Bitter cucumber

Cucurbitacin C Cucumis sativus (bitter cucumber) Bitter [toxic]... 

Coloeynth A Medlteranian and African herbacious vine (Citrullus colocynthls) allied to the watermelon also, its fruit, from which is prepared a powerful cathartic. Called also bitter apple, bitter cucumber end bitter gourd. 

Cucurbitacin is a bitter-tasting principle that can be isolated from members of the family Cucurbitaceae, such as cucumber Cucumis sativus) and melon (Cucumis melo L.). In particular, cucurbitacin149 and momordicine,150 which have an intensely bitter taste, are contained abundantly in Momordica charantia (bitter melon in English, go-yaa in Okinawa, Japan), which people enjoy due to its bitterness. There are more than 18 kinds of cucurbitacin, and among them cucurbitacin B is a typical component. It has been reported that cucurbitacin exhibits anticancer activity.1 1 In addition, it is used for the treatment of hepatic disease in traditional Chinese medicine. It is also found in some herbal teas. 

Leases with yellow patches older leaves mottled and distorted. Cause Mosaic. For an tiiustration of this virus, see page 214. Afflicted plants are unproductive and fruit is bitter. Remove and destroy diseased plants. Control aphids and cucumber beetles, beeause the> spread the virus. 

Bryonia alba, White bryony Bryonia dioica, Red bryony Ecballium elaterium. Squirting cucumber Citrullus colocynthis, Bitter apple... 

Kilham drops to all four limbs and chews on an Indian cucumber plant. A cub that he is raising comes over to sniff his mouth to learn that this is the smell of a food plant. Then the cub locates a plant with similar smell and begins eating it. This is the way bear cubs learn from their mothers which of the many choices of food are acceptable and safe. When they first encounter a plant, they hold the plant in their mouths before they eat or discard it. This is probably a survival behavior to check the taste of the plant to determine if it is edible. Bitter plants are usually toxic. 

Occurrence E)-2-A. Cg-C,3 in citrus oils, especially bitter orange, Cg also in guava and ginger aromas, C, in bread, cucumber, carrot (see vegetable flavors) and rice flavor, c,o in coriander oil, butter, chicken and guava aroma, C,2 in coriander oil, peanut and meat flavor. (Z)-4-Heptenal is found, among others, in "butter, seafood and tea flavor, (Z)-3- and (Z)-6-nonenal in cucumber, melon and fish aroma, and (Z)-4-decenal in calamus oil and Citrus junos oil. ... 

CucurbHacins. Large group (>40) of tetracyclic tri-terpenes, mostly occurring in glycosidic form (exceptions C. A, C. C, and C. F) as poisonous bitter substances in cucumber and pumpkin plants (Cucurbitaceae) as well as in some craciferous plants (Brassicaceae) they have also been isolated from an agaric ( hebevino-... 

The name of about 50 naturally abundant cucurbitanes stems from Cucurbitaceae, the Latin term of cucurbitaceous plants such as cucumbers and pumpkins, known since antiquity for their beneficial and toxic properties. One of the most frequently isolated representatives is the bitter substance (+)-cucurbitacin B from Phormium tenax and Ecballium elaterium (Cucurbitaceae), also found in Iberis species (Cru-ciferae), Euphorbiaceae and Scrophulariaceae. (+)-Cucurbitacin F from Cucumis angolensis and C. dinteri is reported to inhibit the growth of human tumor cells. Toxic cucurbitacines shape the unpleasant bitter taste of salads prepared from spoiled cucumbers Cucumis sativus some representatives are reported to be antihypertonic, antirheumatic, and also active against HIV. 

Other distinguishing features Male flowers have 5 stamens, 4 in pairs and the fifth free. The pulp of the fruit tastes sour or bitter and is greenish-white with a large amount of cucumber-like placenta. 

