In vitro antioxidant activity of banana (Musa spp. ABB cv. Pisang Awak)

The methanolic extract of Musa ABB cv Pisang Awak was investigated for the polyphenolic contents and antioxidant activity. The total phenol and flavonoid contents of the fruit extract were found to be 120 mg gallic acid equivalents (GAE) and 440 mg quercetin equivalents (QE)/100 g of sample dry weight, respectively. The antioxidant activity of the Pisang Awak methanol extract (PAME) (20-500 microg/ml) was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing capacity, 2-2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) radical cation decolourization and hydroxyl radical scavenging capacity (OH*). The EC50 values of DPPH, ABTS and OH* activities of the PAME and butylated hydroxy toluene (BHT) were found to be 65 and 9 microg/ml, 29 and 6 microg/ml, 36 and 42 microg/ml respectively. The reducing capacity increased with increasing concentration (31.5-1000 mg/ml) of the fruit extract and the activity was comparable with the standard BHT. The high performance thin layer chromatography (HPTLC) analysis of the extract revealed the presence of polyphenols. The strong and positive correlations were obtained between total phenol/flavonoid contents (R2 = 0.693-1.0) and free radical scavenging ability was attributed to the polyphenols as the major antioxidants.     

Physico-chemical characterization, antioxidant and anticancer activities in vitro of a novel polysaccharide from Melia toosendan Sieb. Et Zucc fruit

A novel water-soluble polysaccharide pMTPS-3, obtained from Melia toosendan Sieb. Et Zucc fruit by hot-water extraction and ethanol precipitation, was fractionated by DEAE-52 cellulose anion-exchange and Sephadex G-100 gel filtration chromatography. Its primary structural features and molecular weight were characterized by Fourier infrared spectrometry (FTIR), gel permeation chromatography (GPC) and gas chromatography (GC). And the antioxidant activities of pMTPS-3 in vitro were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, superoxide radical scavenging assay and hydroxyl radical scavenging assay. The results suggested that pMTPS-3 was a heteropolysaccharide, composed of arabinose, glucose, mannose, and galactose in the molar ratio of 17.3:28.3:41.6:12.6 with molecular weight 26 100 Da. The purified pMTPS-3 was revealed to have notable scavenging activity against DPPH radical in a concentration-dependent manner and present a moderate inhibition of superoxide radicals with an IC₅₀ (5.6 mg/ml), and potent inhibiting power for hydroxyl radical compared with crude polysaccharide. Further, it exhibited strong inhibition effect in vitro on the growth of human gastric cancer BGC-823 cells. It is strongly evidenced that pMTPS-3 purified from the crude polysaccharides of Melia toosendan Sieb. Et Zucc could be explored as a potential antioxidant and therapeutics.     

黑豆种皮花色苷酶法辅助提取工艺优化及其抗氧化活性分析

优化黑豆种皮花色苷复合酶法辅助提取工艺,并对其抗氧化活性进行评价。通过单因素试验和响应面法优化确定了黑豆种皮花色苷生物酶法辅助提取的最佳工艺为:复合酶(纤维素酶400 U/g,α-淀粉酶50 U/g),酶解温度50℃,液料比26∶1 mL/g,乙醇体积分数64%,酶解时间为59 min。在此条件下,提取花色苷的含量为2.019 mg/g。抗氧化试验研究表明,黑豆种皮花色苷的还原能力、对超氧阴离子自由基清除能力低于抗坏血酸,但对亚硝酸根离子和DPPH自由基、ABTS自由基的清除能力强于抗坏血酸。因此,生物酶法辅助提取是一种高效的黑豆种皮花色苷提取方法,且作为一种新型花色苷资源,黑豆种皮花色苷有着挖掘和应用价值。     

Evaluation of antioxidant properties of root bark of Hemidesmus indicus R. Br. (Anantmul).

Hemidesmus indicus R. Br. (Asclepiadaceae) is a well known drug in Ayurveda system of medicine. In the present study, antioxidant activity of methanolic extract of H. indicus root bark was evaluated in several in vitro and ex vivo models. Further, preliminary phytochemical analysis and TLC fingerprint profile of the extract was established to characterize the extract which showed antioxidant properties. The in vitro and ex vivo antioxidant potential of root bark of H. indicus was evaluated in different systems viz. radical scavenging activity by DPPH reduction, superoxide radical scavenging activity in riboflavin/light/NBT system, nitric oxide (NO) radical scavenging activity in sodium nitroprusside/Greiss reagent system and inhibition of lipid peroxidation induced by iron-ADP-ascorbate in liver homogenate and phenylhydrazine induced haemolysis in erythrocyte membrane stabilization study. The extract was found to have different levels of antioxidant properties in the models tested. In scavenging DPPH and superoxide radicals, its activity was intense (EC50 = 18.87 and 19.9 microg/ml respectively) while in scavenging NO radical, it was moderate. It also inhibited lipid peroxidation of liver homogenate (EC50 = 43.8 microg/ml) and the haemolysis induced by phenylhydrazine (EC50 = 9.74 microg/ml) confirming the membrane stabilization activity. The free radical scavenging property may be one of the mechanisms by which this drug is effective in several free radical mediated disease conditions.     

