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

• Published in: International archives of allergy and immunology Vol. 149; no. 4; pp. 359 - 368
• Main Authors: Kawai, Mari, Hirano, Toru, Arimitsu, Junsuke, Higa, Shinji, Kuwahara, Yusuke, Hagihara, Keisuke, Shima, Yoshihito, Narazaki, Masashi, Ogata, Atsushi, Koyanagi, Mihoko, Kai, Tomoko, Shimizu, Ryosuke, Moriwaki, Masamitsu, Suzuki, Yukio, Ogino, Satoshi, Kawase, Ichiro, Tanaka, Toshio
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.01.2009; S. Karger AG
• Subjects: Adult; Allergies; Biological and medical sciences; Biomarkers - blood; Clinical outcomes; Cryptomeria - immunology; Cryptomeria japonica; Cytokines - blood; Double-Blind Method; Female; Flavonoids - administration & dosage; Flavonoids - chemistry; Flavonoids - therapeutic use; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunopathology; Male; Medical sciences; Middle Aged; Original Paper; Phytochemicals; Pollen; Pollen - immunology; Quercetin - administration & dosage; Quercetin - analogs & derivatives; Quercetin - chemistry; Quercetin - therapeutic use; Rhinitis, Allergic, Seasonal - drug therapy; Rhinitis, Allergic, Seasonal - immunology; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Trees; Asia; Japan; Pollinosis; Flavonoid; Quercetin; Immunopathology; Symptomatology; Polyphenol; Immunology; Phenols; Double blind study; Randomized controlled trial
• ISSN: 1018-2438; 1423-0097; 1423-0097
• DOI: 10.1159/000205582

Background: Flavonoids exert antiallergic and antioxidant effects. We investigated the efficacy of enzymatically modified isoquercitrin (EMIQ), a flavonoid, to relieve symptoms of pollinosis. Methods: In a parallel-group, double-blind placebo-controlled study design, 20 subjects with Japanese cedar pollinosis took two capsules daily of 100 mg EMIQ or a placebo for 8 weeks during the pollen season. Subjective symptoms and activities of daily living (ADL) scores were recorded every day, and the quality of life (QOL) score was obtained every 4 weeks. Blood sampling was performed before and after the study to measure serum cytokines, chemokines, IgE, quercetin and oxidized biomarkers. Results: During the entire study period, total ocular score and ocular itching score for the EMIQ group were significantly lower (p < 0.05) than for the placebo group. When limited to the individual periods, total symptom score for the EMIQ group was significantly lower (p < 0.05, week 4–5) than that for the placebo group while other scores for the EMIQ group, such as total nasal score (p = 0.06, week 4–5), nasal obstruction score (p = 0.08, week 4–5), lacrimation score (p = 0.06, week 5–6), ocular congestion score (p = 0.08, week 4–7) and ADL score (p = 0.08, week 4–7), all tended to be lower. The levels of serum cytokines such as interleukin (IL)-4, IL-5, IL-12, IL-13, interferon-γ, and eotaxin and IgE were not significantly downregulated by the intake of EMIQ but the serum concentrations of oxidized low-density lipoprotein and thymus and activation-regulated chemokine were reduced. Conclusion: Intake of the quercetin glycoside EMIQ was safe and influenced ocular symptoms caused by pollinosis.