Differential Effects of Betacyanin and Betaxanthin Pigments on Oxidative Stress and Inflammatory Response in Murine Macrophages.

SCOPE: Betalain pigments are increasingly highlighted for their bioactive and anti-inflammatory properties, although research is lacking to demonstrate contributions of individual betalains. The work herein aimed to compare effects of four main betalains on inflammatory and cell-protective markers and to highlight potential structure-related relationships of the two main subgroups: betacyanins vs betaxanthins. METHODS AND RESULTS: Murine RAW 264.7 macrophages were stimulated with bacterial lipopolysaccharide following incubation with betacyanins (betanin, neobetanin) and betaxanthins (indicaxanthin, vulgaxanthin I) in concentrations from 1 to 100 µM. All betalains suppressed expression of pro-inflammatory markers IL-6, IL-1ß, iNOS, and COX-2 with tendency for stronger effects of betacyanins compared to betaxanthins. In contrast, HO-1 and gGCS showed mixed and only moderate induction, while more emphasized effects were observed for betacyanins. While all betalains suppressed mRNA levels of NADPH oxidase 2 (NOX-2), a superoxide generating enzyme, only betacyanins were able to counteract hydrogen peroxide induced reactive oxygen species (ROS) generation, in alignment with their radical scavenging potential. Furthermore, betaxanthins exerted pro-oxidant properties, elevating ROS production beyond hydrogen peroxide stimulation. CONCLUSION: In summary, all betalains display anti-inflammatory properties, although only betacyanins demonstrate radical scavenging capacities, indicating potential differing responses under oxidative stress conditions, which requires further research.

Characterization of betalain-loaded liposomes and its bioactive potential in vivo after ingestion.

Betalains are plant pigments characterized by showing a wide range of beneficial properties for health. Its bioactive potential has been studied for the first time after its encapsulation in liposomes and subsequent administration to the animal model Caenorhabditis elegans. Phenylalanine-betaxanthin and indoline carboxylic acid-betacyanin encapsulated at concentrations of 25 and 500 µM managed to reduce lipid accumulation and oxidative stress in the nematodes. Highly antioxidant betalains dopaxanthin and betanidin were also included in the survival analyses. The results showed that phenylalanine-betaxanthin was the most effective betalain by increasing the lifespan of C. elegans by 21.8%. In addition, the administration of encapsulated natural betanidin increased the nematodes' survival rate by up to 13.8%. The preservation of the bioactive properties of betalains manifested in this study means that the stabilization of the plant pigments through encapsulation in liposomes can be postulated as a new way for administration in pharmacological and food applications.

Amyloid-Beta Induces Different Expression Pattern of Tissue Transglutaminase and Its Isoforms on Olfactory Ensheathing Cells: Modulatory Effect of Indicaxanthin.

Herein, we assessed the effect of full native peptide of amyloid-beta (Aß) (1-42) and its fragments (25-35 and 35-25) on tissue transglutaminase (TG2) and its isoforms (TG2-Long and TG2-Short) expression levels on olfactory ensheathing cells (OECs). Vimentin and glial fibrillary acid protein (GFAP) were also studied. The effect of the pre-treatment with indicaxanthin from Opuntia ficus-indica fruit on TG2 expression levels and its isoforms, cell viability, total reactive oxygen species (ROS), superoxide anion (O2-), and apoptotic pathway activation was assessed. The levels of Nestin and cyclin D1 were also evaluated. Our findings highlight that OECs exposure to Aß(1-42) and its fragments induced an increase in TG2 expression levels and a different expression pattern of its isoforms. Indicaxanthin pre-treatment reduced TG2 overexpression, modulating the expression of TG2 isoforms. It reduced total ROS and O2- production, GFAP and Vimentin levels, inhibiting apoptotic pathway activation. It also induced an increase in the Nestin and cyclin D1 expression levels. Our data demonstrated that indicaxanthin pre-treatment stimulated OECs self-renewal through the reparative activity played by TG2. They also suggest that Aß might modify TG2 conformation in OECs and that indicaxanthin pre-treatment might modulate TG2 conformation, stimulating neural regeneration in Alzheimer's disease.

