanolic extract with high performance liquid chromatography （HPLC） and its antioxidant capacity is characterized. The total phenolic compounds and chlorogenic acid contents in Flos Lonicerae are determined. The present results demonstrate that the Flos Lonicerae extracts exhibit antioxidant activity and chlorogenic acid is a major contributor to this activity.     

Antioxidant activity of alcohol aqueous extracts of <Emphasis Type="Italic">Crypthecodinium cohnii</Emphasis> and <Emphasis Type="Italic">Schizochytrium</Emphasis> sp.

Crypthecodinium cohnii (dinoflagellate) and Schizochytrium sp. (thraustochytrid) are the main sources for docosahexaenoic acid (DHA). The present study aimed to evaluate the antioxidant activity of petroleum ether, ethyl acetate, n-butanol, and water fractions of alcohol aqueous extracts of these two microalgae and to provide a theoretical basis for comprehensive utilization. The antioxidant activity was determined by total antioxidant capacity (TAC) determination, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, ferrous ion-chelating ability (FICA) assay, and reducing power (RP) assay. The total phenolic content (TPC) and total flavonoid content (TFC) were also measured by the Folin-Ciocalteu and spectrophotometry methods, respectively. The results indicated that the extracts from these two microalgae possessed good antioxidant capacity. Analysis showed that most antioxidant performance indicators (TAC, DPPH, and RP) were positively correlated with the TPC of the extracts, suggesting that the phenolics might be the major components in C. cohnii and Schizochytrium sp., contributing to their antioxidative function. Therefore, the polar fractions of C. cohnii and Schizochytrium sp. could be further examined and considered for application in health products or cosmetics.     

Antioxidant activity and protective effect of Clitoria ternatea flower extract on testicular damage induced by ketoconazole in rats

Background

Ketoconazole (KET), an antifungal drug, has adverse effects on the male reproductive system. Pre-treatments with antioxidant plant against testicular damage induced by KET are required. The flowers of Clitoria ternatea (CT) are proven to have hepatoprotective potential. However, the protective effect on KET-induced testicular damage has not been reported.

Objective

To investigate the protective effect of CT flower extracts with antioxidant activity on male reproductive parameters including sperm concentration, serum testosterone level, histopathology of the testis, and testicular tyrosine phosphorylation levels in rats induced with KET.

Methods

The antioxidant activity of CT flower extracts was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Male rats were treated with CT flower extracts (10, 50, or 100 mg/kg BW) or distilled water via a gastric tube for 28 d (preventive period: Days 1–21) and induced by KET (100 mg/kg BW) via intraperitoneal injection for 7 d (induction period: Days 22–28). After the experiment, all animals were examined for the weights of the testis, epididymis plus vas deferens and seminal vesicle, serum testosterone levels, sperm concentration, histological structures and diameter of testis, and testicular tyrosine phosphorylation levels by immunoblotting.

Results

The CT flower extracts had capabilities for DPPH scavenging and high reducing power. At 100 mg/kg BW, the extract had no toxic effects on the male reproductive system. Significantly, in CT+KET groups, CT flower extracts (50 and 100 mg/kg BW) alleviated the reduction of reproductive organ weight parameters, testosterone levels, and sperm concentration. In addition, CT flower extracts gave protection from testicular damage in KET-induced rats. Moreover, in the CT100+KET group, CT flower extracts significantly enhanced the expression of a testicular 50-kDa tyrosine phosphorylated protein compared with that of other groups.

Conclusions

C. ternatea flower extracts possessing antioxidant activity are not harmful to the male reproductive system and can protect against testicular damage in KET-induced rats.     

热带植物花卉的抗氧化性研究

为了筛选具有抗氧化性的热带花卉，对海南师范大学校园中的12种花卉的鲜花和干花的水提取物、50％乙醇提取物和70％丙酮提取物进行清除DPPH的实验．结果表明：紫薇、干凤凰花、干洋金凤、大叶龙船花卉和干小叶龙船花卉的抗氧化效果最好．     

Guava extract （Psidium guajava） alters the labelling of blood constituents with technetium-99m

Psidium guajava （guava） leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents （BC） are labelled with technetium-99m （^99mTc） and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with ^99mTC. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with ^99mTc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with ^99mTc after the percentage of incorporated radioactivity （%ATI） in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with ^99mTc. The data showed significant （P〈0.05） alteration of ATI in BC from blood incubated with guava extract.     

