title: In vitro effects of mangiferin on superoxide concentrations and expression of the inducible nitric oxide synthase, tumour necrosis factor-alpha and transforming growth factor-beta genes.
abstract: This study investigated the effects of the natural polyphenol mangiferin (MA) on superoxide anion (O(2)(-)) production, xanthine oxidase (XO) activity, vascular contractility, inducible nitric oxide synthase (iNOS) mRNA levels, tumour necrosis factor-alpha (TNF-alpha) mRNA levels, and tumour growth factor-beta (TGF-beta) mRNA levels. O(2)(-) was generated by the hypoxanthine-xanthine oxidase (HX-XO) and phenazine methosulphate (PMS)-NADH systems. XO activity was determined by measurement of uric acid production with xanthine as substrate. Vascular contraction experiments were performed with intact rat aortic rings. iNOS, TNF-alpha and TGF-beta gene expression in rat macrophages stimulated in vivo with 3% thioglycollate and in vitro with 100 ng/mL lipopolysaccharide and 10U/mL of interferon-gamma were evaluated semiquantitatively by the retrotranscriptase-polymerase chain reaction. MA at 10-100 microM, like the known O(2)(-) scavenger superoxide dismutase (1U/mL), scavenged O(2)(-) produced by the HX/XO and PMS-NADH systems. By contrast MA at 1-100 microM, unlike allopurinol (10 microM), was unable to inhibit XO activity. MA at 1-100 microM did not modify resting tone or the contractile responses elicited by 1 microM phenylephrine or 1 microM phorbol 12-myristate 13-acetate in rat aorta. MA at 1-100 microM, like dexamethasone (100 microM), decreased iNOS mRNA levels in activated macrophages. At 100 microM, MA also reduced TNF-alpha mRNA levels, but increased TGF-beta mRNA levels. These results thus indicate that MA is an O(2)(-) scavenger and that it inhibits expression of the iNOS and TNF-alpha genes, suggesting that it may be of potential value in the treatment of inflammatory and/or neurodegenerative disorders. In addition, the finding that MA enhances TGF-beta gene expression suggests that this polyphenol might also be of value in the prevention of cancer, autoimmune disorders, atherosclerosis and coronary heart disease.
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad de Santiago de Compostela, Spain. mpleiro@usc.es
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Leiro
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Alvarez
authors.forename: Juan Alberto
authors.initials: JA
authors.lastname: Arranz
authors.forename: Isabel González
authors.initials: IG
authors.lastname: Siso
authors.forename: Francisco
authors.initials: F
authors.lastname: Orallo
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000502:physiology; D008297:Male; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013481:Superoxides / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000187:drug effects / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000235:genetics*; D014966:Xanthenes / Q000494:pharmacology*; D044004:Xanthones
chemical_list: D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D014966:Xanthenes; D044004:Xanthones; D013481:Superoxides; C013592:mangiferin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat