Investigation on the preventive effects of total flavonoids extract from Ziziphi Spinosae Semen on depression and associated liver injury

Ziziphus jujuba Mill. var. spinosa yields the desiccated seeds known as Ziziphi Spinosae Semen (ZSS), a botanical classified in China as medicine-food dual-purpose. For centuries, these seeds have been ingested to relieve insomnia and depression. Their total flavonoid fraction (ZSSF) is now recognized as the key active component that provides sedative-hypnotic, antidepressant, antioxidant, and hepatoprotective benefits. However, its therapeutic efficacy and the underlying mechanism have not been elucidated. In this study, we extracted ZSSF and predicted that the primary action of ZSSF is focused on the PI3K/AKT signaling pathway based on network pharmacology. We further explored the preventive effects of ZSSF and the underlying mechanisms against depression and associated liver injury through in vitro and in vivo experiments. In oleic-acid-challenged HepG2 cultures, ZSSF activated the PI3K/AKT signaling pathway, concomitantly lowering AST, ALT, TC, TG, and MDA while elevating SOD, thereby alleviating oxidative stress and liver injury. Furthermore, within a murine paradigm of mood disturbance established through CUMS, ZSSF improved depressive behaviors, increased serum 5-HT levels, and mitigated hepatic steatosis, and oxidative stress. More importantly, Western blotting experiments verified that ZSSF promotes the phosphorylation of PI3K and AKT proteins, thereby regulating the PI3K/AKT signaling pathway to improve depressive symptoms and associated liver injury in CUMS mice. In summary, our results indicate that ZSSF attenuates the development of depression and related liver injury by activating the PI3K/AKT signaling pathway, and its antioxidant effects may contribute to the alleviation of oxidative stress and liver injury during the progression of depression.