Increased BBB permeability contributes to EGCG-caused cognitive function improvement in natural aging rats: pharmacokinetic and distribution analyses.

Previous studies report that (-)-epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic ingredient in green tea, has high efficacy against Alzheimer's disease (AD) in various in vivo and in vitro models. However, as a water-soluble component, how EGCG exerts its anti-AD effects in the brain was not elucidated. In the present study, we investigated the anti-AD mechanisms of EGCG in natural aging rats with cognitive impairments (CIs) assessed using Morris water maze. The rats were treated with EGCG (100 mg/kg per day, intragastrically) for 4 weeks. The expression of ß-amyloid (Aß1-42) in the brain was detected with immunohistochemical staining. We showed that EGCG administration significantly ameliorated the CI in the aging rats with CI and decreased Aß1-42 plaque formation in their brains. Then we used an efficient ultra-performance liquid chromatography-tandem mass spectrometer method to evaluate EGCG concentrations in rat plasma and tissue distribution. We found that EGCG absorption was significantly increased in the aging with CI group compared with control young rats. After oral administration of EGCG (100 mg), EGCG could not be detected in the brain tissues of control young rats, but it was found in the brain tissue of aging rats with CI. By using Evans Blue assay, transmission electron microscopy, and Western blotting assay, we demonstrated that the permeability of blood-brain barrier (BBB) was significantly increased in aging rats with CI. These results suggest that the permeability change of BBB is the physiological structural basis for EGCG treatment to improve learning and memory, thus providing a solid evidence for EGCG druggability in anti-AD therapeutic field.

Artemisinin enhances the anti-tumor immune response in 4T1 breast cancer cells in vitro and in vivo.

BACKGROUND: Breast cancer is a prominent cause of death among women worldwide. Recent studies have demonstrated that artemisinin (ART) displays anti-tumor activity. Using a mouse breast cancer model, we investigated the effects of ART in vitro and in vivo to determine how it influences the anti-tumor immune response. METHODS: We measured the proliferation and apoptosis of 4T1 cells in vitro after ART treatment by MTT assay and FACS. To examine the effects of ART in vivo, tumor volumes and survival rates were measured in 4T1 tumor-bearing mice. FACS was used to determine the frequencies of Tregs, MDSCs, CD4+ IFN-γ+ T cells, and CTLs in the tumors and spleens of the mice. mRNA levels of the transcription factors T-bet and FOXP3 and cytokines IFN-γ, TNF-α, TGF-ß, and IL-10 were also determined by real-time RT-PCR. ELISA was used to measure TGF-ß protein levels in the cell culture supernatants. RESULTS: ART supplementation significantly increased 4T1 cell apoptosis and decreased TGF-ß levels in vitro. ART also impeded tumor growth in 4T1 TB mice and extended their survival. MDSC and Treg frequencies significantly decreased in the 4T1 TB mice after ART treatment while CD4+ IFN-γ+ T cells and CTLs significantly increased. ART significantly increased T-bet, IFN-γ, and TNF-α mRNA levels within the tumor and significantly decreased TGF-ß mRNA levels. CONCLUSION: ART supplementation hindered 4T1 tumor growth in vivo by promoting T cell activation and quelling immunosuppression from Tregs and MDSCs in the tumor.

Development of a UPLC-MS/MS Method for Simultaneous Determination of Six Flavonoids in Rat Plasma after Administration of Maydis stigma Extract and Its Application to a Comparative Pharmacokinetic Study in Normal and Diabetic Rats.

