β-Carotene is a naturally occuring retinol (vitamin A) precursor found in plants and fruits, used to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria.
β-Carotene (beta-carotene), a carotenoid compound, is a naturally-occurring vitamin A precursor. β-Carotene is a modulator of reactive oxygen species (ROS), with antioxidant and antiinflammatory activities. Hmox1 (heme oxygenase 1) mRNA, but not Cox2 (cyclooxygenase-2) and Nos2 (nitric oxide synthase 2) mRNA, was up-regulated by 100 μM β-carotene and lycopene, and by 0.125% TBB (Tri-n-butyl borane). LPS-stimulated Cox2, Nos2 and Tnfa gene expression was inhibited by 50 μM β-carotene and lycopene, and by 0.5-1% TBB. Both β-carotene and lycopene had weak antioxidant activity, but β-carotene showed pro-oxidant activity at higher concentrations[3]. beta-carotene significantly increased PPAR-gamma mRNA and protein levels in time-dependent manner. In addition, beta-carotene increased the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) expression and decreased the prostanoid synthesis rate-limiting enzyme cyclooxygenase-2 expression. Further, reactive oxygen species (ROS) production was induced by beta-carotene, resulting in mitochondrial dysfunction and cytochrome C release[4]. Furthermore, the combination of beta-carotene with ethanol results in hepatotoxicity. Moreover, in smokers who also consume alcohol, beta-carotene supplementation promotes pulmonary cancer and, possibly, cardiovascular complications. Thus ethanol, while promoting a deficiency of vitamin A also enhances its toxicity as well as that of beta-carotene[5]. Supplementation with β-carotene increases the risk of lung cancer in smokers regardless of the tar or nicotine content of cigarettes smoked[6].
Spain
... 展开 >> Department of Biochemistry and Molecular Biology II, Institute of Nutrition and Food Technology, Center for Biomedical Research, University of
Granada, Spain, 18071 收起 <<
Spain
... 展开 >> Department of Biochemistry and Molecular Biology II, Institute of Nutrition and Food Technology, Center for Biomedical Research, University of
Granada, Spain, 18071 收起 <<
Beta-carotene Bioavailability
... 展开 >>
Vitamin A Deficiency 收起 <<
Not Applicable
Completed
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United Kingdom
... 展开 >> Newcastle NIHR Clinical Research Facility, Royal Victoria Infirmary
Newcastle upon Tyne, Tyne & Wear, United Kingdom, NE1 4LP 收起 <<
United States, Wisconsin
... 展开 >>
University of Wisconsin Osteoporosis Clinical Research Program Clinic
Madison, Wisconsin, United States, 53705 收起 <<
Israel
... 展开 >> The Bert W. Strassburger Lipid Center,Sheba Medical Center
Recruiting
Tel-Hashomer, Israel, 52621
Principal Investigator: Shoshna Greenberger, MD
The Bert W. Strassburger Lipid Center
Recruiting
Tel-Hashomer, Israel, 52621
Sub-Investigator: Ofir Artzi, MD 收起 <<
Israel
... 展开 >> Goldschleger Eye Research Institute, Sheba Medical Center,
Not yet recruiting
Tel Hashomer, Israel, 52621
Contact: Ygal Rotenstreich, MD 972-3-530-2880 ygal.rotenstreich@sheba.health.gov.il 收起 <<
Indonesia
... 展开 >> Cipto Mangunkusumo General Hospital
Recruiting
Jakarta, DKI Jakarta, Indonesia, 12440
Contact: Yuyun Lisnawati, Consultant +628161841987 yulisna.er@gmail.com 收起 <<
Israel
... 展开 >> Sheba Medical Center
Recruiting
Tel Hashomer, Israel, 52621
Contact: Ygal Rotenstreich, Dr. 972-3-5302880
Principal Investigator: Ygal Rotenstreich, Dr. 收起 <<
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