Oral bioavailability and pharmacokinetics of esculetin following intravenous and oral administration in rats.

Esculetin is the main active ingredient isolated from Artemisia montana (Nakai) Pamp. and Euphorbia lathyris L. The present study investigated the oral bioavailability and pharmacokinetics of esculetin in rats, following intravenous and oral administration.Twenty Sprague-Dawley rats were randomly assigned to receive 10 mg/kg of esculetin either by the intravenous or oral route. Plasma concentrations of esculetin were measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were estimated using non-compartmental analysis as well as a compartmental modelling approach using WinNonlinTM and ADAPT 5 software, respectively.According to non-compartmental analysis, the mean oral bioavailability of esculetin was 19%. Mean ± standard deviation values of esculetin half-life, steady-state volume of distribution and clearance, following intravenous dosing, were 2.08 ± 0.46 h, 1.81 ± 0.52 L/kg and 1.27 ± 0.26 L/h/kg, respectively. As indicated by compartmental modelling, a two-compartment pharmacokinetic model with first-order absorption and elimination rate constants of 0.98 ± 0.18 h-1 and 2.47 ± 0.28 h-1, respectively, sufficiently described the plasma concentration-time curve of esculetin.Improving our understanding of the pharmacokinetic properties of esculetin could help with future development of herbal medicine products with appropriate bioactivity.

Comparative study of liver injury induced by high-fat methionine- and choline-deficient diet in ICR mice originating from three different sources.

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. It is characterized by the accumulation of lipids without alcohol intake and often progresses to non-alcoholic steatohepatitis (NASH), liver fibrosis, and end-stage liver diseases such as cirrhosis or cancer. Although animal models have greatly contributed to the understanding of NAFLD, studies on the disease progression in humans are still limited. In this study, we used the recently reported high-fat L-methionine-defined and choline-deficient (HFMCD) diet to rapidly induce NASH and compared the responses to HFMCD in ICR mice from three different countries: Korea (supplied by the National Institute of Food and Drug Safety Evaluation), USA, and Japan during 6 weeks. Feeding HFMCD did not cause significant differences in weight gain in comparison with mice fed control diet. Relative weight of the liver increased gradually, while the relative weight of the kidneys remained unchanged. The parameters of liver injury (serum activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) increased rapidly from 1 week and remained elevated for as long as 6 weeks. Histopathological analysis showed that the accumulation of hepatic lipids induced by HFMCD was prominent at 1 week after diet supplementation and increased further at 6 weeks. Inflammatory markers were significantly increased in a time-dependent manner by HFMCD. The mRNA levels of TNF-α and IL-6 were elevated approximately 15-fold relative to control diet and that of IL-1ß was increased more than 20-folds at 6 week after the onset of HFMCD intake. In addition, mRNA expression of fibrosis markers such as α-SMA, TGFß1, and Col1a1 were also significantly increased at 6 week. In summary, the responses of Korl:ICR mice by intake of HFMCD diet were similar to those of ICR mice from other sources, which suggests that Korl:ICR mice is also a useful resource to study the pathogenesis of diet-induced NAFLD.

Antioxidant Effect of Barley Sprout Extract via Enhancement of Nuclear Factor-Erythroid 2 Related Factor 2 Activity and Glutathione Synthesis.

We previously showed that barley sprout extract (BSE) prevents chronic alcohol intake-induced liver injury in mice. BSE notably inhibited glutathione (GSH) depletion and increased inflammatory responses, revealing its mechanism of preventing alcohol-induced liver injury. In the present study we investigated whether the antioxidant effect of BSE involves enhancing nuclear factor-erythroid 2 related factor 2 (Nrf2) activity and GSH synthesis to inhibit alcohol-induced oxidative liver injury. Mice fed alcohol for four weeks exhibited significantly increased oxidative stress, evidenced by increased malondialdehyde (MDA) level and 4-hydroxynonenal (4-HNE) immunostaining in the liver, whereas treatment with BSE (100 mg/kg) prevented these effects. Similarly, exposure to BSE (0.1-1 mg/mL) significantly reduced oxidative cell death induced by t-butyl hydroperoxide (t-BHP, 300 µM) and stabilized the mitochondrial membrane potential (∆ψ). BSE dose-dependently increased the activity of Nrf2, a potential transcriptional regulator of antioxidant genes, in HepG2 cells. Therefore, increased expression of its target genes, heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase catalytic subunit (GCLC) was observed. Since GCLC is involved in the rate-limiting step of GSH synthesis, BSE increased the GSH level and decreased both cysteine dioxygenase (CDO) expression and taurine level. Because cysteine is a substrate for both taurine and GSH synthesis, a decrease in CDO expression would further contribute to increased cysteine availability for GSH synthesis. In conclusion, BSE protected the liver cells from oxidative stress by activating Nrf2 and increasing GSH synthesis.