Maydis stigma is an important medicine herb used in many parts of the world for treatment of diabetes mellitus, which main bioactive ingredients are flavonoids. This paper describes for the first time a study on the comparative pharmacokinetics of six active flavonoid ingredients of Maydis stigma in normal and diabetic rats orally administrated with the decoction. Therefore, an efficient and sensitive ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of six anti-diabetic ingredients (cynaroside, quercetin, luteolin, isorhamnetin, rutin and formononetin) of Maydis stigma in rat plasma has been developed and validated in plasma samples, which showed good linearity over a wide concentration range (r² > 0.99), and gave a lower limit of quantification of 1.0 ng·mL-1 for the analytes. The intra- and interday assay variability was less than 15% for all analytes. The mean extraction recoveries and matrix effect of analytes and IS from rats plasma were all more than 85.0%. The stability results showed the measured concentration for six analytes at three QC levels deviated within 15.0%. The results indicated that significant differences in the pharmacokinetic parameters of the analytes were observed between the two groups of animals, whereby the absorptions of these analytes in the diabetic group were all significantly higher than those in the normal group, which provides an experimental basis for the role of Maydis stigma in anti-diabetic treatment.

Anti-amnesic effect of pseudoginsenoside-F11 in two mouse models of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by amyloid ß (Aß) deposits, elevated oxidative stress, and apoptosis of the neurons. Pseudoginsenoside-F11 (PF11), a component of Panax quinquefolium (American ginseng), has been demonstrated to antagonize the learning and memory deficits induced by scopolamine, morphine and methamphetamine in mice. In the present study, we investigated the effect of PF11 on AD-like cognitive impairment both in mice induced by intracerebroventricular injection of Aß1-42 (410 pmol) and in Tg-APPswe/PS1dE9 (APP/PS1) mice. It was found that oral treatment with PF11 significantly mitigated learning and memory impairment in mice given Aß1-42-treated mice for 15 days at doses of 1.6 and 8 mg/kg and APP/PS1 for 4 weeks at a dose of 8 mg/kg as measured by the Morris water maze and step-through tests. In APP/PS1 mice, PF11 8 mg/kg significantly inhibited the expressions of ß-amyloid precursor protein (APP) and Aß1-40 in the cortex and hippocampus, restored the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased the production of malondialdehyde (MDA) in the cortex. It also noticeably improved the histopathological changes in the cortex and hippocampus and downregulated the expressions of JNK 2, p53 and cleaved caspase 3 in the hippocampus. These findings suggested that the inhibitory effect on amyloidogenesis and oxidative stress and some beneficial effects on neuronal functions might contribute to the recognition improvement effect of PF11 in APP/PS1 mice. Cumulatively, the present study indicated that PF11 may serve as a potential therapeutic agent for the treatment of AD.

[Research on EGCG improving the degenerative changes of the brain in AD model mice induced with chemical drugs].

OBJECTIVE: To study the effect and mechanism of (-)-Epigallocatechin-3-gallate (EGCG) on the degeneretive changes of the brain in Alzheimer's disease (AD) model mice induced with chemical drugs. METHODS: AD model mice were established by subcutaneously injecting with 3% D-gal at the dose of 150 mg/kg body weight once daily for 6 weeks. From the third week, the mice of D-gal + V(E) 280 U/kg group, D-gal + EGCG 2 mg/(kg x d) group and D-gal + EGCG 6 mg/(kg x d) group were intragastricly given with 5.6% V(E) at the dose of 280 IU/kg and EGCG at the dose of 2 mg/kg x d or 6 mg/kg x d respectively after injection of D-gal. The mice of control group, D-gal + dd H2O group and D-gal + oil group were administered with same volume vehicle distilled water and soybean oil respectively. The pathological changes of the brain in AD model mice were observed by HE staining analysis, the immunohistochemical analysis of beta-amyloid (Abeta) and evaluating the expression of amyloid precursor protein (APP) in the hippocampus of mice by Western blot analysis. RESULTS: EGCG 2 mg/(kg x d) or 6 mg/(kg x d) 4 weeks, ig evidently released neuronal injury in the hippocampus of the AD mice induced by D-gal, and significantly reduced the express of Abeta and APP in the hippocampus of AD model mice induced by D-gal (P < 0.01). CONCLUSION: EGCG has a protective effect on AD model mice induced by D-gal by decreasing the expression of APP and beta-Amyloid in the hippocampus of mice.