The Phytochemical Indicaxanthin Synergistically Enhances Cisplatin-Induced Apoptosis in HeLa Cells via Oxidative Stress-Dependent p53/p21waf1 Axis.

Combining phytochemicals with chemotherapics is an emerging strategy to treat cancer to overcome drug toxicity and resistance with natural compounds. We assessed the effects of indicaxanthin (Ind), a pigment obtained from Opuntia ficus-indica (L. Mill) fruit, combined with cisplatin (CDDP) against cervical cancer cells (HeLa). Measured cell viability via Trypan blue assay; cell morphology via fluorescence microscopy; apoptosis, cell cycle, mitochondrial membrane potential (MMP) and cell redox balance via flow-cytometry; expression levels of apoptosis-related proteins via western blot. Cell viability assays and Chou-Talalay plot demonstrated that the combination of CDDP and Ind had synergistic cytotoxic effects. Combined treatment had significant effects (p < 0.05) on phosphatidylserine externalization, cell morphological changes, cell cycle arrest, fall in MMP, ROS production and GSH decay compared with the individual treatment groups. Bax, cytochrome c, p53 and p21waf1 were over-expressed, while Bcl-2 was downregulated. Pre-treatment with N-acetyl-l-cysteine abolished the observed synergistic effects. We also demonstrated potentiation of CDDP anticancer activity by nutritionally relevant concentrations of Ind. Oxidative stress-dependent mitochondrial cell death is the basis of the chemosensitizing effect of Ind combined with CDDP against HeLa cancer cells. ROS act as upstream signaling molecules to initiate apoptosis via p53/p21waf1 axis. Ind can be a phytochemical of interest in combo-therapy.

Indicaxanthin, a multi-target natural compound from Opuntia ficus-indica fruit: From its poly-pharmacological effects to biochemical mechanisms and molecular modelling studies.

Over the latest years phytochemical consumption has been associated to a decreased risk of both the onset and the development of a number of pathological conditions. In this context indicaxanthin, a betalain pigment from Opuntia ficus-indica fruit, has been the object of sound research. Explored, at first, for its mere antioxidant potential, Indicaxanthin is now regarded as a redox-active compound able to exert significant poly-pharmacological effects against several targets in a number of experimental conditions both in vivo and in vitro. This paper aims to provide an overview on the therapeutical effects of indicaxanthin, ranging from the anti-inflammatory to the neuro-modulatory and anti-tumoral ones and favored by its high bioavailability. Moreover, biochemical and molecular modelling investigations are aimed to identify the pharmacological targets the compound is able to interact with and to address the challenging development in the future research.

Indicaxanthin from Opuntia ficus indica (L. Mill) Inhibits Oxidized LDL-Mediated Human Endothelial Cell Dysfunction through Inhibition of NF-κB Activation.

Oxidized low-density lipoproteins (oxLDL) play a pivotal role in the etiopathogenesis of atherosclerosis through the activation of inflammatory signaling events eventually leading to endothelial dysfunction and senescence. In the present work, we investigated the effects of indicaxanthin, a bioavailable, redox-modulating phytochemical from Opuntia ficus indica fruits, with anti-inflammatory activity, against oxLDL-induced endothelial dysfunction. Human umbilical vein cord cells (HUVEC) were stimulated with human oxLDL, and the effects of indicaxanthin were evaluated in a range between 5 and 20 µM, consistent with its plasma level after a fruit meal (7 µM). Pretreatment with indicaxanthin significantly and concentration-dependently inhibited oxLDL-induced cytotoxicity; ICAM-1, VCAM-1, and ELAM-1 increase; and ABC-A1 decrease of both protein and mRNA levels. From a mechanistic perspective, we also provided evidence that the protective effects of indicaxanthin were redox-dependent and related to the pigment efficacy to inhibit NF-κB transcriptional activity. In conclusion, here we demonstrate indicaxanthin as a novel, dietary phytochemical, able to exert significant protective vascular effects in vitro, at nutritionally relevant concentrations.

