The Role of Ethyl Acetate Fraction from Phyllanthus amarus in Down-Regulation of Allergic Inflammatory Responses

This study aimed to investigate the anti-allergic potential of the ethyl acetate fraction (EtOAc) from Phyllanthus amarus using an ovalbumin (OVA)-induced allergic mouse model and in vitro RBL-2H3 mast cell assays. The EtOAc fraction was characterized by high total phenolic and flavonoid contents, reaching 261 ± 18 mg GAE/g EtOAc fraction and 86 ± 7 mg QE/g EtOAc fraction, respectively. It was found that EtOAc fraction significantly reduced histamine release up to 43.3% and suppressed reactive oxygen species (ROS) production from FcɛRI-mediated mast cell activation at a concentration treatment of 200 µg/mL. Furthermore, EtOAc fraction decreased interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-α) release up to 94.2 pg/mL and 195.6 pg/mL, respectively. In the OVA-induced allergic mouse model, EtOAc fraction treatment markedly lowered sneezing frequency and serum IgE and histamine levels by approximately 50% at a dose treatment of 50 mg/kg. In addition, histopathological analysis revealed that the EtOAc fraction significantly alleviated inflammatory cell infiltration, particularly eosinophils, in lung tissue. Accordingly, the results highlight the potential of EtOAc fraction from P. amarus as a natural candidate for managing allergic diseases.