Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatments of Alzheimer's disease: A comprehensive review.

Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder characterized by neuronal loss and cognitive impairment that harshly affect the elderly individuals. Currently, the available anti-AD pharmacological approaches are purely symptomatic to alleviate AD symptoms, and the curative effects of novel anti-AD drugs focused on Aß target are disappointing. Hence, there is a tremendous need to adjust AD therapeutic targets and discover novel anti-AD agents. In AD, mitochondrial dysfunction gradually triggers neuronal death from different aspects and worsens the occurrence and progress of AD. Consequently, it has been proposed that the intervention of impaired mitochondria represents an attractive breakthrough point for AD treatments. Due to chemical diversity, poly-pharmacological activities, few adverse effects and multiple targeting, natural products (NPs) have been identified as a valuable treasure for drug discovery and development. Multiple lines of studies have scientifically proven that NPs display ameliorative benefits in AD treatment in relation to mitochondrial dysfunction. This review surveys the complicated implications for mitochondrial dysregulation and AD, and then summarizes the potentials of NPs and their underlying molecular mechanisms against AD via reducing or improving mitochondrial dysfunction. It is expected that this work may open the window to speed up the development of innovative anti-AD drugs originated from NPs and improve upcoming AD therapeutics.

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.

Baicalin mitigates cognitive impairment and protects neurons from microglia-mediated neuroinflammation via suppressing NLRP3 inflammasomes and TLR4/NF-κB signaling pathway.

AIMS: Baicalin (BAI), a flavonoid compound isolated from the root of Scutellaria baicalensis Georgi, has been established to have potent anti-inflammation and neuroprotective properties; however, its effects during Alzheimer's disease (AD) treatment have not been well studied. This study aimed to investigate the effects of BAI pretreatment on cognitive impairment and neuronal protection against microglia-induced neuroinflammation and to explore the mechanisms underlying its anti-inflammation effects. METHODS: To determine whether BAI plays a positive role in ameliorating the memory and cognition deficits in APP (amyloid beta precursor protein)/PS1 (presenilin-1) mice, behavioral experiments were conducted. We assessed the effects of BAI on microglial activation, the production of proinflammatory cytokines, and neuroinflammation-mediated neuron apoptosis in vivo and in vitro using Western blot, RT-PCR, ELISA, immunohistochemistry, and immunofluorescence. Finally, to elucidate the anti-inflammation mechanisms underlying the effects of BAI, the protein expression of NLRP3 inflammasomes and the expression of proteins involved in the TLR4/NF-κB signaling pathway were measured using Western blot and immunofluorescence. RESULTS: The results indicated that BAI treatment attenuated spatial memory dysfunction in APP/PS1 mice, as assessed by the passive avoidance test and the Morris water maze test. Additionally, BAI administration effectively decreased the number of activated microglia and proinflammatory cytokines, as well as neuroinflammation-mediated neuron apoptosis, in APP/PS1 mice and LPS (lipopolysaccharides)/Aß-stimulated BV2 microglial cells. Lastly, the molecular mechanistic study revealed that BAI inhibited microglia-induced neuroinflammation via suppression of the activation of NLRP3 inflammasomes and the TLR4/NF-κB signaling pathway. CONCLUSION: Overall, the results of the present study indicated that BAI is a promising neuroprotective compound for use in the prevention and treatment of microglia-mediated neuroinflammation during AD progression.

Salinomycin induces selective cytotoxicity to MCF-7 mammosphere cells through targeting the Hedgehog signaling pathway.

