Antioxidative and cytoprotective effects of Artemisia capillaris fractions

The antioxidant effects of Artemisia capillaris fractions against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide (O_2(-)), hydroxyl (HO.) and nitric oxide (NO.) radical. Among five solvent fractions, ethyl acetate fraction showed the highest total polyphenol and total flavonoid contents as 648.75 and 89.09 microg/mg, respectively. Also, the ethyl acetate fraction showed the highest scavenging activity; the 50% inhibitory concentration (IC50, microg/mg) value for DPPH, O_2(-), HO. and NO. radical scavenging were 4.76, 31.54, 69.34 and 74.63, respectively. Additionally, the highest inhibition of rat liver microsomal lipid peroxidation was observed by ethyl acetate fraction. Except for free radical-mediated protein damage, ethyl acetate fraction showed the highest scavenging activity. The effect of Artemisia capillaris fractions on cell viability and DNA damage induced by H2O2 in Raw 264.7 cell were also evaluated by MTT and comet assay, respectively. The protective effect of ethyl acetate fraction, as indicated by cell viability increasing 71% and DNA breakage decreasing 51% as compared with H2O2-treated positive control. These results suggest that ethyl acetate fraction possess significant ROS scavenging and protective effect against oxidative DNA damage.     

藜叶中黄酮类化合物体外抗氧化活性研究

为了探讨藜叶中黄酮类化合物的体外抗氧化活性,采用有机溶剂提取法和色谱柱法对藜叶中化学成分进行提取与分离;以Vc作对照,对分离纯化的芦丁、乙酸乙酯浸膏和正丁醇浸膏进行DPPH·、O2^-·和·OH的清除效果试验。结果表明：三者对DPPH·、O2^-·、·OH均具有清除作用,且与浓度呈量效关系,芦丁对·OH清除效果优于Vc,芦丁具有较强的清除DPPH·能力,其IC50为0．05μg／mL。     

Bioactivity assay of extracts from Calocedrus macrolepis var. formosana bark

Alcoholic extracts from bark of Calocedrus macrolepis var. formosana Florin (Cupressaceae) were extracted successively using n-hexane, dichloromethane, ethyl acetate, 1-butanol and water, which gave 34.8%, 34.1%, 24.1%, 3.3% and 3.7% soluble fractions, respectively. Antioxidation activity of these fractions by DPPH assay and dissimilar IC50 values of the DPPH showed that ethyl acetate fraction had the best antioxidant activity; its IC50 was 2.6 microg/ml. Analyses of the composition and anti-inflammatory activity of the subfractions from n-C6H14 fraction showed that the T3 and H5ppt had the best anti-inflammatory activity in LPS-stimulated murine macrophage J774A. 1 cells, respectively; moreover, their major constituent was sugiol (T3 37.1%, H5ppt 81.1%), which at dosages of 10 microg/ml inhibited proIL-1beta protein production completely. Furthermore, the T1 also exhibited anti-inflammatory activity, and its major constituent was ferruginol (above 85.6%).     

Secondary metabolites of ponderosa lemon (Citrus pyriformis) and their antioxidant, anti-inflammatory, and cytotoxic activities

Column chromatography of the dichloromethane fraction from an aqueous methanolic extract of fruit peel of Citrus pyriformis Hassk. (Rutaceae) resulted in the isolation of seven compounds including one coumarin (citropten), two limonoids (limonin and deacetylnomilin), and four sterols (stigmasterol, ergosterol, sitosteryl-3-beta-D-glucoside, and sitosteryl-6'-O-acyl-3-beta-D-glucoside). From the ethyl acetate fraction naringin, hesperidin, and neohesperidin were isolated. The dichloromethane extract of the defatted seeds contained three additional compounds, nomilin, ichangin, and cholesterol. The isolated compounds were identified by MS (EI, CI, and ESI), 1H, 13C, and 2D-NMR spectral data. The limonoids were determined qualitatively by LC-ESI/MS resulting in the identification of 11 limonoid aglycones. The total methanolic extract of the peel and the petroleum ether, dichloromethane, and ethyl acetate fractions were screened for their antioxidant and anti-inflammatory activities. The ethyl acetate fraction exhibited a significant scavenging activity for DPPH free radicals (IC50 = 132.3 microg/mL). The petroleum ether fraction inhibited 5-lipoxygenase with IC50 = 30.6 microg/mL indicating potential anti-inflammatory properties. Limonin has a potent cytotoxic effect against COS7 cells [IC50 = (35.0 +/- 6.1) microM] compared with acteoside as a positive control [IC50 = (144.5 +/- 10.96) microM].     

