太白乌头提取物抗氧化活性研究

目的研究太白乌头提取物的抗氧化活性。方法将太白乌头乙醇提取物采用溶剂萃取法，分成极性不同的五个部分，并采用DPPH法和邻苯三酚自氧化法测定各部分的清除DPPH·（二苯代苦味肼自由基）和·O2^-（超氧阴离子自由基）的能力，以测定其抗氧化活性，并和抗坏血酸进行比较。结果清除DPPH·能力大小为：抗坏血酸〉乙酸乙酯部分〉正丁醇部分〉石油醚部分〉水部分一氯仿部分，清除·O2^-的能力以石油醚部分、乙酸乙酯部分为好，其他部分认为无清除·O2^-的活性。结论太白乌头醇提物乙酸乙酯部分、正丁醇部分和石油醚有较好的抗氧化活性，有进一步分离纯化的价值。     

天山堇菜鞣质的提取及抗氧化活性研究

目的探讨天山堇菜鞣质的体外抗氧化作用。方法采用超声波法提取天山堇菜中的鞣质,选用邻二氮菲-Fe2+氧化法、二苯代苦味肼基自由基法,测定其对羟自由基(·OH)、二苯代苦味肼基自由基(DPPH.)的清除能力,并与抗氧化剂VC、茶多酚进行比较。结果与结论天山堇菜鞣质对羟自由基、二苯代苦味肼基自由基均有清除作用,在一定范围内,清除效果随质量浓度的增大而加强。其抗氧化能力与浓度呈依赖关系。     

电化学法研究枸杞子及黄精对活性氧自由基的清除作用

 目的:研究枸杞子和黄精对活性氧自由基(O^-·₂和·OH)的清除作用。方法:通过邻苯三酚在碱性环境下自氧化产生O^-·₂,Fenton体系产生·OH,自旋捕集剂PBN捕捉产生的·OH。单扫示波极谱法检测枸杞子和黄精对O^-·₂和·OH的抑制作用。结果:枸杞子和黄精对O^-·₂和·OH具有明显的抑制作用。分别计算了它们的IC₅₀值。枸杞子对O^-·₂和·OH的清除能力为:同仁堂宁夏枸杞>市售宁夏枸杞>河北枸杞>内蒙枸杞。黄精对O^-·₂和·OH的清除效能力:酒制黄精>蜜炙黄精。结论:枸杞子和黄精都能有效地清除活性氧自由基(O^-·₂,·OH)具有抗氧化作用,可能是它们所具有的抗氧化等药理作用机理之一。     

石香薷总黄酮的体外抗氧化作用研究

目的:研究石香薷总黄酮的体外抗氧化活性。方法:采用DPPH法、邻苯三酚自氧化法和FRAP法,考察石香薷总黄酮对DPPH自由基、O2-的清除能力和Fe2+离子的还原能力。结果:石香薷总黄酮对DPPH自由基和O2-具有较好的清除能力,对Fe2+离子具有较强的还原能力。结论:石香薷总黄酮具有显著的抗氧化活性,提示黄酮类化合物可能是石香薷发挥抗氧化活性的主要物质基础。     

褐藻中高相对分子质量褐藻多酚的抗氧化活性研究

目的　评价鼠尾藻和海黍子两种褐藻中高相对分子质量褐藻多酚的抗氧化活性。方法　分别利用 3种体系 ,通过对羟自由基 (· OH)、超氧阴离子 ( O÷2 )和 1,1-二苯基 - 2 -苦味肼基自由基 ( DPPH· )清除效率来评价其抗氧化活性。结果　两种褐藻中高相对分子质量褐藻多酚对· OH、O÷2 和 DPPH·均有很高的清除效率 ,且效果相近。结论　鼠尾藻和海黍子两种褐藻中高相对分子质量褐藻多酚具有较强的抗氧化活性 ,是一类潜在的海洋生物天然抗氧化剂。     

