Phyllanthin and hypophyllanthin from Phyllanthus amarus ameliorates immune-inflammatory response in ovalbumin-induced asthma: role of IgE, Nrf2, iNOs, TNF-α, and IL's.

Background: Asthma is a chronic airway immunoinflammatory disorder characterized by airway remodeling. Phyllanthus amarus has been reported to possess antioxidant and anti-inflammatory potential. Aim: To evaluate the possible mechanism of action of isolated phytoconstituents from P. amarus (PA) against ovalbumin (OVA)-induced experimental airway hyperresponsiveness (AHR). Material and method: Phyllanthin and hypophyllanthin were isolated and characterized (HPLC) from the methanolic extract of PA. AHR was induced in Sprague-Dawley rats by OVA-challenged, and animals were treated with PA (50, 100, and 200 mg/kg, p.o.) for 28 days. Results: The HPLC analysis showed the presence of phyllanthin and hypophyllanthin in methanolic extract of PA at RT of 25.243 and 26.832 min, respectively. OVA-induced alterations in hemodynamic parameters, lung functions test, peripheral blood oxygen level, total, and differential cell count in Bronchoalveolar Lavage Fluid was significantly attenuated (p < .05) by PA (100 and 200 mg/kg). It also significantly decreased (p < .05) the levels of total protein and albumin in serum, BALF, and lungs. OVA-induced increase in IgE (total and OVA-specific), and oxido-nitrosative stress (SOD, GSH, MDA, and NO) levels were significantly (p < .05) decreased by PA. RT-PCR analysis revealed that elevated oxido-nitrosative stress (Nrf2 and iNOs), immune-inflammatory makers (HO-1, TNF-α, IL-1ß, and TGF-ß1), Th2 cytokines (IL-4 and IL-6) levels were significantly attenuated (p < .05) by PA. PA also attenuated histological and ultrastructural aberrations induced by OVA. Conclusion: Results of the present investigation demonstrated that the presence of phyllanthin and hypophyllanthin in P. amarus alleviated Th2 response in OVA-induced AHR via modulation of endogenous markers in a murine model of asthma. Thus, phyllanthin and hypophyllanthin may be a new therapeutic approach for the management of asthma.