Free-radical scavenging by Ouratea parviflora in experimentally-induced liver injuries

The antioxidant potential of crude extracts and fractions from leaves of Ouratea parviflora, a Brazilian medicinal plant used for the treatment of inflammatory diseases, was investigated in vitro through the scavenging of radicals 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), hydroxyl radical (HO*), superoxide anion (O2*-), and lipid peroxidation in rat liver homogenate. The crude extract (CEOP) and hydro-alcoholic fraction (OP4) showed strong inhibitory activity toward lipid peroxidation induced by tert-butyl peroxide (IC50 = 2.3 +/- 0.2 and 1.9 +/- 0.1 microg/ml, respectively). The same products exhibited a strong concentration-dependent inhibition of deoxyribose oxidation (14.9 +/- 0.2 and 0.2 +/- 0.1 microg/ml, respectively), and also showed a considerable antioxidant activity against O2*- (87.3 +/- 0.1 and 73.1 +/- 0.4 microg/ml, respectively) and DPPH radicals (55.4 +/- 0.3 and 38.3 +/- 0.4 microg/ml, respectively). The protective effects of CEOP and OP4 were also studied in mouse liver. CCl4 significantly increased (by 90%) levels of lipid hydroperoxides, carbonyl protein content (64%), DNA damage index (133%), aspartate aminotransferase (261%), alanine aminotransferase (212%), catalase activity (23%), and also caused a decrease of 60% in GSH content. The results showed that CEOP and OP4 exerted cytoprotective effects against oxidative injury caused by CCl4 in rat liver, probably related to the antioxidant activity showed by the in vitro free radical scavenging property.     

Protective effect of Hypericum calabricum Sprengel on oxidative damage and its inhibition of nitric oxide in lipopolysaccharide-stimulated RAW 264.7 macrophages

The present study shows for the first time the phenolic composition and the in vitro properties (antioxidant and inhibition of nitric oxide production) of Hypericum calabricum Sprengel collected in Italy. The content of hypericins (hypericin and pseudohypericin), hyperforin, flavonoids (rutin, hyperoside, isoquercetrin, quercitrin, quercetin and biapigenin) and chlorogenic acid of H. calabricum, have been determined. The ethyl acetate fraction from the aerial parts of H. calabricum exhibited activity against the radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) with IC50 value of 1.6 jig/ml. The test for inhibition of nitric oxide (NO) production was performed using the murine monocytic macrophage cell line RAW 264.7. The ethyl acetate fraction had significant activity with an IC50 value of 102 jig/ml and this might indicate that it would have an anti-inflammatory effect in vivo.     

朱砂根抑制α-葡萄糖苷酶与抗氧化活性研究

对朱砂根抑制α-葡萄糖苷酶与抗氧化活性进行研究.利用96微孔板法筛选α-葡萄糖苷酶抑制活性;采用DPPH、ABTS和FRAP方法分析抗氧化活性.结果表明,乙酸乙酯部位抑制α-葡萄糖苷酶的活性最高(IC50=39.27 μg/mL),石油醚部位次之(IC50 =56.11 μg/mL),正丁醇部位活性最弱(IC50=62.05μg/mL),但均远大于阳性对照Acarbose(IC50=1081.27 μg/mL);乙酸乙酯部位抗氧化能力最强,正丁醇部位次之.乙酸乙酯部位清除DPPH自由基(IC50=38.55 mg/L)的能力比BHT( IC50=18.71 mg/L)低1/2,清除ABTS自由基的能力(IC50=3.60 mg/L)比BHT(IC50=7.44 mg/L)强,但比BHA(IC50=1.74 mg/L)弱,还原Fe3+的能力(FRAP=512.99 ±6.80 μmoTE/g)为BHT(FRAP=1581.68±97.41μmol TE/g)的1/3.结果显示朱砂根乙酸乙酯部位抑制α-葡萄糖苷酶和抗氧化活性最好.     

