Study on the antioxidant activity of tea flowers (Camellia sinensis)

Major chemical compounds in different extracts from tea flowers (Camellia sinensis) were analyzed. Distilled water or 70% ethanol extracts were then fractionated with chloroform, ethyl acetate and n-butanol, respectively. Each extract fraction was tested its scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals. The results showed that ethyl acetate fraction of ethanol-extract of tea flower (EEA) exhibited the highest quenching activity to hydroxyl radicals (SC50 11.6 mug/ml), followed by ethanol-extract (EE) of tea flower (SC50 19.7 microg/ml). Same tea flower extract showed big different scavenging activities on different free radicals. EEA quenched 80% of hydroxyl radicals generated by Fenton's reaction, however, only 40% of DPPH radical was scavenged in the Fe (II)-H2O2 -luminol system. The contents of flavones, polyphenols and catechins in EE and EEA fractions were higher than those in other fractions. We suggest that the stronger scavenging abilities to free radicals might be due to polyphenols, EGCG, ECG and flavones. However, the water extracts of tea flower and their fractions showed lower antioxidant activity for their inhibitory effect on hydroxyl radicals and DPPH radicals.     

新疆红树莓果实不同有效部位提取及其抗氧化活性测定

目的测定树莓果实不同提取部位总酚含量并比较不同提取部位抗氧化活性。方法树莓果实95%乙醇提取物经石油醚脱脂后,依次用乙酸乙酯、正丁醇萃取,对得到的各提取部位浸膏,①以没食子酸为标准品进行总酚含量测定,同时用相对标准偏差(RSD)表示稳定性;②采用1,1-二苯-2-苦肼基和羟自由基清除能力实验测定抗氧化活性。结果①Folin-Ciocalteu比色法具有精密度高、稳定性和重现性好等优点;②各提取部位物总酚含量从GAE10.56mg/g到96.76mg/g,其中以乙酸乙酯部位总酚含量最高(GAE96.76mg/g);③抗氧化实验中,树莓不同提取物均显示了较好的抗氧化活性,其中以乙酸乙酯部位抗氧化活性最高。结论树莓是良好的天然抗氧化剂。     

Antioxidant activities of various extracts of lotus (Nelumbo nuficera Gaertn) rhizome

Lotus rhizome powder was extracted with solvents of different polarities. Antioxidant activities of the extracts were evaluated by a 2, 2'-diphenylpicrylhydrazyl (DPPH) assay and a beta-carotene bleaching assay, and compared with that of butylated hydroxyanisole (BHA) and ascorbic acid. Methanol showed the highest extract yield among all of solvents. Although acetone extract had the highest total phenolics content, methanol extract had the highest total phenolics recovery from lotus powder (20.1 mg catechin equivalents/100g lotus powder). Extract of either methanol or acetone demonstrated the highest DPPH scavenging activity at both 66.7 mg/L and 133.3 mg/L. All extracts exhibited higher antioxidant activity coefficient (AAC) than that of ascorbic acid, furthermore, dichloromethane and petroleum extracts had comparable AAC with BHA by the beta-carotene bleaching assay. The properties of the extracting solvents significantly affected the yield, total phenolics content and antioxidant activity of lotus rhizome extracts.     

Antioxidant properties of selected tropical wild edible mushrooms

Selected species of wild edible mushrooms were obtained from the interior areas of East Malaysia to determine the total phenolics and antioxidant properties, including free radical scavenging, reducing power and metal chelating activities. The in vitro antioxidant activities of petroleum ether (PE) and methanolic extracts of the edible wild mushrooms were comparable to the cultivated oyster mushroom. The radical scavenging activity was the highest in PE extract of Pleurotus porrigens (angel's wings) (85%), while methanolic extract of Hygrocybe conica (witch's hat mushroom) exhibited the highest (94%) chelating effect at 20 mg/ml. PE extracts were more effective than methanolic extract in scavenging ability on DPPH radicals, whereas methanolic extracts were more effective in reducing power and chelating ability on ferrous ions as evidenced by their lower EC₅₀ values. Principal component analysis (PCA) indicated phenolic group was the primary factor contributing to the metal chelating ability for PE extract although phenolic was better correlated with reducing power in methanolic extracts.     