白刺果实活性成分提取及其抗氧化活性研究△

目的：白刺果实活性成分提取及其抗氧化活性的研究。方法：用70％丙酮提取白刺果实,其提取物依次用乙醚、乙酸乙酯和正丁醇进行萃取得各部分及水相,通过分光光度法测定各部分的黄酮及多酚含量,DPPH法和ABTS法测定各部分的体外抗氧化活性,大孔吸附树脂结合制备液相法对活性强的水相部分分离纯化。结果：水相部分黄酮和多酚含量较高且抗氧化活性最强,分离得到两个单体化合物,鉴定为异鼠李素-3—O-芦丁苷和异鼠李素-3-O-芦丁-7-O-葡萄糖苷,并对两个单体的抗氧化活性进行测定,两个单体都有明显抗氧化活性,且异鼠李素-3-O-芦丁苷相比于异鼠李素-3-O-芦丁-7-O-葡萄糖苷清除自由基的能力较强。结论：白刺果实中的黄酮及多酚具有抗氧化活性。     

培植牛黄清除·OH自由基作用的研究

用光度分析法研究培植牛黄对· OH自由基的清除作用。结果显示培植牛黄对· OH自由基有显著的清除能力。其 5 0 %清除率剂量为 0 .0 2 μg/ m l,清除活性远远高于维生素 C。     

兔儿伞不同溶剂提取物的体外抗氧化作用研究

目的 探讨兔儿伞乙醇、丙酮、醋酸乙酯、水提取物体外抗氧化能力.方法 利用微波辅助提取法分别得到了兔儿伞乙醇提取物、丙酮提取物、醋酸乙酯提取物和水提取物,采用Fonton反应体系产生羟基自由基和邻苯三酚自氧化产生超氧阴离子自由基.结果 4种提取物对羟自由基、超氧阴离子自由基(O_2~- ·)均有清除作用,其中以乙醇提取物的效果最佳.结论 兔儿伞可作为抗氧化物质资源,有一定的开发利用价值.     

蒙古口蘑菌丝体提取物抗氧化活性研究

目的 研究蒙古口蘑菌丝体提取物的抗氧化活性.方法 采用Fenton法、邻苯三酚自氧化法、还原力的测定等几种实验方法研究了蒙古口蘑菌丝体提取物抗氧化活性.结果 蒙古口蘑菌丝体提取物具有较强的清除- OH自由基和(一02-)自由基的能力,且具有一定的还原能力;抗氧化活性与提取物浓度成正相关.结论 蒙古口蘑菌丝体提取物具有抗氧化活性.     

紫苏提取物抗氧化活性及酚性成分的研究

目的 研究紫苏体外抗氧化活性.方法 在测定紫苏各酚性成分含量基础上,采用体外抗氧化实验,研究其DPPH清除能力、总还原力和抗脂质体氧化能力.结果 75%乙醇和50%丙酮提取物具有良好的抗氧化活性;紫苏提取物中总黄酮、原花色素含量与其抗氧化能力之间呈正相关.结论 紫苏有显著的抗氧化活性,呈一定的量-效关系.其抗氧化活性可能与黄酮类化合物有关.紫苏提取物可作为一种良好的天然抗氧化剂应用于临床.     

Potent suppressive activity of fresh and dried peels from Satsuma mandarin Citrus unshiu (Marcorv.) on hydroperoxide generation from oxidized linoleic acid

The effects of various extracts prepared from fresh and dried peels of Satsuma mandarin (Citrus unshiu Marcov.) on hydroperoxide generation from oxidized linoleic acid were compared under different extraction conditions. The cold-and hot-water extracts of fresh peels showed significant suppressive activity against hydroperoxide generation in a dose-dependent manner. However, the methanol or acetone extract of fresh peels did not exhibit significant suppressive effects. The commercially available ascorbic acids equivalent to their concentrations in the water extracts of fresh peels showed roughly equal antioxidative activities compared with those of the water extracts of fresh peels. Although the cold- and hot- water extracts of dried peels indicated a considerable reduction of ascorbic acid concentration, they exhibited much higher antioxidative activities than those of the fresh peels. The methanol extract of dried peels also showed significant antioxidative activities, but did not contain significant ascorbic acid. These results suggest that the fresh peels of Satsuma mandarin have potential antioxidant activities, and the drying treatment of fresh peels caused an enhancement of the antioxidant activity. The pharmacological significance of this finding is discussed.     

