531PSIDIUM GUAJAVA LEAF EXTRACT MODULATES CYTOKINE EXPRESSION IN LIPOPOLYSACCHARIDE-ACTIVATED PRIMARY MOUSE NEUTROPHILS THEREBY INHIBITING NF-κB ACTIVITYPlants that are rich in polyphenolic compounds, especially flavonoids, may be used to benefit human health by reducing the incidence of cancer, inflammatory and cardiovascular diseases. Psidium guajava is a medicinal plant with antioxidant, anti-inflammatory, and anti-allergic activities that support its traditional uses. The present study assayed the antioxidant activity, total phenolic and flavonoids content of Psidium guajava leaf extract (GLE). The results confirmed the presence of polyphenols in guava, including flavonoids, and its antioxidant activity. Further, the anti-inflammatory effect of GLE was assessed on lipopolysaccharide (LPS)-induced IL-1β level in primary mouse neutrophils. Our results showed that GLE suppressed LPS-induced production of proinflammatory cytokine IL-1β. In addition, we observed that GLE reduces the activation of transcription factor NF-κB as well as degradation of IκBα in LPS-induced mouse neutrophils. The presence of polyphenolic and flavonoid compound suggests a possible contributory role to the antioxidant, anti-inflammatory activity of the GLE tamizhselvi.r@vit.ac.inResearch5112014Psidium guajava leaf extract,IL-1β,NF-κB, mouse neutrophils,IκBαLeema George,Bhavapriya Rajendran,Venkatraman Manickam,Aravindan Ragothaman,KNS Sirajudeen,Ramasamy Tamizhselvi School of BioSciences and Technology, VIT University, Vellore 632 014. Tamilnadu. India, School of BioSciences and Technology, VIT University, Vellore 632 014. Tamilnadu. India, School of BioSciences and Technology, VIT University, Vellore 632 014. Tamilnadu. India, School of BioSciences and Technology, VIT University, Vellore 632 014. Tamilnadu. India,Department of Chemical Pathology, Universiti Sains Malaysia, 16150-Kubang Kerian, Kelantan, Malaysia, School of BioSciences and Technology, VIT University, Vellore 632 014. Tamilnadu. India