Antioxidant activity of the phenol rich fractions of leaves of Chukrasia tabularis A. Juss

The present study was designed to explore the antioxidant potential of chloroform, ethyl acetate, n-butanol and water fractions of 80% methanol extract of leaves Chukrasia tabularis by 2,2'-diphenyl-1-picrylhydrazyl (DPPH), deoxyribose degradation (non-site specific and site specific), reducing power and DNA nicking assays. The different fractions showed significant activities in all the free radical scavenging tests and these findings have also shown direct relationship between antioxidant activity and phenolic content. Among the fractions, ethyl acetate fraction exhibited highest inhibition of 93.14%, 89.99%, 87.04% in DPPH, non-site specific and site specific deoxyribose degradation assays, respectively and 91.20% reduction of ferricyanide to give Prussian blue coloured complex in reducing power assay at maximum concentration tested. This preliminary study indicates the antioxidant activity of the leaves of Chukrasia tabularis, and moreover the results showed correlation with the amount of phenolic content present in different fractions.     

林檎叶水提物及其不同极性组分的抑菌和清除自由基作用的研究

采用管碟法及体外抗氧化活性测试方法,以抑菌圈大小及对DPPH的半清除率浓度(IC50)为指标,评价林檎叶水提物及其不同极性组分(包括乙酸乙醑、正丁醇萃取物、及乙醇沉淀物和剩余组分)的抑菌及清除DP-PH自由基的能力.结果显示林檎叶乙酸乙酯组分对大肠杆菌、枯草杆菌、金黄色葡萄球菌、黑曲霉、毛霉、红酵母及啤酒酵母均有抑制作用;且对DPPH自由基的清除能力最强,且清除率和质量浓度之间存在剂量依赖的关系,IC50值为0.33 mg/mL.有望成为新型的天然防腐保鲜剂的原料.     

库克诺你果汁提取物体外清除自由基及抗氧化活性研究

本文对诺你果汁多糖、乙醇溶出物和乙酸乙酯萃取物体外对超氧阴离子(O2·)、羟自由基(·OH)、DPPH和脂质过氧化(LPO)的抑制作用进行了研究。超氧阴离子(O2·)由邻苯三酚自氧化产生;羟自由基(·OH)由Fenton反应产生;利用Fe2 诱发卵黄脂蛋白产生丙二醛(MDA),TBA法测定。所有测定均为分光光度法。结果表明,与已知抗氧化剂L抗坏血酸相比,乙醇溶出物和乙酸乙酯萃取物均有明显的捕捉自由基和抗氧化能力,而多糖捕捉自由基和抗氧化能力很低,且对O2·没有抑制作用,反而会增加其生成速度。     

印度块菌提取物抗氧化活性的研究

对印度块菌Tuber indicum子实体的提取物,包括55%乙醇粗提物(ECE)、石油醚提取物(PEF)和乙酸乙酯提取物(EAF)的清除DPPH自由基和羟基自由基能力、铁离子鳌合能力以及各提取物的总酚含量等进行了研究和测定,结果显示,3种提取物的清除自由基能力和铁离子鳌合能力具有显著差异(P0.05);ECE对DPPH自由基的清除活性最高,其EC50值为1.61g/L;EAF对羟基自由基及铁离子表现出较强的清除或螯合的能力,其EC50值分别为3.31g/L和0.70g/L;EAF的总酚含量(2.964mg GAE/g提取物)最高,其次是ECE,总酚含量为(2.618mg GAE/g提取物);PEF的清除自由基和铁离子鳌合能力较差,其总酚含量也最低(1.124mg GAE/g提取物);总酚含量与印度块菌提取物清除自由基以及鳌合铁离子的能力密切相关。     

Enzyme inhibition and radical scavenging activities of aerial parts of Paeonia emodi Wall (Paeoniaceae)

The ethanolic extract derived from aerial parts of an indigenous medicinal plant Paeonia emodi was screened for enzyme inhibition activities against Urease (jack bean and Bacillus pasteurii) and alpha-Chymotrypsin. The extract was also investigated for its radical scavenging activity using DPPH assay. The crude extract was found to possess significant enzyme inhibition activities against jack bean (74%) and Bacillus pasteurii (80%) urease and a moderate activity (54%) against alpha-Chymotrypsin. The extract also displayed excellent (83%) radical scavenging activity. On the basis of these results, the crude extract was subsequently fractionated into n-hexane, chloroform, ethyl acetate, n-butanol and water fractions and tested independently for the aforesaid activities. Significant inhibitory activity against urease enzyme was observed for the ethyl acetate, n-butanol and water fractions while the n-hexane and chloroform fractions were devoid of any such activity. In the alpha-Chymotrypsin enzyme inhibition studies the activity was concentrated into the ethyl acetate fraction. All the fractions displayed potent radical scavenging activity. The crude extract and fractions thereof were also subjected to total phenolic content determination. A correlation between radical scavenging capacities of extracts and total phenolic content was observed in the majority of cases.     

