Qingfan Meng

Studies on the Antidiabetic Activities of Cordyceps militaris Extract in Diet-Streptozotocin-Induced Diabetic Sprague-Dawley Rats

Due to substantial morbidity and high complications, diabetes mellitus is considered as the third “killer” in the world. A search for alternative antidiabetic drugs from herbs or fungi is highly demanded. Our present study aims to investigate the antidiabetic activities of Cordyceps militaris on diet-streptozotocin-induced type 2 diabetes mellitus in rats. Diabetic rats were orally administered with water extract or alcohol extract at 0.05 g/kg and 2 g/kg for 3 weeks, and then, the factors levels related to blood glucose, lipid, free radicals, and even nephropathy were determined. Pathological alterations on liver and kidney were examined. Data showed that, similar to metformin, Cordyceps militaris extracts displayed a significant reduction in blood glucose levels by promoting glucose metabolism and strongly suppressed total cholesterol and triglycerides concentration in serum. Cordyceps militaris extracts exhibit antioxidative effects indicated by normalized superoxide dismutase and glutathione peroxidase levels. The inhibitory effects on blood urea nitrogen, creatinine, uric acid, and protein revealed the protection of Cordyceps militaris extracts against diabetic nephropathy, which was confirmed by pathological morphology reversion. Collectively, Cordyceps militaris extract, a safe pharmaceutical agent, presents excellent antidiabetic and antinephropathic activities and thus has great potential as a new source for diabetes treatment.

Near infrared spectroscopic (NIRS) analysis of drug-loading rate and particle size of risperidone microspheres by improved chemometric model

Microspheres have been developed as drug carriers in controlled drug delivery systems for years. In our present study, near infrared spectroscopy (NIRS) is applied to analyze the particle size and drug loading rate in risperidone poly(d,l-lactide-co-glycolide) (PLGA) microspheres. Various batches of risperidone PLGA microspheres were designed and prepared successfully. The particle size and drug-loading rate of all the samples were determined by a laser diffraction particle size analyzer and high performance liquid chromatography (HPLC) system. Monte Carlo algorithm combined with partial least squares (MCPLS) method was applied to identify the outliers and choose the numbers of calibration set. Furthermore, a series of preprocessing methods were performed to remove signal noise in NIR spectra. Moving window PLS and radical basis function neural network (RBFNN) methods were employed to establish calibration model. Our data demonstrated that PLS-developed model was only suitable for drug loading analysis in risperidone PLGA microspheres. Comparatively, RBFNN-based predictive models possess better fitting quality, predictive effect, and stability for both drug loading rate and particle size analysis. The correlation coefficients of calibration set (Rc(2)) were 0.935 and 0.880, respectively. The performance of optimum RBFNN models was confirmed by independent verification test with 15 samples. Collectively, our method is successfully performed to monitor drug-loading rate and particle size during risperidone PLGA microspheres preparation.

Development of liposomal ginsenoside Rg3: Formulation optimization and evaluation of its anticancer effects

The Ginsenoside Rg3 has been shown to possess antiangiogenic and anticancer properties. Because of its limited water solubility, we decided to design and synthesize liposomal Rg3 (L-Rg3), to optimize preparation conditions, and to investigate further whether liposome could enhance the anticancer activity of Rg3. L-Rg3 was prepared using a film-dispersion method and the preparation conditions were optimized with response surface methodology (RSM). The mean encapsulation efficiency (EE) of 82.47% was close to the predicted value of 89.69%. Therefore, the optimized preparation condition was predicted correctly. We evaluated the cytotoxicity, pharmacokinetics, biodistribution and antitumor activities of L-Rg3. HepG2 and A549 cells were treated with Rg3 or L-Rg3 at different concentrations in vitro. Pharmacokinetics and biodistribution studies were carried out in Wistar rats. Tumor model was established by inoculating a suspension of A549 cells into BALB/c nude mice. The mice were divided into Saline, Rg3 solution, and L-Rg3 groups with the drug given by i.p. injection. Survival of the mice and tumor volume were monitored. In addition, CD34 immunohistochemical analysis was used for measuring microvessel density (MVD) of the tumor tissues. The cytotoxicity and ratio of tumor inhibition of L-Rg3 group were significantly higher than the Rg3 solution group. MVD values in the Rg3 solution and L-Rg3 groups decreased, especially in the L-Rg3 group. Compared to Rg3 solution, the L-Rg3 showed increased Cmax and AUC of Rg3 by 1.19- and 1.52-fold, respectively. This liposomal formulation could potentially produce a viable clinical agent for improving the anticancer activity of Rg3.

