Hop (Humulus lupulus) is one of the richest natural sources of a prenylfalvonoids such as xanthohumol (XN), desmetylxanthohumol (DMX), isoxanthohumol (IX) or 8-prenylnaringenin (8-PN), being XN the most abundant of them in the raw material. So far, obtention of prenylflavonoids have been done by chemical synthesis or extraction with organic solvents, with no described methods for the isolation of IX, which has been reported to have anti-inflammatory properties. In this study, pressurized hot water extraction (PHWE) it is shown not only as effective method to extract some prenylflavonoids but to selectively change the relative amount of them, favoring the extraction of IX against XN. Thus, pressurized water extraction at 150 °C showed a high selectivity towards IX, being proposed as a method to enrich natural hop´s extracts in IX. On the other hand, the extracts thus obtained were chemically characterized and evaluated for their anti-inflammatory activity, which was higher than the expected by its content in IX.

This work has been funded by a CICYT Project (AGL2007-64198/ALI), CONSOLIDER INGENIO 2010 CSD2007-00063 FUN-C-FOOD (MEC) and ALIBIRD-CM 2010–2013 INGREEN.

Peer reviewed