Extension of life-span using a RNAi model and in vivo antioxidant effect of Opuntia fruit extracts and pure betalains in Caenorhabditis elegans.

Betalains are nitrogenous plant pigments known for their high antioxidant capacity. For the first time, this antioxidant nature has been studied in an in vivo system using the model organism Caenorhabditis elegans. The oxidative stress caused in the fluorescent strain TJ375 (hsp-16.2::GFP) was reversed by the presence of both natural and semi-synthetic betalains, with an ED50 value around 25 µM for betacyanins and up to 10 µM for betaxanthins, with indicaxanthin, the major pigments in prickly pear fruits, as the most effective betalain. The effect of model betalains on the lifespan of the wild-type N2 strain was carefully studied using the automatic platform "Lifespan Machine". In a search for different approaches to suppress progeny, pop-1 RNAi was used to avoid FUdR use. The presence of betalains in the medium, both as pure compounds and as enriched Opuntia extracts significantly increased the lifespan of C. elegans.

Indicaxanthin from Opuntia Ficus Indica (L. Mill) impairs melanoma cell proliferation, invasiveness, and tumor progression.

BACKGROUND: A strong, reciprocal crosstalk between inflammation and melanoma has rigorously been demonstrated in recent years, showing how crucial is a pro-inflammatory microenvironment to drive therapy resistance and metastasis. PURPOSE: We investigated on the effects of Indicaxanthin, a novel, anti-inflammatory and bioavailable phytochemical from Opuntia Ficus Indica fruits, against human melanoma both in vitro and in vivo. STUDY DESIGN AND METHODS: The effects of indicaxanthin were evaluated against the proliferation of A375 human melanoma cell line and in a mice model of cutaneous melanoma. Cell proliferation was assessed by MTT assay, apoptosis by Annexin V-Fluorescein Isothiocyanate/Propidium Iodide staining, protein expression by western blotting, melanoma lesions were subcutaneously injected in mice with B16/F10 cells, chemokine release was quantified by ELISA. RESULTS: Data herein presented demonstrate that indicaxanthin effectively inhibits the proliferation of the highly metastatic and invasive A375 cells as shown by growth inhibition, apoptosis induction and cell invasiveness reduction. More interestingly, in vitro data were paralleled by those in vivo showing that indicaxanthin significantly reduced tumor development when orally administered to mice. The results of our study also clarify the molecular mechanisms underlying the antiproliferative effect of indicaxanthin, individuating the inhibition of NF-κB pathway as predominant. CONCLUSION: In conclusion, we demonstrated that indicaxanthin represents a novel phytochemical able to significantly inhibit human melanoma cell proliferation in vitro and to impair tumor progression in vivo. When considering the resistance of melanoma to the current therapeutical approach and the very limited number of phytochemicals able to partially counteract it, our findings may be of interest to explore indicaxanthin potential in further and more complex melanoma studies in combo therapy, i.e. where different check points of melanoma development are targeted.

Betaxanthins and antioxidant capacity in Stenocereus pruinosus: Stability and use in food.

