Biotransformations and biological activities of hop flavonoids

Female hop cones are used extensively in the brewing industry, but there is now increasing interest in possible uses of hops for non-brewing purposes, especially in the pharmaceutical industry. Among pharmaceutically important compounds from hops are flavonoids, having proven anticarcinogenic, antioxidant, antimicrobial, anti-inflammatory and estrogenic effects. In this review we aim to present current knowledge on the biotransformation of flavonoids from hop cones with respect to products, catalysis and conversion. A list of microbial enzymatic reactions associated with gastrointestinal microbiota is presented. A comparative analysis of the biological activities of hop flavonoids and their biotransformation products is described, indicating where further research has potential for applications in the pharmaceutical industry. •Hops are not only a basic brewing raw material, but extracts can be used as health remedies•Many hop flavonoids and their biotransformation products have proven biological activities–anticarcinogenic, antioxidant, antimicrobial, anti-inflammatory and estrogenic effects.•There are many biotransformation reactions applicable to hop flavonoids, resulting in many new molecules with different biological activities.•Biotransformation reactions of flavonoids can be applied in the pharmaceutical industry.