Absorption, metabolism, and functions of ß-cryptoxanthin.

ß-Cryptoxanthin, a carotenoid found in fruits and vegetables such as tangerines, red peppers, and pumpkin, has several functions important for human health. Most evidence from observational, in vitro, animal model, and human studies suggests that ß-cryptoxanthin has relatively high bioavailability from its common food sources, to the extent that some ß-cryptoxanthin-rich foods might be equivalent to ß-carotene-rich foods as sources of retinol. ß-Cryptoxanthin is an antioxidant in vitro and appears to be associated with decreased risk of some cancers and degenerative diseases. In addition, many in vitro, animal model, and human studies suggest that ß-cryptoxanthin-rich foods may have an anabolic effect on bone and, thus, may help delay osteoporosis.

Daily intake of ß-cryptoxanthin prevents bone loss by preferential disturbance of osteoclastic activation in ovariectomized mice.

Although ß-cryptoxanthin, a xanthophyll carotenoid, has been shown to exert an anabolic effect on bone calcification, little attention has been paid thus far to the precise mechanism of bone remodeling. Daily oral administration of ß-cryptoxanthin significantly inhibited osteoclastic activation as well as reduction of bone volume in ovariectomized mice. In vitro studies revealed that ß-cryptoxanthin inhibited differentiation and maturation of osteoclasts by repression of the nuclear factor-κB-dependent transcriptional pathway. Our results suggest that supplementation with ß-cryptoxanthin would be beneficial for prophylaxis and for therapy of metabolic bone diseases associated with abnormal osteoclast activation.

ß-Cryptoxanthin Synergistically Enhances the Antitumoral Activity of Oxaliplatin through ΔNP73 Negative Regulation in Colon Cancer.

BACKGROUND: The acquired resistance to chemotherapy represents the major limitation in the treatment of cancer. New strategies to solve this failure and improve patients' outcomes are necessary. The cancer preventive effect of ß-cryptoxanthin has been widely described in population studies. Few reports support its putative use as an antitumoral compound. Here we focus on the therapeutic potential of ß-cryptoxanthin individually or in combination with oxaliplatin in colon cancer and try to decipher the molecular basis underlying its effect. METHODS: Apoptosis, viability and proliferation assays, mouse models, and an intervention study in 20 healthy subjects were performed. A PCR array was carried out to unravel the molecular putative basis of the ß-cryptoxanthin effect, and further signaling experiments were conducted. Comet Assay was completed to evaluate the genotoxicity of the treatments. RESULTS: ß-Cryptoxanthin differentially regulates the expression of the P73 variants in vitro, in vivo, and in a human intervention study. This carotenoid decreases the proliferation of cancer cells and cooperates with oxaliplatin to induce apoptosis through the negative regulation of ΔNP73. The antitumoral concentrations of oxaliplatin decrease in the presence of ß-cryptoxanthin to achieve same percentage of growth inhibition. The genotoxicity in peripheral blood mononuclear cells of mice decreased in the combined treatment. CONCLUSIONS: We propose a putative novel therapeutic strategy for the treatment of colon cancer based on the combination of ß-cryptoxanthin and oxaliplatin. The combined regimen produced more benefit than either individual modality without increasing side effects. In addition, the concentration-limiting toxicity of oxaliplatin is reduced in the presence of the carotenoid.

Multicarotenoids at Physiological Levels Inhibit Metastasis in Human Hepatocarcinoma SK-Hep-1 Cells.

Several studies have demonstrated that single carotenoid, including lycopene, ß-carotene, and α-carotene, exhibits antimetastatic effects; however, little is known whether multicarotenoids have similar effects. Herein, we investigated the antimetastatic effect of multicarotenoids at physiological serum levels in Taiwanese (MCT at 1.4 µM) and American (MCA at 1.8 µM) populations using human hepatocarcinoma SK-Hep-1 cells in comparison with single carotenoid, such as lycopene (0.3 or 0.6 µM, respectively), α-carotene (0.1 µM), ß-carotene (0.4 µM), lutein (0.4 or 0.5 µM, respectively), and ß-cryptoxanthin (0.2 µM). Results reveal that MCA treatment exhibited an additive inhibition on invasion, migration and adhesion at 24 and 48 h of incubation, whereas MCT treatment possessed additive inhibition at 48 h of incubation. The antimetastatic action of MCT and MCA involved additive reduction on activities of matrix metalloproteinase (MMP)-2, -9, and protein expression of Rho and Rac 1 but additive promotion on protein expression of tissue inhibitor of MMP (TIMP)-1 and -2. All of these effects were stronger in MCA than in MCT at 24 and 48 h of incubation. These results demonstrate that multi-carotenoids effectively inhibit metastasis of human hepatocarcinoma SK-Hep-1 cells. More in vivo studies are needed to confirm these findings.

