Abstract
The rising prevalence of asthma has heightened awareness of the benefits of functional foods and nutraceuticals for managing the condition. Matricaria chamomilla L., a plant with various health benefits, is commonly consumed as tea in China and other countries. We previously reported the chemical composition and anti-asthma effect of the active fraction of M. Chamomile (MC). This study investigated the protective mechanism of MC on asthma using an ovalbumin (OVA)-induced asthma model in rats and lipopolysaccharide (LPS)-induced human bronchial epithelial cells (16HBE). The effect of MC on asthmatic rats was evaluated through biochemical and histological analyses. Following treatment with MC in OVA-induced asthmatic rats, improvements were observed in behavioral measures, total and differential cell counts of leukocytes in bronchoalveolar lavage fluid (BALF), inflammatory cell infiltration, and the structural integrity of lung and bronchial tissues. Additionally, immunohistochemical analysis revealed an increase in the protein expression level of Kif3a, while the expression levels of LC-3B, BECN1, and Caspase-3 were decreased. Furthermore, the effect of MC on autophagy was analyzed using an LPS-induced 16HBE cell model. MC reduced cell damage and determined the optimal treatment concentration at 200 μg/mL for 48 h; LPS-induced cell apoptosis was reversed by MC using flow cytometry analysis. Autophagy flux was measured through mRFP-GFP-LC3 adenovirus, and MC blocked the autophagic flux of 16HBE cells induced by LPS. The mRNA and protein expression of LC3-II, BECN1, and Cleaved Caspase-3 were decreased, whereas Kif3a was increased following treatment with MC. The protective effect of co-treatment with 3-MA and MC was more significant, and MC exhibited similar efficacy to 3-MA in inhibiting autophagy. Hence, MC is a potential autophagy inhibitor, which could inhibit over-activated autophagy levels to enhance Kif3a expression, thereby decreasing apoptosis to against asthma. M. Chamomile is a promising pharmaceutical and dietary supplement candidate for the amelioration of asthma.