Erythrinaline alkaloids from the flowers and pods of Erythrina lysistemon and their DPPH radical scavenging properties

Fourteen different erythrinaline alkaloids have been isolated from the flowers and pods of Erythrina lysistemon with four being reported for the first time in nature and five for the first time in this species and the rest having been re-isolated. The new compounds are (+)-11beta-hydroxyerysotramidine (1), (+)-11beta-methoxyerysotramidine (2), (+)-11beta-hydroxyerysotrine N-oxide (4) and (+)-11beta-hydroxyerysotrine (8). (+)-11alpha-Hydroxyerysotrine N-oxide (3), earlier misidentified as erythrartine N-oxide (beta-hydroxyerysotrine N-oxide 4), was also re-isolated along with four other alkaloids. Correct identification of compounds 4 and 8 was aided by the fact that the two sets of C-11 epimers 3, 4 and 8, 9 were both isolated in this study thus making it easier to identify and assign the individual epimers. (+)-Erythristemine (14) was found distributed in most of the plant parts investigated. Preliminary work on the crude chloroform/methanol (1:1) showed moderate toxicity to brine shrimp (LC50 23 ppm) and moderate (IC50 86 microg/ml) radical scavenging properties against stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging properties of the isolated compounds were assessed using TLC autographic and spectrophotometric assays whereupon only compounds 11 (1 microg; 90 microg/ml) and 12 (0.1 microg; 160 microg/ml) showed any notable activity. It appears the two compounds are slow reacting and do not reach steady state conditions within the standard half an hour time frame but only seemed to have reached steady state conditions after 4 h.     

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.     

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。     

Antioxidant properties and protective effects of a standardized extract of Hypericum perforatum on hydrogen peroxide-induced oxidative damage in PC12 cells

Free radical scavenging and antioxidant activities of a standardized extract of Hypericum perforatum (SHP) were examined for inhibition of lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH). Concentrations between 1 and 50 microg/ml of SHP effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe2+/ascorbate or NADPH system. The results showed that SHP scavenged DPPH radical in a dose-dependent manner and also presented inhibitory effects on the activity of xanthine oxidase. In contrast, hydroxyl radical scavenging occurs at high doses. The protective effect of the standardized extract against H2O2-induced oxidative damage on the pheochromocytoma cell line PC 12 was investigated by measuring cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assays, caspase-3-enzyme activity and accumulation of reactive oxygen species [2',7'-dichlorofluorescin (DCF) assay]. Following 8-h cell exposure to H2O2 (300 microM), a marked reduction in cell survival was observed, which was significantly prevented by SHP (pre-incubated for 24 h) at 1-100 microg/ml. In a separate experiment, different concentrations of the standardized extract (0.1-100 microg/ml) also attenuated the increase in caspase-3 activity and suppressed the H2O2 -induced reactive oxygen species generation. Taken together, these results suggest that SHP shows relevant antioxidant activity both in vitro and in a cell system, by means of inhibiting free radical generation and lipid peroxidation.     

Radical scavenging and radiomodulatory effects of Psoralea corylifolia Linn. substantiated by in vitro assays and EPR spectroscopy

