Citrus agents

M.p. 190-192 C. The enolic form of 3-oxo-L-gulofuranolactone. It can be prepared by synthesis from glucose, or extracted from plant sources such as rose hips, blackcurrants or citrus fruits. Easily oxidized. It is essential for the formation of collagen and intercellular material, bone and teeth, and for the healing of wounds. It is used in the treatment of scurvy. Man is one of the few mammals unable to manufacture ascorbic acid in his liver. Used as a photographic developing agent in alkaline solution. 

Biological and Natural Controls. Parasites and predators are effective in limiting the numbers of pest Insects and plant pathogens both in nature and for crops (35). This basic fact led to the development of biological controls. For example, the vedalia beetle, which was Introduced for control of cottony cushion scale on citrus in California, has provided continuous effective control of this pest for many decades. Worldwide only approximately 1% of the pests have been effectively controlled by Introduced biological control agents (43). 

Ben-Hayyim etal. (1987) demonstrated that cultured citrus cells selected for tolerance to NaCl were most tolerant to polyethylene glycol, followed by NaCl and then CaC. The exposure of the cells to any of these osmotic agents resulted in an increase in intracellular K. The authors concluded that K played a key role in the growth of cells exposed to salt. Other researchers have also suggested that K may play a significant role in the response of plant cells to salinity (Rains, 1972 Croughan, Stavarek Rains, 1978 ... 

Many plant products are very rich in cell wall materials. Cereal brans, seed hulls, various pulps (including beet pulp), citrus peels, apple pomace... are typical exemples of such by-products (1,2). They can be used after simple treatments as dietary fibres, functional fibres or bulking agents, depending on the nutritional claims (2). They can be used also eis sources of some polysaccharides. 

The microorganism was classified as a new species of actinomycete. Streptomyces avermitilis. Its anthelmintic activity was shown to reside in 8 closely related macrocyclic lactones, named avermectins, which were also found to possess activity against free-living and parasitic arthropods. One of the natural components, avermectin is now being evaluated as a pesticide for the control of mites of citrus and cotton crops and control of the Red Imported Fire Ant. A chemical derivative, 22,23-dihydroavermectin or ivermectin, has been developed as an antiparasitic agent. It is being marketed for use in cattle, horses and sheep and is expected to become available for swine and dogs. 

Uses. Heat transfer agent fungistat for citrus fruits in organic synthesis... 

Example 1 Citrus oil or citrus root products can Indeed kill slugs if they are applied as a contact agent or act as a slug repellent. Although some patents have been issued on the use of citrus oil as a slug control agent, such control with a contact agent is difficult and the chemical compositions of citrus oil and root exudate are ill-defined. Other obstacles for commercialization of citrus oil are (1) market size is too small to justify the development cost, and (2) an effective delivery method has yet to be developed. 

Examples 3 and 4 illustrate a potential application of allelo-pathic chemicals in today s agricultural practices, as illustrated in Figure 3 to plant allelopathlc plants as a cover crop in the field, especially for tree crops such as peach and citrus. Such plants produce allelopathlc chemicals to control soil pests such as nematodes. This approach will be appreciated today, because there is no effective agent to control soil pests on a field scale and, as has been noted, there is no economic incentive for a chemical company to develop a minor-crop pesticide. 

Lemon oil from Citrus limon), used as flavouring agent. 

Citrus reticulata Blanco C. reticulata Blanco, var. chachiensis Jiu Hong, Chen Pi (Orange) (external layer of pericarp) Citral, geraniol, linalool, methylanthranilate, stachydrine, putrescine, apyrocatechol, naringin, poncirin, hesperidin, neohespiridin, nobiletin.33 Expectorant, antitussive, treat indigestion, an antiemetic agent. 

BERGAMOT OIL. An essential oil, Brownish-yellow to green liquid, agreeable odor, bitter taste, produced from the nnd of the fruit of Citrus aurantium or C. bergamia, relatives of the orange and lemon, The small trees are cultivated in southern Europe. The oil is expressed from the skin of the small yellow fruits and sometimes is used as a scent for cosmetics. The oil also is used sometimes as a clearing agent in the preparation of material for microscopic examination. 

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