Zhongxi Zhao

Hepatoprotective effects of polysaccharides extracted from Zizyphus jujube cv. Huanghetanzao.

Jujube polysaccharides have been proved to have various bioactivities. This study was designed to evaluate the chemical composition and hepatoprotective function of the polysaccharides extracted from Zizyphus jujube cv. Huanghetanzao (HJP). The composition of HJP was determined as heteropolysaccharides with galactose and arabinose being the main components. The pretreatment of mice with HJP significantly (p<0.01) reduced the activities of serum hepatic AST, ALT, and LDH induced by CCl4 or acetaminophen (APAP) while the commercial liver-injury treatment drug silybin did not show any prevention effects. Mechanistic study results indicate that the administration of the CCl4- or APAP-injured mice with HJP enhanced SOD and GSH-Px and decreased MDA, indicating that anti-oxidation and detoxification could be the pathways for the liver protection observed. In addition, the liver prevention and treatment effects of HJP on the liver damage induced by CCl4 or APAP obtained from the liver enzyme analyses were confirmed by the hepatic histopathology studies in mice. Therefore, HJP could be used as a prevention and treatment agent for liver injury induced by liver toxic chemicals and drugs.

Sustained release of 5-fluorouracil by incorporation into sodium carboxymethylcellulose sub-micron fibers.

This work introduces a novel route to the sodium carboxymethylcellulose sub-micron fibers loaded with hydrophilic anticancer drug, 5-fluorouracil (5-Fu). The results show that 5-Fu is successfully incorporated into the biocompatible polymer, sodium carboxymethylcellulose (NaCMC)-based fibers with good stability, desired drug loading content and 100% entrapment efficiency. Furthermore, the drug release rate of the as-prepared drug-loaded fibers could be well controlled. The drug release behavior of the 5-Fu-loaded NaCMC fibers shows a diffusion mechanism, obeying Ritger-Peppas kinetics model. The drug release behavior of the as-prepared products demonstrates their promising application in drug delivery system.

Folate-modified bexarotene-loaded bovine serum albumin nanoparticles as a promising tumor-targeting delivery system

Bexarotene (BEX), a high-affinity agonist for retinoid X receptors (RXRs), shows apparent biological activities and distinct inhibitive efficacy in both cancer therapy and prevention. This study exploited a folate-decorated delivery of bexarotene-loaded bovine serum albumin nanoparticles, which could solubilize the poorly water-soluble drug and overcome the nonspecific targeting disadvantage. Bexarotene-loaded bovine serum albumin nanoparticles (BEX-BSANPs) were optimized by a desolvation technique, subsequently conjugated with folate by carbodiimide reaction. The resultant folate-modified bexarotene-loaded bovine serum albumin nanoparticles (FA-BEX-BSANPs) showed a spherical shape, with a diameter of 195.3 ± 5.6 nm, a zeta potential of -33.64 ± 1.97 mV, and 71.28 ± 1.93 μg folate was coupled per mg BSA. Differential scanning calorimetry and X-ray diffraction analysis confirmed the amorphous state of bexarotene in the folate-conjugates. The in vitro drug release of bexarotene presented a controlled and sustained release pattern. The in vitro cytotoxicity, cell apoptosis and cellular uptake experiments of the nanoparticles were performed by MTT assay, propidium iodide staining, fluorescence microscopy and flow cytometric analysis on A549 and MCF-7 cancer cells. Both the BEX-BSANPs and FA-BEX-BSANPs induced an enhanced cancer cell apoptotic effect in contrast to BEX solution. The cells showed an excellent binding for folate-modified nanoparticles. Especially, the interference effect on the cellular internalization process by an excess folic acid was relatively dramatic for the FR-positive MCF-7 cells in comparison to the modest change seen in the FR-negative A549 cell lines, indicating that the uptake was mediated by the folate receptors. Together these data suggested that the folate-modified bexarotene-loaded delivery system, which demonstrated better biocompatibility and potential superiority, could be an appropriate cancer therapy in targeting tumors in the future.

Huperzine A-phospholipid complex-loaded biodegradable thermosensitive polymer gel for controlled drug release

