MHTP, a synthetic alkaloid, attenuates combined allergic rhinitis and asthma syndrome through downregulation of the p38/ERK1/2 MAPK signaling pathway in mice

•CARAS is an airway syndrome that affects a large part of the world population.•MHTP synthetic alkaloid by oral and intranasal route inhibits eosinophils.•MHTP reduces the signs of rhinitis by acting on the H1 receptor.•MHTP reduces airway tissue remodeling of CARAS.•MHTP inhibits signal transduction of the p38/ERK1/2 MAPK pathways in granulocytes. The combined allergic rhinitis and asthma syndrome (CARAS) is a chronic airway inflammation of allergic individuals, with a type 2 immune response. Pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study was to evaluate the synthetic alkaloid, MHTP in the experimental model of CARAS. Therefore, BALB/c mice were ovalbumin (OVA) -sensitized and -challenged and treated with MHTP by intranasal or oral routes. Treated animals showed a decrease (p