Ingestion of vegetable salads before rice inhibits the increase in postprandial serum glucose levels in healthy subjects.

This study aims to confirm the "vegetable-first" effect. In addition, because we aimed dietary fiber in vegetable salad, the effect after the ingestion of vegetable salad extract (vegetable salad from which solids have been removed) before carbohydrates on postprandial serum glucose level was also evaluated. A total of 13 healthy men were given meals after one-night of fasting: rice-vegetable salad, vegetable salad-rice, and vegetable salad extract-rice. Blood samples were taken at 0, 30, 45, 60, 90, and 120 min after the ingestion of the test meal to measure serum glucose levels. Serum glucose levels were significantly lower after 45 and 60 min in the vegetable salad-rice group compared to the rice-vegetable salad group. No significant difference was found between the vegetable salad extract-rice group and the vegetable salad-rice/rice-vegetable salad group. The result suggested that it might be important to ingest vegetables to obtain the "vegetable-first" effect.

Egg white hydrolyzate reduces mental fatigue: randomized, double-blind, controlled study.

OBJECTIVES: This study aimed to show that ingesting egg white hydrolyzate (EWH) could improve antioxidant capacity and reduce mental fatigue. Two clinical trials were conducted to examine the antioxidant capacity and the fatigue reduction function of EWH. In Study 1, 19 athlete students were received a single dose of EWH (5 g/day) or placebo. In Study 2, 74 athlete students ingested EWH (5 g/day) or placebo before training for 2 weeks. RESULTS: Single dose of EWH significantly increased the antioxidant ability compared with the placebo group (p < 0.05), and there was no significant difference between the groups in the oxidative stress test results on Study 1. Two-week intake of EWH significantly decreased mental fatigue compared with the placebo (p < 0.05). This study showed that ingesting EWH improved antioxidant capacity with a single dose and reduced mental fatigue after 2 weeks of ingestion. Trial Registration Japan Medical Association Center for Clinical Trials identifier; JMA-IIA00395 (Study1) and JMA-IIA00396 (Study2), both trials were retrospectively registered on 26 October, 2018.

Development of a novel system for estimating human intestinal absorption using Caco-2 cells in the absence of esterase activity.

Both mRNA and protein levels of the carboxylesterase (CES) isozymes, hCE1 and hCE2, in Caco-2 cells increase in a time-dependent manner, but hCE1 levels are always higher than those of hCE2. In human small intestine, however, the picture is reversed, with hCE2 being the predominant isozyme. Drugs hydrolyzed by hCE1 but not by hCE2 can be hydrolyzed in Caco-2 cells, but they are barely hydrolyzed in human small intestine. The results in Caco-2 cells can be misleading as a predictor of what will happen in human small intestine. In the present study, we proposed a novel method for predicting the absorption of prodrugs in the absence of CES-mediated hydrolysis in Caco-2 cells. The specific inhibition against CES was achieved using bis-p-nitrophenyl phosphate (BNPP). The optimal concentration of BNPP was determined at 200 microM by measuring the transport and hydrolysis of O-butyryl-propranolol (butyryl-PL) as a probe. BNPP concentrations of more than 200 microM inhibited 86% of hydrolysis of butyryl-PL, resulting in an increase in its apparent permeability. Treatment with 200 microM BNPP did not affect paracellular transport, passive diffusion, or carrier-mediated transport. Furthermore, the proposed evaluation system was tested for ethyl fexofenadine (ethyl-FXD), which is a superior substrate for hCE1 but a poor one for hCE2. CES-mediated hydrolysis of ethyl-FXD was 94% inhibited by 200 microM BNPP, and ethyl-FXD was passively transported as an intact prodrug. From the above observations, the novel evaluation system is effective for the prediction of human intestinal absorption of ester-type prodrugs.

Identification of esterases expressed in Caco-2 cells and effects of their hydrolyzing activity in predicting human intestinal absorption.

The absorption characteristics of temocapril were investigated using Caco-2 cells, and the esterases expressed in Caco-2 cells were identified. Temocapril was almost completely hydrolyzed to temocaprilat during transport across Caco-2 cells. Hydrolysis experiments of temocapril in Caco-2 cell 9000g supernatant (S9) and brush-border membrane vesicles showed that temocapril was mainly hydrolyzed within the cells after uptake, after which the temocaprilat formed was transported to both the apical and basolateral surfaces. In native polyacrylamide gel electrophoresis by detection of hydrolase activity for 1-naphthylbutyrate, Caco-2 cell S9 showed a band with high esterase activity and another band with extremely low activity. The proteins in the major and minor bands were identified as carboxylesterase-1 (hCE-1) and carboxylesterase-2 (hCE-2). The abundant expression of hCE-1 in Caco-2 cells was supported by reverse transcription-polymerase chain reaction. In the normal human small intestine, hCE-2 is abundantly present, although the human liver expresses much higher levels of hCE-1 and lower levels of hCE-2. The expression pattern of carboxylesterases in Caco-2 cells is completely different from that in human small intestine but very similar to that in human liver. Since the substrate specificity of hCE-1 differs from that of hCE-2, it is suggested that the prediction of human intestinal absorption using Caco-2 cell monolayers should be performed carefully in the case of ester- and amide-containing drugs such as prodrugs.