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

Ethnopharmacological importance

Gastrointestinal disorders and infections are the major pathoaetiologies of diarrhoea causing many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat infectious diseases including diarrhoea and many other ailments by rural people in Africa and Asia. Much of the work done to date on this genus was on the non-polar or intermediate polarity components. Some parameters that may cause diarrhoea and the evaluation of more polar extracts have apparently not been investigated.

Aims

The polar components were extracted and fractionated by solvent–solvent fractionation to yield fractions with different polarities. The activity of these fractions on different parameters that could be involved in factors associated with diarrhoea was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals.

Materials and methods

Phenolic-enriched leaf extracts of Combretum bracteosum (COB), Combretum padoides (COP), Combretum vendae (COV) and Combretum woodii (COW) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. Acetone was removed from a portion of the 70% acetone extract and it was sequentially treated by solvent–solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures The antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2′-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid (ABTS⁺) radical scavenging, ferric reducing antioxidant power (FRAP) methods and lipid peroxidation inhibitory capacity standard methods. The ferric reducing antioxidant activities of the fractions were also determined. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out.

Result

Some of the fractions had much higher antioxidant activity than the positive controls. The average EC₅₀ values of the extracts for the DPPH and ABTS antioxidant assays were 0.21–12 µg/ml (COP), 0.25–16 µg/ml (COV), 0.33–9.41 µg/ml (COW) and 4.97–85 µg/ml (COB) respectively while the mean EC₅₀ values for the positive controls ascorbic acid and trolox were 1.28–1.51 and 1.02–1.19 µg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 µg/ml. COP had the highest antibacterial activity with MICs ranging between 19–2500 µg/ml, followed by COV with MICs ranging between 39–625 µg/ml; COW and COB had similar MICs ranging between 39–2500 µg/ml. COP also had the highest antifungal activity with MICs between 19–625 µg/ml. The MIC for COW and COV ranged from 19 to 1250 µg/ml. COB had the lowest antifungal activity (MIC values were between 39 and 625 µg/ml). In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentration of hydrolysable tannin (gallotannin). A good correlation (R²= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity.

Conclusion

The results obtained in this study with more polar extracts indicate that the use of extracts of these plant species as antidiarrhoeal agents may have a scientific basis. The extractant used here extracted a much higher percentage of the phytochemicals than acetone. It was better for isolating antioxidant compounds (polar) but not good for isolating antimicrobial compounds (non-polar) from the same species compared to acetone, ethyl acetate, dichloromethane, and hexane.     

In vitro antioxidant and in vivo anti-inflammatory activities of Ophioglossum thermale

Antioxidant fractions from Ophioglossum thermale were extracted with five different polar solvents using a Soxhlet type extractor. The total phenolic content of the extracts was determined by the Folin-Ciocalteu method. The ethyl acetate fraction of O. thermale was found to contain maximum phenolics. The dried fractions were screened for their antioxidant activity potential using in vitro model systems such as 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitroblue tetrazolium (NBT) and lipid-peroxidation reduction at different concentrations. Results revealed that the EtOAc fraction exhibited the best performance in the DPPH assay, NBT assay and lipid peroxidation. All fractions showed more potent antioxidant capacity than green tea extract, a well-known antioxidant. Furthermore, the EtOAc fraction has the highest total phenolic content (475.65 mg of EGCG/g). In addition, the EtOAc fraction at 0.005% and 0.01% (g/100 ml) also significantly inhibited UVB irradiation-induced ROS generation in human dermal fibroblasts (HDFs). In a carrageenan-induced edema model, the EtOAc fraction showed an inhibitory effect (21.5%, p < 0.05) at 200 mg/kg (p.o.) after 300 min administration. Consequently, 3-O-methylquercetin (3MQ) was also isolated from the antioxidative EtOAc fraction. The data obtained using the above in vitro and in vivo tests suggest that the antioxidant activity of O. thermale and its anti-inflammatory effect on carrageenan-induced acute inflammation can be attributed to its ameliorating effect on oxidative damage, and thus it has great potential as a source for natural health products. To the best of our knowledge, this is the first report on the antioxidant activity of different polar extracts from O. thermale.     

