Daquan Chen

Anti-inflammatory and Anti-oxidative Activities of Paeonol and Its Metabolites Through Blocking MAPK/ERK/p38 Signaling Pathway

The possible protective and curative effects of paeonol on carrageenan-induced acute hind paw edema in rats and dextran sulfate sodium (DSS)-induced colitis in mice have been evaluated. After oral administration, paeonol (20 and 40 mg/kg) reduced the edema increase in paw volumes and also the development of DSS-induced murine colitis. Furthermore, anti-inflammatory and anti-oxidant activities of paeonol (1) together with its 10 metabolites (M2~M11) were investigated by using in vitro anti-inflammatory and anti-oxidant assays. M3 and M11 exhibited significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities (with EC50 values of 93.44 and 23.24 μM, respectively). All the metabolites except M8 showed hydroxyl radical scavenging activities, and M3 and M11 were the most potent agents (with EC50 values of 336.02 and 124.05 μM, respectively). Inhibitory effects of paeonol, M2~M11 on the overproduction of nitric oxide (NO), and the release of TNF-α were also tested. M3 and M11 potently inhibited lipopolysaccharide (LPS)-induced overproduction of NO in macrophage RAW 264.7. Western blot results demonstrated that paeonol, M3, and M11 downregulated the high expression of inducible nitric oxide synthase (iNOS) and COX-2 proteins, and the effects of M3 and M11 were more potent when compared with paeonol. These findings indicated that paeonol may play anti-inflammatory and anti-oxidant roles by changing to its active metabolites after absorption. In addition, further investigations on the mechanism showed that paeonol, M3, and M11 blocked the phosphorylation of MAPK/ERK 1/2 and p38, whereas they showed no effect on the phosphorylation of JNK. The above results suggested that pre-treatment with paeonol might be an effective therapeutic intervention against inflammatory diseases including colitis.

Design of novel multifunctional targeting nano-carrier drug delivery system based on CD44 receptor and tumor microenvironment pH condition

Abstract In this study, to develop a multifunctional targeting nano-carrier drug delivery system for cancer therapy, the novel pH-sensitive ketal based oligosaccharides of hyaluronan (oHA) conjugates were synthesized by chemical conjugation of hydrophobic menthone 1,2-glycerol ketal (MGK) to the backbone of oHA with the histidine as the linker of proton sponge effect. The multifunctional oHA conjugates, oHA-histidine-MGK (oHM) carried the pH-sensitive MGK as hydrophobic moieties and oHA as the target of CD44 receptor. The oHM could self-assemble to nano-sized spherical shape with the average diameters of 128.6 nm at pH 7.4 PBS conditions. The oHM nanoparticles (oHMN) could release encapsulated curcumin (Cur) with 82.6% at pH 5.0 compared with 49.3% at pH 7.4. The results of cytotoxicity assay indicated that encapsulated Cur in oHMN (Cur-oHMN) were stable and have less toxicity compared to Cur suspension. The anti-tumor efficacy in vivo suggested that Cur-oHMN suppressed tumor growth most efficiently. These results present the promising potential of oHMN as a stable and effective nano-sized pH-sensitive drug delivery system for cancer treatment.

Dual thermoresponsive and pH-responsive self-assembled micellar nanogel for anticancer drug delivery

Abstract In this article, we prepared a dual thermoresponsive and pH-responsive self-assembled micellar nanogel for anticancer drug delivery by using a degradable pH-responsive ketal derivative, mPEG2000-Isopropylideneglycerol (mPEG-IS, PI) polymer. The purpose of this study is to develop an injectable dual-responsive micellar nanogel system which has a sol-gel phase transition by the stimulation of body temperature with improved stability and biocompatibility as a controlled drug delivery carrier for cancer therapy. The pH-responsive PI was designed with pH-responsive ketal group as hydrophobic moieties and PEG group as hydrophilic moieties. The PI micelles encapsulated paclitaxel (PTX) was fabricated. Then, the PI micelles were formed in a thermo-nanogel. The micellar nanogel could improve the solubility and stability of PTX. The physiochemical properties of PI micelles and micellar nanogel were characterized. The results showed that dual-responsive micellar nanogel could carry out sol-gel transition at 37 °C. The PI polymer can spontaneously self-assemble into micellar structure with size of 100–200 nm. The dual-responsive micellar nanogel could be degraded under lower pH condition. The test in vitro PTX release showed that dual-responsive micellar nanogel could release about 70% for 70 h under pH 5.0 while about 10% release at pH 7.4 and pH 9.0. The dual-responsive micellar nanogel was of lower cytotoxicity and suppressed tumor growth most efficiently. The micellar nanogel will be a new potential dual-responsive drug delivery system for cancer therapy.