Betalains are important pigments for the food, pharmaceutical, and cosmetics industry. In the yellow Stenocereus pruinosus fruits (pitayas), total betalain concentration, Folin-Ciocalteu reduction capacity, and antiradical capacity per dry weight were 2345.9µgg-1, 7.3mg gallic acid equivalentsg-1, and 48.8µmol Trolox equivalentg-1, respectively. The stability of betaxanthins, which represent 89% of total betalains in yellow pitayas, was evaluated over a range of pH, temperature, as well as in the presence of food additives. Maximum stability was observed at pH6.6, and addition of ascorbic acid increased the half-life 1.8 times. Thermal stability at pH6.48±0.05 was also evaluated from 50°C to 80°C, over which the activation energy for betaxanthin degradation was determined to be 66.2kJmol-1. Model gelatin gummies and beverages were then prepared with pitaya juice or pulp, and pigment retention and color parameters were investigated during storage under various conditions. To match the yellow color of commercial products, gummies were supplemented with 4.6% w/w juice or pulp, and beverages were supplemented with 5% w/v juice, achieving H° values of 69.0-86.2° and 64.6-87.1°, respectively. Results indicate that betaxanthins were more stable in gummies than in beverages, and that pigment retention increased when products were stored in the dark or at low temperatures. Also, different changes in color during storage were observed between gummies and beverages.

Phytochemical Indicaxanthin Inhibits Colon Cancer Cell Growth and Affects the DNA Methylation Status by Influencing Epigenetically Modifying Enzyme Expression and Activity.

BACKGROUND: Recently, we have shown anti-proliferative and pro-apoptotic effects of indicaxanthin associated with epigenetic modulation of the onco-suppressor p16INK4a in the human colon cancer cell line CACO2. In the present study, the epigenetic activity of indicaxanthin and the mechanisms involved were further investigated in other colorectal cancer cell lines. METHODS: LOVO1, CACO2, HT29, HCT116, and DLD1 cells were used to evaluate the potential influence of consistent dietary concentrations of indicaxanthin on DNA methylation, and the epigenetic mechanisms involved were researched. RESULTS: Indicaxanthin exhibited anti-proliferative activity in all cell lines but HT29, induced demethylation in the promoters of some methylation-silenced onco-suppressor genes involved in colorectal carcinogenesis (p16INK4a, GATA4, and ESR1), and left unchanged others which were basally hypermethylated (SFRP1 and HPP1). In apparent contrast, cell exposure to indicaxanthin increased DNMT gene expression, although indicaxanthin appeared to be an inhibitor of DNMT activity. Indicaxanthin also increased the expression of genes involved in DNA demethylation. Finally, an in silico molecular modelling approach suggested stable binding of indicaxanthin at the DNMT1 catalytic site. CONCLUSIONS: Our findings contribute to new knowledge in the field of phytochemicals and specifically suggest dietary indicaxanthin as a potential epigenetic agent to protect colon cells against tumoral alterations.

Indicaxanthin from Opuntia ficus-indica Crosses the Blood-Brain Barrier and Modulates Neuronal Bioelectric Activity in Rat Hippocampus at Dietary-Consistent Amounts.

Indicaxanthin is a bioactive and bioavailable betalain pigment from the Opuntia ficus-indica fruits. In this in vivo study, kinetic measurements showed that indicaxanthin is revealed in the rat brain within 1 h from oral administration of 2 µmol/kg, an amount compatible with a dietary consumption of cactus pear fruits in humans. A peak (20 ± 2.4 ng of indicaxanthin per whole brain) was measured after 2.5 h; thereafter the molecule disappeared with first order kinetics within 4 h. The potential of indicaxanthin to affect neural activities was in vivo investigated by a microiontophoretic approach. Indicaxanthin, administered in a range between 0.085 ng and 0.34 ng per neuron, dose-dependently modulated the rate of discharge of spontaneously active neurons of the hippocampus, with reduction of the discharge and related changes of latency and duration of the effect. Indicaxanthin (0.34 ng/neuron) showed inhibitory effects on glutamate-induced excitation, indicating activity at the level of glutamatergic synapses. A molecular target of indicaxanthin is suggested by in silico molecular modeling of indicaxanthin with N-methyl-D-aspartate receptor (NMDAR), the most represented of the glutamate receptor family in hippocampus. Therefore, at nutritionally compatible amounts indicaxanthin (i) crosses the rat BBB and accumulates in brain; (ii) can affect the bioelectric activity of hippocampal neurons locally treated with amounts comparable with those measured in the brain; and (iii) modulates glutamate-induced neuronal excitation. The potential of dietary indicaxanthin as a natural neuromodulatory agent deserves further mechanistic and neurophysiologic investigation.

