Bitter principles,

The term bitter principle is used in reference to any one of a group of unrelated constituents responsible for the bitter taste characteristic of many herbs. Most are derived from terpenes, though non-terpene structures such as certain flavonoids and alkaloids are included with the bitters. 

Recent research indicates up to 80 different bitter taste receptors in humans. These are genetically linked to loci that influence bitter perceptions—hence individuals have vastly different abilities to perceive bitter tastes (Drewnowski and Gomez-Carneros 2000). This genetic variability (polymorphism) has been interpreted as a protective mechanism for identification of bitter poisons however, it can also 

Name Class of compounds Main constituents Bitterness index 

Quassia arama Secotriterpenes Quassin 0.1-0.15% 17X10 Wood 40-50 000 

Triterpenes represent a very large group of medicinal plant compounds, and so a separate chapter has been devoted to them (Chapter 6). 

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These methods are employed for the detection and determination of antibiotics and substances with similar effects, like alkaloids, insecticides, fungicides, mycotoxins, vitamins, bitter principles and saponins [14]. 

Manual transfer of the chromatographically separated substance to the detector . These include, for example, the detection of antibiotically active substances, plant and animal hormones, mycotoxins, insecticides, spice and bitter principles and alkaloids. The frequency distribution of their employment is shown in Figure 54 [295]. 

The Aristolochias are used in medicine as tonics due to the presence of bitter principles, though Hesse suggested that A. reticulata Nutt, then the serpentary root of commerce, might contain aristolochine, and the view that the bitter constituents are of alkaloidal character has been confirmed by Krishnaswamy, Manjunath and Rao, for A. indica L. 

The isolation of four terpenes from the bitter principles of Ginkgo by Furukawa in 19326 marked an important advance in the quest for the identification of the active constituents of Ginkgo extracts. A second major milestone was reached in 1967 when Nakanishi and his group reported their extensive and brilliant studies which permitted the structures of these compounds to be fully defined.4 On the basis of spectroscopic data and chemical reactivity... 

Oleuropein (the most abundant bitter principle) and its analog ligstroside, both sec-oiridoid biophenols, were extracted from Hojiblanca black olives (Piperno and others 2004). Secoiridoids are present exclusively in plants of the Oleraceae family (Tripoli and others 2005). Oleuropein is present in high amounts (6000 90 mg/100 g DW) in the leaves of the olive tree (Le Tutour and others 1992), but it is also present in all constituent parts of the fruit peel, pulp, and seed (Servili and others 1999). 

These compounds were first isolated in 1932 by Furukawa [176] from the bitter principles of Ginkgo biloba, but their structures have been resolved only recently. In 1967, Nakanishi s group reported their structures and called them Ginkgolides A, B, C and M (25a,b,c,e) [177-181], These are termed BN 52020, BN 52021, BN 52022 and BN 52023, respectively, in IHB nomenclature. A new ginkgolide, J (BN 52024 25d) has been recently identified [182]. All these compounds differ only by the number and the position of hydroxy groups, which may be present on C1 C3 or C7 of the spirononane framework. 

Kesterson JW, Hendrickson R (1957) Naringin, a bitter principle of grapefmit. Univ Fla Exp Stn Bull 51 lA... 

The aposematic beetle, Metriorrhynchus rhipidius, contains three pyrazines as warning odor components and two amides as bitter principles (Tables III, V, and VIII) (97). Of the three components with the beetlelike odor, the most characteristic is 2-methoxy-3-isopropylpyrazine (24b). The other two components are 2-methoxy-3-methylpyrazine (24a) and 2-methoxy-3-sec-butylpyrazine (24d). It would seem likely that these compounds will occur in the defensive systems of the aposematic beetles. The two amide components, detectable in the hemo-lymph exuded by adult beetles, are 3-phenylpropanamide (130) and l-methyl-2-quinolone (57), the latter being the major component. It seems likely that these bitter principles contribute to distastefulness to potential predators. 

H. A. Donia. Chemical characterization and preliminary pharmacological screening of the bitter principle iso- DC186 lated from Daucus carota L. var. boissieri Schweinf. growing in Egypt. J Drug Res (Egypt) 1979 11 115-120. 

Tannin. Bitter principle of plant containing plant polyphenols. 

Carduus aeaulis Thunb. C. crispus L. C. japonicus Franch. (Syn. Cirsium japonicum) Xiao Ji (Plumeless thistle) (leaf, stem) Essential oils, glycosides, bitter principle.49 Hemostatic. 

Elephantopus scaber L. Tian Ja Cai (Rough elephant s foot) (whole plant) A bitter principle, a glycosidic compound.50-52 Diuretic, tonic, vermifuge, for diarrhea, dysentery, leucorrhea. 

N.A. Apocynum androsaemifolium L. Glucoside apocynamarin, a bitter principle cymarin, apocynein, apocynin, volatile oils, fixed oils, caoutchouc.100 For rheumatism, scrofula and syphilis. 

Industrial plants are working at 300 to 350 bar and 40 to 65°C. Under these conditions all the hop bitter-principles are extracted quantitatively. The content of total resins in the extract is about 90% and a part of the hard resins is extracted, which is not the case with subcritical conditions. 

XXXV) 1 3 - imi the fall poison pierotoxiain (XXXVI), ae well as coriamyrtin1 73 and related substanoes the citrus bitter principle limonin (XXXVII) and the related substances nomilin and obaou-none 4" and the terpenoid substances clerodin1 7.1 and oedre-kne.im.iMa... 

A 2-deoxy-3-0-methylpentose (corchsularose) was isolated, as the crystalline phenylhydrazone, from corchsularin,11 a bitter principle from the alcoholic extract of jute seeds. According to this investigation, the structure of the pentose derivative was adequately corroborated by the isolation of methoxysuccinic acid after permanganate oxidation. It seems remarkable, however, that a 2-deoxypentose derivative should withstand the conditions of hydrolysis (concentrated hydrochloric acid) which were employed to liberate it. 

Rectified spirit is also used for the manufacture of liqueurs, by addition of various substances, such as natural or artificial essences, sugars, bitter principles, etc. 

Investigation of the Bitter Substances.—For the complete investigation of the various injurious bitter principles, reference must be made to the special articles in books dealing with the subject.2... 

Turpentine is an oleo-resin exuded from the trunks of certain conifers (so-called Scio turpentine is obtained from one of the Terebinthaceae, Pistada terebinthus L.) and consists essentially of resin acids, neutral resins, volatile oil and small proportions of various other substances (succinic acid, bitter principles, colouring matters, water). Distillation of turpentine and rectification of the distillate gives oil oj turpentine, the residue being colophony. By dry distillation of the latter resin oils are obtained. The present chapter deals with the natural product, i.e. turpentine, and with the products obtained from it. 

Isolation of nomilin, a new bitter principle from the seeds of oranges and lemons. J. Am. Chem. Soc., 19A8, 7Q, 5A5-5A9. 

Emerson, 0. H. The bitter principle in Navel oranges. Food Tech, 19A9, 3, 2A8-250. 

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