Sterols campesterol

Soils have also been examined directly, not for evidence of possible contamination, but as a study of manuring practice in medieval to early modern Orkney, Scotland. The sterols campesterol, sitosterol, and 5/1-stigmastanol were used as biomarkers for ruminant animal manure and coprostanol for omnivorous animal manure, with hyodeoxycholic acid used to further define the manure as coming from pigs (Bull et al. 1999, Simpson et al. 1999). It is rare to be able to extract sterols from such samples because their natural abundance is generally low. If they can be found, however, then they are useful as unambiguous biomarkers for either plants or animals. 

Cholesterol 4-desmtheyl sterols Campesterol, stigmesterol, p-sitosterol,... 

Recent data indicate that ezetimibe inhibits a specific transport process in jejunal enterocytes, which take up cholesterol from the lumen. The putative transport protein is Niemann-Pick Cl-hke 1 protein (NPCILI). In wild-type mice, ezetimibe inhibits cholesterol absorption by about 70% in NPCILI knockout mice, cholesterol absorption is 86% lower than in wild-type mice, and ezetimibe has no effect on cholesterol absorption. Ezetimibe does not affect intestinal triglyceride absorption. In human subjects, ezetimibe reduced cholesterol absorption by 54%, precipitating a compensatory increase in cholesterol synthesis, which can be inhibited with a cholesterol synthesis inhibitor such as a statin. There is also a substantial reduction of plasma levels of plant sterols (campesterol and sitosterol concentrations are reduced by 48 and 41%, respectively), indicating that ezetimibe also inhibits intestinal absorption of plant sterols. 

Sterols Campesterol, stigmasterol (TMSi derivatives) Giilz et al., 1987... 

The basic C27 sterol is cholesterol, cholesta-5-en-3P-ol or (3fl)-cholest-5-en-3-ol (3-114), with a saturated Cg side chain. The same side chain also occurs in its precursor lathosterol (3-115) unsaturated Cg side chain has its other precursor desmosterol (3-116). Normally, there are also sterols with 28 carbon atoms in the molecule. Their representatives are the A -sterols campesterol (3-117) and brassicasterol (3-118). The most common C29 A -sterol is sitosterol (also called P-sitosterol, 3-119). Also found, at lower levels, are stigmasterol (3-120), avenasterol (or A -avenasterol or 5-avenasterol, 3-121), clerosterol (3-122), poriferas-terol, fucosterol (3-123) and A -sterols, such as spinasterol (3-124), A -campesterol, A -avenasterol and A -stigmasteroL An important A -sterol is ergosterol (3-125). 

Contains choline and shiMmic acid as active constituents. Other compounds present include triterpenes (e.g., free taraxerol and a-amyrin esters of taraxerone, a-amyrin, and P-amyrin friedelin) sterols (campesterol, sitosterol, stigmasterol, etc.) flavonoids (quercitrin, quercetin, leucocyanidin, xantho-rhamnin, etc.) n-alkanes (e.g., hentriacon-tane) phenolic acids (e.g., gallic andellagic), /-inositol, sugars (glucose, fructose, and sucrose), and resins and others (list and horhammer). ... 

Fig. 1. Relative composition of root microsomal membranes from 24 land races, varieties and breeding lines of rice which differ in their salt resistance. Campesterol, Stigmasterol and Sitosterol as % of total sterols 16 0, 18 1, 18 2 and 18 3 fatty acids as % of total fatty acids Na transport on a relative scale from (1) lowest to (9) highest. Data of D.R. Lachno, T.J. Flowers A.R. Yeo (unpublished).

Sterols are seldom detected in archaeological residues due to their low concentration and the tendency to undergo chemical degradation. In any case, the presence of sterols or of their oxidation products in a sample can help distinguish between animal and plant lipid materials cholesterol is the most abundant animal sterol, while campesterol and sitosterol are the two major plant ones. 

Sitosterol Campesterol Stigmasterol Unusual sterols Cycloartenol Cholesterol, minute quantities... 

