Hypoglycemic property of soy isoflavones from hypocotyl in Goto-Kakizaki diabetic rats.

The present study was carried out to investigate the hypoglycemic effect of soy isoflavones from hypocotyl in GK diabetic rats. A single administration and long-term administration tests were conducted in GK diabetic rats to test the hypoglycemic effect of soy isoflavones. At the end of long-term administration trial, blood protein, cholesterol, triglyceride, glycosylated serum protein, C-reactive protein, insulin, aminotransferase, lipid peroxide, interleukin-6, tumor necrosis factor-α were estimated. Inhibition of soy isoflavones against α-amylase and α-glucosidase, as well as on glucose uptake into brush border membrane vesicles or Caco-2 cells were determined in vitro. In single administration experiment, soy isoflavones reduced postprandial blood glucose levels in GK rats. In long-term administration, hypoglycemic effect of soy isoflavones was first observed at week 12 and maintained till week 16. A significant reduction in fasting blood glucose, C-reactive protein, and lipid peroxide was noted at week 16. However, there was no significant treatment effect on blood insulin. Furthermore, soy isoflavone administration resulted in significant decreases in glycosylated serum protein, tumor necrosis factor-α, and interleukin-6. Other biochemical parameters, such as protein, cholesterol, triglyceride and aminotransferases were not modified, however. The results in vitro showed that soy isoflavones showed a potent inhibitory effect on intestinal α-glucosidase, but not on pancreatic α-amylase. Soy isoflavones also decreased glucose transport potency into brush border membrane vesicles or Caco-2 cells. It is concluded that soy isoflavones from hypocotyl, performs hypoglycemic function in GK rats with type 2 diabetes, maybe via suppression of carbohydrate digestion and glucose uptake in small intestine.

[Rhaponticum uniflorum inhibits H2O2-induced apoptosis of liver cells via JNK and NF-κB pathways].

To study the inhibitory effect of Rhaponticum uniflorum on apoptosis induced by H2O2 in HepG2 cells. Human HepG2 cells injury models were established by H2O2, then cell survival rate was assayed by MTT method; levels of LDH, ALT, and AST were detected by chemical colorimetric method;SOD activity was detected by xanthine oxidase method; GSH content was detected by dithio-bis-nitrobenzoic acid(DTNB); MDA level was detected by thiobarbituric acid (TBA) method;and the relative activities of Caspase-3, 8 and 9 were measured by Colorimetry. The expression levels of Cleaved Caspase-3(Casp-3), cytochrome(Cyto c), NF-κB, ERK, JNK, p38 MAPK, as well as the phospharylated proteins were determined with Western blotting method. The results showed that R. unifloru had no significant effect on cell viabilities of HepG2 cells at the concentrations of 25-400 mg•L⁻¹. However, H2O2decreased the cell viabilities, increased the cellular oxidative stress, and up-regulated the protein expressions of Casp-3, cytoplasmic Cyto c, p-JNK and nuclear NF-κB. As compared with the model group,R. unifloru could increase the cell viability, reduce LDH, ALT and AST leakage, reduce the MDA formation, increase the SOD and GSH levels,reduce the relative activities of Caspase-3, 8 and 9, down-regulated the protein expressions of Casp-3 and cytoplasmic Cyto c, and down-regulate the p-JNK and nuclear NF-κB levels.The results indicated that R. unifloru had the inhibitory effect on apoptosis induced by H2O2in HepG2 cells, and the mechanism maybe associated with inhibiting JNK activation and NF-κB nuclear translocation.

Evaluation of doxorubicin-loaded pH-sensitive polymeric micelle release from tumor blood vessels and anticancer efficacy using a dorsal skin-fold window chamber model.

