Substances accompanying lipids

In practice, the non-volatile lipophihc compounds that accompany true lipids in both natural and manufactured products are also classified as lipids. They are termed compounds accompanying lipids (formerly called Kpoids) in food chemistry, and unsaponifiable lipophilic substances in food analysis. Their chemical structure is different and often these compounds do not even contain bound fatty acids. This group includes a large number of lipophilic compounds, for example some terpenoids, especially... 

Cellulose and other structural polysaccharides of cell walls are associated with different polymeric non-sugar materials that fix and firm the cell walls and also form their outer hydrophobic layers, which are impermeable to water. In nutrition, they are classified as dietary fibre. According to their chemical composition, substances accompanying polysaccharides are classified as lignin, phenolic compounds (tannins), proteins or lipids. 

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

The provision of fat-soluble vitamins and lipids is difficult, if not impossible, in various diseases. This is especially true for diseases that are accompanied by a lot of oxidative stress, for example, mucoviscidosis. The requirements of fat-soluble antioxidative substances are certainly high in these cases and can barely be covered by intramuscular injections because fat-soluble vitamins can hardly, if at all, be absorbed from oily preparations. Alternatively, the vitamins can administered via the buccal mucosa the fat-soluble substances have to be packaged in such a way that they can be transported in a watery compartment and are thus able to largely dissolve in the saliva. When they have an adequate size, they can then penetrate the buccal mucosa. One approach is the development of the so-called nanocolloids, that is, particles with a polar nucleus, in which the fat-soluble vitamin is dissolved, and an apolar wrapping (monolayer). This structure makes an oral application of fat-soluble substances possible. First tests demonstrated that vitamin A palmitate, a-tocopherol, as well as coenzyme Qio are thus able to enter the systemic circulation via the buccal mucosa. 

The distribution of these substances in the various species of Mycobacteria is as follows. (a) Phthiocerol dimycocerosate is present in the lipids of 28 out of 30 human strains studied, (b) A compound first called Gb is present in the lipids of 7 out of 7 bovine strains studied (Gb is accompanied by phthiocerol dimycocerosate in virulent, bovine strains), (c) A compound first called Ga is present in the lipids of 17 out of 17 photochromogenic strains, (d) A compound first called Jav is present in the lipids of 11 out of 13 avian strains, and also in the lipids of 3 out of 6 non-photochromogenic strains. 

The co-administration of M. oleifera seed powder with arsenic protects animals from arsenic induced oxidative stress and reduce body arsenic burden (49). Exposure of rats to arsenie (2.5 mg/kg, intraperitoneally for 6 weeks) increases the levels of tissue reaetive oxygen species (ROS), metallothionein (MT) and thiobarbitnrie aeid reaetive substance (TEARS) and is accompanied by a decrease in the aetivities in the antioxidant enzymes such as superoxide dismutase (SOD), eatalase and glutathione peroxidase (GPx). Also, Arsenic exposed mice exhibits hver injury as reflected by reduced acid phosphatase (AGP), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) activities and altered heme synthesis pathway as shown by inhibited blood 8-aminolevulinic acid dehydratase (5-ALAD) activity. Co-administration of M. oleifera seed powder (250 and 500 mg/kg, orally) with arsenie significantly increases the activities of SOD, catalase, GPx with elevation in redueed GSH level in tissues (liver, kidney and brain). These ehanges are accompanied by approximately 57%, 64% and 17% decrease in blood ROS, liver metallothionein (MT) and lipid peroxidation respectively in animal eo-administered with M. oleifera and arsenic. There is a reduced uptake of arsenie in soft tissues (55% in blood, 65% in liver, 54% in kidneys and 34% in brain) following eo-administration of M. oleifera seed powder (particularly at the dose of 500 mg/kg). This points to the fact that administration of M. oleifera seed powder could be beneficial during chelation therapy with a thiol chelator (26). 

PAF also has potent effects on many other biological systems. For example, PAF induces hepatic phosphoinositide turnover and glycogenolysis which is accompanied by glucose release into the plasma. PAF has also been implicated as a mediator of ischemic bowel necrosis since it can independently induce lesions morphologically similar to those present during human necrotizing enterocolitis. Furthermore, the role of PAF or a PAF-like lipid as an endogenous antihypertensive substance is currently under intense experimental scrutiny. 

S-Adenosyl-L-methionine (50 mg/kg given i.p.ever day for 3 days 1 h before ischaemia/reper-fusion) in a combined model of permanent focal ischaemia and global reperfusion in the rat brain reduced the production of thiobarbituric acid-reactive substances after induction with ferrous salt as an indicator of brain lipid peroxidation (Villalobos et al. 2000). Total glutathione production was increased. These changes were accompanied by an increase in mitochondrial capacity to reduce tet-raphenyl tetrazolium. 

Inhibition of root growth in wheat caused by the grass herbicide haloxyfop [2-(4-[(3-chloro-5-trifluoromethyl)2-pyridinyl)oxo]phenoxy)propanoic acid) is accompanied by a relative increase in linolenate in the membrane lipids of the root tips (Banas et aL, 1993a). A number of substances which counteract the growth inhibition also counteract the increase in linolenate (Banas et aL, 1993b). In order to elucidate possible relationship between these antagonistic compounds and their effect on polyunsaturated fatty acid content, we report in this communication the effect of two of these substances, salicylic acid (SAL) and salicylhydroxamic acid (SHAM), on the production of polyunsaturated fatty acids in vivo and in vitro,... 

Triterpenoids and steroids are the major group of the lipid-accompanying substances in all natural lipids. Triterpenoids and steroids belong to a large group of compounds known as terpenoids or isoprenoids (through the oxidation or rearrangement modified terpenes). Six isoprene (2-methylbuta-1,3-diene) units... 

Esters of higher fatty adds are classified either as Kpids or lipid accompanying substances. Some of these (esters of higher fatty acids with lower aliphatic alcohols, such as ethanol) are odour-active constituents found mainly in alcohoUc beverages, but they usually only affect the taste or are flavour-indifferent substances. 

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