Biological and chemical standardization of a hop (Humulus lupulus) botanical dietary supplement

Abstract

Concerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus, L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8-prenylnaringenin (8-PN), its isomer 6-prenylnaringenin (6-PN), and pro-estrogenic isoxanthohumol (IX) and its isomeric chalcone xanthohumol (XN), all of which were measured using high performance liquid chromatography-tandem mass spectrometry (LC/MS-MS). The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy.

A standardized Humulus lupulus (L.) ethanol extract partially prevents ovariectomy-induced bone loss in the rat without induction of adverse effects in the uterus

“…As reported previously (Krause et al, 2014), using a LC-MS/MS method, XN is the major constituent of the extract (35.78 %), followed by 6-PN (2.18 %), IX (1.35 %) and 8-PN with (0.42 %). Accordingly, there is an approximate 100:1 ratio between the abundance of XN and 8-PN.…”

“…In 2014, Krause et al described the chemical standardization of a hops botanical supplement which has also been standardized for estrogenic properties (Krause et al, 2014). Subsequently, the pharmacokinetic of this hops extract was investigated in five post-menopausal women (van Breemen et al, 2014).…”

“…The preparation and standardization (chemical and biological) of the hops extract that was used in the present and other parallel studies has been described in detail previously (Krause et al, 2014; van Breemen et al, 2014). In brief, hops with an optimum content of prenylated flavonoids were extracted with ethanol under GLP conditions, the bitter acids removed by supercritical CO 2 extraction of the dried crude extract, and the resulting spent hops extract processed to yield a dry, yellow powder (Hopsteiner, New York, NY, USA).…”

“…In brief, hops with an optimum content of prenylated flavonoids were extracted with ethanol under GLP conditions, the bitter acids removed by supercritical CO 2 extraction of the dried crude extract, and the resulting spent hops extract processed to yield a dry, yellow powder (Hopsteiner, New York, NY, USA). Details of the LC-MS chemical standardization of this bulk spent hops extract for four marker compounds (XN, IX, 8PN, 6PN) have been reported using LC-MS (Krause et al, 2014) as well as by UHPLC and qHNMR (Ramos Alvarenga et al, 2014) as part of the development of hops extracts from this bulk extract. The material was stored at −25 °C until use and has shown no detectable signs of degradation over time.…”

“…1) (Krause et al, 2014) for potential use in the management of menopausal complaints. Ovariectomized rats are an established preclinical model of osteoporosis caused by estrogen defficiency that has been previously used to assess bone protective effects of dietary compounds (Lelovas et al, 2008).…”