Pro-oxidant activity of indicaxanthin from Opuntia ficus indica modulates arachidonate metabolism and prostaglandin synthesis through lipid peroxide production in LPS-stimulated RAW 264.7 macrophages.

Macrophages come across active prostaglandin (PG) metabolism during inflammation, shunting early production of pro-inflammatory towards anti-inflammatory mediators terminating the process. This work for the first time provides evidence that a phytochemical may modulate the arachidonate (AA) metabolism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, promoting the ultimate formation of anti-inflammatory cyclopentenone 15deoxy-PGJ2. Added 1 h before LPS, indicaxanthin from Opuntia Ficus Indica prevented activation of nuclear factor-κB (NF-κB) and over-expression of PGE2 synthase-1 (mPGES-1), but up-regulated cyclo-oxygenase-2 (COX-2) and PGD2 synthase (H-PGDS), with final production of the anti-inflammatory cyclopentenone. The effects were positively related with concentration between 50 and 100 µM. Indicaxanthin did not have any effect in the absence of LPS. A kinetic study investigating the redox status of LPS-stimulated macrophages between 0.5 and 12 h, either in the absence or in the presence of 50-100 µM indicaxanthin, revealed a differential control of ROS production, with early (0.5-3 h) modest inhibition, followed by a progressive (3-12 h) concentration-dependent enhancement over the level induced by LPS alone. In addition, indicaxanthin caused early (0.5-3 h) concentration-dependent elevation of conjugated diene lipid hydroperoxides, and production of hydroxynonenal-protein adducts, over the amount induced by LPS. In LPS-stimulated macrophages indicaxanthin did not affect PG metabolism when co-incubated with either an inhibitor of NADPH oxidase or vitamin E. It is concluded that LPS-induced pro-oxidant activity of indicaxanthin at the membrane level allows formation of signaling intermediates whose accumulation modulates PG biosynthetic pathway in inflamed macrophages.

Anti-proliferative and pro-apoptotic activity of whole extract and isolated indicaxanthin from Opuntia ficus-indica associated with re-activation of the onco-suppressor p16(INK4a) gene in human colorectal carcinoma (Caco-2) cells.

Phytochemicals may exert chemo-preventive effects on cells of the gastro-intestinal tract by modulating epigenome-regulated gene expression. The effect of the aqueous extract from the edible fruit of Opuntia ficus-indica (OFI extract), and of its betalain pigment indicaxanthin (Ind), on proliferation of human colon cancer Caco-2 cells has been investigated. Whole extract and Ind caused a dose-dependent apoptosis of proliferating cells at nutritionally relevant amounts, with IC50 400±25 mg fresh pulp equivalents/mL, and 115±15 µM (n=9), respectively, without toxicity for post-confluent differentiated cells. Ind accounted for ∼80% of the effect of the whole extract. Ind did not cause oxidative stress in proliferating Caco-2 cells. Epigenomic activity of Ind was evident as de-methylation of the tumor suppressor p16(INK4a) gene promoter, reactivation of the silenced mRNA expression and accumulation of p16(INK4a), a major controller of cell cycle. As a consequence, decrease of hyper-phosphorylated, in favor of the hypo-phosphorylated retinoblastoma was observed, with unaltered level of the cycline-dependent kinase CDK4. Cell cycle showed arrest in the G2/M-phase. Dietary cactus pear fruit and Ind may have chemo-preventive potential in intestinal cells.

Indicaxanthin from cactus pear fruit exerts anti-inflammatory effects in carrageenin-induced rat pleurisy.

