Hypocholesterolemic

Saponins. Although the hypocholesterolemic activity of saponins has been known since the 1950s, thek low potency and difficult purification sparked Htde interest in natural saponins as hypolipidemic agents. Synthetic steroids (292, 293) that are structurally related to saponins have been shown to lower plasma cholesterol in a variety of different species (252). Steroid (292) is designated CP-88,818 [99759-19-0]. The hypocholesterolemic agent CP-148,623 [150332-35-7] (293) is not absorbed into the systemic ckculation and does not inhibit enzymes involved in cholesterol synthesis, release, or uptake. Rather, (293) specifically inhibits cholesterol absorption into the intestinal mucosa (253). As of late 1996, CP-148,623 is in clinical trials as an agent that lowers blood concentrations of cholesterol (254). 

Therapeutic Function Hypocholesterolemic agent Chemical Name 2,2-Dimethyl-5-(2,5-xylyloxy)valeric acid Common Name —... 

Various mechanisms have been proposed to explain the hypocholesterolemic effect of GA (Annison et al., 1995 Tiss et al., 2001). Some studies have suggested that the viscosity of fermentable dietary fiber contributes substantially to the reduction of lipids in animals and humans (Gallaher et al., 1993 Moundras et al., 1994). However, other studies suggested that this property is not related to plasma lipids (Evans et al., 1992). The mechanism involved is clearly linked to increased bile acid excretion and fecal neutral sterol or a modification of digestion and absorption of lipids (Moundras et al., 1994). 

The current weight of evidence suggests that soy does have a beneficial effect on cardiovascular health however, the active component has yet to be identified. Studies have also demonstrated that dietary inclusion of phytoestrogen-rich foods can lower plasma cholesterol levels (Ridges et al., 2001). However, these data do not conclusively demonstrate that phytoesfrogens are responsible for the hypocholesterolemic effect, and it is possible that some other component in soy may be responsible (Erdman and Fordyce, 1989 Ling and Jones, 1995). 

POTTER s M (1995) Overview of proposed mechanisms for the hypocholesterolemic effect of soy. J Nutr. 125 (3 Suppl) 606S-611S. 

In our study, consumption of rye bread or rye bread with phloem did not have an effect on serum lipids (total, LDL or HDL cholesterol or triglycerides) (Table 14.4). This is contrary to a recent finding suggesting that soluble fiber from rye bread decreased the concentrations of cholesterol (Leinonen et al., 2000). In that study ingestion of rye bread (220 g/d) with naturally high amounts of insoluble (18 g/d) and soluble fiber (4 g/d) decreased the LDL concentrations by 8% in hypercholesterolemic men. The researchers speculated that soluble fiber, maybe P-glucan, was responsible for the hypocholesterolemic effect. The amount of rye bread (70 g/d vs 220 g/d), the amount of total (5.9-11.8 g/d vs 22.1 g/d) and soluble fiber (0.6-1.3 g/d vs 4 g/d) ingested in this study was considerably less, and could explain the lack of effects on blood lipids in our study. 

Cardiovascular disease (CVD) is characterized by the involvement of the heart and allied vascular system. High cholesterol, associated lipid abnormahties and high blood pressure are recognized as the major risk factors of CVD. There have been several animal experiments and clinical studies using rice bran and rice bran oil, which have demonstrated a hypocholesterolemic effect (Raghuram et al., 1989 Rukmini and Raghuram, 1991 Sugano and Tsuji, 1997). The mechanisms involved are briefly summarized. 

KAHLON T s, CHOW F I (1997) Hypocholesterolemic effect of oat, rice and barley dietary fibers and fractions. Review. Cereal World, 42(2) 86-92. 

QURESHi N, QURESHi A A (1992) Tocotrieuols novel hypocholesterolemic agents with antioxidant properties. In Vitamin E in Health and Disease. Eds Packer, L, Fuch, J, New York, Marcel Dekker 245-67. 

Fuhrman, B. et al., Hypocholesterolemic effect of lycopene and beta-carotene is related to suppression of cholesterol synthesis and augmentation of LDL receptor activity in macrophages, Biochem. Biophys. Res. Commun., 233, 658, 1997. 

The importance of some pectic substances (pectin or pectins) either due to the great amounts that certain raw materials contain, or the existence of any specific food use, as well as its hypocholesterolemic effect (based in in vitro and in vivo studies) would explain the increasing interest on deepening physico-chemical studies of pectic substances. 

The clinical success of clofibrate has naturally led to the synthesis of numerous analogues intended for use as hypocholesterolemic agents. One of these, clofenpyride (84), is synthesized readily from p-< hlorophenoxy-2,2-dimethylacetic acid (83) by conversion to the acid chloride and reaction with 3-hydroxy-40... 

The synthesis of the decalin unit of compactin (59), a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, which acts as an effective hypocholesterolemic agent, was planned to incorporate an intramolecular Diels-Alder reaction (Scheme 9.15) [57]. 

Bile acids and salts have been found to enhance the absorption of both calcium and vitamin D hence, to increase calcium absorption both directly and indirectly (3,37). However, the ability of some dietary fibers such as lignin and pectin to absorb conjugated and deconjugated bile salts onto their surfaces to be excreted in the feces (a mechanism credited to the hypocholesterolemic effect of some dietary fibers) may result in an overall decrease in calcium absorption from the gastrointestinal tract (7,33,38-40). 

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