Structural Elucidation of Humulone Autoxidation Products and Analysis of Their Occurrence in Stored Hops

Taniguchi, Yoshimasa; Taniguchi, Harumi; Matsukura, Yasuko; Kawachi, Yasuji; Shindo, Kazutoshi

doi:10.1021/np4008427

Cited by 23 publications

(35 citation statements)

References 23 publications

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“…In contrast, oxidation of α-and β-acids produces bitter acid oxides, such as matured hop bitter acids (MHBA). All of the structurally elucidated compounds of MHBA possess a common β-tricarbonyl moiety similar to α-, β-, and isoα-acids (Taniguchi et al, 2013(Taniguchi et al, , 2014a(Taniguchi et al, , 2014b(Taniguchi et al, , 2015. We demonstrated that MHBA suppresses diet-induced body fat accumulation in animals (Morimoto-Kobayashi et al, 2015).…”

Section: Introductionmentioning

confidence: 76%

Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops

et al. 2018

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It has been demonstrated that successive ingestion of matured hop extract (MHE), produced by extraction from heat-treated hops, results in body fat reduction in animals and humans; however, preclinical safety studies have not been reported. In this study, we conducted in vitro and in vivo safety studies for MHE. Genotoxicity was evaluated using the Ames test, in vitro chromosomal aberration test, and in vivo micronucleus test. To assess acute safety, a single, oral administration of MHE to rats was monitored. Subchronic safety was assessed by repeated feeding with MHE for 90 days. The in vitro chromosomal aberration test was positive at 3,330 μg/mL and 5,000 μg/mL without metabolic activation. However, MHE did not induce any reverse mutation with or without metabolic activation in the Ames test, and no abnormalities were observed at a dose of 2,000 mg/kg body weight in the rat micronucleus test. In the acute and subchronic safety studies, no deaths or toxicological signs were recorded during the observation period. In addition, no changes in body weights, feed/water consumption, clinical signs, ophthalmoscopy, urinalysis, hematology, blood biochemistry, organ weights, or histopathology were observed after repeated administration of MHE. Therefore, the no-observed-adverse-effect-level (NOAEL) of MHE was considered to be over 3,484 and 4,022 mg/kg body weight/day in males and females, respectively. These results indicate that there is no safety concern for MHE in the present preclinical safety study.

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Section: Introductionmentioning

confidence: 76%

Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops

et al. 2018

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“…The obtained respective solid was dissolved in EtOH (0.500 mg/mL) and analyzed by a Prominence UFLC system (Shimadzu, Kyoto, Japan). The analyses were performed using the following conditions 32,33) : column: 100 × 2.1 mm id, 3 μm, Alltima C 18 column (Systech, Tokyo, Japan); solvent: H 2 O/H 3 PO 4 (85%), 1000/0.2, (v/v) containing EDTA (0.02% w/v) (solvent A) and MeCN (solvent B), a linear gradient from 10 to 52% B in 0 → 26.7 min, 52% B for 26.7 → 30 min, 52 to 75% B in 30 → 32.7 min, 75 to 85% B in 32.7 → 36.7 min, and 85% B for 36.7 → 37.7 min; flow rate: 0.6 mL/min; detector: 270 nm; and column temperature: 40°C. The injection volume was 3.0 μL.…”

Section: Methodsmentioning

confidence: 99%

“…1). 32,33) We also revealed that 4′-hydroxyallohumulinones (6a-c) isomerize into 4′-hydroxyallo-cis-humulinones (7a-c) and degrade into cis-oxyhumulinic acids (8a-c) during the wort boiling process (Fig. 1).…”

mentioning

confidence: 88%

Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components

Taniguchi¹,

Matsukura²,

Taniguchi³

et al. 2015

Bioscience, Biotechnology, and Biochemistry

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The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS(2) revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides.