Nutritional research has shifted recently from alleviating nutrient deficiencies to chronic disease prevention. We investigated the activity of indicaxanthin, a bioavailable phytochemical of the betalain class from the edible fruit of Opuntia ficus-indica (L. Miller) in a rat model of acute inflammation. Rat pleurisy was achieved by injection of 0.2 mL of λ-carrageenin in the pleural cavity, and rats were killed 4, 24, and 48 h later; exudates were collected to analyze inflammatory parameters, such as nitric oxide (NO), prostaglandin E(2) (PGE(2)), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α); cells recruited in pleura were analyzed for cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) expression, and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) activation. Indicaxanthin (0.5, 1, or 2 µmol/kg), given orally before carrageenin, time- and dose-dependently, reduced the exudate volume (up to 70%) and the number of leukocytes recruited in the pleural cavity (up to 95%) at 24 h. Pretreatment with indicaxanthin at 2 µmol/kg inhibited the carrageenin-induced release of PGE(2) (91.4%), NO (67.7%), IL-1ß (53.6%), and TNF-α (71.1%), and caused a decrease of IL-1ß (34.5%), TNF-α (81.6%), iNOS (75.2%), and COX2 (87.7%) mRNA, as well as iNOS (71.9%) and COX-2 (65.9%) protein expression, in the recruited leukocytes. Indicaxanthin inhibited time- and dose- dependently the activation of NF-κB, a key transcription factor in the whole inflammatory cascade. A pharmacokinetic study with a single 2 µmol/kg oral administration showed a maximum 0.22 ± 0.02 µmol/L (n = 15) plasma concentration of indicaxanthin, with a half-life of 1.15 ± 0.11 h. When considering the high bioavailability of indicaxanthin in humans, our findings suggest that this dietary pigment has the potential to improve health and prevent inflammation-based disorders.

Physical, chemical, and antioxidant activity characterization of pitaya (Stenocereus pruinosus) fruits.

Fruits with red and orange flesh of the columnar cactus pitaya (Stenocereus pruinosus) were studied to evaluate physical characteristics, total soluble solids, betalains and soluble phenols content, and antioxidant activity. Fruits had, in average, weight of 179.0 g, 9.8 °Brix, 9.4 % carbohydrates, 1.25 % protein, 0.11 % ethereal extract, 0.60 % crude fiber, and 0.62 % ash. Also, fruits resulted rich in Fe (22.8-27.8 mg/kg). Hue angle and contents of betacyanins, betaxanthins (µg/g dry sample), and total soluble phenols (mg GAE/g fresh sample) were 19.8°, 2860.0, 3210.0, and 1.6 in the red material, and 28.9°, 470.0, 2670.0, and 1.2, respectively, in the orange fruit. The antioxidant capacity was higher in the red material, since the ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) technique reported 1090.6 and 735.4 µmol of Trolox equivalents/g fresh flesh in red and orange fruits, respectively, while the oxygen radical absorbance capacity (ORAC) assay reported 7.84 and 5.16 µmol of Trolox equivalents/g fresh flesh, respectively. The chromatographic profile showed five betalains in red fruits, but only four of them were observed in those orange fleshed.

Phytochemical indicaxanthin suppresses 7-ketocholesterol-induced THP-1 cell apoptosis by preventing cytosolic Ca(2+) 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 Ca²âº, with progressive depletion of total thiols. 7-KC-dependent activation of the redox-sensitive NF-κB was observed. Co-incubation of 2·5 µm 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-κB 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.

Inhibitory effects of indicaxanthin on mouse ileal contractility: analysis of the mechanism of action.

