Polyphenols are a broad class of naturally occurring compounds found in plants, known for their antioxidant and anti-inflammatory properties. There is growing scientific interest in the potential of polyphenols, such as those found in green tea (epigallocatechin gallate), curcumin (from turmeric), resveratrol (from grapes), and flavonoids (from various fruits and vegetables), as adjunctive treatments for Chronic Obstructive Pulmonary Disease (COPD).

Preclinical studies (cell culture and animal models) have demonstrated that polyphenols can reduce oxidative stress and inflammation in lung tissues—two key pathological mechanisms in COPD. Some human studies, though mostly small and preliminary, have reported that polyphenol supplementation may modestly improve biomarkers of oxidative stress, reduce inflammatory cytokines, and possibly improve some aspects of lung function or quality of life in COPD patients. For example, a few randomized controlled trials have suggested that supplementation with curcumin or green tea extract could help reduce exacerbation frequency or improve respiratory symptoms.

However, the evidence base remains limited: large, well-designed clinical trials are lacking, and the optimal type, dose, and duration of polyphenol supplementation are not established. Thus, while the scientific rationale is plausible and early data are promising, polyphenols are not yet recommended as a primary treatment for COPD. They may, however, be considered as supportive agents alongside standard therapies, pending further research.