Psidium guajava L. Inhibit Inflammatory and Improve Antioxidant Activity in Mouse Macrophage Cell Lines

Background: Chronic inflammation has been proven to be a factor in the development on pathogenesis of several chronic diseases such as diabetes, obesity and cancer. Psidium guajava L., a Thai traditional fruit, has been reported to have biological properties such as antioxidant and anti-diabetic, however its mechanism related to inflammation has not been studied. This study aims to determine the inhibitory effects of P. guajava fruit ethanol extract on anti-inflammation and intracellular ROS accumulation in lipopolysaccharideactivated RAW 264.7 murine macrophage cells line. Methods: RAW264.7 cells were pre-treated with the P. guajava fruit extract at 0.25, 0.5, 1 and 2 mg/mL for 1 h before inducing with lipopolysaccharide 5 ng/ml for further 24 h. Cell viability and nitric oxide production were determined by cell proliferation WST-1 assay and Griess reaction. Intracellular ROS was assessed by fluorescent signal from oxidized 2.,7.-dichlorofluorescein diacetate. TNF-alpha and IL-6 production were measured by ELISA. Results: Pre-treatment of P. guajava fruit extract significantly suppressed LPS-induced nitric oxide, Intracellular ROS, TNF-alpha and IL-6 production in a dose-dependent manner. Conclusion: These results suggested that P. guajava fruit extract has a potential to reduce inflammation and to improve antioxidant activity in cellular level. However, the effect of P guajava in reducing inflammationassociated chronic diseases should be explored in further study.