Recently, we have showed that indicaxanthin, the yellow betalain pigment abundant in the fruit of Opuntia ficus indica, has remarkable spasmolytic effects on the intestinal contractility in vitro. Thus, the purpose of the present study was to investigate the mechanism of action underlying the observed response. We used organ bath technique to record the mechanical activity of the mouse ileum longitudinal muscle and ELISA to measure the levels of cAMP. Indicaxanthin induced inhibitory effects on spontaneous mechanical activity, which were unaffected by indomethacin, a non-selective inhibitor of cycloxygenase; 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a selective inhibitor of nitric oxide-dependent guanylyl cyclase; 2'5'dideoxyadenosine, an adenylyl cyclase inhibitor; and zaprinast, a selective inhibitor of the cGMP phosphodiesterase isoenzyme. Indicaxanthin effects were reduced significantly in the presence of 3-isobutyl-1-methylxanthine (IBMX), a non selective inhibitor of phosphodiesterases (PDEs). Indicaxanthin and IBMX significantly reduced the carbachol-evoked contractions and the joint application of both drugs did not produce any additive effect. Indicaxanthin and IBMX increased the inhibitory effects of forskolin, an adenylyl cyclase activator, and the joint application of both drugs did not produce any additive effect. Indicaxanthin, contrarily to IBMX, did not affect the inhibitory action of sodium nitroprusside, a soluble guanylyl cyclase activator. Indicaxanthin increased both basal and forskolin-induced cAMP content of mouse ileal muscle. The present data show that indicaxanthin reduces the contractility of ileal longitudinal muscle by inhibition of PDEs and increase of cAMP concentration and raise the possibility of using indicaxanthin in the treatment of motility disorders, such as abdominal cramps.

Inhibition of the mechanical activity of mouse ileum by cactus pear (Opuntia Ficus Indica, L, Mill.) fruit extract and its pigment indicaxanthin.

We investigated, using an organ bath technique, the effects of a hydrophilic extract from Opuntia ficus indica fruit pulp (cactus fruit extract, CFE) on the motility of mouse ileum, and researched the extract component(s) responsible for the observed responses. CFE (10-320 mg of fresh fruit pulp equivalents/mL of organ bath) reduced dose-dependently the spontaneous contractions. This effect was unaffected by tetrodotoxin, a neuronal blocker, N(omega)-nitro-l-arginine methyl ester, a nitric oxide synthase blocker, tetraethylammonium, a potassium channel blocker, or atropine, a muscarinic receptor antagonist. CFE also reduced the contractions evoked by carbachol, without affecting the contractions evoked by high extracellular potassium. Indicaxanthin, but not ascorbic acid, assayed at concentrations comparable with their content in CFE, mimicked the CFE effects. The data show that CFE is able to exert direct antispasmodic effects on the intestinal motility. The CFE inhibitory effects do not involve potassium channels or voltage-dependent calcium channels but rather pathways of calcium intracellular release. The fruit pigment indicaxanthin appears to be the main component responsible for the CFE-induced effects.

Cytoprotective effects of the antioxidant phytochemical indicaxanthin in beta-thalassemia red blood cells.

Antioxidant phytochemicals are investigated as novel treatments for supportive therapy in beta-thalassemia. The dietary indicaxanthin was assessed for its protective effects on human beta-thalassemic RBCs submitted in vitro to oxidative haemolysis by cumene hydroperoxide. Indicaxanthin at 1.0-10 microM enhanced the resistance to haemolysis dose-dependently. In addition, it prevented lipid and haemoglobin (Hb) oxidation, and retarded vitamin E and GSH depletion. After ex vivo spiking of blood from thalassemia patients with indicaxanthin, the phytochemical was recovered in the soluble cell compartment of the RBCs. A spectrophotometric study showed that indicaxanthin can reduce perferryl-Hb generated in solution from met-Hb and hydrogen peroxide (H2O2), more effectively than either Trolox or vitamin C. Collectively our results demonstrate that indicaxanthin can be incorporated into the redox machinery of beta-thalassemic RBC and defend the cell from oxidation, possibly interfering with perferryl-Hb, a reactive intermediate in the hydroperoxide-dependent Hb degradation. Opportunities of therapeutic interest for beta-thalassemia may be considered.