Human intestine

Saponins dismpt red blood cells and may produce diarrhea and vomiting. They may also have a beneficial effect by complexing with cholesterol [57-88-5] and thus lowering semm cholesterol levels (24,25). In humans, intestinal microflora seem to either destroy saponins or inactivate them in small concentrations. 

Human intestinal mucosa as weU as livei can peifomi this conversion (344,345). Desogestiel and 3-ketodesogestiel can be measured by radioimmunoassay or hplc (339,345). 

Important physical and functional properties of maltose and maltose symps include sweetness, viscosity, color stabiUty, humectancy, freezing point depression, and promotion of beneficial human intestinal microflora growth. Maltose possesses ca 30—40% of the sweetness of sucrose in the pure state (32). 

Up to 80% of oral doses of ascorbic acid are absorbed in humans with intakes of less than 0.2 g of vitamin C. Absorption of pharmacological doses ranging from 0.2 g to 12 g results in an inverse relationship, with less than 20% absorption at the higher doses. A single oral dose of 3 g has been reported to approach the absorptive capacity (tissue saturation) of the human intestine. Higher blood levels can be attained by providing multiple divided vitamin C doses per day. 

D. F. Hentges, ed., Human Intestinal Microflora in Health and Disease, Academic Press, New York, 1983. 

The practical development of plant sterol drugs as cholesterol-lowering agents will depend both on structural features of the sterols themselves and on the form of the administered agent. For example, the unsaturated sterol sitosterol is poorly absorbed in the human intestine, whereas sitostanol, the saturated analog, is almost totally unabsorbable. In addition, there is evidence that plant sterols administered in a soluble, micellar form (see page 261 for a description of micelles) are more effective in blocking cholesterol absorption than plant sterols administered in a solid, crystalline form. 

Human intestinal absorption of 5 (01JPS749) and 6 (01MI30) was predicted by using five Abraham descriptors and CaCo-2 monolayer, respectively. The effect of hydrophobicity and molecular mass on the accumulation of 10 fluoroquinolones, including 5, by Staphylococcus aureus were evaluated (01MI14). 

Because of its convenience and good patient compliance, oral administration is the most preferred drug delivery form. As a result, much of the attention of in silico approaches is focused on modeling drug oral absorption, which mainly occurs in the human intestine. In general, drug bioavailability and... 

Artursson P and Karlsson J. Correlation between oral drug absorption in humans and apparent drug permeability coefficients in human intestinal epithelial (Caco-2) cells. Biochem Biophys Res Commun 1991 175 880-5. 

Zmuidinavicius D, Didziapetris R, Japertas P, Avdeef A and Petrauskas A. Classification structure-activity relations (C-SAR) in prediction of human intestinal absorption. J Pharm Sci 2003 92 621-33. 

Figure 14-13. G i ganglioside, a monosialoganglio-side, the receptor in human intestine for cholera toxin.

RABOT s, GUERIN c, NUGON-BAUDON L and SZYLIT o (1995) Glucosinolate degradation by bacterial strains isolated from a human intestinal microflora , Proc. 9th International Rapeseed Congress, 1 212-14. 

KIM D H, PARK E K, BAE E A, HAN M J (2000) Metabolism of rhaponticin and chrysophanol 8-o-beta-D-glucopyranoside from the rhizome of rheum undulatum by human intestinal bacteria and their anti-allergic actions. Biol Pharm Bull. 23 830-33. 

HUR H G, LAY J o Jr, BEGER R D, FREEMAN J p and RAFii F (2000) Isolation of human intestinal bacteria metabolizing the natural isoflavone glycosides daidzin and genistin. Arch Microbiol. 174 (6) 422-8. 

During, A., Albaugh, G., and Smith, J.C., Characterization of 3-carotene 15,15-dioxygenase activity in TC7 clone of human intestinal cell line Caco-2 cells, Biochem. Biophys. Res. Commun., 249, 467, 1998. 

Salvini, S. et al.. Functional characterization of three clones of the human intestinal Caco-2 cell hne for dietary lipid processing, Br. J. Nutr., 87, 211, 2002. 

Chitchumroonchokchai, C., Schwartz, S.J., and Failla, M.L., Assessment of lutein bioavailability from meals and a supplement using simulated digestion and Caco-2 human intestinal cells, J. Nutr, 134, 2280, 2004. 

Wang X-Y, H-G Hur, JH Lee, KT Kim, S-I Kim (2005) Enantioselective synthesis of 5-equol from dihydro-daidzein by a newly isolated anaerobic human intestinal bacterium. Appl Environ Microbiol 71 214-219. 

Winter J, LH Moore, VR Dowell, VD Bokkenheuser (1989) C-ring cleavage of flavonoids by human intestinal bacteria. Appl Environ Microbiol 55 1203-1208. 

For 31 passively transported dmgs, excellent sigmoidal relationships were found between human intestinal absorption and their H-bond acceptor and donor factors [65] ... 

C. N., Boutina, D., Beck, G., Sherbom, B., Cooper, J., Platts, J. A. Evaluation of human intestinal absorption data and subsequent derivation of a quantitative structure-activity relationship (QSAR) with the Abraham descriptors. J. Pharm. Sci. 2001, 90, 749-784. 

Walle, T. Vincent, T. S. Walle, U. K. Evidence of covalent binding of the dietary flavonoid quercetin to DNA and protein in human intestinal and hepatic cells. Biochem. Pharmacol. 2003, 65, 1603-1610. 

---