AIM: To evaluation the doxorubicin (DOX)-loaded pH-sensitive polymeric micelle release from tumor blood vessels into tumor interstitium using an animal vessel visibility model, the so-called dorsal skin-fold window chamber model. METHODS: DOX-loaded pH-sensitive polyHis-b-PEG micelles and DOX-loaded pH-insensitive PLLA-b-PEG micelles were prepared. The uptake of the micelles by MDA-MB-231 breast cancer cells in vitro and in vivo was examined using flow cytometry. The pharmacokinetic parameters of the micelles were determined in SD rats after intravenous injection of a DOX dose (6 mg/kg). The release of the micelles from tumor vasculature and the antitumor efficacy were evaluated in MDA-MB-231 breast cancer xenografted in nude mice using a dorsal skin-fold window chamber. RESULTS: The effective elimination half-life t1/2 of the pH-sensitive, pH-insensitive polymeric micelles and DOX-PBS in rats were 11.3 h, 9.4 h, and 2.1 h, respectively. Intravital microscopy in MDA-MB-231 breast cancer xenografted in nude mice showed that the pH-sensitive polymeric micelles rapidly extravasated from the tumor blood vessels, and DOX carried by the pH-sensitive micelles was preferentially released at the tumor site as compared to the pH-insensitive polymeric micelles. Furthermore, the pH-sensitive polymeric micelles exhibited significant greater efficacy in inhibition of tumor growth in the nude mice. CONCLUSION: When DOX is loaded into pH-sensitive polymeric micelles, the acidity in tumor interstitium causes the destabilization of the micelles and triggers drug release, resulting in high local concentrations within the tumor, thus more effectively inhibiting the tumor growth in vivo.

Improved anti-tumor efficiency against prostate cancer by docetaxel-loaded PEG-PCL micelles.

This study primarily focused on the systematic assessment of both in vitro and in vivo anti-tumor effects of docetaxel-loaded polyethylene glycol (PEG)2000-polycaprolactone (PCL)2600 micelles on hormone-refractory prostate cancer (HRPC). By using solvent evaporation method, PEG-PCL was chosen to prepare doxetaxel (DTX)-loaded mPEG-PCL micelles (DTX-PMs), with the purpose of eliminating side effects of the commercial formulation (Tween 80) and prolonging the blood circulation time. The prepared DTX-PMs had an average particle size of 25.19±2.36 nm, a zeta potential of 0.64±0.15 mV, a polydispersity index of 0.56±0.03, a drug loading of (8.72±1.05)%, and an encapsulation efficiency of (98.1±8.4)%. In vitro cytotoxicity studies indicated that DTX-PMs could effectively kill LNCap-C4-2B cells and show a dose- and time-dependent efficacy. The hemolysis test showed that DTX-PMs had less hemocytolysis than the commercial product of Duopafei®. A sustained in vitro release behavior and prolonged circulation time in blood vessels were observed in the DTX-PMs. Furthermore, when compared with Duopafei®, the DTX-PMs dramatically reduced the prostate specific antigen (PSA) level and tumor growth of prostate tumor-bearing nude mice in vivo. In conclusion, the DTX-PMs can lower systemic side effects, improve anti-tumor activity with prolonged blood circulation time, and will bring an alternative to patients with HRPC.

[Protective effect of soyasaponins on acute liver injury induced by D-galactosamine and lipopolysaccharide in mice].

OBJECTIVE: To investigate the protective effect of soyasaponins on acute liver injury induced by D-galactosamine (GalN) and lipopolysaccharide (LPS) in mice. METHOD: The mice were randomly divided into five groups: the normal control, the model group, the silymarin (positive control) group, and soyasaponins high and low-dose groups. They were administered with drugs once every day for 7 days. At the end of the experiment, GalN and LPS were injected intraperitoneally to all of the groups except for the normal group to establish the acute liver injury model. The pathological changes were detected with hematoxylin & eosin (HE) staining, tumor necrosis factor-alpha (TNF-alpha) was detected by ELISA method, and the alanine aminotransferase (ALT), aspartate aminotransferase (AST), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), and the activation of Caspase-3 and Caspase-8 were detected by the colorimetric method. RESULT: Soyasaponins could reduce the activities of serum ALT and AST, the acute hepatic injury induced by GalN/LPS, serum TNF-alpha level, hepatic NO and MDA contents, and the Caspase-3 and Caspase-8 activations of liver tissues, and increase the hepatic CAT, GPx, GST and GSH levels. CONCLUSION: Soyasaponins shows the protective effect on acute liver injury induced by GalN and LPS in mice, which may be related to its antioxidative ability and anti-liver apoptosis.

Preparation and characterization of polymeric nanoparticles for siRNA delivery to down-regulate the expressions of exogenous and endogenous target genes.

