N-3 polyunsaturated fatty acid attenuates cholesterol gallstones by suppressing mucin production with a high cholesterol diet in mice.

BACKGROUND AND AIM: The increasing prevalence of cholesterol gallstone (CG) disease has become an economic burden to the healthcare system. Ursodeoxycholic acid (UDCA) is the only established medical agent used to dissolve gallstones. In investigating novel therapeutics for CG, we assessed the preventive effects of n-3 polyunsaturated fatty acids (n-3PUFA) on the formation of CG induced by feeding a lithogenic diet (LD) containing high cholesterol levels to mice. METHODS: Mice were divided into the following six groups: (A) regular diet (RD); (B) RD+n-3PUFA; (C) LD; (D) LD+n-3PUFA; (E) LD+UDCA; (F) LD+n-3PUFA+UDCA. After RD/LD feeding for 2 weeks, n-3PUFA or UDCA was administered orally and the diet maintained for 8 weeks. The levels of phospholipids and cholesterol in bile, CG formation, gallbladder wall thickness, MUC gene expression in gallbladder were analyzed. RESULTS: No stone or sludge was evident in the RD groups (Groups A, B). Mice in the n-3PUFA treatment (Groups D, F) showed significantly lower stone formation than the other LD groups (Groups C, E). The combination treatment of n-3PUFA and UDCA suppressed stone formation more than mono-therapy with n-3PUFA or UDCA. Bile phospholipid levels were significantly elevated in the Group F. Hypertrophy of the gallbladder wall was evident in mice fed LD. MUC 2, 5AC, 5B and 6 mRNA expression levels were significantly elevated in the LD-fed group, and this was suppressed by n-3PUFA with or without UDCA. CONCLUSIONS: N-3PUFA attenuated gallstone formation in mouse, through increasing the levels of bile phospholipids and suppressing bile mucin formation.

Determination of the esculetin contents of medicinal plants by liquid chromatography-tandem mass spectrometry.

We developed a LC-MS/MS method for the determination of esculetin contents in medicinal plants. The analysis was performed using multiple reaction monitoring in negative mode, and an XBridge™ C(18) column (2.1 × 100 mm, 3.5 µm) was used. Methanol and 0.1% formic acid were used for gradient analysis. The calibration curve showed good linearity (r(2) > 0.9993). The limits of detection and quantitation were 0.02 and 0.07 ng/mL, respectively. The intra-day and inter-day precisions were 1.5-6.8 and 2.0-5.3%, respectively, and the accuracy was 102.0-110.2%. The contents of esculetin in 35 different plants were determined, and Fraxini Cortex showed the highest content of esculetin (761-5475 mg/kg). In Mori Folium and Artemisiae Capillaris Herba, 5.2-21.5 and 7.0-17.6 mg/kg of esculetin were found, respectively. In other medicinal plants, no esculetin was detected, or it was present at a concentration less than 10 mg/kg. The analysis method appears to be simple, sensitive and reproducible. Contrary to expectations based on traditional medical knowledge, although Artemisiae Capillaris Herba contains a large amount of esculetin, it appears from this study that Fraxini Cortex contains a greater amount. The pharmacological effects of esculetin isolated from medicinal plants should be investigated as part of new medicines development.

Concentrations of Bisphenols in Canned Foods and Their Risk Assessment in Korea.

The purpose of this study was to survey concentrations of bisphenols in canned foods using liquid chromatography-tandem mass spectrometry, to estimate the dietary exposure to bisphenols, and to assess the related risk for the Korean population from the intake of canned foods. The linearity of bisphenols in the range of 2.5 to 725 µg/L was satisfactory with correlation coefficients ( r2) of 0.999. The limit of detection was 0.14 to 5.85 µg/L, and the limit of quantitation was 0.44 to 17.73 µg/L. Sample recoveries were 70.56 to 113.6%, with relative standard deviations below 10% for spiking levels of 50 and 250 µg/kg (15 and 75 µg/kg for BPS). The bisphenol concentrations in 104 canned foods ranged from undetectable to 1,525 µg/kg. The estimated mean daily intake of bisphenols was 0.54 to 78.69 ng/kg of body weight per day, and the 95th percentile daily intake was 1.92 to 134 ng/kg of body weight per day. Therefore, the intake of bisphenols from canned foods for the population in Korea is unlikely to cause human health problems. The analytical methods used are suitable for regular monitoring and assessment of human exposure to bisphenols from foods.

p38 MAPK activation is required for esculetin-induced inhibition of vascular smooth muscle cells proliferation.

The phenolic compound esculetin is known to inhibit the proliferation of vascular smooth muscle cells (VSMC). However, the signaling pathway by which esculetin mediates its molecular effects in VSMC remains to be identified. The present results suggest an unexpected role of the p38 MAPK signaling pathway in esculetin-induced inhibition of VSMC growth. Treatment of VSMC with esculetin resulted in significant growth inhibition and G1-phase cell-cycle arrest, which was followed by down-regulation of cyclins and cyclin-dependent kinase (CDK) expression. This G1-phase cell-cycle arrest was due to up-regulation of p21WAF1 expression. In addition, esculetin treatment activated p38 MAPK and ERK1/2. Pretreatment with SB203580, which is a p38 MAPK specific inhibitor, or expression of the dominant negative p38 MAPK (DN p38 MAPK) gene blocked esculetin-induced p38 MAPK activation and p21WAF1 expression. Finally, both the growth inhibition and the down-regulation of CDKs induced by esculetin were suppressed by either SB203580 or the DN p38 MAPK mutant gene. In conclusion, these results demonstrate that activation of p38 MAPK contributes to esculetin-induced p21WAF1 expression in VSMC by decreasing both the cyclin D1/CDK4 and cyclin E/CDK2 complexes. These novel results regarding the molecular mechanism of esculetin action suggest new preventive and therapeutic treatments for atherosclerosis.