Studies On The Molecular Mechanism Of β-Cryptoxanthin On Anti-Cancer And Immune Enhancing Effects

Stress is inevitable in the process of transfer and transport of animals, while excessive stress is capable to cause stress related diseases, such as acute diarrhoea and sudden death. Therefore, effective anti-stress measures (e.g., nutrition regulation) should be adopted to protect the health of animals during transfer and transport and enhance animal productivity.Carotenoids are obtained from the diet in humans, and approximately 12 types are measurable in blood and other tissues, including seven predominant carotenoids as lycopene, lutein, α-carotene, β-carotene, zeaxanthin, α-cryptoxanthin, and β-cryptoxanthin. β-Cryptoxanthin, a major carotenoid that is rich in mandarin fruits, holds promise to be a chemopreventive agent against serious diseases including stomach cancer, and the anti-atherogenesis and anti-obesity effects of β-cryptoxanthin have recently been reported. There are plenty citrus fruits resources in China with first cultivated area and first outcome of the whole world, it would be meaningful for the exploration of citrus processing. So it has very important strategic significance to make comprehensive studies on the effects of β-cryptoxanthin from citrus fruits on the human health.The objective of this study was to gain insight into the dose-dependent anti-proliferative activity of β-cryptoxanthin from mandarin fruit in vitro system, using BGC-823 stomach cancer cells, furthermore an association was determined among different concentrations of β-cryptoxanthin on the induction of the mRNA levels of RARβ and provide strong evidence that β-cryptoxanthin can be active uptaken in THP-1 macrophages and exhibits anti-atherogenic effect on THP-1 macrophages by inducing CYP27A1 expression via RAR. The results are as follows:1 Purification of carotenoids β-cryptoxanthin from citrus fruitsCarotenoids in Citrus.unshiu Marc.cv.Guoqing No.1 were extracted with a mixture of methanol, acetone and petroleum ether (1:1:1, v/v/v). Then one of the major carotenoids, named β-cryptoxanthin, was separated by thin layer chromatography (TLC) and prepare high performance liquid chromatography. The purified fraction was analyzed by HPLC-APCI-MS (high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry). The identification of β-cryptoxanthin was also carried out by comparing their spectroscopic and chromatographic characteristics with standard carotenoid, respectively.2 The chemopreventive effect of β-cryptoxanthin from mandarin on human stomach cells (BGC-823)(3-Cryptoxanthin, a provitaminic carotenoid, present in many fruits and vegetables, has been associated with decreased risk of chronic diseases including cancer. The influence of β-cryptoxanthin derived from mandarin on the proliferation of the stomach tumour cell line BGC-823 was tested using MTT and cell count assay at 72 h and dose-response (from 0.01 to 20 μM). P-Cryptoxanthin suppressed the cell migration by the scratch assay. Furthermore, P-cryptoxanthin induced an accumulation of cells in the G1/G0 phase of the cell cycle (as detected by flow cytometry), which was in accordance with an increased expression of p21 and down regulations of cyclinD1 and cyclinE detected by Western blot analysis, and the mRNA levels of retinoic acid receptor β (RARβ) was increased significantly by treatment with β-cryptoxanthin at 10 μM for 24 h. Collectively, the above findings suggest that P-cryptoxanthin could be therapeutic in the treatment of stomach cancer cell in vitro.3 β-Cryptoxanthin uptake in THP-1 macrophases up induces CYP27A1 signaling pathway via RARCYP27A1, an enzyme with several important roles in cholesterol homeostasis and vitamin D3 metabolism, has been ascribed anti-atherogenie properties. Many studies suggest that ATRA can be used for the treatment of atherogenesis, which upregulating the expression of CYP27A1 by RAR. We hypothesized that β-cryptoxanthin, as a natural ligand of RAR, can be also anti-atherognesis by upregulating CYP27A1, which is benefit for the choice of the treatment of atherogensis.We found that P-cryptoxanthin treatment significantly increased genes, involving in the uptake, transport and metabolism of retinoids and the signaling pathway of CYP27A1, expression in THP-1 macrophages by microarray analysis. Meanwhile, intracellular levels of P-cryptoxanthin were correlation to the concentration of exposure medium. The expression of genes, involving in signaling pathway of CYP27A1, was dramatically decreased by repressing the activity of RAR. Higher 27-hydroxycholesterol was detected in P-cryptoxanthin treated macrophages by HPLC. Docking simulation showed that P-cryptoxanthin can interact with CRABP2. These findings further confirmed the microarray results. Our results provide strong evidence that β-cryptoxanthin can be active uptaken in THP-1 macrophages and exhibits anti-atherogenic effect on THP-1 macrophages by inducing CYP27A1 expression via RAR.