Alkaloids from Zanthoxylum bungeanum Maxim. alleviate MASLD via dual modulation of cannabinoid receptors and activation of Akt/GSK3β/Nrf2 signaling

Abstract Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a growing global health challenge, necessitating the discovery of safe and effective therapeutic agents from natural dietary sources. Zanthoxylum bungeanum Maxim. (huajiao), a widely consumed pharma-food, contains abundant alkaloids with reported lipid-regulating, antioxidant, and anti-inflammatory activities, but its underlying mechanisms against MASLD remain unclear. This study aimed to evaluate the hepatoprotective effects of alkaloids from Z. bungeanum (ZBA) and elucidate its molecular targets using an integrated approach combining network pharmacology, transcriptomics, and experimental validation. To this end, FFAs-stimulated HepG2 cells and HFD-fed mice were employed to assess the effects of ZBA. The results showed that ZBA significantly alleviated hepatic lipid accumulation, improved insulin sensitivity, and reduced systemic inflammation. Mechanistically, omics analysis and molecular docking predicted the endocannabinoid system as a key target, and the cellular thermal shift assay confirmed that ZBA directly binds to both CB1 and CB2 receptors. Furthermore, pharmacological interventions using specific agonists and antagonists revealed that ZBA exerts a dual modulatory effect on the endocannabinoid system by suppressing CB1 overexpression and enhancing CB2 activity. This modulation subsequently activates the Akt/GSK3β/Nrf2 signaling cascade to restore lipid metabolism homeostasis and mitigate lipotoxicity in a dose-responsive regulatory trend. In conclusion, the present findings highlight that ZBA ameliorates MASLD by rebalancing the expression of CB1 and CB2 receptors, thereby modulating Akt/GSK3β/Nrf2 axis, thus providing a scientific basis for the development of ZBA as a functional food ingredient for metabolic health.