Saikosaponin A and Its Epimers Alleviate LPS-Induced Acute Lung Injury in Mice

The purpose of this work was to illustrate the effect of processing with vinegar on saikosaponins of Bupleurum chinense DC. (BC) and the protective effects of saikosaponin A (SSA), saikosaponin b1 (SSb1), saikosaponin b2 (SSb2), and saikosaponin D (SSD) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice. We comprehensively evaluated the anti-inflammatory effects and potential mechanisms of SSA, SSb1, SSb2, and SSD through an LPS-induced ALI model using intratracheal injection. The results showed that SSA, SSb1, SSb2, and SSD significantly decreased pulmonary edema; reduced the levels of IL-6, TNF-α, and IL-1β in serum and lung tissues; alleviated pulmonary pathological damage; and decreased the levels of the IL-6, TNF-α, and IL-1β genes and the expression of NF-κB/TLR4-related proteins. Interestingly, they were similar in structure, but SSb2 had a better anti-inflammatory effect at the same dose, according to a principal component analysis. These findings indicated that it may not have been comprehensive to only use SSA and SSD as indicators to evaluate the quality of BC, especially as the contents of SSb1 and SSb2 in vinegar-processed BC were significantly increased.