Anti-inflammatory/Anti-oxidative Stress Activities and Differential Regulation of Nrf2-Mediated Genes by Non-Polar Fractions of Tea Chrysanthemum zawadskii and Licorice Glycyrrhiza uralensis

Accumulating evidence from epidemiological studies indicates that chronic inflammation and oxidative stress play critical roles in neoplastic development. The aim of this study was to investigate the anti-inflammatory, anti-oxidative stress activities, and differential regulation of Nrf2-mediated genes by tea Chrysanthemum zawadskii (CZ) and licorice Glycyrrhiza uralensis (LE) extracts. The anti-inflammatory and anti-oxidative stress activities of hexane/ethanol extracts of CZ and LE were investigated using in vitro and in vivo approaches, including quantitative real-time PCR (qPCR) and microarray. Additionally, the role of the transcriptional factor Nrf2 (nuclear erythroid-related factor 2) signaling pathways was examined. Our results show that CZ and LE extracts exhibited potent anti-inflammatory activities by suppressing the mRNA and protein expression levels of pro-inflammatory biomarkers IL-1 beta, IL-6, COX-2 and iNOS in LPS-stimulated murine RAW 264.7 macrophage cells. CZ and LE also significantly suppressed the NO production of LPS-stimulated RAW 264.7 cells. Additionally, CZ and LE suppressed the NF-kappa B luciferase activity in human HT-29 colon cancer cells. Both extracts also showed strong Nrf2-mediated antioxidant/Phase II detoxifying enzymes induction. CZ and LE induced NQO1, Nrf2, and UGT and antioxidant response element (ARE)-luciferase activity in human hepatoma HepG2 C8 cells. Using Nrf2 knockout [ Nrf2 (-/-)] and Nrf2 wild-type (+/+) mice, LE and CZ showed Nrf2-dependent transactivation of Nrf2-mediated antioxidant and phase II detoxifying genes. In summary, CZ and LE possess strong inhibitory effects against NF-kappa B-mediated inflammatory as well as strong activation of the Nrf2-ARE-anti-oxidative stress signaling pathways, which would contribute to their overall health promoting pharmacological effects against diseases including cancer.