Total phenolic content and free radical scavenging activities of methanolic extract powders of tropical fruit residues

Methanolic extract powders of acerola, passion fruit and pineapple industrial residues, including pulp, seeds and peel, altogether (except for acerola) devoid of seeds, were screened for antioxidant capacity. The total phenolic contents (TPCs) of the extract powders were compared with their radical-scavenging activities (RSA) against both DPPH(center dot) and superoxide anion (O(2)(center dot-)) radicals, and their protective effect against liposome peroxidation, triggered by peroxyl radical. Lipid peroxidation was followed by the fluorescence decay of the probe, 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C(11)-BODIPY(581/591)). The TPCs of acerola, passion fruit and pineapple extract powders were (94.6 +/- 7.4); (41.2 +/- 4.2) and (9.1 +/- 1.3) mg of gallic acid equivalents g(-1) of dry extract, respectively. Acerola showed the best RSA-DPPH(center dot) scores, whereas passion fruit was more protective on the RSA-O(2)(center dot-) system. Together with the protective effects against lipid peroxidation (rate of BODIPY decay) which, were similar for acerola and passion fruit extracts, these data suggest that the methanolic extracts of acerola and passion fruit residues may be useful as antioxidant supplements, particularly the acerola extract, due to its high phenolic content. (C) 2008 Elsevier Ltd. All rights reserved

HPLC microfractionation of flavones and antioxidant (radical scavenging) activity of Saccharum officinarum L.

The antioxidant activity of sugarcane (Saccharum officinarum L.) juice towards DPPH reagent was determined (EC50) and the main compounds with radical scavenging activity in juice and leaves extracts were identified by HPLC-UV/PAD analysis combined with HPLC microfractionation monitored by TLC using β-carotene and DPPH as the detection reagents. In sugarcane leaves, luteolin-8-C-(rhamnosylglucoside) (1) was the most important compound with radical scavenging activity; in sugarcane juice, the flavones diosmetin-8-C-glucoside (2), vitexin (3) schaftoside (9), isoschaftoside (10) and 4',5'-dimethyl-luteolin-8-C-glucoside (11) were the most relevant compounds. The content of juice flavonoids (0.241 ± 0.001 mg total flavonoids/mL juice), comparable to other food sources of flavonoids, suggest the potential of sugarcane as a dietary source of natural antioxidants. However, the low antioxidant ability of sugarcane juice (EC50 = 100.2 ± 2.6 g L-1) also points to the need for further studies about the dietary intake of sugarcane flavonoids and its effects on human health.

Garlic (Allium sativum L.) and ready-to-eat garlic products: in vitro antioxidant activity

Garlic contains polyphenol and sulphur compounds, which are responsible for its antioxidant activity (AA). This study aimed at evaluating the AA of fresh garlic and its commercialised products and their shelf life. Fresh garlic (FG) and its products, i.e. chopped with salt (CGS), chopped without salt (CG), fried (FRG) and mixed garlic (FG with dehydrated garlic; MG) antioxidant activity was evaluated by three different methods: DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, ß-carotene/linoleic acid assay and Rancimat® method. Amongst all the analysed products, fried garlic presented the highest antioxidant activity. The free radical-scavenging activity decreased during the shelf life of all analysed products that correlated with the decrease in the total polyphenol content. Our findings suggest that some compounds other than phenol may have contributed towards this outcome