Gene silencing induced by RNA interference using small interfering RNA (siRNA) provides a promising therapeutic approach for cancers. However, the lack of siRNA delivery vector has limited the development of siRNA therapy. The purpose of this study was to use the novel copolymer (mPEG5k-PCL1.2k)1.4-g-PEl10k to prepare siRNA-loaded nanoparticles for siRNA delivery. The results suggested that (mPEG5k-PCL1.2k)1.4-g-PEl10k could load siRNA to form nanoparticles with particle size less than 200 nm in a narrow distribution. Moreover, a certain density of positive charge existed onto the surfaces of nanoparticles. MTT assay results demonstrated that (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles showed very low cytotoxicity. The gene silencing efficiency of (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles was investigated through luciferase reporter gene assays. The expression of exogenous luciferase gene was significantly downregulated at a range of N/P ratio from 50 to 125, and was maximally inhibited at the N/P ratio of 125 with 54% and 59% reduction in MCF-7 and HepG2 cells, respectively. In the 4T1-luc cell line expressing luciferase stably, the silencing of endogenous luciferase gene also has a similar overall profile with maximal 54% reduction of luciferase expression. These results suggested that (mPEG5k-PCL1.2k)1.4-g-PEI10k/SiRNA nanoparticles could serve as a kind of highly efficient siRNA delivery system for down-regulating the expression of exogenous and endogenous target genes.

Multifunctional nanoparticles for targeting cancer therapy.

Chemotherapy drug Doxorubicin and MRI imaging agent Iron Oxide were encapsulated in dual functional nanoparticles which is compose of PEG-Foliate acid polymers. The particle size was about 45 nm with a mono-dispersion measured by zeta-sizer instrument. The contrast of images in liver was enhanced after injection Nanoparticles via rabbit ear vein. PEG-FA coated Iron Oxide nanoparticles can selectively target to tumor site and effectively inhibit tumor growth which is subcutaneously bearing A2780 Overran cancer cells. It is feasible for cancer treatment with MRI imaging and chemotherapy simultaneously in vivo by injection dual functional nanoparticles.

Thermal reversible microemulsion system for poorly water-soluble YH439 for oral delivery.

To improve bioavailability of poorly water-soluble YH439, a thermal reversible microemulsion system was prepared using modified fatty acids such as capric acid and palmitic acid with PEG 400. A combination of Capric-PEG 400 and Palmitic-PEG 400 with a ratio of 1 : 3 used as a lipid matrix and Cremophor RH40 and Neobee M-5 were selected as an oil and a surfactant, respectively. The microemulsion with melting point of 36.5 degrees C was produced by mixing the lipid matrices, Cremophor RH40 and Neobee M-5 with a volume ratio of 5 : 4 : 1. After the microemulsion was dispersed in the aqueous medium, the average particle size of 28 nm was obtained. At the release measurements of YH439 after 45 min suspension in pH 1.2 aqueous medium, about 80%, 65%, 10% and less than 5% of drug were released from the thermal reversible microemulson, Gelucire formulation, 5% Ca-carboxymethylcellulose (CMC) suspension and YH439 powder, respectively. The apparent permeability of YH439 in microemulsion either from apical to basolateral or basolateral to apical after measuring YH439 across a Caco-2 cell monolayer in a Transwell larger than Gelucire formulation or 5% Na-CMC suspension. The area under the drug concentration-time curves (AUC) and maximal blood concentration (C(max)) after oral administration of YH439 loaded on thermal reversible microemulsion were significantly increased than drug loaded on either Gelucire formulation or 5% Na-CMC suspension. Thus, the present work demonstrates that the thermal reversible microemulsion system of YH439 greatly enhances the bioavailability of YH439 after oral administration due to the improvement of solubility and dispersion of the drug in the artificial gastrointestinal tract without pepsin.

Dendroaspis natriuretic peptide relaxes gastric antral circular smooth muscle of guinea-pig through the cGMP/cGMP-dependent protein kinase pathway.

