Preparation of enzymatic hydrolysates of mulberry leaf flavonoids and investigation into its treatment and mechanism for zebrafish inflammatory bowel disease.

Introduction: The incidence of inflammatory bowel disease (IBD) has been increasing year by year in recent years. Flavonoids are the main components of mulberry leaves exerting anti-inflammatory effects and have potential applications in drug screening for IBD treatment. Enzymatic hydrolysis can enhance the bioavailability and activity of flavonoid glycosides. No relevant reports on the potentiation of mulberry leaf flavonoids (MLF) after deglycosylation have been retrieved.

Methods: An enzymatic method was used to prepare enzymatic hydrolysates of MLF (EMLF). The protective effect of EMLF on zebrafish with IBD was evaluated by observing zebrafish intestinal length and width, intestinal histopathological morphology, as well as neutrophil and goblet expression. Network pharmacology and metabolomics were performed to explore the mechanism of action of EMLF against IBD. Finally, the mechanism of EMLF against IBD was validated using Western Blot and real-time quantitative polymerase chain reaction (RT-qPCR).

Results: The EMLF was successfully prepared by hydrolyzing MLF with snailase for the first time, and the anti-inflammatory effect of EMLF was clarified to be superior to that of MLF in IBD zebrafish. The network pharmacology and metabolomics studies showed that the mechanism of EMLF for IBD may be related to regulation of purine metabolic pathway. The expression levels of adenosine deaminase (ADA), critical targets in purine metabolism, were significantly down-regulated, while the expression of adenine phosphoribosyltransferase (APRT) and xanthine dehydrogenase (XDH) was significantly increased when compared with the TNBS group.

Conclusion: The results suggested that enzymatic deglycosylation is an effective measure to enhance the anti-inflammatory activity of MLF, which provides referable ideas and methods for the deep processing and utilization of natural drug resources.