葡多酚对活性氧自由基的清除作用研究

目的 :　探讨葡多酚 ( GPC)对活性氧自由基的清除作用。方法 :　采用电子自旋共振 ( ESR)和自旋捕集技术直接测定不同浓度 GPC对 Fenton反应体系产生的羟自由基 (· OH)、光照核黄素 /EDTA体系产生的超氧阴离子 ( O·2 )及 Fe2 + 启动线粒体膜脂质过氧化产生的脂类自由基 ( LOO· )清除作用。结果 :　 GPC浓度为 1 mg/L、1 0 mg/L、1 0 0 mg/L、1 0 0 0 mg/L对·OH的清除率 ( % )依次为 9.0、2 0 .6、47.7、57.7,对 O·2 的清除率 ( % )分别为 1 0 .9、1 7.0、50 .9、72 .1 ,对LOO·的清除率 ( % )依次为 39.8、49.6、65.9、71 .4。葡多酚对· OH、O·2 及 LOO· 50 %的清除浓度 ( IC50 值 )分别为 1 2 8.9mg/L、89.4mg/L、1 0 .4mg/L。结论 :　葡多酚对三种活性氧自由基均有不同程度的清除作用 ,其中 LOO· >O·2 >· OH。     

Comparison of antioxidant capacities of Ganoderma lucidum (Curtis) P. Karst and Funalia trogii (Berk.) Bondartsev & Singer by using different in vitro methods

The aim of the study was to investigate antioxidant activities of Ganoderma lucidum and Funalia trogii. Ethanol and water crude extracts from G. lucidum and F. trogii were investigated for their antioxidant capacity in some different assays, namely, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal chelating activity against ferrous ions, and plasma lipid peroxidation inhibitory. In addition, the amounts of total phenol, ascorbic acid, β-carotene, and lycopene components in the extracts were determined. Among the four mushroom extracts, G. lucidum water extract and G. lucidum ethanol extract showed the highest scavenging activity against DPPH radicals (50% inhibitory concentration?=?0.055?±?0.001?mg/mL). Total phenol was the major antioxidant component found in the mushroom extracts. These results showed that G. lucidum may be used in pharmaceutical applications because of its effective antioxidant properties.     

Antioxidant levels and activities of selected seeds of malaysian tropical fruits

The aims of this study are to determine and compare the antioxidant levels and activities (i.e. primary and secondary) between selected seeds of Malaysian tropical fruits - guava (Psidium guajava), mango (Mangifera indica L.) and papaya (Carica papaya L.). Seeds are among byproducts from the processing of fruitsbased products. Instead of discarding seeds as waste, seeds with high potential as antioxidants could be utilised for commercial purposes. Accordingly, the selected seeds of Malaysian tropical fruits were tested in this study for total phenolic content (TPC), free radical scavenging activity by 1, 1- diphenyl-2-picrylhydrazyl (DPPH) assay and metal ion chelating effect by ferrous ion chelating (FIC) assay. Extraction of antioxidant compounds from sample was done with 70% ethanol. TPCs of the seeds were expressed as gallic acid equivalents (GAE) in mg per 100 g fresh seed weight. TPC assay showed that mango seeds had the highest TPC (i.e. 32 ± 0.001 mg GAE) followed by guava seeds (i.e. 20 ± 0.001 mg GAE) and papaya seeds (8 ± 0.003 mg GAE). For DPPH assay, IC50 data showed that mango seed extract scavenged 50% DPPH radicals at the lowest concentration (0.11 ± 0.01 mg/mL) followed by the positive control BHA (0.13 ± 0.01 mg/mL), guava seed extract (0.26 ± 0.01 mg/mL) and papaya seed extract (0.34 ± 0.01 mg/mL). Interestingly, all seed extracts showed higher free radical scavenging activities than BHA after sample concentration of 0.60 mg/mL. However, FIC assay indicated that metal ion chelating effects of all seed extracts were weaker than BHA suggesting that the fruit seeds are not sources of good metal ion chelators. Overall, present results suggest that TPC of the seeds show strong negative correlation with their primary antioxidant activity (r= -0.985, R2= 0.970), and not all compounds in extracts which could scavenge DPPH radicals are good metal ion chelators. Mango seeds relatively showed the highest antioxidant level and primary antioxidant activity followed by guava seeds and papaya seeds.     

The antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts

Antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts were evaluated using various antioxidant measurements, i.e., inhibitory effect on thiobarbituric acid-reactive substances (TBARS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating effect, reducing power effect, and total phenolic compounds. When the extraction solvents n-hexane, chloroform, ethanol, and water were compared, the water extract showed the highest yield in extracted mass. Total phenolic compounds were the highest in the ethanol extract, with 127.4 mg/g. The TBARS inhibition of chloroform and ethanol extracts at 10 mg/mL was 90.9% and 80.9%, respectively. DPPH radical scavenging capacity was more than 90% in all extracts at 1 mg/mL. The chloroform extract exhibited the highest metal ion chelating ability of 69.6% at 10 mg/mL. The reducing power was found to be the highest in the ethanol extract at 10 mg/mL, showing an effect similar to ascorbic acid. Thus, the ethanol extract of S. siliquastrum has potential as a natural antioxidant.     

Antioxidant activity of far-infrared radiated rice hull extracts on reactive oxygen species scavenging and oxidative DNA damage in human lymphocytes

The antioxidant activities of methanolic extracts of far-infrared irradiated rice hull (FRH) and non-irradiated intact rice hull (IRH) were determined. The antioxidant effects against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide, hydrogen peroxide (H2O2), and nitric oxide radical and capacity for chelating metals. Except for H2O2 scavenging activity, FRH showed higher scavenging activity than IRH; for example, the 50% inhibitory concentration (mg/mL) values for DPPH radical scavenging of FRH and IRH were 0.067 and 0.085, respectively, as compared with 0.362 and 0.012 for butylated hydroxytoluene and alpha-tocopherol, respectively. The effect of rice hull extract on DNA damage induced by H2O2 in human lymphocytes was also evaluated by comet assay. The protective effect of rice hull extract increased as its concentration increased from 12.5 to 50 microg/mL, as indicated by DNA strand breakage decreasing from 38% to 22% with FRH and from 49% to 28% with IRH as compared with H2O2-treated positive controls. When human lymphocytes were post-incubated with rice hull extract for 30 minutes after exposure to H2O2, the protective ability of the rice hulls remained unchanged. These results suggest that methanol extracts of rice hulls possess significant ROS scavenging and metal chelating activities and protective effect against oxidative DNA damage.     

Phenolic composition and antimicrobial and antioxidant activities of Leucoagaricus leucothites (Vittad.) Wasser

Leucoagaricus leucothites (Vittad.) Wasser is an edible macrofungus found limitedly in Turkey. The ethanolic extract of L. leucothites has shown strong antimicrobial activity against some foodborne and spoilage bacteria. Therefore, the phenolic composition of L. leucothites ethanolic extract was analyzed by using high-performance liquid chromatography. Catechin (288 mg/L) was found to be the major component in the extract. Antioxidant activity of the extract was evaluated by studying the scavenging ability of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and chelating ability of the extract was assessed in a ferrous ion assay. The scavenging effect on DPPH radicals was 71% at 10 mg/mL, whereas the chelating effect on ferrous ions was 82% at 15 mg/mL. The total contents of phenol (3.40 ± 0.5 mg/g), ascorbic acid (2.10 ± 0.3 mg/g), β-carotene (0.02 ± 0.0 mg/g), and lycopene (0.01 ± 0.0 mg/g) in the macrofungi ethanolic extract were also determined.     