AIM: To systematically investigate if cGMP/cGMP-dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle. METHODS: The content of cGMP in guinea pig gastric antral smooth muscle tissue and perfusion solution were measured using radioimmunoassay; spontaneous contraction of gastric antral circular muscles recorded using a 4-channel physiograph; and Ca(2+)-activated K(+) currents (I(K(Ca))) and spontaneous transient outward currents (STOCs) in isolated gastric antral myocytes were recorded using the whole-cell patch clamp technique. RESULTS: DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in the perfusion medium. DNP induced relaxation in gastric antral circular smooth muscle, which was inhibited by KT5823, a cGMP-dependent PKG inhibitor. DNP increased I(K(Ca)). This effect was almost completely blocked by KT5823, and partially blocked by LY83583, an inhibitor of guanylate cyclase to change the production of cGMP. DNP also increased STOCs. The effect of DNP on STOCs was abolished in the presence of KT5823, but not affected by KT-5720, a PKA-specific inhibitor. CONCLUSION: DNP activates I(K(Ca)) and relaxes guinea-pig gastric antral circular smooth muscle via the cGMP/PKG-dependent singling axis instead of cAMP/PKA pathway.

[Anti-atherosclerotic effect of soybean isofalvones and soyasaponins in diabetic rats].

OBJECTIVE: To study the influence of soybean phytochemical extract containing isoflavones and soyasaponins (SPE) on blood glucose, blood lipids, plasma lipid peroxide and platelet aggregation activity in diabetic rats. METHODS: Diabetic rats were fed with fodder containing 20 g/kg of SPE for 20 weeks. Their plasma very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) were separated by sequential ultracentrifugation. RESULTS: Twenty weeks after experiment, level of blood glucose, atherosclerotic index and plasma level of lipid peroxide were (11.9 +/- 0.9) mmol/L, 0.40 +/- 0.14 and (15.7 +/- 0.5) mmol/L, respectively in diabetic rats fed with SPE, significantly lower than those in control rats not fed with it, (14.2 +/- 2.0) mmol/L, 0.58 +/- 0.22 and (20.7 +/- 3.0) mmol/L, respectively. Accordingly, platelet aggregation rates induced by ADP and collagen in the two groups were (54.1 +/- 8.8)% vs (66.6 +/- 12.4)% and (58.0 +/- 7.9)% vs (69.6 +/- 9.4)%, respectively. Changes in all these indices were significantly different between the two groups. CONCLUSION: SPE could significantly decrease blood glucose, improve atherosclerotic index, and inhibit lipid peroxidation and platelet aggregation in diabetic rats, which might be useful in prevention and control of diabetes mellitus and diabetes-associated atherosclerosis.

Effect of Boschniakia rossica on expression of GST-P, p53 and p21(ras)proteins in early stage of chemical hepatocarcinogenesis and its anti-inflammatory activities in rats.

AIM:To investigate the effect of Boschniakia rossica (BR) extract on expression of GST-P, p53 and p21(ras) proteins in early stage of chemical hepatocarcinogenesis in rats and its anti-inflammatory activities.METHODS:The expression of tumor marker-placental form glutathione S-transferase (GST-P), p53 and p21(ras) proteins were investigated by immunohisto-chemical techniques and ABC method. Anti-inflammatory activities of BR were studied by xylene and croton oil-induced mouse ear edema, carrageenin, histamine and hot scald-induced rat pow edema, adjuvant-induced rat arthritis and cotton pellet induced mouse granuloma formation methods.RESULTS:The 500mg/kg of BR-H2O extract frac-tionated from BR-Methanol extract had inhibitory effect on the formation of DEN-induced GST-P-positive foci in rat liver (GST-P staining was 78% positive in DEN+AAF group vs 20% positive in DEN+AAF+BR group, P<0.05) and the expression of mutant p53 and p21(ras) protein was lower than that of hepatic preneoplastic lesions (33% and 22% positive respectively in DEN+AAF group vs negative in DEN+AAF+BR group). Both CH(2)Cl(2) and H(2)O extracts from BR had anti-inflamatory effect in xylene and crotonoil induced mouse ear edema (inhibitory rates were 26%-29% and 35%-59%, respectively). BR H(2)O extract exhibited inhibitory effect in carrageenin, histamine and hot scald-induced hind paw edema and adjuvant-induced arthritis in rats and cotton pellet-induced granuloma formation in mice.CONCLUSION:BR extract exhibited inhibitory effect on formation of preneoplastic hepatic foci in early stage of rat chemical hepato-carcinogenesis.Both CH(2)Cl(2) and H(2)O extracts from BR exerted anti-inflammatory effect in rats and mice.