The paradox of Picroside II: As a natural antioxidant, but may instead futher aggravate liver injury by exacerbating mitochondrial oxidative stress

Abstract Background Picroside II (PII), an iridoid glycoside extracted from the rhizomes and stems of the genus Picroside, exhibits pronounced hepatoprotective properties. Pre-administration of PII protects against acute liver injury caused by D-galactosamine (D-Gal), carbon tetrachloride (CCl4), and acetaminophen (APAP). This study aimed to elucidate the ramifications of PII administration subsequent to the initiation of acute hepatic injury. Methods Exploring the role of PII treatment in APAP-treated cell and rat models and in D-Gal and CCl4-treated rat models. Results In rats, APAP treatment increased serum aspartate transaminase, alanine transaminase, and alkaline phosphatase levels and decreased glutathione activity and the fluidity of the liver mitochondrial membrane. In L-02 cells, APAP exposure resulted in a decrement in membrane potential, an augmentation in the liberation of reactive oxygen species, and an acceleration of apoptotic processes. Moreover, PII pre-administration protected against D-Gal-induced acute hepatic injury and CCl4-induced chronic hepatic injury in rodent models, whereas PII administration post-injury aggravated CCl4-induced chronic hepatic injury. Conclusions Our results suggest that the effects of PII depend on the hepatic physiological or pathological state at the time of intervention. While PII possesses the potential to avert drug-induced acute hepatic injury through the mitigation of oxidative stress, its administration post-injury may exacerbate the hepatic damage, underscoring the critical importance of timing in therapeutic interventions.