Breast cancer stem cells (BCSCs) are believed to be responsible for tumor chemoresistance, recurrence, and metastasis formation. Salinomycin (SAL), a carboxylic polyether ionophore, has been reported to act as a selective breast CSC inhibitor. However, the molecular mechanisms underlying SAL-induced cytotoxicity on BCSCs remain unclear. The Hedgehog (Hh) signaling pathway plays an important role in CSC maintenance and carcinogenesis. Here, we investigated whether SAL induces cytotoxicity on BCSCs through targeting Hh pathway. In the present study, we cultured breast cancer MCF-7 cells in suspension in serum-free medium to obtain breast CSC-enriched MCF-7 mammospheres (MCF-7 MS). MCF-7 MS cells possessed typical BCSC properties, such as CD44+CD24-/low phenotype, high expression of OCT4 (a stem cell marker), increased colony-forming ability, strong migration and invasion capabilities, differentiation potential, and strong tumorigenicity in xenografted mice. SAL exhibited selective cytotoxicity to MCF-7 MS cells relative to MCF-7 cells. The Hh pathway was highly activated in BCSC-enriched MCF-7 MS cells and SAL inhibited Hh signaling activation by downregulating the expression of critical components of the Hh pathway such as PTCH, SMO, Gli1, and Gli2, and subsequently repressing the expression of their essential downstream targets including C-myc, Bcl-2, and Snail (but not cyclin D1). Conversely, Shh-induced Hh signaling activation could largely reverse SAL-mediated inhibitory effects. These findings suggest that SAL-induced selective cytotoxicity against MCF-7 MS cells is associated with the inhibition of Hh signaling activation and the expression of downstream targets and the Hh pathway is an important player and a possible drug target in the pathogenesis of BCSCs.

Overexpression of Rsf-1 correlates with pathological type, p53 status and survival in primary breast cancer.

AIM: The incidence of breast cancer in developing countries still increasing, to identify novel molecular markers associated with carcinogenesis and prognosis of breast cancer still being implemented. The largest subunit of Remodeling and spacing factor (RSF), Rsf-1, mediates ATPase-dependent chromatin remodeling. Its oncogenic properties have been demonstrated in certain carcinomas. The aim of this study was to examine the prognostic value of Rsf-1 in patients with primary breast carcinoma. METHODS: A total of 537 patients with primary breast cancer, and 54 with benign breast hyperplasia, were performed resection surgery in the same period were enrolled. Rsf-1 immunoexpression was retrospectively assessed by immunohistochemistry (IHC). As well as, it relationship with clinicopathological factors and patient survival (LRFS, DFS and OS) was investigated. RESULTS: Compared with benign breast hyperplasia tissues, higher percentage of Rsf-1 positive expression was detected in malignant breast carcinomas. Based on IHC staining extent × intensity scores and ROC analysis, 278 of 526 cancers (52.9%) had high-expression (cut-off values 2.5) of Rsf-1, which correlated significantly to pathologic subtypes of breast cancer (DCIS vs. IDC, P < 0.001; ILC vs. IDC, P = 0.036), bigger tumor size (P = 0.030), higher TNM stage (P = 0.044), and p53-positive expression. In addition, there was a trend that high-expression of Rsf-1 associated with younger age (P = 0.053). We further prove that combined positive-expression of Rsf-1 and p53 (Rsf-1 (+)/p53 (+)) was correlated with the bigger tumor size (P = 0.018), and higher TNM stage (P = 0.024). Kaplan-Meier survival analysis showed that Rsf-1 high-expression and combined positive-expression of Rsf-1 and p53 (Rsf-1 (+)/p53 (+)) exhibited a significant correlation with poor overall survival of patients with primary breast cancer, and no association has been identified in relation to LRFS or DFS. Especially, Univariate and multivariate survival analysis demonstrated Rsf-1 expression is an independent prognostic parameter for the overall survival of patients with breast cancer. CONCLUSIONS: High-expression of Rsf-1 is associated with pathologic subtypes of breast cancer, aggressive phenotype, p53 positive and poor clinical outcome, which confers tumor aggressiveness through chromatin remodeling, and targeting Rsf-1 gene and the pathway it related may provide new therapeutic avenues for treating breast cancer.

[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.

Pharmacokinetic properties and bioequivalence of two formulations of arbidol: an open-label, single-dose, randomized-sequence, two-period crossover study in healthy Chinese male volunteers.

