Abstract
Hops (Humulus lupulus L.) is a plant species with a multitude of uses in medicine, food science and agriculture. Xanthohumol, the major prenylflavonoid in hop cone extract, possesses anti-cancer activity. Xanthohumol also exhibits strong antimicrobial activity against Gram-positive bacteria (e.g., S. aureus), but not against Gram-negative bacteria. Xanthohumol can reduce blood glucose levels and body fat in obese male rats (not females), and mature hop bitter acids (MHBAs) have been found to decrease visceral and abdominal human fat. Xanthohumol can increase bone mineral density, decrease osteoclast numbers, and protect osteoblasts from oxidative stress in osteoporotic mice. Further clinical research, xanthohumol and bitter acids could be sourced from hop cone extracts to formulate novel drugs that can successfully treat a variety of diseases and potentially replace current therapies that have negative effects. In the food industry, hop cone extracts are mainly used in the brewing industry, with 98% of the world’s hop cones being used in brewing beer. Hop cone extracts are also used as food/drink preservatives due to their antimicrobial abilities, as previously mentioned, although there is less of a need for hops in extending food/drink shelf-life. Finally, hop cone extracts have several uses in agriculture, mainly as pesticides. For example, hop extracts can kill varroa mites, a parasite that impairs honeybee health. This benefits honeybee farmers as increased bee survival means more honey production, increasing profits. Overall, this review paper brings together recent studies that highlight hop extracts as valuable bioactive compound mixtures with many useful applications.