[ß-Cryptoxanthin and the risk for lifestyle-related disease: findings from recent nutritional epidemiologic studies].

  Antioxidant micronutrients, such as vitamins and carotenoids, exist in abundance in fruits and vegetables and have been known to contribute to the body's defense against reactive oxygen species. Numerous recent epidemiologic studies have demonstrated that a high dietary consumption of fruit and vegetables rich in carotenoids or with high serum carotenoid concentrations results in lower risks of certain cancers, diabetes, and cardiovascular disease. These epidemiologic studies have suggested that antioxidant carotenoids may have a protective effect against several lifestyle-related diseases. ß-Cryptoxanthin is a carotenoid pigment found in Japanese mandarin (Citrus unshiu MARC.) fruit, which is mainly produced in Japan. Our nutritional epidemiologic survey, the Mikkabi Study, utilized data derived from health examinations of inhabitants performed in the town of Mikkabi in Shizuoka, Japan. In this survey, we measured serum ß-cryptoxanthin as a specific biomarker to estimate the consumption of Japanese mandarin fruit. From the cross-sectional analyses from the Mikkabi Study, we found inverse associations of serum ß-cryptoxanthin with the risks for atherosclerosis, insulin resistance, liver dysfunction, metabolic syndrome, low bone mineral density, and oxidative stress. In this review, recent epidemiologic studies about the associations between serum ß-cryptoxanthin with the risk for several lifestyle-related diseases were reviewed.

Prevention and reversal of lipotoxicity-induced hepatic insulin resistance and steatohepatitis in mice by an antioxidant carotenoid, ß-cryptoxanthin.

Excessive hepatic lipid accumulation promotes macrophages/Kupffer cells activation, resulting in exacerbation of insulin resistance and progression of nonalcoholic steatohepatitis (NASH). However, few promising treatment modalities target lipotoxicity-mediated hepatic activation/polarization of macrophages for NASH. Recent epidemiological surveys showed that serum ß-cryptoxanthin, an antioxidant carotenoid, was inversely associated with the risks of insulin resistance and liver dysfunction. In the present study, we first showed that ß-cryptoxanthin administration ameliorated hepatic steatosis in high-fat diet-induced obese mice. Next, we investigated the preventative and therapeutic effects of ß-cryptoxanthin using a lipotoxic model of NASH: mice fed a high-cholesterol and high-fat (CL) diet. After 12 weeks of CL diet feeding, ß-cryptoxanthin administration attenuated insulin resistance and excessive hepatic lipid accumulation and peroxidation, with increases in M1-type macrophages/Kupffer cells and activated stellate cells, and fibrosis in CL diet-induced NASH. Comprehensive gene expression analysis showed that ß-cryptoxanthin down-regulated macrophage activation signal-related genes significantly without affecting most lipid metabolism-related genes in the liver. Importantly, flow cytometry analysis revealed that, on a CL diet, ß-cryptoxanthin caused a predominance of M2 over M1 macrophage populations, in addition to reducing total hepatic macrophage and T-cell contents. In parallel, ß-cryptoxanthin decreased lipopolysaccharide-induced M1 marker mRNA expression in peritoneal macrophages, whereas it augmented IL-4-induced M2 marker mRNA expression, in a dose-dependent manner. Moreover, ß-cryptoxanthin reversed steatosis, inflammation, and fibrosis progression in preexisting NASH in mice. In conclusion, ß-cryptoxanthin prevents and reverses insulin resistance and steatohepatitis, at least in part, through an M2-dominant shift in macrophages/Kupffer cells in a lipotoxic model of NASH.

Effect of ß-cryptoxanthin plus phytosterols on cardiovascular risk and bone turnover markers in post-menopausal women: a randomized crossover trial.

