Betanin inhibits the myeloperoxidase/nitrite-induced oxidation of human low-density lipoproteins

Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scavenger. In addition, unidentified oxidation product(s) of betanin by MPO/nitrite inhibit(s) the MPO/nitrite-induced LDL oxidation as effectively as the parent compound. In the light of betanin bioavailability and post-absorbtion distribution in humans, present findings may suggest favourable in vivo activity of this phytochemical

Absorption, excretion, and distribution of dietary antioxidant betalains in LDLs: potential health effects of betalains in humans

ABSTRACT Background: Betalains were recently identified as natural antioxidants. However, little is known about their bioavailability from dietary sources. Objective: The objective was to evaluate the bioavailability of betalains from dietary sources. Design: The plasma kinetics and urinary excretion of betalains were studied in healthy volunteers (n 8) after a single ingestion of 500 g cactus pear fruit pulp, which provided 28 and 16 mg indicaxanthin and betanin, respectively. The incorporation of betalains inLDLand the resistance of the particles to ex vivo–induced oxidation was also researched. Results: Betanin and indicaxanthin reached their maximum plasma concentrations 3 h after the fruit meal and declined according to first-order kinetics. The half-life of betanin (0.94 0.07 h) was shorter than that of indicaxanthin (2.36 0.17 h). Both compounds had disappeared from plasma by 12 h after intake. The urinary excretion of indicaxanthin and betanin over 12 h represented 76 3.0% and 3.7 0.2%, respectively, of the ingested compounds. LDL isolated 3 and 5 h after the fruit meal incorporated betalains at concentrations of 100.5 11and50 7.2pmol/mgLDLprotein, respectively. In addition, the particles appeared more resistant to ex vivo–induced oxidative injury than did the samples isolated before fruit ingestion (P 0.05)—the higher the amount of betalains incorporated, the higher the resistance. The concentrations of vitamin E and -carotene in LDL did not change significantly after fruit ingestion. Conclusion: Our results show that cactus pear fruit is a source of bioavailable betalains and suggest that indicaxanthin and betanin may be involved in the observed protection of LDL against ex vivo– induced oxidative modifications

Biothiols, taurine, and lipid-soluble antioxidants in the edible pulp of Sicilian cactus pear (Opuntia ficus-indica) fruits and changes of bioactive juice components upon industrial processing

Biothiols, taurine, and flavonols, as well as tocopherols and carotenoids have been assessed in the edible pulp of Sicilian red (Sanguigna), yellow (Surfarina), and white (Muscaredda) cultivars of cactus pear. The yellow cultivar has the highest level of reduced glutathione (GSH, 8.1 ( 0.78 mg/100 g pulp), whereas the white cultivar showed the highest amount of cysteine (1.21 ( 0.12 mg/100 g pulp). Taurine accounted for 11.7 ( 1.0 mg/100 g in the yellow pulp, while lower levels were measured in the others. With the exception of kaempferol in the yellow cultivar (2.7 ( 0.2 íg/100 g pulp), the edible pulp of cactus pear was not a source of flavonols. Very low amounts of lipid-soluble antioxidant vitamins such as vitamin E and carotenoids were measured in all cultivars. As a consequence of industrial processing, a total loss of GSH and â-carotene and a net decrease of vitamin C and cysteine were revealed in the fruit juice, whereas betalains, taurine, and vitamin E appeared to be less susceptible to degradation

Distribution of betalain pigments in red blood cells after consuption of cactus pear fruits and increased resistance of the cells to ex vivo induced oxidative hemolysis in humans

Betalain pigments are bioavailable phytochemicals recently acknowledged as natural radical scavengers. This work, which extends previous research on the postabsorbitive fate of dietary betalains, investigated the distribution of betanin and indicaxanthin in red blood cells (RBCs) isolated from healthy volunteers (n ) 8), before and during the 1-8 h interval after a cactus pear fruit meal, and the potential antioxidative activity of the pigments in these cells. A peak concentration of indicaxanthin (1.03 ( 0.2 íM) was observed in RBCs isolated at 3 h after fruit feeding, whereas the concentration at 5 h was about half, and even smaller amounts were measured at 8 h. Indicaxanthin was not detected at 1 h. Betanin (30.0 ( 5.2 nM) was found only in RBCs isolated at 3 h from fruit feeding. In comparison with homologous RBCs before fruit ingestion, a significant delay (P < 0.05) of the onset of an ex vivo cumene hydroperoxide (cumOOH)-induced hemolysis was evident in the RBCs isolated at 3 h (33.0 ( 4.5 min) and at 5 h (16.0 ( 2.0 min). Neither vitamins C and E nor GSH was modified in the RBCs at any time point. Blood collected from the same volunteers after a 12-h fasting was incubated with the purified betalains in the range of 5-25 íM, to enrich the erythrocytes with either betanin or indicaxanthin, and then the cells were exposed to cumOOH. When compared to the relevant nonenriched cells, the betalain-enriched erythrocytes exhibited an enhanced resistance to the cumOOH-induced hemolysis, which was positively correlated (r 2 ) 0.99) to the amount of the incorporated compound. On a micromolar basis, betanin and indicaxanthin showed a comparable effectiveness. Taken together, these findings provide evidence that human RBCs incorporate dietary betalains and support the concept that these phytochemicals may offer antioxidative protection to the cells