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

Plectranthus barbatus Andrews (Lamiaceae) is a popular medicinal plant used to treat gastrointestinal and hepatic ailments. In this work, we assessed the antioxidant activity of the aqueous extract of P. barbatus leaves on Fe(2+)-citrate-mediated membrane lipid peroxidation in isolated rat liver mitochondria, as well in non-mitochondrial systems: DPPH reduction, (center dot)OH scavenging activity, and iron chelation by prevention of formation of the Fe(2+)-bathophenanthroline disulfonic acid (BPS) complex. Within all the tested concentrations (15-75 mu g/ml), P. barbatus extract presented significant free radical-scavenging activity (IC(50) = 35.8 +/- 0.27 mu g/ml in the DPPH: assay and IC(50) = 69.1 +/- 0.73 mu g/ml in the (center dot)OH assay) and chelated iron (IC(50) = 30.4 +/- 3.31 mu g/ml). Over the same concentration range, the plant extract protected mitochondria against Fe(2+)/citrate-mediated swelling and malondialdehyde production, a property that persisted even after simulation of its passage through the digestive tract. These effects could be attributed to the phenolic compounds, nepetoidin - caffeic acid esters, present in the extract. Therefore, P. barbatus extract prevents mitochondrial membrane lipid peroxidation, probably by chelation of iron, revealing potential applicability as a therapeutic source of molecules against diseases involving mitochondrial iron overload. (C) 2010 Elsevier Ltd. All rights reserved.

Garlic (Allium sativum L.) and ready-to-eat garlic products: In vitro antioxidant activity

Garlic contains polyphenol and sulphur compounds, which are responsible for its antioxidant activity (AA). This study aimed at evaluating the AA of fresh garlic and its commercialised products and their shelf life. Fresh garlic (FG) and its products, i.e. chopped with salt (CGS), chopped without Salt (CG), fried (FRG) and mixed garlic (FG with dehydrated garlic; MG) antioxidant activity was evaluated by three different methods: DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, beta-carotene/linoleic acid assay and Rancimat method. Amongst all the analysed products, fried garlic presented the highest antioxidant activity. The free radical-scavenging activity decreased during the shelf life of all analysed products that correlated with the decrease in the total polyphenol content. Our findings suggest that some compounds other than phenol may have contributed towards this outcome. (c) 2008 Elsevier Ltd. All rights reserved.

Characterization of Brazilian lager and brown ale beers based on color, phenolic compounds, and antioxidant activity using chemometrics

BACKGROUND: Epidemiological studies have shown that beer has positive effects on inhibiting atherosclerosis, decreasing the content of serum low-density lipoprotein cholesterol and triglycerides, by acting as in vivo free radical scavenger. In this research, the antioxidant activity of commercial Brazilian beers (n = 29) was determined by the oxygen radical absorbance capacity (ORAC) and 1,1 -diphenyl-2-picrylhydrazyl (DPPH(center dot)) assays and results were analyzed by chemometrics. RESULTS: The brown ale samples (n = 11) presented higher (P < 0.05) flavonoids (124.01 mg L(-1)), total phenolics (362.22 mg L(-1)), non-flavonoid phenolics (238.21 mg L(-1)), lightness (69.48), redness (35.75), yellowness (55.71), color intensity (66.86), hue angle (59.14), color saturation (0.9620), DPPH(center dot) values (30.96% inhibition), and ORAC values (3,659.36 mu mol Trolox equivalents L(-1)), compared to lager samples (n = 18). Brown ale beers presented higher antioxidant properties (P < 0.05) measured by ORAC (1.93 times higher) and DPPH (1.65 times higher) compared to lager beer. ORAC values correlated well with the content of flavonoids (r = 0.47; P = 0.01), total phenolic compounds (r = 0.44; P < 0.01) and DPPH (r = 0.67; P < 0.01). DPPH values also correlated well to the content of flavonoids (r = 0.69; P < 0.01), total phenolic compounds (r = 0.60; P < 0.01), and non-flavonoid compounds (r = 0.46; P = 0.01). CONCLUSION: The results suggest that brown ale beers, and less significantly lager beers, could be sources of bioactive compounds with suitable free radical scavenging properties. (C) 2010 Society of Chemical Industry

Phenolic compounds content and antioxidant activity in pomace from selected red grapes (Vitis vinifera L. and Vitis labrusca L.) widely produced in Brazil