Neuroprotection and free radical scavenging effects of <Emphasis Type="Italic">Osmanthus fragrans</Emphasis>

The ethanol extract of dried flowers Osmanthus fragrans (OFE) was assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the hydroxyl anion, investigation of the ferric reducing/antioxidant power (FRAP) and lipid-peroxidation inhibition in rat tissues. OFE contained a high amount of total flavonoid and polyphenol. OFE presented the effects in the metal reducing power, FRAP assay with IC₅₀ values of 0.23 μg/ml, and 7.74 μg/ml, respectively. OFE presented similar activities toward the DPPH and hydroxyl anion scavenging ability with IC₅₀ values of 10 μg/ml. OFE with IC₅₀ values between 46 and 97 μg/ml inhibited lipid peroxidation initiated by ferrous chloride in rat brain, liver, heart and kidney mitochodrias. Moreover, the neuroprotective activity of OFE was investigated under different insults (glutamate, arachidonic acid, and 6-hydroxydopamine) in Wistar rat primary cortical neurons. OFE with EC₅₀ values between 66 and 165 μg/ml attenuated the neurotoxicity on MTT and LDH assays. In addition, the AKT protein expression of excitotoxicity and oxidative stress was displayed by western blotting analysis. OFE could up-regulate the glutamate and 6-OHDA decreased AKT expression. This is the first demonstration of the neuroprotective, free radical scavenging and anti-oxidative effects of O. fragrans.     

Antioxidant activity of leaf extracts from Bauhinia monandra

Bauhinia monandra Kurz. is used in Brazil for the treatment of diabetes. Since this activity may be correlated with the presence of antioxidant compounds, leaf extracts of B. monandra were evaluated for their radical scavenging capacity (RSC). An ethanolic extract was taken up in aqueous methanol and partitioned with hexane, chloroform, ethyl acetate to yield three organic extracts together with remaining aqueous extract. The RSC was determined spectrophotometrically using 1,1-diphenylpicrylhydrazyl free radical (DPPH). The chloroform and ethyl acetate extracts were the most appropriate as sources of antioxidant compounds as shown by their inhibition concentration (IC50) and inhibition percentage (IP) values. The antioxidant activity of such extracts was attributed to the presence of three compounds of different polarities (flavonoids and steroids). The chloroform and ethyl acetate extracts exhibited an IC50 of approximately 2 mg/g DPPH and IP values in the range of 60-65%. The results indicate that the extracts of B. monandra have a very potent antioxidant activity, compared with the pure catechins used as positive controls and with other plant extracts.     

怀山药醇提取物抗DPPH自由基活性研究

将怀山药乙醇提取物采用溶剂萃取的方法,分成极性不同的五个部分,并首次用DPPH(2,2-diphenyl-1-picrylhydrazyl)方法测定各部分的抗自由基活性,发现乙酸乙酯萃取部分活性最强,氯仿萃取部分次之,再其次是正丁醇和水溶性部分。乙酸乙酯和氯仿萃取部分较强的抗自由基活性主要归因于其中所含的多酚类成分。同时利用薄层层析(TLC)、紫外光谱(UV)、^13C核磁共振(NMR)技术及显色反应对酚性成分进行了定性检验,并用Folin-Denis法测定了各萃取部位中酚性成分含量,发现抗自由基活性与萃取物中多酚性成分含量有一定的相关性。因而在评价怀山药质量时,其中所含的酚性成分不应忽视。     

Antioxidant and radioprotective effect of the active fraction of Pilea microphylla (L.) ethanolic extract