酸石榴汁红色素的树脂吸附及石榴提取物的抗氧化作用研究

研究了7种吸附树脂对酸石榴汁红色素的吸附及石榴各部分提取物对DPPH（1,1-Dphenyl-2-picrylhydrazyl）的清除作用.实验结果表明：HPD-300对草莓红色素的吸附效果最好;2 mg/mL的酸石榴汁红色素对DPPH的清除率达91.48%,与Vc的抗氧化作用相比,酸石榴各部分提取物对DPPH的清除率顺序为：Vc〉酸石榴汁红色素〉酸石榴皮的醇洗脱部分〉酸石榴皮水洗脱部分〉酸石榴汁水洗脱部分,表明酸石榴汁红色素具有良好的抗氧化活性.     

Survey of antioxidant capacity and phenolic composition of blueberry, blackberry, and strawberry in Nanjing

Berries are a good source of natural antioxidants. In the present study, the total antioxidant capacity and phenolic composition of three berry fruits (blueberry, blackberry, and strawberry) cultivated in Nanjing were investigated. Blueberry, with a Trolox equivalent antioxidant capacity (TEAC) value of 14.98 mmol Trolox/100 g dry weight (DW), exhibited the strongest total antioxidant capacity using both the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Blueberry also had the highest total phenolic content (TPC, 9.44 mg gallic acid/g DW), total flavonoid content (TFC, 36.08 mg rutin/g DW), and total anthocyanidin content (TAC, 24.38 mg catechin/g DW). A preliminary analysis using high performance liquid chromatography (HPLC) showed that the blueberry, blackberry, and strawberry samples tested contained a range of phenolic acids (including gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, ferulic acid, ellagic acid, and cinnamic acid) and various types of flavonoids (flavone: luteolin; flavonols: rutin, myricetin, quercetrin, and quercetin; flavanols: gallocatechin, epigallocatechin, catechin, and catechin gallate; anthocyanidins: malvidin-3-galactoside, malvidin-3-glucoside, and cyanidin). In particular, the blueberries had high levels of proanthocyanidins and anthocyanidins, which might be responsible for their strong antioxidant activities. These results indicate a potential market role for berries (especially blueberries) as a functional food ingredient or nutraceutical.     

小叶女贞果实抗氧化活性研究

以乙醇为溶剂提取小叶女贞果实,经减压浓缩后,依次用乙酸乙酯和正丁醇进行萃取。用DPPH自由基的清除能力来评价两个部位的抗氧化活性。结果表明,乙酸乙酯部位浓度为500μg/mL时自由基清除率大于75%,IC50=302.818μg/mL,正丁醇部位浓度为300μg/mL时自由基清除率大于75%,IC50=189.241μg/mL。正丁醇部位抗氧化能力比乙酸乙酯部位更好,是乙酸乙酯部位的1.6倍。     

商洛何首乌提取物的抗氧化活性研究

为了研究商洛何首鸟提取物抗氧化能力。采用DPPH、超氧阴离子、亚硝酸基和总还原能力等方法对商洛何首乌提取物和二苯乙烯苷进行体外抗氧化活性研究。结果表明：商洛何首鸟提取物具有抗氧化活性,并且何首乌提取物抗氧化活性高于二苯乙烯苷的抗氧化活性。     

Optimization of extraction of phenolics from leaves of Ficus virens

In this research, the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology (RSM). The extraction abilities of phenolics (EAP) and flavonoids (EAF), the 2,2-diphenyl-1-pierylhydrazyl (DPPH) free-radical scavenging potential, and the ferric reducing/antioxidant power (FRAP) were used as quality indicators. The results of single-factor experiments showed that temperature, ethanol concentration, extraction time, and the number of extraction cycles were the main influencing variables, and these provided key information for the central composite design. The results of RSM fitted well to a second degree polynomial model and more than 98% of the variability was explained. The ideal extraction conditions for EAP, EAF, DPPH free-radical scavenging potential, and FRAP were obtained. Considering the four quality indicators overall, the ideal extraction conditions were 58% ethanol at 57 °C for 37 min with three extraction cycles. At the ideal extraction conditions, the values of EAP, EAF, DPPH free-radical scavenging potential, and FRAP were 5.72%, 3.09%, 58.88 mg ascorbic acid equivalent (AAE)/g dry weight (DW), and 15.86 mg AAE/g DW, respectively. In addition, linear correlations were observed between EAP, EAF, and antioxidant potential.     