The phenolic compounds content and antioxidant activity of pomace from the vinification of grape varieties widely produced in Brazil (Cabernet Sauvignon, Merlot, Bordeaux and Isabel) were investigated with a view to their exploitation as a potential source of natural antioxidants. Cabernet Sauvignon grape pomace was found to have the highest content of total phenolic compounds (74.75 mg gallic acid equivalent (GAE)/g), the highest antioxidant activity (determined using the 2,2`-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods; 485.42 and 505.52 mu Mol Trolox equivalent antioxidant capacity (TEAC)/g, respectively), and the highest reducing power (determined using the FRAP method; 249.46 mu Mol TEAC/g). The Bordeaux variety showed the highest oxidation inhibition power (41.13%), determined using the beta-carotene/linoleic acid method and the highest content of total anthocyanins (HPLC; 29.17 mg/g). Catechin was the most abundant non-anthocyanic compound identified in the grape pomace (150.16 mg/100 g) for all varieties. In this study, pomaces of the red wine vinification of Cabernet Sauvignon and Bordeaux varieties showed the highest potential as a source of antioxidant compounds and natural colourants, respectively. (C) 2011 Elsevier Ltd. All rights reserved.

Bixin and lycopene modulation of free radical generation induced by cisplatin-DNA interaction

This work evaluated the Modulation of reactive oxygen species (ROS) produced by the cisplatin-human DNA interaction in a cell-free experimental model by the carotenoids bixin and lycopene extracted from, natural dietary Sources and purified through luminol- and Cypridina luciferin methoxy-analogue (MCLA)- enhanced chemiluminescence assays. The results showed that the ROS generation by DNA-cisplatin interaction was inhibited by both lycopene and bixin in a concentration-dependent manner. At a concentration of 100 mu M, lycopene and bixin inhibited Superoxide anion (O center dot(2)) generation at 90% and 82%, respectively, and the total ROS generation at 44% and 42%, respectively. The formation of significant amounts of isomers or degradation products of both carotenoids was not observed after ROS scavenging, as evaluated by high-performance liquid chromatography. Taken together, these results Suggest that carotenoids can be helpful to Modulate the oxidative stress found in cancer therapy with cisplatin. (c) 2008 Elsevier Ltd. All rights reserved.

Antioxidant Activity of Uruguayan Propolis. In Vitro and Cellular Assays

The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than those of other natural products (8000 mu mol Trolox equiv/g propolis). ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteu method) and UV absorption. Total polyphenol content (150 mg gallic acid equiv/g propolis) and flavonoids (45 mg quercetin equiv/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis. Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low-density lipoprotein lipoperoxidation and tyrosine nitration. In addition, Uruguayan propolis was found to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase, suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.

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

In the scope of our ongoing researchers on antioxidant compounds, twenty four extracts and fractions obtained from Piper arboreum Aublet and Piper tuberculatum Jacq. (Piperaceae) were screened for radical scavenging capacity (RSC) by using DPPH colorimetric assay. The strongest activity was found in ethyl acetate fractions from the leaves of P. arboreum IC(50) = 5.70 mu g/mL) and P. tuberculatum IC(50) = 8.40 mu g/mL). Hydromethanol fractions of the leaves of P. tuberculatum and P. arboreum showed moderate RSC, with values of IC(50) (mu g/mL) of 11.9 and 19.2, respectively. Additionally, a brief phytochemical study of the ethyl acetate fraction of P. arboreum leaves affording quercetin (1) and quercitrin (2), two flavonols with antioxidant activity previously described in the literature.

Caracterização físico-química de polpas de frutos da Amazônia e sua correlação com a atividade anti-radical livre

Características físico-químicas (cor, pH, acidez total titulável, sólidos solúveis totais, conteúdo de lipídios e umidade) e níveis de compostos bioativos (ácido ascórbico, fenólicos totais) foram determinados em quinze amostras de polpas de frutos procedentes da região Amazônica (abiu, acerola, açaí, araçá-boi, bacaba, bacuri, buriti, cajá, cajarana, caju, cupuaçu, graviola, murici, noni e tamarindo). A atividade de radicais livres foi avaliada pelo método de ABTS. Algumas polpas apresentaram alta potencialidade antioxidante, associada com a atividade antirradicais livres obtida e os conteúdos dos componentes bioativos como compostos fenólicos e ácido ascórbico, destacando-se acerola e acaí. O conteúdo total de compostos fenólicos foi correlacionado à capacidade antioxidante das polpas.