The present study is the first report of the radiomodulatory effects of Psoralea corylifolia Linn. The extract (IBG-RA-26) prepared from P. corylifolia was chemically analysed by HPLC, LC-MS/MS and NMR. The total polyphenolic content of IBG-RA-26 was 0.287 mg/ml of quercetin equivalents. IBG-RA-26 exhibited a dose-dependent increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. It exhibited comparable (> 50%) site-specific and non-site-specific hydroxyl radical scavenging activity in higher concentration ranges (500-1000 microg/ml), while at lower concentrations (5-50 microg/ml) it exhibited significantly (p < 0.05) higher non-site-specific scavenging ability compared to site-specific activity. Nitric oxide scavenging activity of IBG-RA-26 (5-1000 microg/ml) increased in a concentration-dependent manner, while maximum superoxide ion scavenging ability (79%) was observed at 50 microg/ml. The electron donation potential of IBG-RA-26 was found to be higher than that of ascorbic acid at lower concentrations (up to 5 microg/ml). Analysis of the ability of IBG-RA-26 to protect membranes against gamma-radiation, utilizing an artificial membrane system (liposome), revealed a significant (p < 0.05) decrease in the formation of malondialdehyde (MDA) as a function of the concentration of IBG-RA-26. Radiation-induced lysis of human erythrocytes was monitored and efficacy of IBG-RA-26 was tested in the concentration range 25-1000 microg/ml, with significant protective efficacy observed in the range 25-50 microg/ml. IBG-RA-26 rendered significant (p < 0.05) protection against radiation (0.25 kGy)-induced DNA damage. EPR spectroscopy was used to investigate the DPPH radical scavenging capacity of IBG-RA-26. IBG-RA-26 exhibited a good DPPH radical scavenging capacity in a concentration-dependent manner. By direct EPR spectroscopy we have also demonstrated the possible formation of free radical species in a solution of IBG-RA-26. The wide spectrum of radioprotective and antioxidant properties exhibited by IBG-RA-26 indicate that P. corylifolia has potential as a radiomodulatory agent.     

响应面法优化干花豆总黄酮提取工艺研究

干花豆( Fordia cauliflora)的主要有效成分为黄酮类、生物碱、有机酸等,具有益智、抗衰老、抗炎等作用。目前的研究主要集中在化学成分及药理活性等方面,对总黄酮成分提取工艺优化报道较少。该研究以新鲜干花豆为材料,以总黄酮提取量为评价指标,在提取温度、料液比、乙醇浓度和提取时间单因素实验基础上,采用响应面法优化了干花豆总黄酮提取工艺,同时测定了总黄酮对1,1-二苯基苦基苯肼自由基( DPPH.)和羟基自由基(.OH)清除能力。结果表明：干花豆总黄酮提取最佳工艺条件为提取温度78℃、料液比为1∶30(g.mL-1)、乙醇浓度71％和提取时间为187 min。在此条件下,总黄酮得率预测值为10.61 mg.g-1,实际为10.53 mg.g-1,理论值与预测值的相对误差为0.76％;干花豆总黄酮对DPPH和OH自由基清除能力IC50值分别为14.09和78.43μg.mL-1,弱于Vc(8.11和67.95μg.mL-1)。该提取工艺稳定合理,准确可靠,是提取干花豆总黄酮的可行方法。该研究结果为干花豆中总黄酮成分的进一步开发利用奠定了基础。     

In vitro antioxidant activity of Hedyotis corymbosa (L.) Lam. aerial parts

The methanolic extract of the aerial part of Hedyotis corymbosa (L.) Lam. (Rubiaceae) was screened for antioxidant activity using 1,1-diphenyl-2-picryl hydroxyl (DPPH) quenching assay, 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) cation decolorization test, ferric reducing power (FRP), scavenging capacity towards hydroxyl ion (OH*) radicals and nitric oxide (NO) radical inhibition activity using established assay procedures. Total phenolics and total flavonoid contents were, also determined. The plant yielded 210 mg gallic acid equivalent/100 g phenolic content and 55 mg quercetin equivalent/100 g flavonoid content. The extract exhibited high antiradical activity against DPPH, ABTS, nitric oxide and hydroxyl radicals with EC50 value of 82, 150, 130, and 170 microg/ml, respectively. The FRP increased with increasing concentration of the sample. The antioxidant activity of the extract was comparable with that of the standard butylated hydroxyl toluene (BHT). High correlation between total phenolic/flavonoid contents and scavenging potential of different reactive oxygen species (R2 = 0.785-0.998) indicated the polyphenols as the main antioxidants.     

纤维素酶-超声波协同提取黑木耳黑色素工艺及其抗氧化活性分析

黑色素是黑木耳的主要活性成分之一,在黑木耳的药理活性上发挥着重要作用。为了提高黑木耳黑色素的提取得率,实验采用正交法和响应面法对纤维素酶-超声波协同提取黑木耳黑色素的提取工艺进行了优化,并对最优条件下提取的黑木耳黑色素体外抗氧化活性进行了分析。实验结果表明,纤维素酶-超声波协同提取黑木耳黑色素的最优条件为:酶添加量12mg,酶解温度40℃,酶解pH 5.0,酶解时间120min,NaOH浓度1.27mol/L,料液比1:40,超声功率300W,超声时间52min,超声温度60℃。在最优条件下,黑木耳黑色素提取得率可达到10.48%,相比于实验设置的未添加纤维素酶的超声波组黑色素提取得率提高了12.93%。抗氧化结果表明,采用纤维素酶-超声波协同提取的黑色素相比于未加纤维素酶提取的黑色素清除ABTS、DPPH和羟基自由基的能力更强。研究结果为黑木耳黑色素的高效提取及其产品的应用开发奠定了基础。     

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.     

