Free radical scavenging activity of Pterogyne nitens Tul. (Fabaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Free radical scavenging activity of Kielmeyera variabilis (Clusiaceae)

As part of our ongoing research on antioxidant agents from Brazilian flora, we screened the free radical scavenging activity of two extracts and eight fractions of Kielmeyera variabilis (Clusiaceae) using DPPH (2,2-diphenyl-1- picrylhydrazyl-hydrate) and ABTS+ [2,2'-azinobis(3- ethylenebenzothiazoline-6-sulfonic acid)] colorimetric assays. The ethyl acetate and n-butanol fractions of the leaves of K. variabilis displayed the strongest activity (IC50 of 3.5 ± 0.3 and 4.4 ± 0.2 μg mL -1 for DPPH and 6.6 ± 0.4 and 3.1 ± 0.1 μg mL -1 for ABTS+, respectively). Chromatographic fractionation of the most potent fractions led to identification of three flavonols with previously described antioxidant activity, quercitrin (1), quercetin-3-O- glucoside (3), and quercetin-3-O-galactoside (4), and of one biflavone, podocarpusflavone A (2). This is the first time that the presence of these flavonoids in Kielmeyera variabilis has been reported. © 2013 by the authors.

Comparation of free radical scavenging activity between seven species of Passiflora L.

Antioxidant capacities of seven species of Passiflora were evaluated through comparation of the free radical DPPH scavenging activity. The studied species included cultivated and traditionally used P. edulis, P. incarnata and P. alata and less common species P. coccinea, P. laurifolia, P. mucronata and P. gardneri. The experimental design was completely randomized with ANOVA and Tukey test as main statistical analyses. The results showed that species of Passiflora had variable antioxidant capacities, ranging from 28 to 95% of free radical DPPH scavenging activity.

Free radical scavenging profile and myeloperoxidase inhibition of extracts from antidiabetic plants: Bauhinia forficata and Cissus sicyoides

There is abundant evidence that reactive oxygen species are implicated in several physiological and pathological processes. To protect biological targets from oxidative damage. antioxidants must react with radicals and other reactive species faster than biological substrates do. The aim of the present study was to determine the in vitro antioxidant activity of aqueous extracts from leaves of Bauhinia forficata Link (Fabaceae - Caesalpinioideae) and Cissus sicyoides L. (Vitaceae) (two medicinal plants used popularly in the control of diabetes mellitus), using several different assay systems, namely, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) decolorization. superoxide anion radical (O-2 center dot-) scavenging and myeloperoxidase (MPO) activity. In the ABTS assay for total antioxidant activity, B. forficata showed IC50 8.00 +/- 0.07 mu g/mL, while C. sicyoides showed IC50 13.0 +/- 0.2 mu g/mL. However, the extract of C. sicyoides had a stronger effect on O-2 center dot- (IC50 60.0 +/- 2.3 mu p/mL) than the extract of B. forficata (IC50 90.0 +/- 4.4 mu g/mL). B. forficata also had a stronger inhibitory effect on MPO activity, as measured by guaiacol oxidation, than C. sicyoides. These results indicate that aqueous extracts of leaves of B. forficata and C. sicyoides are a potential source of natural antioxidants and may be helpful in the prevention of diabetic complications associated with oxidative stress.

Interconverting flavanone glucosides and other phenolic compounds in Lippia salviaefolia Cham. ethanol extracts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

ANTIOXIDANT PROPERTIES of LENTINUS EDODES and AGARICUS BLAZEI EXTRACTS

This work aimed to evaluate the antioxidant activity of Lentinus edodes and Agaricus blazei mushrooms, as well as to measure the content of total phenolic compounds of mushroom extracts and verify the oxidative stability of soybean oil added with mushroom extracts that showed higher antioxidant activity according to the methods of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and the beta-carotene/linoleic acid system. According to the DPPH method, the maximum antioxidant activity for L. edodes and A. blazei methanol extracts was 92.84 and 95.10%, respectively. For the beta-carotene/linoleic acid system, the highest values of antioxidant activity were 93.06% for L. edodes and 78.96% for A. blazei. The content of total phenolic compounds ranged from 7.21 to 128.44 and 26.67 to 134.67 mg gallic acid equivalent/g for L. edodes and A. blazei, respectively. The oxidative stability values provided by the Rancimat method indicated that the two varieties presented similar induction period of 19.85 h.

Myeloperoxidase inhibitory and radical scavenging activities of flavones from Pterogyne nitens

Two new flavone glucosides, nitensosides A and B (1, 2), together with four known compounds, sorbifolin (3), sorbifolin 6-O-β-glucopyranoside (4), pedalitin (5), and pedalitin 6-O-β-glucopyranoside (6) were isolated from Pterogyne nitens. Their structures were elucidated from 1D and 2D NMR analysis, as well as by high resolution mass spectrometry. All the isolated flavones were evaluated for their myeloperoxidase (MPO) inhibitory activity. The most active compound, pedalitin, exhibited IC 50 value of 3.75 nM on MPO. Additionally, the radical-scavenging capacity of flavones 1-6 was evaluated towards ABTS and DPPH radicals and compared to standard compounds quercetin and Trolox®. © 2008 Pharmaceutical Society of Japan.