Evaluation of Indigenous Grains from the Peruvian Andean Region for Antidiabetes and Antihypertension Potential Using In Vitro Methods

The health-relevant functionality of 10 thermally processed Peruvian Andean grains (five cereals, three pseudocereals, and two legumes) was evaluated for potential type 2 diabetes-relevant antihyperglycemia and antihypertension activity using in vitro enzyme assays. Inhibition of enzymes relevant for managing early stages of type 2 diabetes such as hyperglycemia-relevant alpha-glucosidase and alpha-amylase and hypertension-relevant angiotensin I-converting enzyme (ACE) were assayed along with the total phenolic content, phenolic profiles, and antioxidant activity based on the 1,1-diphenyl-2-picrylhydrazyl radical assay. Purple corn (Zea mays L.) (cereal) exhibited high free radical scavenging-linked antioxidant activity (77%) and had the highest total phenolic content (8 +/- 1 mg of gallic acid equivalents/g of sample weight) and alpha-glucosidase inhibitory activity (51% at 5 mg of sample weight). The major phenolic compound in this cereal was protocatechuic acid (287 +/- 15 mu g/g of sample weight). Pseudocereals such as Quinoa (Chenopodium quinoa Willd) and Kaniwa (Chenopodium pallidicaule Aellen) were rich in quercetin derivatives (1,131 +/- 56 and 943 +/- 35 mu g [expressed as quercetin aglycone]/g of sample weight, respectively) and had the highest antioxidant activity (86% and 75%, respectively). Andean legumes (Lupinus mutabilis cultivars SLP-1 and H-6) inhibited significantly the hypertension-relevant ACE (52% at 5 mg of sample weight). No alpha-amylase inhibitory activity was found in any of the evaluated Andean grains. This in vitro study indicates the potential of combination of Andean whole grain cereals, pseudocereals, and legumes to develop effective dietary strategies for managing type 2 diabetes and associated hypertension and provides the rationale for animal and clinical studies.

Seasonal Variation, Chemical Composition and Antioxidant activity of Brazilian Propolis Samples

Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin-Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Candido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginopolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being alpha-and beta-amyrins. Methanolic extracts from Itapecerica and Paula Candido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginopolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis.

Single reaction interface flow system for chemiluminescent monitoring of mannitol based on its hydroxyl radical scavenger activity

A single reaction interface flow analysis (SIFA) system for the monitoring of mannitol in pharmaceutical formulations and human urine is presented. The developed approach takes advantage of the mannitol scavenger aptitude to inhibit the chemiluminescent reaction between luminol and myoglobin in the absence of H(2)O(2). The SIFA system facilitated the fully automation of the developed methodology, allowing the in-line reproducible handling of chemical species with a very short lifetime as is the case of the hydroxyl radical generated in the abovementioned luminol/myoglobin reaction. The proposed methodology allowed the determination of mannitol concentrations between 25 mmol L(-1) and 1 mol L(-1), with good precision (R.S.D. < 4.7%, n = 3) and a sampling frequency of about 60 h(-1). The procedure was applied to the determination of mannitol in pharmaceuticals and in human urine samples Without any pretreatment process. The results obtained for pharmaceutical formulations were statistically comparable to those provided by the reference method (R.D. < 4.6%); recoveries values obtained in the analysis of spiked urine samples (between 94.9 and 105.3% of the added amount) were also satisfactory. (C) 2008 Elsevier B.V. All rights reserved.

Comparative study on free-running locomotor activity circadian rhythms in Brazilian subterranean fishes with different degrees of specialization to the hypogean life (Teleostei: Siluriformes; Characiformes)

In this paper we report findings on the presence of circadian rhythms in six species of cave-dwelling fishes from Brazil. Locomotor activity of islolated individuals was automatically recorded for 10 consecutive days under constant darkness. The species tested show varied degrees of specialization to subterranean life and we found varying degrees of the circadian components of locomotor activity as measured by the periodogram algorhythm of Lomb-Scargle. Both the presence and robustness of the circadian components seem to vary according to the degree of specialization to subterranean life, the more specialized, the less circadian rhythmicity was detected.