Anti-inflammatory effect of Streblus asper leaf extract in rats and its modulation on inflammation-associated genes expression in RAW 264.7 macrophage cells

Aim of this studyStreblus asper is a medicinal plant from Thailand used in folk medicine for the treatment of several inflammatory diseases. In this study, we investigated the anti-inflammatory effect of Streblus asper leaf ethanolic extract (SAE).Materials and methodsThe experimental carrageenan-induced paw edema in rats was performed in which the SAE at doses of 125, 250, 500 mg/kg body weight was intraperitoneally administered to the rats. Then, reverse transcriptive polymerase chain reaction (RT-PCR) technique was also performed to determine the effect of SAE on the expression of inflammation-associated genes in RAW 264.7 macrophage cells stimulated with lipopolysaccharide (LPS).ResultsThe SAE at all given doses caused a significant dose-dependent inhibition of edema (p < 0.05). Moreover, the significant and dose-dependent LPS-induced cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) mRNA expressions were demonstrated in RAW 264.7 cells treated with SAE. The inhibition is selective, since COX-1 mRNA expression did not change in the presence of SAE.ConclusionThe results of this study are the first scientific evidence on the molecular effects of Streblus asper as a potential anti-inflammatory agent, which supports the fact that the plant is employed in traditional remedies.