BACKGROUND: Arbidol is an antiviral drug indicated for the prevention and treatment of all types of influenza infection and some other kinds of acute respiratory infections, specifically against influenza groups A and B, and severe acute respiratory syndrome. It is used to help prevent influenza infection as long as necessary with little risk for influenza mutation rendering it less effective. OBJECTIVE: The aim of this study was to compare the pharmacokinetic properties and tolerability, and to determine bioequivalence, of a newly developed generic dispersible tablet formulation (test) and a branded capsule formulation (reference) of arbidol 200 mg in healthy Chinese fasted male volunteers. METHODS: This open-label, single-dose, randomized-sequence, 2-period crossover study was conducted in healthy native Chinese male volunteers. Eligible subjects were randomly assigned in a 1:1 ratio to receive a single 200-mg dose of the test or reference formulation, followed by a 1-week washout period and administration of the alternate formulation. The study drugs were administered after a 12-hour overnight fast. After the study drug administration, serial blood samples were collected for 72 hours after administration. Plasma drug concentrations were determined using high-performance liquid chromatography coupled with tandem mass spectrometry. Several pharmacokinetic pararameters, including C(max), T(max), t((1/2)), AUC(0-t), and AUC(0-infinity), were determined from the plasma concentrations of the 2 formulations of arbidol using noncompartmental analysis. The formulations were to be considered bioequivalent if the log-transformed ratios of C(max) and AUC were within the predetermined bioequivalence range of 80% to 125% established by the State Food and Drug Administration (SFDA) of the People's Republic of China. Tolerability was assessed by monitoring vital signs (blood pressure, heart rate, temperature, and electrocardiography), laboratory analysis (hematology, blood biochemistry, hepatic function, and urinalysis), and subject interview on adverse events. RESULTS: Twenty subjects were enrolled and completed the study (mean [SD] age, 21.1 [1.1] years; weight, 64.7 [5.1] kg; and height, 172.3 [3.1] cm). Neither period nor sequence effect was observed. The main pharmacokinetic properties with the test and reference formulations were as follows: C(max), 417.4 (107.6) and 414.8 (95.1) ng/mL, respectively (P = NS); median (range) T(max), 0.63 (0.25-1.0) and 0.75 (0.5-1.5) hours (P = 0.035); AUC(0-t), 2033.6 (564.9) and 1992.0 (483.3) ng/mL/h (P = NS); AUC(0-infinity), 2285.4 (597.7) and 2215.2 (604.0) ng/mL/h (P = NS); and t(1/2), 6.9 (4.2) and 6.1 (5.2) hours (P = NS). The 90% CIs for the log-transformed ratios of C(max), AUC(0-t), and AUC(0-infinity) were 91.7% to 109.7%, 91.0% to 112.8%, and 92.0% to 116.3%, respectively (all, P < 0.05), which were within the predetermined range for bioequivalence. No adverse events were found on analysis of vital signs or laboratory tests or reported by subjects in this study. CONCLUSION: In this study in healthy Chinese male volunteers, the dispersible tablet formulation and the 200-mg capsule formulation of arbidol met the SFDA's regulatory definition of bioequivalence based on the rate and extent of absorption.

Neuroprotective effects of (-)-epigallocatechin-3-gallate on aging mice induced by D-galactose.

The aim of the present study was to investigate the protective effects of (-)-epigallocatechin-3-gallate (EGCG), the main polyphenolic constituent of green tea, in aging mice induced by D-galactose (D-gal). The aging mice model was induced by subcutaneous (s.c.) injection of D-gal (150 mg/kg) once daily for 6 weeks. EGCG (2 mg/kg or 6 mg/kg) was administered intragastrically (i.g.) once daily for 4 weeks after 2-week D-gal injection. The water maze test was used to evaluate the learning and memory function of mice. The activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) and the contents of malondialdehyde (MDA) in the hippocampus were measured using different biochemical kits to estimate the changes in the antioxidative ability of mice. TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining method was used to detect neuronal apoptosis, and the activation and expression of proapoptotic protein caspase-3 in the hippocampus were observed and analyzed using immunohistochemical staining and the Western blot method to evaluate apoptosis in the brain. The results indicated that subcutaneous injection of D-gal induced learning and memory impairment in mice, decreased T-SOD and GSH-Px activities, increased MDA contents in the hippocampus, and increased the cell apoptosis index and cleaved caspase-3 protein expression in the hippocampus. Oral administration of EGCG (2 mg/kg or 6 mg/kg) for 4 weeks significantly improved the cognitive deficits in mice and elevated T-SOD and GSH-Px activities, decreased MDA contents in the hippocampus, and reduced the cell apoptosis index and expression of cleaved caspase-3 in the mouse hippocampus. The results suggest that EGCG has potent neuroprotective effects on aging mice induced by D-gal through antioxidative and antiapoptotic mechanisms, indicating that EGCG is worthy of further study in aging.