Hydrolysis and Transport Characteristics of Tyrosol Acyl Esters in Rat Intestine.

Lipophenols such as palmitoyl esters of green-tea polyphenols (GTP) have been allowed for use as food additives for oxidation control. However, their digestive absorption remains unexplored. In this paper, the hydrolysis and transport characteristics of tyrosol acyl esters (TYr-Es) with various fatty acids (C12:0, C14:0, C16:0, C18:0, C18:1, and C18:2) were evaluated using the everted-rat-gut-sac model for the first time. HPLC-UV measurements demonstrated that TYr-Es were hydrolyzed to TYr, which contributed significantly to TYr transport across the sacs. The hydrolysis and transport rates correlated negatively with the chain lengths of their lipid moieties but showed a positive correlation with the degree of unsaturation. In general, all TYr-Es exhibited sustained-release behavior; therefore, the production of TYr-Es may serve as a useful way to prolong the duration of action and further improve the bioactivities of TYr.

Transport properties of puerarin and effect of extract of Radix Angelicae dahuricae on puerarin intestinal absorption using in situ and in vitro models.

The root of Angelica dahurica (Radix Angelicae Dahuricae, RAD), which contains coumarins and volatile oil as its main classes of active components, is often given in conjunction with Pueraria root (Radix Puerariae, RP), which contains the phytoestrogen puerarin. The two herbs are considered to be compatible 'herb-pairs' in traditional Chinese medicine. The present investigation investigates the absorption of puerarin from RP and the effect of the total coumarins and volatile oil from RAD on its absorption. The everted gut sac and single-pass intestinal perfusion methods were used, respectively. The results showed that the absorption of puerarin in the jejunum was significantly increased in the presence of the coumarins and/or volatile oil. The absorption rate constant (K(a)) of puerarin increased gradually until the concentration reached 160 µg · mL(-1), after which its absorption became saturated and the apparent permeability (P(app)) values significantly decreased. The results showed that the intestinal absorption mechanisms of puerarin involved active transportation processes and that puerarin is likely to be a substrate of P-gp because verapamil significantly affected its P(app) and K(a). The absorption of puerarin significantly increased (p < 0.01) when combined with RAD extracts, as shown by the increase in concentration of puerarin in blood from the hepatic portal vein, supporting the concept of RAD and RP as a compatible herb-pair.

Selection of the quality control ingredients based on absorption of multicomponent in Fructus Lycii / 国际中医中药杂志

Objective To select the components for quality control of Fructus Lycii based on the absorption of its extract. Methods To investigate metabolism of components of Fructus Lycii, everted rat gut sacs was carried out as well as the blood was taken from abdominal aorta,.and all samples were analysised by HPLC. Results There are twelve constituents absorbed between ileum and jejunum of rat , and four constituents were detected in the blood. Compound 2, 3, 4, 5, 6, 9, 10, 11 were absorbed in prototype forms in the intestine directly,and compound 1, 7, 8, 12 were new ones. On the other hand, four compositions(3, 7, 10, 13)could be absorbed into blood through analysis serum samples obtaining from aorta abdominalis of rats. Two of them (3, 10)could be absorbed directly by intestine, while(7)was absorbed into blood in new form . Conclusion Based on the intestinal absorption experiment and analysion of compsition in blood, components (3, 10, 13) can be the quality control ingredients of Fructus Lycii.