Vinegar-Processed Bupleuri Radix in the Treatment of Liver Meridian Diseases via PI3K/Akt Pathway

Vinegar-processed Bupleuri Radix (VPBR) is a processed product of the traditional Chinese herbal medicine Bupleuri Radix and is widely used for liver meridian diseases. Chemical analysis revealed that vinegar processing converts type I saikosaponins (a, d) to type II (b1, b2), enriches flavonoids (fraxetin, petunidin, narcissoside) and organic acids (gluconic acid, citric acid, D-(-)-quinic acid), and reduces volatile oil content by 20%, with 10 components lost and 15 gained. Mechanistically, these changes enhance VPBR's regulation of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway, contributing to antiapoptotic, antifibrotic, anticancer, antidepressant, anti-inflammatory, and lipid-regulating effects. Clinically, VPBR is used alone, in herb pairs, in classical formulas (Chaihu Shugan San, Xiaoyao San, Xiao Chaihu Tang), and in modern preparations for chronic hepatitis, liver fibrosis, non-alcoholic fatty liver disease, and depression. This review systematically summarizes the chemical transformations induced by vinegar processing, elucidates the molecular mechanisms by which VPBR and its active components modulate the PI3K/Akt signaling pathway in the context of liver meridian diseases, and highlights its clinical applications, providing a comprehensive chemical–biological rationale for the traditional concept that vinegar processing guides the herb into the liver and enhances its therapeutic efficacy.