The huperzine A-phospholipid complex loaded biodegradable thermosensitive PLGA-PEG-PLGA polymer gel was studied as injectable implant system for controlled release of huperzine-A (HA). First, HA molecules were successfully incorporated into the soybean phosphatidylcholine (SP) molecules to form the huperzine-A-soybean phosphatidylcholine complexes (HA-SPC), which was proved by FT-IR, DSC, XRD, solubility study, TEM, etc. The results indicated that hydrogen bonds and electrostatic interaction between HA and SP molecules play an important role in the formation of HA-SPC. Secondly, the HA-SPC was loaded into biodegradable PLGA-PEG-PLGA thermosensitive gel as injectable implant material to control the release of HA. The in vitro and in vivo drug release behaviors of the prepared products were studied. The in vitro release studies demonstrated that the HA-SPC-loaded gel significantly reduced the initial burst of drug release and extended the release period to about 2 weeks. The in vivo pharmacokinetics study of HA-SPC-loaded gel in rabbits showed that plasma concentration of HA (2.54-0.15ng/mL) was detected for nearly 2 weeks from delivery systems upon single subcutaneous injection. Whats more, the in vitro release pattern correlated well with the in vivo pharmacokinetics profile. The present study indicates that HA-SPC loaded PLGA-PEG-PLGA thermal gel may be an attractive candidate vehicle for controlled HA release.

Docetaxel-loaded PEO–PPO–PCL/TPGS mixed micelles for overcoming multidrug resistance and enhancing antitumor efficacy

There are two major hurdles for the current anti-cancer drug delivery systems. One is the emergence of multidrug resistance (MDR) and the other is the conflict between long-circulation and cellular uptake. In the present study, the anticancer drug docetaxel (DTX) was successfully loaded into three series of micelles via self-assembly using a mixture of PEO-PPO-PCL and d-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS), for the purpose of prolonging the blood circulation time as well as overcoming MDR of DTX. Three series of copolymers with different PCL molecular weights, PEO68-PPO34-PCL9, PEO68-PPO34-PCL18 and PEO68-PPO34-PCL36, were synthesized. The prepared spherical mixed micelles (MM) were found to possess nanoscale size (25-135 nm). The PEO-PPO-PCL/TPGS mixed micelles had a low critical micelle concentration (∼10-6 g mL-1) and a low hemolysis rate (<5%), which has proved that they are safe for use in vivo. Moreover, they had obvious sustained release behavior in vitro and a longer circulation time than free DTX in vivo. The P-gp inhibition assay, cellular uptake and MTT assay in cancer cells exhibited that DTX-loaded MM could overcome MDR, show higher cellular uptake and higher antitumor efficacy than free DTX. The IC50 values demonstrated that the three series of DTX-loaded MM were 69, 82 and 100 fold effective than free DTX after 72 h treatment with MCF-7 cells, respectively. Therefore, these results demonstrated that the prepared DTX-loaded MM provide desirable application in cancer chemotherapy.

Synthesis, characterization, in vitro and in vivo evaluation of PEGylated oridonin conjugates

Oridonin (ORI), a diterpenoid compound with promising antitumor activity, was proved to possess potent antileukemia efficacies in vitro and in vivo recently. However, the development and application of ORI was limited by its poor solubility and rapid plasma clearance. The purpose of this study was to solve these problems. PEGylated oridonin linked with succinic acid (SA) as spacer moiety (PEG-SA-ORI conjugate) was synthesized. mPEG amines with four specifications of molecular weight (MW) were utilized. All polymeric conjugates showed satisfactory aqueous solubility and in vitro studies implied that the drug solubility and release features of conjugates were relevant to PEGs. The drug solubility increased more when the MW of PEG was lower, while more significant sustained-release effect was shown with higher PEG MW. Moreover, the release behaviors of conjugates showed a pH-sensitive property. In vivo pharmacokinetic studies demonstrated that the elimination half-life was prolonged in comparison with ORI solution. PEGylation could be a promising method to obtain better efficacy in the field of drug delivery system.

In vitro antioxidative and immunological activities of polysaccharides from Zizyphus Jujuba cv. Muzao.

Zizyphus jujuba has been used as a traditional Chinese medicinal herb since ancient time. Polysaccharides have been found to be important bioactive compounds in the jujube. This work was designed to investigate the physicochemical characteristics and bioactivities of polysaccharides purified from Zizyphus jujuba cv. Muzao. Water-soluble polysaccharides were extracted using an ultrasonically assisted extraction method. The purified polysaccharides (HJP) were obtained by deproteinization and decoloration. Three main fractions (HJP1, HJP2 and HJP3) were isolated using DEAE-Sepharose fast flow ion-exchange chromatography. The purified polysaccharides were found to consist of mannose, rhamnose, galactose, galacturonic acid, glucose and arabinose at various levels for different fractions. The HJP and its three main fractions displayed DPPH radical scavenging activities as well as relatively strong reducing power and HJP had stronger activities than homogeneous compositions. Moreover, the results from in vitro immunological activities studies indicated that HJP could improve the phagocytosis activity of THP-l cells and had effect on the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). In conclusion, the polysaccharides from Zizyphus jujuba cv. Muzao were discovered to have antioxidative and immunological activities.

Immuno-enhancement effects of Yifei Tongluo Granules on cyclophosphamide-induced immunosuppression in Balb/c mice.