BACKGROUND AND AIM: Post-menopausal women are at higher risk of cardiovascular disease and bone demineralization. Phytosterols (PS) may be used for hypercholesterolemia in some groups and ß-cryptoxanthin (ß-Cx) displays a unique anabolic effect on bone. Our aim was to assess the changes in cardiovascular and bone turnover markers from the oral intake of ß-Cx and PS in post-menopausal women. METHODS AND RESULTS: A randomized, double-blind, crossover study with ß-Cx (0.75 mg/day) and PS (1.5 g/day), single and combined, was performed in 38 postmenopausal women. Diet was supplemented with 1 × 250 mL milk-based fruit drink/day for 4 weeks with a wash-out period of 4-weeks in between. Serum ß-Cx and PS were determined by UPLC and CG-FID respectively. Outcome variables included markers of bone turnover and cardiovascular risk. Biological effect was assessed by paired t test and generalized estimating equations analysis that included the previous treatment, the order of intervention and the interactions. The intake of beverages containing ß-Cx and PS brought about a significant increase in serum levels of ß-Cx, ß-sitosterol and campesterol. Intervention caused changes in almost all the markers while the order, previous treatment and the interaction did not reach statistical significance. Only the intake of the beverage containing ß-Cx plus PS brought about significant decreases in total cholesterol, c-HDL, c-LDL and bone turnover markers. CONCLUSIONS: ß-Cx improves the cholesterol-lowering effect of PS when supplied simultaneously and this combination may also be beneficial in reducing risk of osteoporosis. CLINICAL TRIAL REGISTRY: ClinicalTrials.gov number NCT01074723.

ß-Cryptoxanthin alleviates diet-induced nonalcoholic steatohepatitis by suppressing inflammatory gene expression in mice.

Recent nutritional epidemiological surveys showed that serum ß-cryptoxanthin inversely associates with the risks for insulin resistance and liver dysfunction. Consumption of ß-cryptoxanthin possibly prevents nonalcoholic steatohepatitis (NASH), which is suggested to be caused by insulin resistance and oxidative stress from nonalcoholic fatty liver disease. To evaluate the effect of ß-cryptoxanthin on diet-induced NASH, we fed a high-cholesterol and high-fat diet (CL diet) with or without 0.003% ß-cryptoxanthin to C56BL/6J mice for 12 weeks. After feeding, ß-cryptoxanthin attenuated fat accumulation, increases in Kupffer and activated stellate cells, and fibrosis in CL diet-induced NASH in the mice. Comprehensive gene expression analysis showed that although ß-cryptoxanthin histochemically reduced steatosis, it was more effective in inhibiting inflammatory gene expression change in NASH. ß-Cryptoxanthin reduced the alteration of expression of genes associated with cell death, inflammatory responses, infiltration and activation of macrophages and other leukocytes, quantity of T cells, and free radical scavenging. However, it showed little effect on the expression of genes related to cholesterol and other lipid metabolism. The expression of markers of M1 and M2 macrophages, T helper cells, and cytotoxic T cells was significantly induced in NASH and reduced by ß-cryptoxanthin. ß-Cryptoxanthin suppressed the expression of lipopolysaccharide (LPS)-inducible and/or TNFα-inducible genes in NASH. Increased levels of the oxidative stress marker thiobarbituric acid reactive substances (TBARS) were reduced by ß-cryptoxanthin in NASH. Thus, ß-cryptoxanthin suppresses inflammation and the resulting fibrosis probably by primarily suppressing the increase and activation of macrophages and other immune cells. Reducing oxidative stress is likely to be a major mechanism of inflammation and injury suppression in the livers of mice with NASH.

Certain carotenoids enhance the intracellular glutathione level in a murine cultured macrophage cell line by inducing glutamate-cysteine-ligase.

SCOPE: Glutathione (GSH) increases in RAW264 murine macrophage cells exposed to ß-carotene or ß-cryptoxanthin, however, the underlying mechanism has not been clarified. In the present study, we investigated the expression of glutamate-cysteine-ligase (GCL), the rate-limiting enzyme in GSH synthesis, in these cells. METHODS AND RESULTS: Both the protein and mRNA expression of GCL increased in a ß-carotene concentration-dependent manner. Buthionine sulfoximine, a GCL inhibitor, abolished the ß-carotene-induced GSH increase without affecting the ß-carotene-induced GCL protein expression. Both cycloheximide, a translation inhibitor, and actinomycin D, a transcription inhibitor, completely suppressed the ß-carotene-induced GCL protein expression and the concomitant GSH increase. Actinomycin D inhibited the ß-carotene-induced Gcl mRNA expression as well. Similarly to ß-carotene, ß-cryptoxanthin upregulated the GCL protein expression, but lutein did not. The c-Jun N-terminal kinase (JNK) inhibitor, SP600125, suppressed the ß-carotene-induced GSH increase, whereas a p38 mitogen-activated protein kinase inhibitor or an extracellular signal-regulated kinase 1/2 inhibitor did not. The JNK inhibitor also suppressed the ß-carotene-induced GCL protein expression, and consistently ß-carotene induced JNK phosphorylation. CONCLUSION: These findings revealed that certain carotenoids induce the Gcl mRNA expression in RAW264 cells and subsequently the GCL protein expression, which concomitantly enhances the intracellular GSH level, in a JNK pathway-related manner.