Natural and newly synthesized hydroxy-1-aryl-isochromans: a class of potential antioxidants and radical scavengers

We investigated the antioxidant and radical scavenging activity of polyphenolic isochromans. To assess the relation between structure and scavenging properties the natural occurring 1-(3'-methoxy-4'-hydroxy)phenyl-6,7-dihydroxy-isochroman (ISO-3, three OH groups) was compared with three newly synthesized derivatives that differ in their degree of hydroxylation by substitution with methoxy-groups (ISO-4: four OH groups; ISO-2: two OH groups and ISO-0: fully methoxylated). We found that ISO-4 is a 2-fold better scavenger for the artificial radical 1,1-diphenyl-2-picrylhydrazyl (DPPH, 100 microM) with an EC50=10.3 microM compared to the natural ISO-3 (EC50=22.4 microM) and to ISO-2 (EC50=25.1 microM), while ISO-0 did not react with DPPH. The scavenging capacity for superoxide enzymatically generated in a hypoxanthin-xanthinoxidase reaction was the highest for ISO-4 (EC50=34.3 microM) compared to those of ISO-3 (EC50=84.0 microM) and ISO-2 (EC50=91.8 microM), while ISO-0 was inactive. In analogy, ISO-4 scavenged peroxynitrite (ONOO-, EC25=23.0 microM) more effective than ISO-3, ISO-2 and ISO-0.When C6 rat glioma cells loaded with the reactive oxygen/nitrogen (ROS/RNS)-sensitive fluorochrome 2,7-dichlorodihydrofluorescein, were exposed to hydrogen peroxide, the lowest stress level as indicated by the fluorescence signal was detected when the cells were pretreated with ISO-4 or ISO-2 but to a much lesser extent with ISO-3, while ISO-0 did not show any effect. All tested hydroxyisochromans superceded the scavenging effect of trolox.The excellent radical and ROS/RNS scavenging features of the hydroxy-1-aryl isochromans and their simple synthesis let these compounds appear to be interesting candidates for pharmaceutical interventions that protect against the deleterious action of ROS/RNS.     

Vialinin A, a novel 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenger from an edible mushroom in China

While screening for bioactive compounds from edible mushrooms, a new potent antioxidant, vialinin A (1), together with a known compound, ganbajunin B (2), and a mixture of ganbajunins D (3) and E (4), were isolated from the dry fruiting bodies of Thelephora vialis. The structure of 1, 5',6'-bis(phenylacetoxy)-1,1':4',1'-terphenyl-2',3',4,4'-tetraol, was elucidated by spectroscopic and chemical methods. This compound had strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity with an EC(50) value of 14.0 microM, nearly equal to that of butylated hydroxytoluene (BHT; EC(50) = 10.0 microM). A radical scavenging experiment using 1 and DPPH radicals indicated that 1 donated two hydrogen atoms to two molecules of the DPPH radical under hydrophobic conditions.     

Antioxidative polyphenols from walnuts (Juglans regia L.)

Three hydrolyzable tannins, glansrins A-C, together with adenosine, adenine, and 13 known tannins were isolated from the n-BuOH extract of walnuts (the seeds of Juglans regia L.). Glansrins A-C were characterized as ellagitannins with a tergalloyl group, or related polyphenolic acyl group, based on spectral and chemical evidence. The 14 walnut polyphenols had superoxide dismutase (SOD)-like activity with EC(50) 21.4-190 microM and a remarkable radical scavenging effect against 1,1-diphenyl-2-picrylhydrazyl (DPPH) (EC(50) 0.34-4.72 microM).     

