Chemistry and Biology of Hop Flavonoids

Stevens, Jan F.; Miranda, Cristobal L.; Buhler, Donald R.; Deinzer, Max L.

doi:10.1094/asbcj-56-0136

Cited by 60 publications

(65 citation statements)

References 24 publications

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“…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.…”

Section: Prenylated Flavonoidsmentioning

confidence: 99%

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

2006

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SummaryAs the population ages, there is an ever-increasing need for therapeutic agents that can be used safely and efficaciously to manage symptoms related to postmenopausal estrogen deficiency. Endogenous estrogens, e.g., 17β-estradiol, of exogenous mammalian origin, e.g., horses, have long been used to manage such symptoms. There are more than twenty different classes of phytochemicals that have demonstrated affinity for human estrogen receptors in vitro. Some studies on exogenous estrogenic substances of botanical origin ("phytoestrogens"), such as standardized formulations of plant extracts with in vitro and in vivo estrogenic activity from soy (Glycine max Merill.) and red clover (Trifolium pratense L.), suggest clinical efficacy. Few clinical data for phytoestrogens other than isoflavonoids are available. In an exhaustive review of the literature through 2003, only two clinical trials were identified that were designed to evaluate the effect of hops (Humulus lupulus L.) on symptoms related to manopause. Folkloric, chemical, and biological literature relating primarily to the use of hops for their estrogenic activity, and two human clinical trials, are reviewed.

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Section: Prenylated Flavonoidsmentioning

confidence: 99%

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

2006

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“…In addition to the agronomic and brewing characteristics of hops, their pharmacological properties have recently been studied with promising results (eg Stevens et al, 1998). Different compositions of medicinal components have been found in wild hops (Stevens et al, 2000).…”

Section: Breeding and Genetic Resourcesmentioning

confidence: 99%

Molecular phylogeny of wild Hops, Humulus lupulus L.

et al. 2006

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We have analysed wild hops collected widely from the Northern Hemisphere, assessing the genetic diversity and the geographical distribution of haplotypes, to investigate the evolution and phylogeny of hops, Humulus lupulus. The haplotypes were characterized by the nuclear ribosomal DNA spacer region (length and DNA sequence) and chloroplast DNA noncoding regions (DNA sequences). The results indicated that primary divergence into European (including Caucasus and Altai hops), and Asian-North American types, was 1.0570.28 to 1.2770.30 million years ago. Although an Eastern boundary for European nuclear haplotype distribution was unclear due to the ambiguous origin of Northern Chinese samples, the European hop group showed a wide geographical distribution across Eurasia from the Altai region to Portugal. The low genetic variation in this group suggested rapid and recent expansion. The North American hop group showed high diversity, and is considered to include hops that have migrated from Asia. Japanese and Chinese hops were identified as genetically distinct. This study has shown that wild hops in each growing region are genetically differentiated with considerable genetic diversity. It gives insights into the evolution and domestication of hops that are discussed.

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“…The strobiles of Humulus lupulus L. (Cannabaceae) (hops) are primarily used to flavor beer, and have been studied since 1953 for a potential estrogenic mechanism of action [13][14][15]. In the past, the flavonoids 8-PN and 6-PN, and the chalcone, isoxanthohumol (IX), have been isolated and reported to be estrogenic in vitro and/or in vivo [16,17].…”

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confidence: 99%

In vivo estrogenic comparisons of Trifolium pratense (red clover) Humulus lupulus (hops), and the pure compounds isoxanthohumol and 8-prenylnaringenin

Overk

Guo

Chadwick

et al. 2008

Chemico-Biological Interactions

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The lack of a safe and reliable alternative to hormone therapy (HT) for treating menopausal symptoms underscores the need for alternative therapies. OBJECTIVE: The purpose of this study was to assess the in vivo estrogenic effects of the botanical dietary supplements Trifolium pratense (red clover) and Humulus lupulus (hops), and two compounds obtained from H. lupulus, isoxanthohumol and 8-prenylnaringenin (8-PN) using the ovariectomized uterotrophic adult rat model. A H. lupulus extract and a 30% isoflavone extract of T. pratense were tested at three escalating doses as was one dose of isoxanthohumol for 21 days. 8-Prenylnaringenin, the major estrogen in H. lupulus, was also tested at three relevant escalating doses. In order to determine the in vivo metabolism of 8-PN, the major Phase I and Phase II metabolites were also identified. The primary outcome measure, uterus weight gain, indicated that H. lupulus and T. pratense did not have an estrogenic effect on the uterus, and none of the secondary outcome measures were positive. In contrast, there was a clear dose response when 8-PN was evaluated where the middle and high doses of 8-PN were active. 8-Prenylnaringenin in rat plasma, liver, and mammary gland was measured and the major Phase I and Phase II 8-PN metabolites were detected. Our findings suggest that while both the H. lupulus and T. pratense extracts do not have an effect on the rat uterus, 8-PN at equivalent doses to those previously used in humans did have an effect, and may therefore have a deleterious effect in women. IntroductionSymptoms associated with menopause such as insomnia, loss of libido, vaginal atrophy, depression, and hot flashes can greatly affect the quality of life for women. Many women have used hormone therapy (HT) to alleviate menopausal symptoms; however, with the publication The strobiles of Humulus lupulus L. (Cannabaceae) (hops) are primarily used to flavor beer, and have been studied since 1953 for a potential estrogenic mechanism of action [13][14][15]. In the past, the flavonoids 8-PN and 6-PN, and the chalcone, isoxanthohumol (IX), have been isolated and reported to be estrogenic in vitro and/or in vivo [16,17]. The most potent estrogen in H. lupulus is 8-PN, which is in actuality an artifact formed through isomerization of the precursor chalcone, desmethylxanthohumol [18,19]. 8-Prenylnaringenin has been shown in a variety of in vitro assays to be estrogenic in the nanomolar range [16,17,20,21]. It can also be formed from precursors such as IX, and xanthohumol (XH), through metabolism [22].In previous metabolic studies, it has been shown that human liver microsomes convert 8-PN to 12 metabolites [22]. Among them, are the most abundant monooxygenated metabolites (Figure 1). The estrogenicities of the 8-PN alcohols have been previously determined [23] and were found to be ∼10 fold less estrogenic than 8-PN. Phase II metabolites of 8-PN, including glucuronides and sulfate conjugates, have been identified in incubations with human Caco-2 cells and human hepatocytes [2...

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Chemistry and Biology of Hop Flavonoids

Cited by 60 publications

References 24 publications

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

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

Molecular phylogeny of wild Hops, Humulus lupulus L.

In vivo estrogenic comparisons of Trifolium pratense (red clover) Humulus lupulus (hops), and the pure compounds isoxanthohumol and 8-prenylnaringenin

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