ETHNOPHARMACOLOGICAL RELEVANCE Traditional Chinese medicine Yifei Tongluo Granules has been employed clinically with the combination of chemotherapy agents to treat patients with multidrug-resistant tuberculosis. However, the mechanisms underlying the therapeutic potential have not been well elucidated. The present study was employed to verify immunomodulatory effect and to investigate the underlying mechanisms which have not been explored. MATERIALS AND METHODS The study samples of total extracts (FB-E) and polysaccharides (FB-P) were prepared by the extraction of the Yifei Tongluo Granules using appropriate techniques. A simple immunodeficient mice model was established by challenging Balb/c mice with cyclophosphamide in order to avoid the handling of tuberculosis viruses. The in vivo study was thus designed to systematically elucidate the immuno-enhancement effects of Yifei Tongluo Granules extracts in immunosuppressed mice induced by cyclophosphamide. Balb/c mice were orally ingested once daily with the low and high doses of two different extracts for ten consecutive days, respectively, accompanied by intraperitoneal injection of cyclophosphamide (60mg/kg) on days 1-3 and 10. RESULTS Compared with the model group, the treatment of immunodeficient mice with the low and high doses of the extracts FB-E or FB-P enhanced spleen and thymus indices, T- and B-cell proliferation as well as increased the activities of splenic natural killer, lymphokine activated killer, cytotoxic T lymphocyte cells and peritoneal macrophage phagocytosis. In addition, the FB-E or FB-P treatment balanced the ratio of Th1/Th2 and up-regulated the CD4+/CD8+ ratio in the serum. CONCLUSIONS These results demonstrate, for the first time, that the treatment of the cyclophosphamide-challenged mice with the Yifei Tongluo Granules extracts resulted in accelerated recovery of immunosuppression, sugguesting that the immunomodulation might be the mechanism for the observed clinical benefits of Yifei Tongluo Granules. Our findings provide preliminary mechanistic study evidences for clinical application of Yifei Tongluo Granules in patients with immunodeficient diseases such as tuberculosis.

S‐Allylmercaptocysteine Attenuates Cisplatin‐Induced Nephrotoxicity through Suppression of Apoptosis, Oxidative Stress, and Inflammation

Cisplatin is a potent chemotherapeutic agent, but its clinical usage is limited by nephrotoxicity. S-allylmercaptocysteine (SAMC), one of the water-soluble organosulfur garlic derivatives, has antioxidant and anti-inflammatory properties and plays an important role in protecting cells from apoptosis. This study aims to examine the protective effects of SAMC on cisplatin nephrotoxicity and to explore the mechanism of its renoprotection. Rats were treated with cisplatin with or without pre-treatment with SAMC. Renal function, histological change, oxidative stress markers and antioxidant enzyme activities were investigated. Apoptotic marker, nuclearfactor (NF)-κB activity, expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H:quinone oxidoreductase 1 (NQO1) and inflammatory cytokines were also examined. The effect of SAMC on cell viability and apoptosis was examined in cultured human kidney (HK-2) cells. SAMC was confirmed to significantly attenuate cisplatin-induced renal damage by using histological pathology and molecular biological method. Pre-treatment with SAMC reduced NF-κB activity, up-regulated Nrf2 and NQO1 expression and down-regulated inflammatory cytokine levels after cisplatin administration. Cisplatin-induced apoptosis in HK-2 cells was significantly attenuated by SAMC. Thus our results suggest that SAMC could be a potential therapeutic agent in the treatment of the cisplatin-induced nephrotoxicity through its anti-apoptotic, anti-oxidant and anti-inflammatory effects.

Protective effect of allyl methyl disulfide on acetaminophen-induced hepatotoxicity in mice

Multiple sulfur compounds of garlic have shown versatile medicinal activities in the prevention and treatment of various diseases. Allyl methyl disulfide (AMDS) was identified as one of the bioactive components in fresh garlic paste in our previous study. The purpose of this study was to investigate the hepatoprotective effect of AMDS against acetaminophen (APAP)-induced acute liver damage in mice. Results reveal that AMDS significantly alleviates APAP-induced elevation of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in mice. Furthermore, AMDS significantly (p < 0.05) reduced the maleic dialdehyde (MDA) level in liver tissues and restored the activities of antioxidant enzymes SOD, GSH-PX and GSH towards normal levels. IL-6 and TNF-alpha (TNF-α) levels in the serum and liver were clearly increased by acetaminophen-damage (p < 0.05) and AMDS intake significantly suppressed acetaminophen-induced increase of the two cytokines (p < 0.05). The immunohistochemical and pathological analyses showed that AMDS could ameliorate the liver injury through the strong attenuation of the CD45 expression and HNE formation. All the results indicate that AMDS had the ability to protect hepatocytes from APAP-induced liver damage.