Humulus lupulus is a dioecious perennial plant well known throughout the world as the raw material in the brewing industry. The female inflorescences, rich in polyphenolic components and acyl phloroglucides, are widely used to protect beer and to give it a characteristic aroma and flavor. In addition, hop cones have long been used for medicinal purposes. In particular, hop preparations were mainly suggested for the treatment of sleeping disorders, and a mild sedative, and for the activation of gastric function as bitter stomachic.

In the recent studies, hop extracts showed strong inhibitory activities against acne causing bacteria such as P. acnes, S. epidermidis, S. aureus, K. rhisophila, and S. pyogenes. Also active ingredients of H. lupulus , such as xanthohumol, humulones, and lupulones, showed moderate to strong anti-collagenase inhibitory activities. Xanthohumol showed the activity in total oxygen radical absorbance capacity as

well as singlet oxygen absorbance capacity.