Isoxanthohumol and Its Derivatives: Antioxidant Activity and Effects on the Gut Microbiota

Isoxanthohumol (IX) is a prenylated flavonoid derived from hop cones (Humulus lupulus) that is gaining increasing recognition for its potential biological effects. Despite numerous studies on its precursor, xanthohumol, studies on IX remain limited. Of particular interest is its metabolism, particularly its biotransformation by gut microbiota to 8-prenylnaringenin (8-PN), a potent phytoestrogen, which indicates the complex nature of its biological activity and potential health implications. This review summarizes the current state of knowledge on IX and its derivatives, covering their microbial metabolism, their impact on the gut microbiome, and the metabolic consequences of this conversion. Furthermore, it examines the relationship between the molecular structure of IX and its derivatives and their biological activity, highlighting existing research gaps and the need for further research on the safety and therapeutic potential of these compounds.