Sterol isolated from Sargassum horneri attenuated particulate matter-exacerbated allergic asthma through the Th17 response

Abstract Particulate matter (PM) has become a serious health issue causing pulmonary diseases such as asthma. Due to the side effects and non-specificity of conventional drugs, it is a need to develop alternative treatment using natural product. Sargassum horneri (S. horneri) is an edible species of large brown algae inhabiting the coasts of northeastern Asia extensively. S. horneri has sterols and has been used in oriental medicine to treat allergic condition. Therefore, we investigated if sterol isolated from S. horneri ethanol extract (SHE-sterol) could mitigate the PM-exacerbated allergic asthma. To establish a mouse model of asthma, BALB/c mice were sensitized with ovalbumin (OVA, 10 mg) and challenged with PM (5 mg/m 3) for 7 days consecutively. SHE-sterol (50, 200 mg/kg), Prednisone (5 mg/kg). In SHE-sterol, fucosterol was specially identified as 0.701 μg/mL. SHE-sterol attenuated the PM-aggravated granulocytes infiltration. Moreover, SHE-sterol further attenuated PM-exacerbated eosinophil infiltration in the lung, trachea, and BALF. In addition, SHE-sterol markedly mitigated the activation of mast cells and the IgE level in serum. Concomitantly, SHE-sterol further restrained the Th17 cell response in PM-exposed allergic mice through attenuating expression of relevant effector cytokine IL-17A. This resulted in mitigated neutrophil infiltration in the lung. Also, SHE-sterol significantly suppressed PM-exacerbated hypersecretion of mucus in asthmatic mice. Taken together, these results suggest that sterol isolated from SHE has therapeutic potential for treating PM-exacerbated allergic asthma. This research was funded by the Ministry of Education (2019R1A6A1A10072987 and 2022R1I1A1A01072505). This research was funded by the Ministry of Education (2019R1A6A1A10072987 and 2022R1I1A1A01072505).