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“…Ještě menší je pokles obsahu beta kyselin (8,3 % rel.). Je to dáno tím, že řada transformačních reakcí alfa kyselin, na rozdíl od beta kyselin, nevyžaduje přítomnost kyslíku (Taniguchi, 2014). Skladování granulovaného chmele za přístupu vzduchu při teplotách kolem 20 °C má na kvalitu chmele silně destruktivní vliv.…”

Section: Hořké Látky a Stáří Chmeleunclassified

“…Even lower is the decrease in beta acid content (8.3% rel.). This is due to the fact that unlike in beta acids, a number of transformation reactions of alpha acids do not require the presence of oxygen (Taniguchi, 2014). Storage of granulated hop in air at temperatures around 20 °C has a strong destructive effect on the quality of hops.…”

Section: Vliv Ročníku Na Obsah Hořkých Látek Ve Chmelumentioning

confidence: 99%

Determination of Bitter Compounds in Hops - Effect of Crop Year and Hops Age

et al. 2017

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Krofta, K., Mikyška, A., Jurková, M., Mravcová, L., Vondráčková, P., 2017: Stanovení hořkých látek v chmelu -vliv ročníku a stáří chmele. Kvasny Prum. 63(5): [241][242][243][244][245][246][247] Práce je zaměřena na vzájemné porovnání čtyř metod stanovení alfa kyselin ve chmelu (EBC 7.4, EBC 7.5, ČSN a EBC 7.7) a jejich aplikaci při hodnocení chmele skladovaného za různých podmínek. Dále jsou diskutovány výsledky porovnání prognózovaných a skuteč-ných hodnot alfa kyselin v dlouhodobém sledování sklizní tří českých odrůd chmele. Největší rozdíly byly zjištěny mezi metodami EBC 7.5 (KH) a EBC 7.7 (HPLC), prvá dává systematicky vyšší výsledky a rozdíl exponenciálně stoupá s hodnotou indexu skladování chmele (HSI), u čerstvých chmelů je rozdíl 10 -15 % rel., u starších chmelů s HSI 0,6 -0,7 je rozdíl 25 -45 % rel. Předsklizňová prognóza i sklizňový odhad alfa kyselin v Žateckém poloraném červeňáku jsou v dobré shodě se skutečností (kr = 0,93; kr = 0,95), totéž platí i pro relaci sklizňového odhadu a skutečnosti odrůd Sládek a Premiant (kr = 0,93; kr = 0,97). Our study is focused on mutual comparison of four methods of determination of alpha acids in hops (EBC 7.4, EBC 7.5, ČSN and EBC 7.7) and their application in evaluation of hops stored under different conditions. Furthermore, the results of the comparison of predicted and actual alpha acid values in the long-term monitoring of harvesting of three Czech hop varieties are discussed. The largest differences were found between the EBC 7.5 (LCV) and EBC 7.7 (HPLC) methods; the fi rst method gives systematically higher results and the difference exponentially increases with the hop storage index (HIS) value. The difference in HSI in fresh hops is 10 -15% rel. while the difference in older hops with HSI 0.6 -0.7 is 25 -45% rel. Pre-harvest prognosis and harvest estimate of alpha acids in the Saaz variety are in good agreement with the facts (kr = 0.93, kr = 0.95) and the same holds for the harvest estimation relation and the reality of the varieties Sládek and Premiant (kr = 0.93; 0.97). KroftaKrofta, K., Mikyška, A., Jurková, M., Mravcová, L., Vondráčková, P., 2017: Die Bestimmung von Bitterstoffen -der Einfl uss des Jahrganges und des Alters. Kvasny Prum. 63(5): 241-247Der Artikel beschäftigt sich mit einem Gegenvergleich von vier Methoden zur Bestimmung α-Säuren im Hopfen (EBC 7.4, EBC 7.5, Tschechische Norm ČSN und EBC 7.7) und ihre Applikation im unter unterschiedlichen Bedingungen gelagerten Hopfen. Weiterhin werden die Ergebnisse der Vergleichung vom vorhersagten und wichtigen Gehalt an α-Säuren im Hopfen während der langfristigen Ernten Verfolgung von drei tschechischen Hopfensorten diskutiert. Die größten Unterschiede wurden unter folgenden Methoden EBC 7.5 (KH) und EBC 7.7 (HPLC) festgestellt, die erste systematisch gibt höhere Ergebnisse, der Unterschied exponentiell steigt mit dem Wert des Hopfenlagerungsindex (HSI), bei dem frischen Hopfen tut der Unterschied 10 -15% (rel.) bei älteren Hopfen mit dem Wert HSI 0,6-0,7 gibt's schon Unterschied 25 -45 % (rel.)...

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Structural Elucidation of Humulone Autoxidation Products and Analysis of Their Occurrence in Stored Hops

Cited by 23 publications

References 23 publications

Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops

Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops

Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components

Determination of Bitter Compounds in Hops - Effect of Crop Year and Hops Age

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