Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2008
Publication Date: 9/25/2008
Citation: Manthey, J.A., Bendele, P. 2008. Anti-inflammatory activity of an orange peel polymethoxylated flavone, 3’,4’,3,5,6,7,8,-heptamethoxyflavone, in the rat carrageenan/paw edema and mouse Lipopolysaccharide-challenge assays. Journal of Agricultural and Food Chemistry. 56:9399-9403. Interpretive Summary: A compound from orange peel was evaluated for its ability to combat inflammation in two animal studies. These studies showed that when this compound was injected into rats and mice, it was very effective in lowering inflammation, but when given orally, this compound showed no activity. The reason for this latter lack of activity may be due to the conversion of the original compound into inactive derivatives bound to sugar acids.
Technical Abstract: The anti-inflammatory properties of 3',4',3,5,6,7,8-heptamethoxyflavone (HMF), a citrus polymethoxylated flavone, were studied in the bacterial lipopolysaccharide (LPS)-challenge/tumor necrosis factor-a (TNFa) response in mice, and in the carrageenan/paw edema assay in rats. In each of these trials, HMF administered by intraperitoneal (i.p.) injection exhibited anti-inflammatory activity, whereas HMF administered orally (p.o.) produced no effects. The inhibition observed in the LPS-challenge/TNFa assay correlated with the HMF levels in the blood sera of mice dosed (i.p.) with either 33 or 100 mg/kg body weight. Low levels of HMF (0.035±0.024 ppm) were detected in the blood sera of mice dosed orally (100 mg HMF (suspended in vegetable oil)/kg;), whereas i.p. injection led to higher levels (0.517±0.051 ppm). This may account for the different levels of anti-inflammatory effects observed in mice following i.p. versus oral HMF administration. HMF metabolites, including a number of mono- and di-demethylated HMF metabolites and their glucuronic acid conjugates were also detected, but results of these studies suggest that the glucuronidated metabolites of HMF are inactive in these inflammation models.