Triplaris gardneriana seeds extract exhibits in vitro anti-inflammatory properties in human neutrophils after oxidative treatment.

Abstract

Triplaris gardneriana Wedd. (Polygonaceae family) is a plant species from Brazilian semiarid region which is used in local traditional medicine for the treatment of inflammatory conditions such as hemorrhoids. In this study, the in vitro anti-inflammatory activity of different concentrations of ethanolic extract from T. gardneriana seeds (EETg) was performed in order to contribute to the knowledge about etnomedicinal use of this plant species. The anti-inflammatory properties were evaluated through different approaches, such as in vitro protein anti-denaturation test, scavenging of reactive oxygen species (ROS) and myeloperoxidase (MPO) inhibition in human neutrophils activated by phorbol-12-myristate-13-acetate (PMA). Besides that, molecular docking was performed to provide new insights about the interaction between the major phenolic components in the plant extract and MPO. EETg was characterized showing a total phenol content of 153.5±6.3μg gallic acid equivalent/mg extract, ability to remove hydrogen peroxide (H2O2) in a concentration-dependent manner and had a spectroscopic profile which suggests the presence of hydroxyl groups. EETg was able to prevent protein denaturation ranging from 40.17 to 75.09%. The extract, at 10 and 20μg/mL, was able to modulate neutrophils pro-inflammatory functions, such as degranulation and burst respiratory. In both assays, the EETg had anti-inflammatory effect comparable to nonsteroidal anti-inflammatory drugs. Among the main phenolic compounds of EETg, quercitrin, quercetin and catechin showed the highest binding affinity in silico to MPO. This study demonstrated, for the first time, that the anti-inflammatory effect of T. gardneriana seeds occurs due to its modulatory effect on human neutrophil degranulation and free-radical scavenging activity.