Stigmasterol inhibits lipopolysaccharide-induced innate immune responses in murine models

Stigmasterol is a naturally occurring steroid alcohol which occurs in vegetables, soya and a large variety of medicinal plants. Stigmasterol and other phytosterols have been documented as immunomodulators with huge therapeutic potential. We assessed the mitigating effect of stigmasterol on non-fatal and fatal innate immune responses in murine models after intraperitoneal challenge with an endotoxin, lipopolysaccharide, LPS. The effect of stigmasterol on LPS-induced febrile response, inflammatory cell proliferation, multiple organ damage and mortality were respectively investigated. Pretreatment with stigmasterol 10, 50 and 100mg/kg reduced total LPS-induced fever response by 39.93±10.52%, 53.05±5.84% and 77.27±6.25% respectively. Neutrophil proliferation both in blood and recovered peritoneal fluid was significantly reversed by stigmasterol at 50 and 100mg/kg. Lung and liver histopathology showed stigmasterol effectively controlled organ damage. The lung inflammation score of 9.20±0.73 for the polyethylene glycol, PEG-treated disease control mice was reduced respectively to 6.50±0.54, 4.60±0.40 and 4.10±0.42 with 10, 50 and 100mg/kg of stigmasterol. Serum levels of liver enzyme markers, alanine transaminase, ALT and aspartate transaminase, AST were consistent with the observed histological changes. Stigmasterol at 50 and 100mg/kg significantly protected mice from LPS-induced mortality with 40% survival. Overall, stigmasterol inhibits LPS-induced innate immune responses in murine models.