Biodegradable poly(D, L-lactide-co-glycolide) (PLGA) microspheres for sustained release of risperidone: Zero-order release formulation

The preparation and investigation of sustained-release risperidone-encapsulated microspheres using erodible poly(D, L-lactide-co-glycolide) (PLGA) of lower molecular weight were performed and compared to that of commercial Risperdal Consta™ for the treatment of schizophrenia. The research included screening and optimizing of suitable commercial polymers of lower molecular weight PLGA50/50 or the blends of these PLGA polymers to prepare microspheres with zero-order release kinetics properties. Solvent evaporation method was applied here while studies of the risperidone loaded microsphere were carried out on its drug encapsulation capacity, morphology, particle size, as well as in vitro release profiles. Results showed that microspheres prepared using 50504A PLGA or blends of 5050-type PLGAs exerted spherical and smooth morphology, with a higher encapsulation efficiency and nearly zero-order release kinetics. These optimized microspheres showed great potential for a better depot preparation than the marketed Risperdal Consta™, which could further improve the patient compliance.

Liquiritin modulates ERK‑ and AKT/GSK‑3β‑dependent pathways to protect against glutamate‑induced cell damage in differentiated PC12 cells

Glutamate has a key role in the neuronal cell damage associated with Alzheimer’s and Parkinson’s diseases. Liquiritin (LQ), a major constituent of Glycyrrhiza Radix, possesses various pharmacological activities. The present study investigated the neuroprotective effect of LQ against glutamate-induced cell damage in the differentiated PC12 (DPC12) rat pheochromocytoma cell line. Pretreatment with 25 and 50 μM LQ for 3 h resulted in a significant increase in cell viability and inhibited excessive lactate dehydrogenase release in glutamate-exposed DPC12 cells. LQ also ameliorated glutamate-induced nuclear and mitochondrial apoptotic alterations, intracellular calcium overload and the abnormal expression of apoptosis-related proteins, including cytochrome c, B-cell lymphoma (Bcl)-2 and Bcl2-associated X protein. Treatment with LQ alone or in combination with glutamate was found to enhance the phosphoactivation of extracellular signal-regulated kinases (ERKs), AKT and its downstream element glycogen synthase kinase-3β (GSK3β), in a time-dependent manner. However, no effect was observed on the expression of total-ERKs, -AKT and -GSK3β. Furthermore, pre-incubation with 10 μM PD98059 or LY94002, inhibitors of ERK and phosphatidylinositide 3-kinase, respectively, for 30 min significantly suppressed the LQ-induced increase in glutamate-exposed DPC12 cell viability. To the best of our knowledge, the present study provides the first experimental evidence that LQ has a neuroprotective effect against glutamate toxicity in DPC12 cells, predominantly through the ERK and AKT/GSK-3β pathways. Therefore, LQ may have potential for the treatment of neurodegenerative diseases.

Studies on the preparation, characterization and pharmacological evaluation of tolterodine PLGA microspheres.

In this study, poly(d,l-lactide-co-glycolide) (PLGA) microspheres of tolterodine depot formulation were prepared using oil in water (o/w) method to investigate their potential pharmacokinetic and pharmacodynamic advantages over tolterodine l-tartrate tablets. Morphological studies of the microspheres showed a spherical shape and smooth surface with mean size of 50.69-83.01 microm, and the encapsulation efficiency was improved from 62.55 to 79.10% when the polymer concentration increased from 180 to 230 mg/ml. The addition of stearic or palmitic acids could significantly raise the drug entrapment efficiency but only slightly affected the in vitro release. A low initial burst followed by a proximately constant release of tolterodine was noticed in the in vitro release profiles. The in vivo study was carried out by intramuscular (i.m.) administration of tolterodine-loaded microspheres on beagle dogs, and a sustained release of drug from the PLGA microspheres was achieved until the 18th day with a low initial burst. Since the absence of hepatic first pass metabolism, only a single active compound-tolterodine was detected in the plasma. This avoided the coexistence of two active compounds in plasma in the case of oral administration of tolterodine, which may lead to a difficulty in dose control due to the different metabolic capacity of patients. In the pharmacodynamic study, the influence of tolterodine PLGA microspheres on the inhibition of carbachol-induced rat urinary bladder contraction was more significant than that of tolterodine l-tartrate tablets. There were invisible changes in rat bladder slices between tolterodine-loaded PLGA microspheres group and tolterodine l-tartrate tablets group. These results indicate that the continuous inhibition of muscarinic receptor may offer an alternative therapy of urge incontinence.