Antioxidative effects of glycoprotein isolated from Solanum nigrum L

Glycoprotein from Solanum nigrum L. (SNL glycoprotein) was isolated and tested for antioxidative effects on oxygen free radicals using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The free radical scavenging activities of the SNL glycoprotein are optimal in acidic pH and up to 60 degrees C. However, it has minimal activities in the presence of EDTA, although such activities are not dependent on M(2+) ions (Ca(2+), Mn(2+), and Mg(2+)) in the presence of EDTA. Interestingly, when SNL glycoprotein was treated with deactivation agents (pronase E and NaIO(4)), the DPPH radical scavenging activity was decreased compared with the SNL glycoprotein treatment alone. The antioxidative effects of SNL glycoprotein on superoxide anion and hydroxyl radical under optimal conditions revealed that SNL glycoprotein has remarkable scavenging effects on both radicals, but exhibited slightly higher scavenging effects on superoxide anion generated by the enzymatic hypoxanthine/xanthine oxidase system than on hydroxyl radicals generated by the Fenton reaction. However, SNL glycoprotein was more effective against hydroxyl radials in cell cultures (NIH/3T3). Consequently, 20 microg/mL SNL glycoprotein has a scavenging ability against superoxide anion corresponding to that of ascorbic acid. On the other hand, its hydroxyl radical scavenging activity corresponds to 0.1 microg/mL catalase. From these results, we suggest that SNL glycoprotein has potent antioxidative potential.     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1-15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86?μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R?=?0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

番石榴叶提取物对小鼠肝脏抗氧化作用研究

目的研究番石榴叶提取物抗氧化活性。方法干燥的番石榴叶分别用蒸馏水、65%和95%乙醇浸提,浸提液过滤、浓缩、干燥得到3种提取物。测定各提取物对羟自由基清除率和脂质过氧化抑制率。紫外分光光度法分析提取物中总黄酮含量,高效液相色谱(HPLC)和紫外可见吸收光谱法(UV)对黄酮类化合物初步鉴定。结果水、65%和95%乙醇提取物均具有清除羟自由基和抑制脂质过氧化作用,且呈剂量-效应关系,对羟自由基清除作用的半数有效浓度(EC50)分别为0.63、0.47和0.58g/L,对脂质过氧化抑制作用的半数有效浓度(EC50)分别为0.20、0.035和0.18g/L,总黄酮含量分别为3.28、30.71和55.98g/kg。结论番石榴叶水和乙醇提取物具有较强的抗氧化作用,其中黄酮类化合物可能是其功效成分之一。     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1–15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86 μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R = 0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Tomato waste: a potential source of hydrophilic antioxidants

Waste obtained from six genotypes of tomato was subjected to evaluation as potential sources of hydrophilic antioxidants on the basis of content of total phenolics (TPh; from 11.7 to 18.6 mg/g), total flavonoids (TFl; from 7.62 to 12.1 mg/g) and ascorbic acid (AA; from 0.51 to 1.89 mg/g), and antioxidant activities. The antioxidant activities of tomato waste extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion chelating activity (CA) and reducing power (RP) assay. The O(2) tomato waste extract was found to have the strongest antioxidant activity in scavenging DPPH radicals (effective concentration, EC(50) = 0.18 mg/ml). The Saint Pierre tomato waste extract showed the best performance in RP assay (EC(50) = 1.57 mg/ml). The Rutgers tomato waste extract exhibited a strongest CA (EC(50) = 1.49 mg/ml). The linear correlation analysis produced moderate-to-high correlation coefficients between the antioxidant activities and TPh, TFl and AA.     

Effect of different polarities leaves crude extracts of Omani juniperus excels on antioxidant,antimicrobial and cytotoxic activities and their biochemical screening

