Quercetin shines again: study

Asthma, cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are serious and even life-threatening conditions. However, these health problems share something with a usually minor infection -- the common cold. The connection? Rhinovirus (RV), a single-stranded RNA virus from the picornaviridae family, causes the majority of colds and RV is also known to trigger exacerbations of CF, asthma and COPD.

But now University of Michigan at Ann Arbor scientists have found that a natural substance, the flavonoid quercetin, puts the brakes on the ability of Rhinovirus (RV) to replicate. It also fights inflammation. According to their research just presented at the American Thoracic Society (ATS) 2010 International Conference held in New Orleans, quercetin could be a treatment for rhinovirus-caused infections and could be particularly beneficial for people with serious underlying chronic lung diseases.

The research team tested quercetin on cells infected with RV. The results suggested that quercetin actually inhibited the ability of the virus to replicate. The flavonoid also appeared to reduce the RV-triggered immune system response that can cause cytokines (proteins that are secreted by specific cells of the immune system) to induce excess inflammation. "Therefore, quercetin may be beneficial in the treatment of viral infections, particularly in patients with underlying chronic lung disease," the researchers stated.