Antiproliferative and cytotoxic effects of prenylated flavonoids from hops (Humulus lupulus) in human cancer cell lines

The pharmacognosy of Humulus lupulus L. (hops) with an emphasis on estrogenic properties

“…With the exception of two geranylated compounds, which have only been detected by MS (Stevens et al, 1999), all known constituents of hops from this series are prenylated at either the 6-or 8-position, or both. There are three known series of compounds present in hops based on this nucleus,…”

“…A mixture of prenylated, geranylated, oxidized and/or cyclized chalcones, of which 30 have been isolated to date, is secreted by the lupulin glands along with the bitter acids and volatile oils (Milligan et al, 1999;Mizobuchi and Sato, 1994;Stevens et al, 1997;Stevens et al, 1999;Stevens et al, 2000;Zuurbier et al, 1998). The chalcone xanthohumol (XH) is the most abundant prenylated flavonoid in fresh and properly preserved hops, present at a concentration of ca.…”

“…The chalcone xanthohumol (XH) is the most abundant prenylated flavonoid in fresh and properly preserved hops, present at a concentration of ca. 0.01-0.5% (Stevens et al, 1999;Stevens et al, 2000). In a chemotaxonomic study by Deinzer et al , the compound xanthogalenol (XG) was identified as being present in hops containing germplasm from east of the Rocky Mountains in the U. .…”

“…The major chalcone XH isomerizes to isoxanthohumol (IX), the reaction reportedly taking place more rapidly with increasing pH (Stevens et al, 1998;Stevens et al, 1999). The corresponding isomerization is possible in any chalcone containing a free 2′-or 6′-hydroxyl group, and in cases where there is a hydroxyl at both 2′ and 6′, two isomers are produced.…”

“…Hop extracts and/or compounds have been reported to be "active" or the equivalent by the authors of the given studies in the following assays: various antioxidant and/or chemoprevention (Gerhäuser et al, 2002;Gerhäuser et al, 2001;Liegeois et al, 2000;Masaki et al, 1995;Oyaizu et al, 1994;Stevens et al, 2002;Tagashira et al, 1995), antimicrobial, particularly against Gram positive bacteria (Grange and Davey, 1990;Langezaal et al, 1992;Matos et al, 2001;Ohsugi et al, 1997;Racz et al, 1980;Simpson and Smith, 1992;Tagashira et al, 1997), and cytotoxicity (Bae et al, 1996;Liu et al, 2001;Miranda et al, 1999;Shipp et al, 1994). Many constituents have been reported from hops (Farnsworth, 2003), among which in addition to the aforementioned estrogenic properties, many have been shown to possess other types of biological activity (Honma et al, 1998;Shipp et al, 1994;Tabata et al, 1998;Tobe et al, 1995;Tobe et al, 1997;Yasukawa et al, 1995) such as potential cancer chemopreventive activity (Gerhäuser et al, 2001a;Miranda et al, 2000a) and suppression of COX-2 gene transcription (Yamamoto et al, 2000).…”