刺梨茶总黄酮的提取工艺的建立及其抗氧化活性

为进一步开发并利用贵州独特野生资源刺梨茶,研究其总黄酮的提取工艺及体外抗氧化活性,本文采用单因素实验和响应曲面分析法优化刺梨茶中总黄酮的提取工艺,并经1,1-二苯基-2-三硝基苯肼(DPPH)法初步评价其抗氧化活性。结果表明,刺梨茶总黄酮最佳提取工艺为料液比(g∶mL)1∶26,乙醇浓度74%,提取温度75℃,提取时间120min。此条件下,刺梨茶总黄酮得率为2.190%,与预测值2.216%接近。刺梨茶总黄酮对DPPH具有较好的清除能力,其EC50值为0.012 27mg/mL,其清除DPPH的能力微弱于Vc,但强于2,6-二叔丁基对甲酚(BHT)。刺梨茶总黄酮表现出良好的抗氧化活性,可作为天然抗氧化剂开发利用。     

四种野生食用菌粗多糖的抗氧化活性

利用DPPH自由基清除法、羟基自由基(OH.)清除法、铁离子鳌合能力及测定还原能力等方法对鸡油菌Cantharellus cibarius、变绿红菇Russula virescens、蜜环菌Armillaria mellea和棕灰口蘑Tricholoma myomyces等4种食用菌的粗多糖进行了抗氧化活性评价。结果显示,4种真菌粗多糖均不同程度地具有抗氧化活性。在DPPH自由基清除试验中,棕灰口蘑和蜜环菌表现出很强的活性,其EC50值分别为1.35 g/L、1.53 g/L;棕灰口蘑和蜜环菌对羟基自由基的清除能力也要优于其他2种食用菌,其EC50值分别为0.65 g/L、0.78 g/L;棕灰口蘑的铁离子螯合能力明显优于其他3种测试菌,其EC50值为1.69 g/L;在还原力方面同样是棕灰口蘑活性最强,蜜环菌次之,其EC50值为1.05 g/L、1.37 g/L。     

Antioxidant potential of n-butanol fraction from extract of Jasminum mesnyi Hance leaves

Methanolic extract of Jasminum mesnyi Hance leaves having antidiabetic activity was subjected to fractionation to obtain antioxidant and antihyperglycemic rich fraction. Different concentrations of ethyl acetate and n-butanol fractions were subjected to antioxidant assay by DPPH method, nitric oxide scavenging activity and reducing power assay. The fractions showed dose dependent free radical scavenging property in all the models. IC50 values for ethyl acetate and n-butanol fractions were 153.45 +/- 6.65 and 6.22 +/- 0.25 microg/ml, respectively, as compared to L-ascorbic acid and rutin (as standards; IC50 values 6.54 +/- 0.24 and 5.43 +/- 0.21 microg/ml, respectively) in DPPH model. In nitric oxide scavenging activity, IC50 values were 141.54 +/- 9.95 microg/ml, 35.12 +/- 1.58 microg/ml, 21.06 +/- 0.95 microg/ml and 29.93 +/- 0.32 microg/ml for ethyl acetate, n-butanol fractions, L-ascorbic acid and rutin, respectively. n-Butanol fraction showed a good reducing potential and better free radical scavenging activity as compared to ethyl acetate fraction. Potent antioxidant n-butanol fraction showed better oral glucose tolerance test (antihyperglycemic) at par with metformin (standard drug), n-Butanol fraction contained secoiridoid glycosides which might be responsible for both antioxidant and antihyperglycemic activity.     

Cat's claw inhibits TNFalpha production and scavenges free radicals: role in cytoprotection

Cat's claw (Uncaria tomentosa) is a medicinal plant from the Amazon River basin that is widely used for inflammatory disorders and was previously described as an inhibitor of NF-kappaB. Cat's claw was prepared as a decoction (water extraction) of micropulverized bark with and without concentration by freeze-drying. Murine macrophages (RAW 264.7 cells) were used in cytotoxicity assays (trypan blue exclusion) in response to the free radical 1, 1-diphenyl-2-picrilhydrazyl (DPPH, 0.3 microM) and ultraviolet light (UV) light. TNFalpha production was induced by lipopolysaccharide (LPS 0.5 microg/ml). Cat's claw was an effective scavenger of DPPH; the EC(50) value for freeze-dried concentrates was significantly less than micropulverized (18 vs. 150 microg/ml, p <.05). Cat's claw (10 microg/ml freeze-dried) was fully protective against DPPH and UV irradiation-induced cytotoxicity. LPS increased TNFalpha media levels from 3 to 97 ng/ml. Cat's claw suppressed TNFalpha production by approximately 65-85% (p <.01) but at concentrations considerably lower than its antioxidant activity: freeze-dried EC(50) = 1.2 ng/ml, micropulverized EC(50) = 28 ng/ml. In conclusion, cat's claw is an effective antioxidant, but perhaps more importantly a remarkably potent inhibitor of TNFalpha production. The primary mechanism for cat's claw anti-inflammatory actions appears to be immunomodulation via suppression of TNFalpha synthesis.