As indicated previously, plant sterols are thought to be formed in most cases through cycloartenol which is often converted to 24-methylenecycloartenol, a substance present in grapefruit peel and in many other plants. The methylene carbon is donated by S-adenos-ylmethionine (AdoMet) as shown in Eq. 22-13, which implies a transient intermediate carbocation. Saturation of the side chain and oxidative demethylation similar to that shown in Fig. 22-8175 and introduction of a double bond176 leads to campesterol (Fig. 22-9). 

The Arabidopsis mutant dwf7/ste 1 is defective in C5-desaturation of episterol (Fig. (2)) [18], thus impaired in an enzyme function involved in a very early step of brassinosteroid precursor biosynthesis. The enzymatic block of dwf7/stel was determined by feeding experiments using l3C-labelled mevalonic acid and a subsequent analysis of endogenous sterol and brassinosteroid precursors. The mutant accumulates episterol with a simultaneous decrease of downstream intermediates (24-methylenecholesterol, campesterol, castasterone, brassinolide). 

The TMS ether derivatives of sterols (including cholesterol) and their oxidation products in foods are well resolved by GLC. The TMS ether derivatives are eluted in the following order cholesterol, campesterol, stigma-sterol, and (i-sitosterol. 

Unsaturated sterols such as cholesterol, campesterol, sitosterol and bile alcohols with unsaturated side chains can be transfer hydrogenated efficiently and with high yields under microwave irradiation, using ammonium formate and a Pd/C catalyst in methylene chloride/propylene glycol solvents (Scheme 4.3)17. 

Figure 9.15 Chemical structures of some of the important sterols used as biomarkers in estuaries (e.g., /3-sistosterol, stigmasterol, campesterol, brassicasterol, and cholesterol).

The proportions of delta 8-cholesterol and desmosterol in the serum rose while those of cholestanol, campesterol and sitosterol dropped, implying a decreased absorption of cholesterol and a compensatory increase in its synthesis. High basal precursor sterol proportions were predictive of a large decrement in titer of LDL cholesterol. It appeared that partial substitution of normal dietary lipid consumption with sitostanol was a safe and effective therapeutic measure for children with FH (Lees et al., 1977 Wang and Ng, 1999). The effect of a small amount of sitosterol, sitostanol and sitostanol esters dissolved in rapeseed oil on serum lipids and cholesterol metabolism in patients with primary hypercholesterolemia and various apolipoprotein E phenotypes on a rapeseed oil diet showed a diminution in TC and LDL-cholesterol levels in the serum (Gylling and Miettinen, 1994). 

Sterols isolated from clove include sitosterol, stigmasterol and campesterol (Brieskorn et al., 1975). 

Among fatty acids, linoleic acid was the major constituent (nearly 50%), followed by oleic ( 24%) and palmitic acids ( 15%). Table 20.4 gives the fatty acid composition of the seed oil of tamarind. Among sterols, betasitosterol constituted 66-72%, followed by campesterol (16-19%) and stigmasterol (Andriamanantena et al., 1983). 

Sitosterol and stigmasterol were the major components of celery seed oil. The other components were cholesterol, brassicasterol, campesterol, 97-campesterol, 95-avenasterol, 97-stigmasterol and 9 7-avenasterol (Zlatanov and Ivanov, 1995). Oil bodies isolated from celery cell suspension cultures contained at least 60% of the total steryl ester present in the cells. Free sterols comprised < 0.5% of the total lipid in the oil body. Sterylesters constituted 4.5% of the total lipid of celery oil bodies. The proportion of precursor 4-methylsterols in the free sterol fraction of celery was greater in the oil body (Dyas... 

Acid composition Sum of the trans-oleic isomers Sum of the trans-linoleic and trans-linolenic isomers (%) Chole- sterol (%) Brassica- Campesterol sterol Stigma- sterol (%) p- sitosterol apparent (%) 8-7- Stigma- stenol (%) Total sterols (mg/kg) Erytro- diol + uvaol (%)... 

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