Biological Effects of Quercetin in COPD

This study determines whether quercetin supplementation reduces the inflammation and oxidative stress markers in patients with chronic obstructive pulmonary disease. It is small study with 8 subjects receive quercetin 2000 mg/day and 4 subjects receive placebo.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder and affects millions of people globally. Although the exact mechanisms of pathogenesis of this disease are not well-understood, the general consensus is that oxidative stress and inflammation induced by exposure to cigarette smoke or other environmental or occupational hazards are responsible for development of COPD. Therefore, therapies aimed at decreasing oxidative stress and inflammation constitutes an important component of treating COPD.

The current pharmacological therapies may provide temporary symptom relief, reduce acute exacerbations and hospitalizations, but are associated with side effects. Therefore complementary method of treatment with potentially fewer side effects and relatively well-tolerated provide promising alternative. One such compound is quercetin, which is plant polyphenol and is present in variety of foods that we consume. Quercetin has potent antioxidant and anti-inflammatory properties and reduces oxidative stress and inflammation in a preclinical model of COPD. Quercetin exerts it antioxidant properties not only by neutralizing free radical species, but also by enhancing the expression of antioxidant enzymes. Similarly, quercetin inhibits various protein and lipid kinases by competing for adenosine triphosphate (ATP) binding sites thus reducing the inflammatory pathways.

Eligibility Criteria:
Inclusion Criteria:

* Subjects with COPD, 40 - 80 yrs of age
* Post-bronchodilator forced expiratory volume (FEV)1/forced vital capacity (FVC) ratio 0.7, FEV1% predicted between 40 to 70
* Both active and ex-smokers with at least 10 pack-years history of smoking
* COPD patients taking H2 antagonists, loperamide or loratadine and willing to stop during the study period

Exclusion Criteria:

* Known allergy/sensitivity to quercetin
* Subjects with primary current diagnosis of asthma
* Upper respiratory tract infection within two weeks of the screening visit
* Acute bacterial infection requiring antibiotics within two weeks of screening
* Emergency treatment or hospitalization within one month of screening for any reasons
* Unwillingness to stop flavonoid supplementation
* Dietary intake exceeding or averaging 150 mg quercetin daily as assessed by Bioflavonoid Food and Supplement Screener
* Daily warfarin or cyclosporine (Neoral, Sandimmune)
* Subjects taking H2 antagonists (cimetidine, ranitidine), loperamide (Imodium) or loratadine and not willing to stop during study period
* Lung cancer history or undergoing chemo- or radiation therapy
* Inflammatory bowel disease
* Subjects with no detectable levels of inflammatory CRP or SP-D in blood and/or IL-

  1β or 8-isoprostane in the exhaled breath condensate
* Women of child-bearing age and unwilling to take pregnancy test
* Child-bearing age, who are unwilling to use adequate contraception or abstain during the course of the study.
* Pregnant or lactating mothers