Preventative effect of a flavonoid, enzymatically modified isoquercitrin on ocular symptoms of Japanese cedar pollinosis.
BACKGROUND
Flavonoids are nutrients that exert anti-allergic effects. We investigated the preventative effect of enzymatically modified isoquercitrin (EMIQ), a flavonoid, to relieve the symptoms of Japanese cedar pollinosis.


METHODS
In a parallel-group, double-blind placebo-controlled study design, 24 subjects with Japanese cedar pollinosis took 100mg EMIQ or a placebo for 8 weeks, starting 4 weeks prior to the onset of pollen release. Subjective symptoms, ADL scores and the usage of drugs were recorded daily, and the QOL score was obtained every 4 weeks. Blood sampling was performed before and after the study to measure serum levels of IgE and flavonoids.


RESULTS
During the entire study period, ocular symptom + medication score for the EMIQ group was significantly lower (p < 0.05) than that of the placebo group. When limited to the period, ocular symptom scores (p < 0.05, weeks 5-6), and ocular congestion scores (p < 0.05, weeks 5-6) for the EMIQ group was significantly lower than that for the placebo group while other scores for the EMIQ group, such as ocular itching scores (p = 0.09, weeks 4-5), lacrimation scores (p = 0.07, weeks 5-6), and ocular congestion scores (p = 0.06, weeks 4-5), all tended to be lower. However no significant differences were found in nasal symptoms between the two groups. Serum concentrations of IgE were not significantly downregulated but the serum concentrations of quercetin and its derivatives were elevated significantly by the intake of EMIQ.


CONCLUSIONS
Intake of the quercetin glycoside EMIQ proved to be effective for the relief of ocular symptoms caused by Japanese cedar pollinosis.
Hirano
Toru
T
Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Osaka University Graduate School of Medicine, Osaka, Japan.
Kawai
Mari
M
Arimitsu
Junsuke
J
Ogawa
Masako
M
Kuwahara
Yusuke
Y
Hagihara
Keisuke
K
Shima
Yoshihito
Y
Narazaki
Masashi
M
Ogata
Atsushi
A
Koyanagi
Mihoko
M
Kai
Tomoko
T
Shimizu
Ryosuke
R
Moriwaki
Masamitsu
M
Suzuki
Yukio
Y
Ogino
Satoshi
S
Kawase
Ichiro
I
Tanaka
Toshio
T
D000328:Adult; D000485:Allergens / Q000009:adverse effects; D018926:Anti-Allergic Agents / Q000737:chemistry / Q000627:therapeutic use*; D003233:Conjunctivitis, Allergic / Q000209:etiology / Q000517:prevention & control*; D032485:Cryptomeria / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D005419:Flavonoids / Q000737:chemistry / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D011058:Pollen / Q000009:adverse effects; D011537:Pruritus / Q000209:etiology / Q000517:prevention & control*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000627:therapeutic use; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy* / Q000209:etiology; D013666:Tears / Q000187:drug effects
D000485:Allergens; D018926:Anti-Allergic Agents; D005419:Flavonoids; C016527:isoquercitrin; D011794:Quercetin