The ethanolic extract of Pilea microphylla (L.) was defatted, successively fractionated with acetone and the residue so obtained was found to be most potent when subjected to detailed free radical scavenging and in vivo radioprotection studies. The most active fraction reacts with free radicals, such as DPPH (50 microM), ABTS(.)(-) (100 microM) and (.)OH (generated by Fenton reaction) with IC(50) value of 23.15 microg/ml, 3.0 microg/ml and 310 microg/ml, respectively. The most active fraction inhibited iron-induced lipid peroxidation in phosphatidyl choline liposomes with an IC(50) of 13.74 microg/ml. The kinetics of scavenging of DPPH and ABTS(.)(-) radicals were followed at different concentrations of the fraction by employing stopped-flow studies. The observed first order decay rate constants at 200 microg/ml and 50 microg/ml of fraction with DPPH (50 microM) and ABTS(.)(-) (50 microM) were found to be 0.4s(-1) and 2.1s(-1), respectively. The fraction when screened for in vivo radioprotection in Swiss albino mice showed 80% protection at a dose of 900 mg/kg and with a DRF of about 1.12. The fraction was also found to protect livers of irradiated mice from depletion of endogenous antioxidant enzymes like glutathione, GST, SOD, catalase and thiols. The fraction also protected the villi height, increased the number of crypt cells while offering general protection to the intestine from acute radiation effects. The fraction also protected the hematopoietic system as assessed by endogenous spleen colony assay, contributing to the overall radioprotective ability.     

Antioxidant and anti-inflammatory activity of extract obtained from Aspergillus candidus MTCC 2202 broth filtrate

Antioxidant potential of Aspergillus candidus MTCC 2202 broth filtrate extract was studied using different antioxidant models, whereas anti-inflammatory potential was studied using carrageenan-induced rat paw oedema model. The ethyl acetate extract at 1000 microg/ml showed maximum scavenging activity of the stable radical 1,1-diphenyl,2-picryl hydrazyl upto 96.65% (IC50=430.36 microg/ml) and scavenging of the radical cation, 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonate) upto 92.25% (IC50=606.29 microg/ml) at the same concentration. The extract had good reducing power, however showed moderate inhibition for conjugated dienes and thiobarbituric acid reactive acid substances (59.56 and 51.45%). The total phenolic content of various extracts of A. candidus broth filtrate was measured and a correlation between radical scavenging activities of extracts with total phenolic content was observed. The ethyl acetate extract (125 mg/kg ip) showed significant anti-inflammatory activity in carrageenan-induced rat paw oedema model. The exhibited antioxidant activity of ethyl acetate extract of A. candidus broth filtrate was comparable with BHA and ascorbic acid, while anti-inflammatory activity was comparable with standard diclofenac sodium.     

In vitro antioxidant activity of Diospyros malabarica Kostel bark

Antioxidant activity of defatted methanol extract of D. malabarica bark was studied for its free radical scavenging property on different in vitro models e.g. 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide, superoxide, hydroxyl radical and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models except in hydroxyl radical inhibition assay. IC50 values were found to be 9.16, 13.21, 25.27 and 17.33 microg/ml respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. In hydroxyl radical inhibition assay 1000 microg/ml extract showed only 10% inhibition with respect to the control. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1 mg of the extract contained 120.7 microg equivalent of pyrocatechol. The results indicate that the antioxidant property of the extract may be due to the high content of phenolic compounds. However, the underlying mechanism may not involve hydroxyl radical scavenging property.     

Lipoxygenase inhibiting and antioxidant iridoids from Buddleja crispa

Phytochemical investigations on the ethyl acetate-soluble fraction of the whole plant of Buddleja crispa led to the isolation of the iridoids 1-7. Compound 2 displayed significant inhibitory potential against enzyme lipoxygenase in a concentration-dependant fashion with IC(50) value of 39.7 +/- 0.02microM, along with DPPH radical scavenging activity with IC(50) value 0.638 mM.     

凹叶厚朴抑制α-糖苷酶与抗氧化活性研究

首次采用96微孔板法检测贵州和河南产凹叶厚朴抑制α-葡萄糖苷酶活性;并采用DPPH、ABTS和FRAP三种方法测定其抗氧化活性.贵州产凹叶厚朴乙酸乙酯(IC50 =7.22 μg,/mL)和正丁醇提取部位(IC50=36.59 μg/mL),河南产凹叶厚朴石油醚(IC50=107.04 μg/mL)和乙酸乙酯提取部位(IC50=17.17μg/mL),它们的活性都远高于于阳性对照Acarhose( IC50=1081.27 μg/mL).贵州产凹叶厚朴乙酸乙酯提取部位清除ABTS自由基的能力最强(IC50=8.81 μg/mL),强于阳性对照BHT(IC50=11.94 μg/mL);其次为河南产凹叶厚朴乙酸乙酯提取部位(IC50=12.73 μg/mL).研究结果表明,贵州产凹叶厚朴乙酸乙酯提取部位抑制α-葡萄糖苷酶和抗氧化活性最好.