Suppressive effects of rutin, quercitrin, and isoquercitrin on atypical allergic asthma in an animal model

Quercetin and isoquercitrin were reported to have anti-inflammatory effects on typical asthma. Therefore, we investigated quercetin-3-O-glycosides to clarify the potential for treating atypical asthma. The inhibitions of quercetin-3-O-glycosides on PDE1–5 activities and on high-affinity rolipram binding sites were measured. The sensitized guinea-pig trachealis was challenged by ovalbumin (OVA) to induce contractions. Ten female BABL/c mice in each group were sensitized by OVA on days 0 and 14. On day 21, these mice were injected a mixture of 1% OVA and Freund’s complete adjuvant (1:1). Mice were challenged using 1% OVA in saline for 30 min on days 28, 29, and 30 by ultrasonic nebulization. Twenty-four hours after the last nebulization, the blood and bronchoalveolar lavage fluid (BALF) of these mice were collected. Total immunoglobulin (Ig)E or IgG_2a level in the serum and cytokines in the both were determined. The number of inflammatory cells was counted using a hemocytometer. Rutin (30 and100 μmol/kg, p.o.) and quercitrin (100 μmol/kg, p.o.) significantly suppressed the increases in the inflammatory cells and cytokines in the BALF of mice. In contrast to rutin, quercitrin significantly increased the IFN-γ level. Both significantly increased the IgG_2a level in the serum and suppressed total and OVA-specific IgE levels in the serum and BALF of mice. Rutin, quercitrin, and isoquercitrin did not affect xylazine/ketamine-induced anesthesia. In conclusion, the above results suggest that quercetin-3-O-glycosides have few adverse effects and that rutin and quercitrin, but not isoquercitrin, may have the potential for treating atypical asthma.