Contributions to the Antimicrobial Spectrum of Hop Constituents

Srinivasan, Vanita; Goldberg, Daniel E.; Haas, Gerhard

doi:10.1663/0013-0001(2004)58[s230:cttaso]2.0.co;2

Cited by 42 publications

(35 citation statements)

References 11 publications

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“…We have previously found that the treatment of the birds with lupulone led to decreased plate counts of C. pefringens in our colonization model (Siragusa et al , 2008). Lactobacillus and C. perfringens are Gram‐positive bacteria, and we had expected that hop extract would have an antimicrobial effect as found previously (Teuber & Schmalreck, 1973; Srinivasan et al , 2004). Interestingly, Lactobacillus counts did not significantly decrease with hop exposure in the cecum.…”

Section: Discussionmentioning

confidence: 64%

“…Among these are bacteriocins, antimicrobial peptides, bacteriophages, probiotics, competitive exclusion cultures and plant products (Nurmi & Rantala, 1973; Teuber & Schmalreck, 1973; Chen & Stern, 2001; Joerger, 2003). Extracts from the hop plant, Humulus lupulus , used in beer brewing for centuries, exert antimicrobial effects on Gram‐positive bacteria (Teuber & Schmalreck, 1973; Srinivasan et al , 2004). The efficacy of whole hop flowers as growth promotants in chicken feed has been demonstrated (Cornelison et al , 2006), but as with other AGP in feed, little is known about the effective mechanisms of hop extracts on growth promotion.…”

Section: Introductionmentioning

confidence: 99%

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Chicken intestine microbiota following the administration of lupulone, a hop-based antimicrobial

Tillman

Haas

Wise

et al. 2011

FEMS Microbiology Ecology

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The use of antibiotic growth promotants in poultry rearing is a public health concern due to antibiotic resistance in bacteria and the harborage of resistance genes. Lupulone, a hop b-acid from Humulus lupulus, has been considered as a potential feed additive growth promotant. Here, the effect of lupulone was evaluated for its effect on the microbiota of the chicken intestine. The intestinal microbiota of broilers was quantified after the addition of 125 mg L À1 lupulone to water and challenge with Clostridium perfringens. Microbial DNA was extracted from the broiler midgut and cecal sections and bacterial groups were quantified using real-time PCR. The predominant cecal bacterial groups were Clostridium leptum subgroup 16S rRNA gene Cluster IV, Clostridium coccoides subgroup 16S rRNA gene Clusters XIVa and XIVb and Bacteroides, whereas Lactobacillus, the Enterobacteriaceae family and Enterococcus dominated the midgut. Lupulone at 125 mg L À1 significantly decreased the C. perfringens subgroup 16S rRNA gene Cluster I, which contains several pathogenic species, in both the midgut and the cecum and Lactobacillus in the midgut. No significant changes were noted in the overall microbiota for the cecum or the midgut. Lupulone warrants further evaluation as a botanical agent to mitigate C. perfringens overgrowth in antibiotic-free reared poultry.

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Section: Discussionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Chicken intestine microbiota following the administration of lupulone, a hop-based antimicrobial

Tillman

Haas

Wise

et al. 2011

FEMS Microbiology Ecology

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“…In 1937, Shimwell discovered that the antibiotic properties and bacteriostatic power of hops are restricted to Gram‐positive bacteria, while the Gram‐negative species were mostly unaffected by the hop acids . It was later found that hop acids are also mildly antifungal (on selected fungi species) and antiprotozoal . Among the Gram‐positive bacteria some species of lactic acid bacteria are less sensitive (i.e.…”

Section: Hop Contributions To Beermentioning

confidence: 99%

Humulus lupulus- a story that begs to be told. A review

Schönberger²,

et al. 2014

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The hop cones of the female plant of the common hop species Humulus lupulus L. are grown almost exclusively for the brewing industry. Only the cones of the female plants are able to secrete the fine yellow resinous powder (i.e. lupulin glands). It is in these lupulin glands that the main brewing principles of hops, the resins and essential oils, are synthesized and accumulated. Hops are of interest to the brewer since they impart the typical bitter taste and aroma to beer and are responsible for the perceived hop character. In addition to the comfortable bitterness and the refreshing hoppy aroma delivered by hops, the hop acids also contribute to the overall microbial stability of beer. Another benefit of the hop resins is that they help enhance and stabilize beer foam and promote foam lacing. In an attempt to understand these contributions, the very complex nature of the chemical composition of hops is reviewed. First, a general overview of the hop chemistry and nomenclature is presented. Then, the different hop resins found in the lupulin glands of the hop cones are discussed in detail. The major hop bitter acids (α-and β-acids) and the latest findings on the absolute configuration of the cis and trans iso-α-acids are discussed. Special attention is given to the hard resins; the known δ-resin is reviewed and the ε-resin is introduced. Recent data on the bittering potential and the antimicrobial properties of both hard resin fractions are disclosed. Attention is also given to the numerous essential oil constituents as well as their contributions to beer aroma. In addition to the aroma contribution of the well-known essential oil compounds, a number of recently identified sulfur compounds and their impact on beer aroma are reviewed. The hop polyphenols and their potential health benefits are also addressed. Subsequently, the importance of hops in brewing is examined and the contributions of hops to beer quality are explained. Finally, the beer and hop market of the last century, as well as the new trends in brewing, are discussed in detail. Hop research is an ever growing field of central importance to the brewing industry, even in areas that are not traditionally associated with hops and brewing. This article attempts to give a general overview of the different areas of hop research while assessing the latest advances in hop science and their impact on brewing.

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“…Tannins may play a part in the clarification of beer by precipitating proteins during boiling. Hops bitter acids may protect the beer against lactic acid bacteria (genera of Lactobacillus and Pediococcus) and add to the improvement of the stability of beer foam [5]. Much of attention has been devoted to the polyphenolic content of hops, and specific compounds, such as xanthohumol and 8-prenylnaringenin, have been identified as multipotent bioactive compounds.…”

Section: Introductionmentioning

confidence: 99%

Supercritical carbon dioxide hops extracts with antimicrobial properties

et al. 2015

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Extracts obtained from hops (Humulus lupulus L., Cannabaceae) by supercritical fluid extraction (SFE), SFE followed by isomerization, as well as by conventional technique, were investigated for their chemical composition and antibacterial activity against selected foodborne pathogens and microorganisms capable to cause the food spoilage. The antibacterial activity of the extracts was compared with the antibacterial activity of xanthohumol, compound known for its broad pharmacological properties, isolated from the raw material remained after the SFE. Xanthohumol (XH, 96%) proved to posses the most prominent activity against all the tested strains, with the MIC values ranged between 2.5 and 20 μg mL -1 . Supercritical hops extract and potassium isomerized supercritical hops extract showed strong antibacterial activity against the tested strains as well. Escherichia coli was not affected by the extracts, meaning that their oral admission would not cause the same problem as antibiotic application in intestinal flora. The chemical composition of the investigated hops extracts was analysed by GC-MS. Contents of α-acids, β-acids, iso-α-acids and xanthohumol in the samples were determined by HPLC.

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Contributions to the Antimicrobial Spectrum of Hop Constituents

Cited by 42 publications

References 11 publications

Chicken intestine microbiota following the administration of lupulone, a hop-based antimicrobial

Chicken intestine microbiota following the administration of lupulone, a hop-based antimicrobial

Humulus lupulus- a story that begs to be told. A review

Supercritical carbon dioxide hops extracts with antimicrobial properties

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