Potent antioxidative and antigenotoxic activity in aqueous extract of Japanese rice bran--association with peroxidase activity

To estimate the preventive potential of Japanese rice bran (Oryza sativa japonica) against the oxygen radical-related chronic diseases such as cardio-vascular diseases and cancer, antioxidative and antigenotoxic activities of the rice bran extracts were analyzed by using assay systems for lipid peroxidation and genotoxin-induced umu gene expression. When effects of the rice bran extracts under different extraction conditions on hydroperoxide generation from auto-oxidized linoleic acid were examined using aluminum chloride method, the water extract showed strong antioxidant activity, but the methanol and acetone extracts did not exhibit significant activity. The water extract of rice bran was divided into the ethanol-precipitable (EP) and supernatant fractions, and EP fraction showed the dominant antioxidant activity, but the supernatant fraction did not exhibit significant antioxidant activity. When the effect of EP fraction on umu C gene expression in SOS response associated with DNA damage in Salmonella typhimurium (TA 1535/pSK 1002) induced by 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) was analyzed, it showed a dose-dependent suppressive activity against Trp-P-1-induced umu C gene expression. The bio-chemical analysis of EP fraction indicates that the major antioxidative and antigenotoxic activity of EP fraction is associated with a proteinous component with the molecular weight of more than 30 KDa. As a possible active principle for the antioxidative and antigenotoxic activity in EP fraction, the strong activity of an oxygen radical-scavenging enzyme, peroxidase was detected, and the purified horseradish peroxidase also caused the similar antioxidative and antigenotoxic activities. The significance of this finding is discussed from the viewpoint of the preventive role of rice bran against oxygen radical-related chronic diseases.     

泽兰抗氧化活性的研究及活性部位的筛选

目的:对中药泽兰进行抗氧化活性的研究,并筛选其主要的活性部位。方法:采用高通量活性筛选技术,以清除DPPH和超氧阴离子自由基能力、还原Fe3+能力及抑制脂质过氧化能力为指标,评价泽兰乙醇总提取物及不同极性部位的抗氧化能力。结果:泽兰及其乙酸乙酯部位(LLE-A.E,MCCM2921)和正丁醇部位(LLE-A.B,MCCM2922)具有较强的清除DPPH(二苯代苦味肼)、超氧阴离子自由基能力、还原Fe3+能力和抑制脂质过氧化能力。结论:泽兰及其不同极性部位具有清除自由基作用,这可以用来解释其在传统应用中的活血化瘀、抗纤维化作用。     

In vitro bioactivity-guided fractionation and characterization of polyphenolic inhibitory fractions from Acacia nilotica (L.) Willd. ex Del

The present study was undertaken to evaluate antimutagenic and cytotoxic effects of different extracts/fractions of Acacia nilotica prepared by maceration method. The potency order of different extracts was more or less similar in Ames assay as well as in cytotoxic assay. Considering the maximum potential of acetone extract in both the assays, the studies were initiated to fractionate this extract. Two pure fractions, namely AN-1 and AN-2, were obtained from acetone extract, of which AN-2 was found to be of gallic acid and AN-1 fraction is still to be identified. In conclusion, the antimutagenic and cytotoxic activities exhibited by acetone extract may partially be ascribed to the presence of gallic acid and other polyphenols.     

