Effects of Green Tea Extract (GTE) on Systemic Oxidative and Antioxidative Status in Chinese Patients With Stable Asthma

Asthma is a disease characterized by chronic inflammation in the airways. Recent research has demonstrated that one of the reasons for the chronic inflammatory state is an imbalance between oxidative stress and antioxidative defenses in patients with asthma. Green tea is a common beverage consumed by Chinese patients from all walks of life. Green tea contains chemical components that are thought to have immunomodulatory actions in chronic inflammation. The investigators propose to recruit 35 patients with stable asthma. Recruited subject will be given oral tablets containing Green tea extract (GTE) to be taken daily for three months. Clinical follow up and assessment will be done at baseline, on completion of GTE intake at three months, and at three months after GTE intake has been stopped. A questionnaire on their health status and the frequency of symptoms and use of bronchodilators and inhaled steroids will be completed, spirometry will be done and a venous blood sample will be taken during recruitment and during each reassessment at 3 and 6 months. Measurement of oxidants/antioxidants (GSH, GSSG, SOD, CAT and GPx) will be carried out on the blood samples. Oxidants/antioxidants will be compared and correlated with lung function results. This study would provide us with pilot data as to whether GTE, a strong antioxidant with immunomodulatory actions, has any effect on reducing the oxidative stress and improving the antioxidant status in patients with asthma and whether these changes are accompanied improvement in clinical status. Hypothesis Green tea extract (GTE) reduces oxidative stress and improves antioxidant defenses in Chinese patients with asthma