ObjectiveTo prepare different polarities leave crude extracts of Juniperus excels (J. excels) and to determine their phytochemical screening, antioxidant, antimicrobial and cytotoxic activities.MethodsThe phytochemical screening of different crude extracts was determined by well-established methods. The antioxidant activity was determined by free radical scavenging (2,2-diphenyl-1-picrylhydrazyl, DPPH) method. The antimicrobial activity was evaluated by agar disc diffusion method and cytotoxic activity was determined through brine shrimp lethality assay.ResultsThe phytochemical tests showed that alkaloids, flavonoids, saponins, steroide, triterpenoids and tannins are present in all leave crude extracts except chloroform crude extract do not contain tannins. The antioxidant results of crude extracts were found to be in the order of hydro alcoholic > chloroform> ethyl acetate >hexane. All leave crude extracts showed moderate antibacterial against gram positive and gram negative food borne pathogen bacteria. The cytotoxicity results revealed that hexane and chloroform extracts have killed all the shrimp larvae at the concentration of 500 μg/mL.ConclusionMore in-vivo and in-vitro studies along with detailed phytochemical investigations are needed in order to potentially use this plant in the prevention and therapies of some oxidative damage related diseases.     

Antioxidant activities and determination of phenolic compounds isolated from oriental plums (Soldam, Oishiwase and Formosa)

The purposes of this study were to determine phenolic compounds and to evaluate antioxidant activities of plums (Soldam, Oishiwase and Formosa). Soldam contains the highest amount of total phenolics among cultivars (Formosa: 4.0%, Oishiwase: 3.3%, Soldam: 6.4% for total phenolic) as well as the total flavonoids of which constituents were mainly myricetin and anthocyanidin. The antioxidant activities were measured by DPPH, ABTS radical scavenging, and SOD-like activities. The DPPH radical scavenging activity of Korean plum extracts (200 µg/mL) showed more than 43%, and the Soldam turned out to be the highest : ID₅₀ value: 160-177 µg/mL for Formosa and Oishiwase; 58-64 µg/mL for Soldam. The ABTS radical scavenging activity of Korean plum extracts (200 µg/mL) was found to be more than 50%. The SOD-like activity of Korean plum extracts (200 µg/mL) showed more than 70%. Among three kinds of cultivars, Soldam had the highest antioxidant activity. The nitrite scavenging activity of Soldam was 61.5%, which is the highest, compared with that of the other cultivars, about 50%. From these results, Korean plums turned out to be phytochemical rich fruit as well as to show high antioxidant activities.     

狼毒大戟石油醚提取物和乙酸乙酯提取物的半数致死量测定

目的：研究狼毒大戟石油醚提取物和乙酸乙酯提取物对小鼠的半数致死量（LD50）。方法：150只昆明种小鼠,完全随机平均分组,每组10只。腹腔注射给药,分别给予不同浓度的狼毒大戟石油醚提取物和乙酸乙酯提取物,以小鼠急性死亡率为指标,求狼毒大戟石油醚提取物和乙酸乙酯提取物的半数致死量（LD50）和LD50的95％可信区间。结果：狼毒大戟石油醚提取物和乙酸乙酯提取物对小鼠的半数致死量（LD50）分别为31．03mg／kg、1538．58mg/kg。结论：狼毒大戟石油醚租乙酸乙酯提取物具有一定的毒性,实验结果为进一步研究和开发狼毒大戟提供了毒性依据。     

In vitro antioxidant and enzyme inhibitory properties of Rubus caesius L

The genus Rubus (Rosaceae) has great potential for and a history of use as natural agents in several traditional folk remedies. Based on this concept, this study focused on the antioxidant activities and enzyme inhibitory effects of extracts and fractions from Rubus caesius. Different chemical assays were performed to detect antioxidant capacity, namely, free radical scavenging (ABTS and DPPH assays), reducing power (CUPRAC and FRAP), phosphomolybdenum and metal chelating. Enzyme inhibitory effects were tested towards cholinesterases (AChE and BChE), tyrosinase, α-amylase and α-glucosidase. In addition, total amounts of phenolics and flavonoids were detected by colorimetric assays. Among the samples, the ethyl acetate fraction exhibited the strongest antioxidant potential with its higher concentration of total phenolics. The highest AChE and α-amylase inhibitory activities were observed in the diethyl ether fraction, while the n-butanol fraction had the strongest anti-tyrosinase inhibitor ability. The present study demonstrated that R. caesius may be considered a source of biologically active compounds to develop novel functional products or drugs in the pharmaceutical field.