Antioxidant and anticancer activities of organic extracts from Platycodon grandiflorum A. De Candolle roots

This study examined the antioxidant and anticancer activities of the petroleum ether extracts from the roots of Platycodon grandiflorum A. DC, which is a plant used as both a herbal medicine and food in Asia. Extracts from Platycodon grandiflorum in petroleum ether were fractionated (fractions I-V) by silica gel column chromatography using gradient solvents (petroleum ether: ethyl ether, 9:1-5:5, v/v). The antioxidant activities of the fractions were evaluated in terms of their inhibition of lipid peroxidation as well as their free radical scavenging activity. Fraction II, which was extracted at an 8:2 mixture of petroleum ether and ethyl ether, exhibited the greatest antioxidant activity among the fractions. On the other hand, the cytotoxicity of each fraction, which was evaluated by the MTT assay using human cancer cell lines (HT-29, HRT-18 and HepG2), was greatest in fraction III, which was extracted with a 7:3 petroleum ether and ethyl ether mixture. Both fractions, II and III, were sub-fractionated by thin layer chromatography, and the sub-fractions each were screened for their antioxidant and anticancer activities. In addition, the antioxidant activity was closely related to the content of phenolic compounds, and the anticancer active fraction exhibited a typical UV absorbance spectrum of polyacetylene.     

Antibacterial and antioxidant activity of Sutherlandia frutescens (Fabaceae), a reputed anti-HIV/AIDS phytomedicine

Dried ground leaves of Sutherlandia frutescens were extracted by both sequential extraction with four solvents, starting with the least polar and separately with acetone, ethanol and water. The extracts were tested for antibacterial and antioxidant activity. The hexane extract was, generally, the most active extract against S. aureus, E. faecalis and E. coli with MIC values of 0.31, 1.25 and 2.50 mg/mL, respectively. The second method extracted compounds with antioxidant activity as shown by the DPPH free-radical scavenging assay. The use of Sutherlandia frutescens for topical staphylococcal infections, when formulated in an oily base appears to have a rational basis.     

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??OBJECTIVE To determine the antioxidant activities of different extracts from Phellinus robustus (PR) and analyze the active components of the extract with the highest antioxidant activity. METHODS PR was first extracted by ethanol and then the ethanol extract was sequentially partitioned into four fractions. To determine the antioxidant abilities of different extracts, the contents of total phenols and total flavonoids, scavenging activity on DPPH and ABTS radicals, reducing power and inhibition of lipid peroxidation were measured. RESULTS The ethyl acetate fraction (EAF) showed the highest contents of total phenols and flavonoids and the largest antioxidant capacity, meanwhile, its DPPH radical scavenging activity was comparable to that of the positive control, ascorbic acid (P>0.05). TPC and TFC showed strong positive correlations with FRAP (r²=0.984, P<0.01). Three phenolic acids (protocatechuic acid, vanillic acid and caffeic acid) had been isolated and identified from EAF by HPLC-ECD, and anilic acid and caffeic acid were first isolated from PR. CONCLUSION EAF from PR has strong potential to be a source of phenolic compounds with antioxidant proprieties and a promising source of food and drugs.     

Crown gall -- a plant tumour with biological activities

Petroleum ether, acetone, 80% MeOH and water extracts of crown gall, a plant tumour, obtained from Eucalyptus globulus tree were screened for cytotoxic, antioxidant, antiinflammatory, embryotoxic, antitumour-promoting and antimicrobial activities.In terms of bioactivity the 80% MeOH extract was most effective followed by the acetone extract. The petroleum ether extract showed weak to moderate cytotoxic activity in dose-dependent manner against PC12 cells, mouse L fibroblasts and 1321N1 glia cells, whereas the hydroalcohol extract had no or a weak cytotoxic effect. The 80% MeOH extract exhibited strong antioxidant activity. Based on the in vitro HET-CAM assay all the extracts were effective against inflammation. The extracts did not show any embryotoxic effect at the concentrations tested. Antitumour-promoting activity (100% inhibition; 100 microg/mL) was observed in the 80% MeOH and acetone extracts. In the antimicrobial screening all extracts displayed predominantly antifungal activity against Candida sp. The extracts also showed various levels of antibacterial activity against E. faecalis, Ps. aeruginosa, Bac. subtilis and Staph. epidermidis.From the results of the investigations it can be concluded that crown gall is a valuable plant tumour tissue having interesting biological activities.