Protective effect of Loranthus tanakae Franch. & Sav. on allergic asthma induced by ovalbumin

Allergic asthma is a widespread disease with elevated eosinophil levels. Although corticosteroids are widely prescribed for allergic asthma, numerous patients experience limited sensitivity and side effects. Loranthus tanakae Franch. & Sav., a traditional herbal plant, has anti-inflammatory and antioxidant properties in pulmonary inflammation caused by Asian sand dust and cigarette smoke condensate. To assess the protective effects of L. tanakae, we examined the influence of an L. tanakae ethanol extract (LTE) in ovalbumin (OVA)-induced asthma. Mice received intraperitoneal sensitisation with OVA, and challenged using OVA inhalation. LTE was consecutively orally gavaged for 6 days. Following sacrifice, the bronchoalveolar lavage fluid (BALF) and lung tissue was analysed. The LTE treatment considerably reduced inflammatory cell counts, proinflammatory cytokine levels in the BALF, and immunoglobulin E, compared with the OVA group, along with a reduction in airway hyperresponsiveness. The LTE also improved airway inflammation and suppressed mucus hypersecretion in the lung tissues. Additionally, the expression of MMP-9 and activation of ERK, JNK, and p38 were notably diminished in the LTE groups. This study revealed reduced airway inflammation in OVA-induced asthma via suppressing the MMP-9 and mitogen-activated protein kinase-associated factors. Consequently, our findings demonstrated that LTE is suggested as a potential remedy for allergic asthma.