Bitter acids

Bitrex Bitter acids Bitter ale Bitter almond oil Bitter bark Bitter magnet... 

Hop "bitter" acids are isomeric mixtures of cyclohexadienone stmctures in both keto and enol forms, substituted at various positions on the ring by hydroxyl, acyl, and alkenyl groups. See Figure 2. 

In addition to the bitter acids and essential oils, the flowers of hops offer a rich array of polyphenolic compounds, primarily chalcones and their accompanying flavanones, many of which are prenylated derivatives (Stevens et al., 1997,1999a, b). The most prominent flavonoid in all plants studied was xanthohumol [342] (3 -prenyl-6 -0-methylchalconaringenin chalconaringenin is 2, 4, 6, 4-tetrahydroxychalcone) (see Fig. 4.11 for structures 342-346). Several additional chalcones—variously adorned with 0-methyl and/or C-prenyl functions—were also encountered, along with their respective flavanones. Three new compounds were described in the Stevens et al. 

Szcs, R., Van Hove, E., Sandra, P. (1996). Micellar and microemulsion electrokinetic chromatography of hop bitter acids. J. High Resolut. Chromatogr. 19 189-192. 

PS Hughes, WJ Simpson. Interactions between hop bitter acids and metal cations assessed by ultraviolet spectroscopy. Cerevisiae Biotechnol 20(2) 35-39, 1995. 

H Claus, J Van Dyck, M Verzele. Photometric constants of hop bitter acids. J Inst Brew 84 218-220, 1978. 

ACJ Hermans-Lokkerbol, R Verpoorte. Preparative separation and isolation of three bitter a-bitter acids from hop, Humulus lupulus L., by centrifugal partition chromatography. J Chromatogr A 664 45-53, 1994. 

PS Hughes. Preparative regime for the purification of bitter acids derived from hops (Humulus lupulus L.). J Chromatogr A 731 327-330, 1996. 

A Holtzel, G Schlotterbeck, K Albert, E Bayer. Separation and characterisation of hop bitter acids by HPLC- H-NMR coupling. Chromatographia 42 499-505, 1996. 

M Verzele, D de Keukeleire. Chemistry and analysis of hop and beer bitter acids. London Elsevier, 1991. 

J Vindevogel, P Sandra. Micellar electrokinetic chromatography of ionic compounds The analysis of hop bitter acids. J High Res Chromatogr 14 795-801, 1991. 

Main actives About 10% of a and fi bitter acids including humulone and lupulone,... 

Benefits Hops are a traditional sedative and soporific (sleep promoter). The bitter acids have been shown to be antibacterial and antifungal and also to stimulate die secretion of gastric juices. Hormonal anaphrodisiac effects have also been reported. 

Bitter acids from hops high wax content 5... 

Many of the hop s constituents, including valerianic acid, have a sedative effect, and it is now used to treat insomnia, restlessness, and anxiety. Its bitter principals, humulon and lupulon, are gastrointestinal stimulants used to treat indigestion and loss of appetite. These bitter acids also have antibacterial and antimicrobial properties. The hop is believed to contain chemicals that promote menstruation, and certain flavonoids have shown potential chemopreventive activity against breast and ovarian cancer. 

For the composition of vegetable flavourings it is essential to distinguish the flavour from the taste part this taste is a balanced composition of harsh, slight bitter acids with salt, some taste enhancers (nucleotides) and sugar to impart a slight sweetness. 

Properties White powder bitter acid taste. Slowly decomposed by heat. D 2.47 (20C), mp 384C. Soluble in water slightly soluble in alcohol. 

Separation of hop bitter acids by CZE and MEKC with UV-diode array detection a-acid and P-acid fractions from commercial hop extract Described by M. Verzele, J. Inst. Brew., 92 (1986) 32... 

The hitter acids of hops [9] have been selectively extracted in a three-step method away from the essential oil fraction (fraction 1) and a hpid fraction (fraction 3). All of the bitter acids were contained in the middle fraction... 

Verschuere et al. [25] observed a similar trend in the extraction of essential oils and bitter acids of hops when using samples as small as 0.25 grams. They observed, "Compared to conventional methods for extraction of alpha-acids and beta-acids, % rsd s are higher with SFE. Typical values are in the order of 10 % for 6 replicates on the same hop sample. This is due to the small sample size requirements if contamination problems have to be avoided. With the extractor used and taken into consideration that the concentration of the bitter acids in hops range as high as 10 %, 250 milligram sample size is the maximum which can be extracted without breakthrough or contamination (of the lipid-free... 

Chromatography methods combined with NMR have been used for the analysis of hop acids and beer bitter acids.378 379 Supercritical fluid chromatography has been used in the analysis of ascorbigens in Brassicas, but in this case the NMR was not on line with the chromatography system.380... 

Humuli iupuli strobulus Hops Humulus lupulus L. Moraceae (Cannabaceae) DAB 10, BHP 83 Acyl phlorogluddes humulone ( a-adds, 3%-12%) Lupulone ( (3-acids,, 3%-5%) unstable compoutids, hop bitter acids... 

Salicylacetatc, CMH20N2O6, a -carhoxy-o anhie acid compound with antipyrirteT l yrosat Crystals mp 149-15B, Bitter acid taste. Sparingly soluble in water soluble in ale. Noie Not to be confused with antipyrine acetyl salicylate,... 

Hydrochloride, C HjjCljNO, HAT 256, Bioteriussin. Per-toxil, Silomat. Minute crystals, mp 169-170. Slightly bitter. acidic taste. Numbs the tongue. Sol in water- LDM in mice 600 mg/kg orally 130 mg/kg i.p., Engelhom, toe. cit. 

Humulon. 3,5t6 Trihydroxy-4,6-bis(3-methyl-2-butenyl) 2 3-methyi-l-oxobutyl) 2,4-cyctohexadien-l-one ct -bitter acid a-lupulic acid- CjgH Oj mol wt 362.45. C 69.58%, H 8.34%, O 22,07%. Antibiotic constituent of hops... 

Picrolicbenic Acid. 6-Hydroxy-2 -methoxy-2,4 dioxo-4,6 -dlpentylspi rofben zofuran-3 2H),T -[2,5jcyclo-hexadieneJ-5-carboxylic acid picrolichenin. C H O, md wt 442.49. C 67.85%, H 6.83%, O 25.31%. Bitter acidic principle of crustose lichen, Pertusaria amara (Ach.) Nyl., Pertusariaceae. Isoln Alms, Ann. Pharm. 1, 61 (1832). 

Tciste is determined in drinking waters only by sensory methods and is expressed by description only (salty, fresh, bitter, acid, or also the taste is... 

Ellagitannins are astringent as compared to gal-lotannins, which give a bitter, acidic impression. The benchmark, procyanidin B3, is both astringent and bitter. 

Structural isomers of essential natural compounds, such as carotenoids and hop bitter acids, show different biological activities. For structure-activity correlation studies in modem medical treatment it is of extreme relevance to know the stereochemical structure of the active ingredient. The classical method of isolation, sample enrichment, purification and transfer to an NMR sample tube frequently fails because the isolated compound isomerizes and decomposes. 

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