Galangin, a dietary flavonol inhibits tumor initiation during experimental pulmonary tumorigenesis by modulating xenobiotic enzymes and antioxidant status

Abstract

The aim of present study was to elucidate anti-initiating efficacy of galangin against benzo(a)pyrene (B(a)P)-induced lung carcinogenesis in male Swiss albino mice. Therefore, the activities of xenobiotic metabolic enzymes such as phase I and II were examined in lung as well as liver tissues (to compare the effects between target and non-target organs). Besides, the activities/levels of tissue marker enzymes, antioxidants, lipid peroxidation (LPO), cytochrome P450 1A1 (CYP1A1) expressions and histological observation of lungs were also analyzed. B(a)P (50mg/kg body weight) was administered to male Swiss albino mice (20-25g) to experimentally induce lung cancer. B(a)P-induced animals showed increased activity of phase I (Cytochrome P450, Cytochrome b5, NADPH Cytochrome P450 redcutase and NADH Cytochrome b5 reductase) drug metabolic enzymes, LPO levels, tissue marker enzymes and decreased activity of phase II metabolic enzymes (glutathione-S-transferase, DT-diaphorase and UDP-glucuronyl transferase) as well as antioxidant levels. Histological examination of lungs revealed severe alveolar and bronchiolar damages in B(a)P-induced mice. Immunohistochemical and western blot analysis of CYP1A1 increased significantly in lung tissues of B(a)P-induced animals. Treatment with galangin (20mg/kg body weight) efficiently counteracted all the above anomalies and restored cellular homeostasis. Our results demonstrate that galangin can modify xenobiotic enzymes in murine model of pulmonary tumorigenesis.