Anti-inflammatory activity of Ternstroemia gymnanthera stem bark extracts in bacterial lipopolysaccharide-stimulated RAW264.7 murine macrophage cells

Context:Ternstroemia gymnanthera Sprague (Theaceae) possesses various known pharmacological properties. However, its anti-inflammatory activity has not been reported. Objective: The anti-inflammatory activity of Ternstroemia gymnanthera stem bark aqueous extract (TGSBE) was evaluated using LPS-stimulated RAW264.7 macrophages. Materials and methods: Cytotoxicity was assessed by MTT assay after 24 h with TGSBE (25–200 μg/mL). Further testing used TGSBE at 100 and 200 μg/mL. Griess and ELISA methods after 24 h with TGSBE determined NO and cytokine levels, respectively; then, mRNA levels (iNOS & cytokines) were analyzed by Quantitative-PCR after 12 h. NF-κB and MAPK were assessed by immunoblotting after TGSBE treatment for 12 h, followed by LPS for 30 min. Immunofluorescence assay was also performed for NF-κB. ROS and MMP, after 12 h with TGSBE, were determined by flow cytometry. The antioxidant potential of TGSBE was analyzed by ABTS assay. The Folin–Ciocalteu method determined the total phenolic content of TGSBE. LPS concentration was 0.5 μg/mL. Results: TGSBE at 200 μg/mL showed about 96.2% viability while suppressing the production of NO (88.99%), TNFα (24.38%), IL-6 (61.70%) and IL-1β (55.12%) and gene expression by 67.88, 45.24, 65.84, and 70.48%, respectively. TGSBE decreased ROS (79.26%) and improved MMP (48.01%); it inhibited translocation of NF-κB and MAPK activation. Radical scavenging activity was 50% at 402.17 μg/mL (ascorbic acid standard: 88.8 μg/mL). Total phenolic content was 240.9 mg GAE/g. Discussion and conclusion: TGSBE suppresses the inflammatory response by inhibiting the NF-κB and MAPK cascades exhibiting therapeutic potential to treat inflammatory diseases associated with increased activation of macrophages.