Phytochemical indicaxanthin suppresses 7-ketocholesterol-induced THP-1 cell apoptosis by preventing cytosolic Ca++ increase and oxidative stress

7-Ketocholesterol (7-KC)-induced apoptosis of macrophages is considered a key event in the development of human atheromas. In the present study, the effect of indicaxanthin (Ind), a bioactive pigment from cactus pear fruit, on 7-KC-induced apoptosis of human monocyte/macrophage THP-1 cells was investigated. A pathophysiological condition was simulated by using amounts of 7-KC that can be reached in human atheromatous plaque. Ind was assayed within a micromolar concentration range, consistent with its plasma level after dietary supplementation with cactus pear fruit. Pro-apoptotic effects of 7-KC were assessed by cell cycle arrest, exposure of phosphatidylserine at the plasma membrane, variation of nuclear morphology, decrease of mitochondrial trans-membrane potential, activation of Bcl-2 antagonist of cell death and poly(ADP-ribose) polymerase-1 cleavage. Kinetic measurements within 24 h showed early formation of intracellular reactive oxygen species over basal levels, preceding NADPH oxidase-4 (NOX-4) over-expression and elevation of cytosolic Ca2þ, with progressive depletion of total thiols. 7-KC-dependent activation of the redox-sensitive NF-kB was observed. Co-incubation of 2·5mM of Ind completely prevented 7-KC-induced pro-apoptotic events. The effects of Ind may be ascribed to inhibition of NOX-4 basal activity and over-expression, inhibition of NF-kB activation, maintaining cell redox balance and Ca homeostasis, with prevention of mitochondrial damage and consequently apoptosis. The findings suggest that Ind, a highly bioavailable dietary phytochemical, may exert protective effects against atherogenetic toxicity of 7-KC at a concentration of nutritional interest

Cactus pear fruit extract exerts anti-inflammatory effects in carrageenin-induced rat pleurisy

Nutritional research has recently shifted from alleviating nutrient deficiencies to chronic disease prevention. In this study activity of cactus pear fruit extract (CPFE) from Opuntia ficus-indica (L.) Mill. has been investigated in carrageenin-induced pleurisy, a rat model of acute inflammation. In our experimental design rat pleurisy was achieved by the injection of 0.2 ml of λ-carrageenin in the pleural cavity. At selected time points, rats were sacrificed; cells recruited in pleura were counted and exudates collected to analyse inflammatory parameters such as NO, PGE2, IL-1β, TNF-α. CPFE (in the range between 5 and 20 g fresh fruit equivalent/kg), orally given 30 min before the injection, time- and dose-dependently reduced the exudate volume (up to 72%) and the number of leukocytes recruited in the pleural cavity (up to 96%), at 24 h. These anti-inflammatory effects were accompanied by an inhibited release of inflammatory mediators (PGE2, NO, IL-1β, TNF-α). Our in vivo findings unveil for the first time an anti-inflammatory potential for cactus pear fruit and suggest further investigations to propose cactus pear fruit as a functional food able to improve health, possibly by preventing inflammation-based disorders. © 2015, International Society for Horticultural Science. All rights reserved

Pro-apoptotic activity of the phytochemical Indicaxanthin on colorectal carcinoma cells (Caco-2) and epigenetic CpG demethylation of the promoter and reactivation of the expression of p16

Phytochemicals play prominent roles in human diet and nutrition as protective redo-active substances in prevention of several disorders and chronic diseases in humans. Today, their function as potent modulators of the mammalian epigenome-regulated gene expression is rapidly emerging. In the present study antiproliferative effects of Indicaxanthin (Ind) from the fruits of Opuntia ficus-indica (1), and potential influence on DNA methylation has been investigated on Caco-2 cells, a human cell line of colorectal carcinoma. Ind caused a clear dose- and time-dependent decrease of the cell proliferation (IC(50) 50 M) associated to apoptosis as demonstrated by phosphatidylserine externalization and depolarization of mithocondrial membrane. Ind decreased the Go-G1phase whereas increased S and G2-M phases of the cell cycle. The phytochemical did not altered the intracellular ROS levels but decreased the [Ca2+]i. Investigation on DNA methylation using MESAP-PCR (Methylation-Sensitive Arbitrarily-Primed Polymerase Chain Reaction) (2), showed that 100 M Ind induced a slight global demethylation after a 48 h treatment. Analysis of epigenetic changes in the DNA methylation pattern at CpG promoter of p16 (INK4a), using MSRE (Methylation-Sensitive Restriction Endonucleases Multiplex-Polymerase Chain Reaction), showed that Ind caused CpG demethylation. Western blotting analysis carried out with p16 monoclonal antibody, confirmed the reactivation of the protein expression. Present data, suggesting that a long-term exposure to indicaxanthin in diet might potentially affect epigenetic machines of the intestinal cells, preventing or repairing initial derangements/disorders, encourage studies on the mechanism involved