Ethanolic extract of Puhuang (Pollen Typhae) modulates lipopolysaccharide-induced inflammatory response through inducible nitric oxide synthase / cyclooxygenase-2 signaling in RAW 264.7 macrophage.

Objective: To evaluate the immune modulatory response of Puhuang (Pollen Typhae), ethanolic extract of dried pollens (TP-E) and charcoal activated pollens (CTP-E) were used for their phytochemical evaluation and their modulatory response against lipopolysaccharide (LPS) induced inflammatory activity on RAW264.7 macrophage cells.

Methods: Biochemical assays were carried out to quantify the 1,1-Diphenyl-2-picrylhydrazyl Radical Scavenging Activity, Reducing Power, Ferrous ion chelating ability and total polyphenol content and flavonoids. Non-toxic dose of the extract (TP-E and CTP-E) was chosen based on 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Effect of TP-E and CTP-E on lipopolysaccharides-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression was measured by Western blot and quantitative PCR (qRT-PCR). Expression of inflammatory cytokines, such as interleukins (IL-1β and IL-6) and tumor necrosis factor α (TNF-α), was quantified using qRT-PCR. Mitogen-activated protein kinase pathway was analyzed using Western blot.

Results: Phytochemical analysis revealed that both TP-E and CTP-E have strong antioxidant activities and high flavonoid and phenolic contents. TP-E and CTP-E effectively inhibit the expression of iNOS and COX-2, thereby inhibiting its downstream proinflammatory regulators, the extracellular signal-related kinase-1/2, that decreases the expression of IL-1β, IL-6 and TNF-α.

Conclusion: Phytochemical constituents present in Typha angustifolia Linn could be used for treating inflammation-related diseases.