Comparation of free radical scavenger activity between seven species of Passiflora L.

Antioxidant capacities of seven species of Passiflora were evaluated through comparation of the free radical DPPH scavenging activity. The studied species included cultivated and traditionally used P. edulis, P. incarnata and P. alata and less common species P. coccinea, P. laurifolia, P. mucronata and P. gardneri. The experimental design was completely randomized with ANOVA and Tukey test as main statistical analyses. The results showed that species of Passiflora had variable antioxidant capacities, ranging from 28 to 95% of free radical DPPH scavenging activity.

Radical scavenging activity of orange and tangerine varieties cultivated in Brazil

Four citrus fruit varieties cultivated in Brazil (two kinds of sweet orange and two kinds of tangerine) were analyzed for physicochemical characteristics contents of total phenolics, total carotenoids and ascorbic acid, and antioxidant activities. The antioxidant activities of aqueous, methanolic, and acetone extracts of the citrus fruit juices were assessed on the basis of their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH(center dot)). The cravo tangerine has the highest content of citric acid, while the pera orange is richest in ascorbic acid. The lima orange has the highest total phenolic contents, and the ponkan the highest total carotenoids. The antioxidant activities, expressed as the concentration of antioxidant able to scavenge 50% of the initial DPPH(center dot) (EC(50)), ranged from 139.1+/-27.3 to 182.2+/-28.8 g extract/l for juice of orange varieties and 186.3+/-29.6 to 275.5+/-3.3g extract/l for juice of tangerine citrus varieties. In methanolic extracts the EC(50) ranged from 192.5+/-43.1 to 267.4+/-41.4 g extract/l for orange varieties and from 225.2+/-69.8 to 336.3+/-27.2 g extract/l for tangerine varieties. For EC(50) values of acetone fractions, there were no statistically significant differences between the different varieties. For every citrus fruit in the present study, the radical scavenging capacity was higher in the aqueous than in the methanolic or acetone fractions.

Radical Scavenging Capacity of Piper arboreum and Piper tuberculatum (Piperaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigations on the new free radical scavenger polynitroxyl-albumin to prevent ischemia and reperfusion injury after orthotopic heart transplantation in the pig model

Objective: Nitroxides have strong antioxidant capacity but their effectiveness is limited by their rapid intracellular inactivation. Poly nitroxyl-Albumin (PNA) is capable of regenerating inactivated nitroxide. We tested the effect of PNA against reperfusion injury in heart transplantation. Methods: Pig hearts were transplanted orthotopically. In the control group (n = 9) reperfusion was performed without reperfusion modifications. In the experimental group (n = 10) 1 ml/kg PNA was given before cross-clamp release. Results: Hemodynamic performance was impaired after transplantation in both groups without significant intergroup differences. Plasma malonedialdehyde levels were significantly diminished in the PNA group as compared to the controls. CK-MB levels in both groups were increased within the first 2 h of reperfusion without significant intergroup differences. In contrast, there were found significant higher values of myocardial specific lactate dehydrogenase (LD1) in the controls versus PNA group. Conclusions: PNA was able to reduce lipid peroxidation and attenuate free radical activity. Contractile dysfunction could no be improved, indicating that (a) the radical scavenging effect was to weak or (b) other mechanisms than free oxygen radicals are responsible for myocardial damage in this experimental model. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Profile of Maytenus aquifolium action over free radicals and reactive oxygen species

Reactive oxygen species (ROS) and free radical species have been implicated in initiating, accompanying or causing many diseases in living organisms; there is thus, a continual need for antioxidants molecules to inactivate ROS/free radicals. Many studies of plants crude extracts have demonstrated free-radical scavenging and antioxidant action. Maytenus species have long been used, in several countries, as traditional medicines against gastric ulcers, dyspepsia and others gastric problems and for their anti-inflammatory properties. In this study, Maytenus aquifolium (Celastraceae) root bark ethanol extract was assessed for its ability to scavenge free radicals and reactive oxygen species. The results were expressed as percentage inhibition of the active species. The extract was efficient against studied reactive species: DPPH radical (obtained inhibition = 35.5 ± 1.3 %), ABTS.+ (IC50 = 0.0036 ± 0.0003 mg/mL), HOCl (IC50 = 0.002 ± 0.0001 mg/mL), O2 .- (obtained inhibition = 36.0 ± 2.1 %), and NO. (obtained inhibition = 18.3 ± 0.4 %). Uniterms Oxidant species Free radicals Maytenus aquifolium Oxidative damage.

Efeito do processo de obtenção do catchup sobre seus compostos antioxidantes, capacidade seqüestrante do radical DPPH e cor

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Salacia campestris root bark extract: peroxidase inhibition, antioxidant and antiradical profile

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Iron chelating-mediated antioxidant activity of Plectranthus barbatus extract on mitochondria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)