The beneficial effects of lupeol on particulate matter–mediated pulmonary inflammation

Particulate matter (PM) poses significant health risks, especially fine particles (PM_2.5) that can cause severe lung injuries. Lupeol, a phytosterol from medicinal plants, has potential anti-cancer properties. This study investigated lupeol's protective effects against PM_2.5-induced lung damage. Mice received lupeol following intratracheal PM_2.5 exposure. Results showed lupeol reduced lung damage, lowered wet/dry (W/D) weight ratio, and suppressed increased permeability caused by PM_2.5. Additionally, lupeol decreased plasma inflammatory cytokines, total protein concentration in bronchoalveolar lavage fluid (BALF), and PM_2.5-induced lymphocyte proliferation. Lupeol also reduced expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), and autophagy-related proteins microtubule-associated protein 1 A/1 B-light chain 3 (LC3) II and Beclin 1, while increasing phosphorylated mammalian target of rapamycin (mTOR) phosphorylation. These findings suggest lupeol's potential as a therapeutic agent for PM_2.5-induced lung damage via modulation of the TLR4-MyD88 and mTOR-autophagy pathways.