桐花树叶多酚提取物的抗氧化活性及其影响因子

采用总抗氧化能力体系、羟自由基清除体系、螯合铁离子能力体系测定评价桐花树叶多酚提取物的抗氧化活性,同时在DPPH·自由基清除体系下进行该多酚提取物自由基清除能力的影响因子分析．结果表明：桐花树叶多酚提取物的总抗氧化能力为38U／mg,清除羟自由基的IC50为0．008mg／mL,螯合铁离子能力的IC50约为42mg／mL,表现出较强的抗氧化性能;在DPPH·自由基清除体系下,考察添加食品添加剂或金属离子对桐花叶多酚提取物清除自由基活性的影响,结果显示：苯甲酸钠、柠檬酸与Mn^2＋、Cu^2＋、Ca^2＋、Fe^3＋等金属离子表现为抑制作用,香兰素与K^＋、Na^＋、Mg^2＋、Al^3＋、Zn^2＋等金属离子表现为增效作用．     

马蹄莲不同部位化学成分预试的对比研究

目的通过预试验,研究马蹄莲根、茎、叶三个部位可能的化学成分,以寻找有效成分的主要存在部位.方法采用试管法和纸色谱法,对马蹄莲不同部位的酸性乙醇、纯化水、MeOH及95%乙醇提取物进行研究,通过多种指示剂和显色剂的沉淀反应或颜色反应,对马蹄莲不同部位可能含有的化学成分进行了初步对比研究.结果马蹄莲根、茎、叶中均可能含有酚类、生物碱、多糖、黄酮、有机酸、植物甾醇或三萜类等化学成分.结论马蹄莲的主要有效成分为生物碱、黄酮,主要存在于根与叶中,茎中较少.     

虎杖提取物抑菌作用的研究

用乙醇、乙醚和水3种溶剂对虎杖进行提取。采用一系列真菌和细菌，测试虎杖提取物的抑菌作用，与苯甲酸钠的抑菌效果相比较，并选择有代表性的食品进行防腐试验。结果表明：虎杖提取物对所试细菌有较强的抑制作用，而对霉菌的抑制作用却不如苯甲酸钠明显；对食品的防腐效果良好。并确定了虎杖提取物的最低抑菌浓度。     

Anti-adipogenic effects of extracts of Ficus deltoidea var. deltoidea and var. angustifolia on 3T3-L1 adipocytes简

Objective

This study examined the anti-adipogenic effects of extracts of Ficus deltoidea var. deltoidia and var. angustifolia, a natural slimming aid, on 3T3-L1 adipocytes.

Methods

Methanol and water extracts of leaves of the F. deltoidea varieties were analyzed to determine their total flavonoid content (TFC) and total phenolic content (TPC), respectively. The study was initiated by determining the maximum non-toxic dose (MNTD) of the methanol and water extracts for 3T3-L1 preadipocytes. Possible anti-adipogenic effects were then examined by treating 2-d post confluent 3T3-L1 preadipocytes with either methanol extract or water extract at MNTD and half MNTD (1/2MNTD), after which the preadipocytces were induced to form mature adipocytes. Visualisation and quantification of lipid content in mature adipocytes were carried out through oil red O staining and measurement of optical density (OD) at 520 nm, respectively.

