Narirutin Inhibits Airway Inflammation in an Allergic Mouse Model

Abstract

1. Flavonoids are naturally occurring compounds that possess anti-allergic, anti-inflammatory, antiproliferative and anti-oxidant properties. In the present study, we investigated whether the flavonoid narirutin could reduce airway inflammation in ovalbumin (OVA)-sensitized/challenged NC/Nga mice, a model of allergic eosinophilic airway inflammation. 2. Mice were initially immunized intraperitoneally with OVA on Days 0 and 7 and then challenged with inhaled OVA on Days 14, 15 and 16. In addition, some mice received narirutin orally at doses of 0.1, 1 or 10 mg/kg bodyweight daily on Days 7-16. 3. At 10 mg/kg, but not 0.1 or 1 mg/kg, narirutin significantly diminished OVA-induced airway inflammation caused by infiltration of lung tissue with inflammatory and mucus-producing cells, as well as reduced eosinophil counts in the peripheral blood and bronchoalveolar lavage fluid (BALF), interleukin (IL)-4 levels in BALF and IgE levels in serum. 4. The mechanism of the anti-inflammatory effect of narirutin are likely to be associated with a reduction in the OVA-induced increases of IL-4 and IgE in a murine model of allergic eosinophilic airway inflammation. These findings suggest that narirutin may be an effective new tool in the treatment of bronchial asthma.

Anti-inflammatory effects of flavonoids in Citrus jabara fruit peels

“…Thinking about the abundance ratio of flavonoids, narirutin is considered to contribute to antiinflam matory effect at oral ingestion of C. jabara fruit peels. Funaguchi et al also reported that oral administration of narirutin inhibited airway inflammation in allergic model mouse [25] . On the other hand, in vitro cell assay, narirutin did not exhibited enough anti-inflammatory effects (Figures 2-5) nor anti-degranulating effects [26] .…”

Effect of Enzymatically Modified Isoquercitrin, a Flavonoid, on Symptoms of Japanese Cedar Pollinosis: A Randomized Double-Blind Placebo-Controlled Trial

“…Furthermore, an epidemiologic study found that a higher intake of flavonoids was associated with a lower incidence of asthma [44]. In experimental models, oral administration of flavonoids has been demonstrated to prevent allergic diseases including asthma, anaphylaxis, food allergies and atopic dermatitis [16, 17,32,33,34,35,36,37]. This study showed that the ocular symptoms were reduced in the EMIQ group.…”

“…We and others have shown that some kinds of flavonoids including apigenin, fisetin, luteolin and quercetin suppress the expression of Th2-type (IL-4, IL-5 and IL-13) [13, 14], proinflammatory cytokines [31] and CD40 ligand [15] in basophils or in mast cells. In addition to these in vitro antiallergic activities, studies with allergic animal models have demonstrated that flavonoids exert preventative and therapeutic effects by modifying Th2-type cytokine expression and suppressing IgE elevation [16, 17,32,33,34,35,36,37]. In our study we measured the serum levels of cytokines and chemokines before and after the study but found no significant reduction in Th2 cytokines (IL-4, IL-5 and IL-13), chemokines (eotaxin) or IgE concentration as a result of EMIQ intake except for TARC (fig.…”

Efficacy of Flavonoids for Patients with Japanese Cedar Pollinosis

“…It was also found that nobiletin, a polymethoxyflavonoid, when given intraperitoneally to OVA-sensitized rats at a dose of 1.5 or 5 mg/kg, reduced OVA-induced increases in eosinophils and eotaxin expression (Wu et al, 2006). In subsequent investigations, flavonoids such as quercetin, isoquercitrin, rutin, 3-O-methylquercetin 5,7,3',4'-O-tetraacetate, narirutin, apigenin, luteolin, sulfuretin, hesperdin, fisetin and kaempferol have been shown to suppress responses in various types of allergic animals (Makino et al, 2001;Fernandez et al, 2005;Rogerio et al, 2007;Jung et al, 2007;Jiang et al, 2007;Funaguchi et al, 2007;Yano et al, 2007;Cruz et al, 2008;Choi et al, 2009;Li et al, 2010;Leemans et al, 2010;Shishebor et al, 2010;Kim et al, 2011;Wu et al, 2011;Gong et al, 2012).…”