Quercetin is the Active Component of Yang-Yin-Qing-Fei-Tang to Induce Apoptosis in Non-Small Cell Lung Cancer.

Yang-Yin-Qing-Fei-Tang (YYQFT) is a well-known traditional Chinese medicine used in the treatment of chronic obstructive pulmonary emphysema, bronchitis, cytomegaloviral pneumonia, but the mechanisms of the medicine are not clear. This study aimed to identify the active components of YYQFT and elucidate the underlying mechanism on non-small cell lung cancer. First, YYQFT was extracted with different solvents, and then the most effective extract was determined by assessing their effects on non-small cell lung cancer cell growth. Second, several active compounds from YYQFT were identified, and quercetin was the one of the important active ingredients. Subsequently, the antitumor activity of quercetin was confirmed in a lung cancer xenograft model in mice. 200 g/mL quercetin significantly reduced tumor volume without affecting body weight of the mice. Furthermore, induction of apoptosis by quercetin was detected in tumor tissues treated with quercetin. Multiple apoptosis related genes including p53, Bax and Fas were upregulated by quercetin in tumor tissue and the ratio of Bax/Bcl-2 was increased accordingly. Our results demonstrated that quercetin, as the main effective component of the YYQFT, has potent inhibitory activity on non-small cell lung cancer by regulating the ratio of Bax/Bcl-2.