Although cucurbitacins serve as allomones for most other insects, these compounds are kairomones, or attractants, for many insects associated with the Cucurbitaceae (Metcalf, 1985). For example, when cucumber beetles are offered a choice of nonbitter and bitter (cucurbitacin containing) fruits, they feed almost exclusively on the bitter fruits (11 1). When given the same choice, the honeybee. Apis mellif-era, will select food materials lacking the cucurbitacins (Har-bome, 1982). 

Humans are very sensitive to some types of secondary products. The bitter taste of the alkaloid brucine (D 21.3), may be recognized in concentrations of 10 %, the odor of cucumber in a concentration of 10 %. The threshold concentrations are different in different persons and depend on the physiological state even in one and the same person. 

Cucurtbitacins are tetracyclic compounds produced by plants of Cucurbitaceae family and humans sense their taste as bitter. Some specialized cucumber leaf beetles of can efficiently detoxify these compounds. Limonoids are a large group of oxygenated triterpenoids produced by plants in Rutaceae and Meliaceae famihes. 

Bitter and nonbitter forms of the many Cucur-bitaceae are known. The bitter forms contain cu-curbitacins (III) in fruits and seeds. For example, Citrullus lanatus (watermelon) contains HIE in glycosidic form while Cucumis sativus (cucumber) contains IOC and Cucurbita spp. (pumpkin) contains IIIB, D, E and I (cf. Formula 18.6). 

Vegetables of the cucurbit family (Cucurbitaceae), which includes squashes, melons, pumpkins, cucumbers and gourds of the genera Benincasa, Citrullus, Cucumic, Cucurbita, Lagemria and Lujfa, occasionally show bitter taste in response to various... 

Horie H., Ito H., Ippoushi K., Azuma K., Sakata Y., Igarashi I. Cucurbitacm C-bitter principle in cucumber plants Japan Agricultural... 

In recent times, the English have developed seedless varieties of cucumbers that set fruit without pollination and are grown exclusively in greenhouses from which bees are excluded. Pollination of these varieties results in seedy, bitter fruit that is unsuitable for marketing. 

Raw cucumbers or pickles may be diced or sliced and added to relish trays, salads, and sandwiches. It is noteworthy that the slightly bitter flavor of the raw vegetable is improved by dressing with acid-flavored items such as lemon juice, mayonnaise, sour cream, vinegar, and yogurt whereas pickles are acid-flavored to begin with, and have no need for such dressing. 

Melons Cucumis melo) are relatives of cucumbers. The first melons were bitter, but they were bred to produce sweeter fruit and introduced into Europe from Africa by the Moors. They reached France in the fifteenth century and were taken to the New World by Columbus. Melons and cantaloupes contain high levels of carotenes. Watermelons Citrullus lanatus) are distant relatives of melons, widely spread throughout Africa. They were known to the Egyptians and wild watermelons grow in the Kalahari Desert. Watermelons were introduced to Europe in the fifteenth century. Watermelon can contain high levels of carotenes, particularly lycopene 23-72 mg/1 have been reported (van den Berg et al. 2000). 

Another example of partial modification in the insect is found with the beetle Diabrotica speciosa. It feeds normally on plants of the Cucurbita-ceae (cucumbers) which contain bitter triterpenoids (Chapter 7) called cucurbitacins. D. speciosa when fed on [ C]-cucurbitacin B converts it by removing the C-25 acetate and reduces the side-chain double bond to give dihydrocucurbitacin D (Figure 10.17). Other species raised on diets free of cucurbitacins, when fed cucurbitacin D, were able to glycosylate it (at the 2-OH), hydrogenate, desaturate and acetylate it. 

Termination reactions may lead to the formation of both high and low molecular weight products of the peroxidation reactions. Depending on the lipid, some of the low molecular mass compounds may be important flavours (or aromas) of foods (section 5.2.3). For example, short to medium chain aldehydes formed from unsaturated fatty acids may give rise to rancidity and bitter flavours on the one hand or more pleasant attributes such as those associated with fresh green leaves, oranges or cucumbers on... 

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