Liquiritigenin Induces Tumor Cell Death through Mitogen-Activated Protein Kinase- (MPAKs-) Mediated Pathway in Hepatocellular Carcinoma Cells

Liquiritigenin (LQ), separated from Glycyrrhiza radix, possesses anti-inflammatory, antihyperlipidemic, and antiallergic effects. Our present study aims to investigate the antihepatocellular carcinoma effects of LQ both in cell and animal models. LQ strikingly reduced cell viability, enhanced apoptotic rate, induced lactate dehydrogenase over-release, and increased intracellular reactive oxygen species (ROS) level and caspase 3 activity in both PLC/PRL/5 and HepG2 cells. The expression of cleaved PARP, the hall-marker of apoptosis, was enhanced by LQ. LQ treatment resulted in a reduction of the expressions of B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xL), and an increase of the phosphorylation of c-Jun N-terminal kinases (JNK) and P38. LQ-mediated cell viability reduction, mitochondrial dysfunction, apoptosis related protein abnormal expressions, and JNK and P38 activation were partially abolished by N-Acetyl-L-cysteine (a ROS inhibitor) pretreatment. Moreover, LQ suppressed the activation of extracellular signaling-regulated kinase (ERKs) and reduced the translocation of phosphor-ERKs from cytoplasm to nucleus. This antitumor activity was further confirmed in PLC/PRL/5-xenografted mice model. All these data indicate that the antihepatocellular carcinoma effects of LQ are related to its modulation of the activations of mitogen-activated protein kinase (MAPKs). The study provides experimental evidence supporting LQ as a potential therapeutic agent for hepatocellular carcinoma treatment.

ERKs and mitochondria-related pathways are essential for glycyrrhizic acid-mediated neuroprotection against glutamate-induced toxicity in differentiated PC12 cells

The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.

First-order Derivative Spectrophotometry for the Determination of Vitamin C in Medicament

Abstract A novel method for the determination of vitamin C(Vc) is proposed in this article. After the reaction with Folin-Ciocalteau reagent at ambient temperature, Vc solution was scanned at 750—1100 nm, and its first-order derivative spectrum were obtained from the original spectrum. The values of derivative selected at 995 nm were used for determination. It was proved that Vc could quickly react with Folin-Ciocalteau reagent within 5 min and the product was quite stable for a long time. The conditions required for this method is not very complicated, its precision and accuracy are similar to those of the iodometric titration described in Chinese Pharmacopoeia, and the limit of detection is 0.312 μg/mL. The determination of the results of vitamin C tablet, pill, and injection demonstrates that this method has wide pharmaceutical applications.

Measurement of filter paper activities of cellulase with microplate-based assay

It is always a challenge to determine the total cellulase activity efficiently without reducing accuracy. The most common total cellulase activity assay is the filter paper assay (FPA) established by the International Union of Pure and Applied Chemistry (IUPAC). A new procedure to measure the FPA with microplate-based assay was studied in this work, which followed the main idea of IUPAC to dilute cellulase preparation to get fixed glucose release. FPAs of six cellulase preparations were determined with the microplate-based assay. It is shown that FPAs of cellulase Youtell, RCconc, R-10, Lerkam, Yishui and Sinopharm were 67.9, 46.0, 46.1, 27.4, 7.6 and 8.0 IU/ml respectively. There was no significant difference at the 95% confidence level between the FPA determined with IUPAC and the microplate-based assay. It could be concluded that the FPA could be determined by the microplate-based assay with the same accuracy and much more efficiency compared with that by IUPAC.