Results

The TFCs of the methanol extracts were 1.36 and 1.97 g quercetin equivalents (QE)/100 g dry weight (DW), while the TPCs of the water extracts were 5.61 and 2.73 g gallic acid equivalents (GAE)/100 g DW for var. deltoidea and var. angustilofia, respectively. The MNTDs determined for methanol and water extracts were (300.0±28.3) and (225.0±21.2) μg/ml, respectively, for var. deltoidea, while much lower MNTDs [(60.0±2.0) μg/ml for methanol extracts and (8.0±1.0) μg/ml for water extracts] were recorded for var. angustifolia. Studies revealed that the methanol extracts of both varieties and the water extracts of var. angustifolia at either MNTD or 1/2MNTD significantly inhibited the maturation of preadipocytes. Conclusions: The inhibition of the formation of mature adipocytes indicated that leaf extracts of F. deltoidea could have potential anti-obesity effects.     

采用DPPH法测定四大药用名菊抗氧化活性

采用DPPH法测定四大药用名菊抗氧化活性,比较它们之间抗氧化活性的差别。采用乙醇浸提,AB-8大孔树脂纯化制备总黄酮,紫外分光光度法测定总黄酮含量。取一定量的总黄酮配制成溶液,采用DPPH法测定抗氧化活性。结果显示经醇提、AB-8大孔树脂纯化后四大药用名菊总黄酮含量分别为黄山贡菊2．45％、滁菊2．05％、亳菊2．01％、杭白菊1．26％。经DPPH法检测,四大名菊抗氧化活性的IC50分别是滁菊139．59、黄山贡菊167．40、亳菊174．42、杭白菊175．36,即抗氧化活性的强弱依次为滁菊、黄山贡菊、亳菊、杭白菊,其顺序与还原力的大小顺序一致。说明中国四大药用名菊都具有丰富的总黄酮成分和较强的抗氧化活性．其中总黄酮含量以黄山贡菊最高．抗氧化活性以滁菊最强。     

小蓟抗氧化作用的研究

采用H2O2/Fe2+体系,通过Fenton反应产生羟自由基(HFR),用邻苯三酚自氧化体系产生超氧阴离子自由基(SAFR),用分光光度法(波长为536nm)监测小蓟冠毛部分提取物对HFR和SAFR的清除作用.结果表明:60%乙醇,50%甲醇,丙酮,蒸馏水浸提物,对HFR和SAFR均有明显的清除作用,其中对HFR清除率;水>60%乙醇>50%甲醇>丙酮;对SAFR清除率;50%甲醇>60%乙醇>水>丙酮.     

白茅根提取物的抑菌效果研究

研究白茅根提取物的抑菌效果.以水、50%乙醇、乙酸乙酯和丙酮为溶剂对白茅根进行提取,将获得提取物进行抑菌实验.使用药敏纸片法和二倍稀释法测定了其提取物对产气肠杆菌、大肠杆菌、金黄色葡萄球菌、假丝酵母及枯草芽孢杆菌5种细菌的抑菌效果.乙酸乙酯提取物对于假丝酵母,水煮提取物对于大肠杆菌,丙酮提取物对于金黄色葡萄球菌,水煮提取物枯草芽孢杆菌及其50%乙醇提取物对于产气肠杆菌的抑菌效果最好,抑菌圈直径分别为12.0、13.0、13.5、13.5和15.0mm.白茅根的各种提取物对供试菌种的最低抑菌浓度(MIC)为:白茅根水煮提取物对大肠杆菌的抑菌效果最好,其MIC值为0.125 g/mL;其水煮、50%乙醇及乙酸乙酯提取物对大肠杆菌、产气肠杆菌及假丝酵母的MIC值均为0.500 g/mL;而其丙酮提取物对金黄色葡萄球菌的MIC值为0.250 g/mL.其5种提取物对革兰氏阳性、革兰氏阴性菌和真菌均有一定抑制作用,且对大肠杆菌的抑菌效果最明显.     

都匀楼梯草总黄酮提取工艺及其抗氧化性能研究

采用正交试验法优化都匀楼梯草中总黄酮的超声波提取工艺,考察超声波作用时间、乙醇浓度和液料比3个因素对都匀楼梯草总黄酮提取率的影响,确定都匀楼梯草总黄酮的优化超声波提取工艺条件为：提取溶剂80％乙醇,料液比1∶25,超声波作用时间40 min,最佳提取率为1.62％.乙醇提取物抑制DPPH自由基的能力IC50=125.25μg/mL,说明都匀楼梯草不同极性部位均具有一定的抗氧化活性.