Redox-sensitive and hyaluronic acid functionalized liposomes for cytoplasmic drug delivery to osteosarcoma in animal models

Abstract This study aimed to develop redox‐sensitive and CD44‐targeted liposomes to improve chemotherapy of osteosarcoma. Cationic liposomes were prepared and stabilized with a novel detachable polyethylene glycol (PEG2000) conjugated with cholesterol through a bio‐reducible disulfide linker (Chol‐SS‐mPEG). Hyaluronic acid (HA, MW 20–40 kDa), a ligand to CD44, was non‐covalently coated on the cationic liposomes. Doxorubicin (DOX) was actively loaded in the liposomes as a model drug. The roles of HA and Chol‐SS‐mPEG on intracellular drug delivery efficiency, and antitumor efficacy were studied. The structure of Chol‐SS‐mPEG was confirmed with Fourier‐transform infrared and nuclear magnetic resonance (1H NMR). The liposomes, Chol‐SS‐mPEG/HA‐L had a mean diameter of 165 nm, zeta potential −28.9 mV, and destabilized in reducing or acidic (pH 5–6) conditions. In vitro release of DOX was well‐controlled at physiological conditions, but a burst release of 60% was observed in the presence of 10 mM glutathione (GSH), in contrast to non‐redox sensitive liposomes (Chol‐mPEG/HA‐L and Chol‐mPEG‐L). MTT cell viability assay showed that the dual‐functional Chol‐SS‐mPEG/HA‐L with a drug loading of 15.0% (w/w) had significantly higher cytotoxicity to MG63 osteosarcoma cells compared with non‐reduction sensitive or non‐HA coated liposomes (p < 0.01), consistent with the cellular uptake and intracellular trafficking studies using confocal microscopy and flow cytometry. Furthermore, the HA‐coated GSH‐responsive liposomes preferentially internalized to MG63 over human liver cells LO2. In rats, liposomes stabilized with either Chol‐SS‐mPEG or Chol‐mPEG, with or without HA, increased the half‐life of DOX by >10‐fold. In a MG63 xenograft mouse model, Chol‐SS‐mPEG/HA‐L showed the most effective tumor suppression with minimal uptake by the liver compared with other liposomes. All animals treated with liposomal formulations survived, in contrast to those free‐DOX treated. In conclusion, the easily prepared Chol‐SS‐mPEG/HA‐L was demonstrated as an excellent CD44‐mediated intracellular delivery system capable of long‐circulation and GSH‐triggered cytoplasmic drug release. Further translational and multidisciplinary research is required to make it real clinical benefits to cancer patients. Graphical abstract Figure. No Caption available.

Curcumin and its major metabolites inhibit the inflammatory response induced by lipopolysaccharide: Translocation of nuclear factor-κB as potential target

The aim of the present study was to investigate and compare the anti‑inflammatory activities of curcumin and its three metabolites, tetrahydrocurcumin, hexahydrocurcumin and octahydrocurcumin in lipopolysaccharide (LPS)‑stimulated RAW 264.7 macrophage cells. The results demonstrated that overproduction of nitric oxide (NO) was potently inhibited following treatment with curcumin and its three metabolites. In addition, curcumin and tetrahydrocurcumin significantly inhibited the release of prominent cytokines, including tumor necrosis factor‑α (TNF‑α) and interleukin‑6 (IL‑6); however, hexahydrocurcumin and octahydrocurcumin did not significantly alter cytokine release. Furthermore, the present study investigated the effect of curcumin and its metabolites on the expression of inducible NO synthase (iNOS), cyclooxygenase‑2 (COX‑2) and activated‑nuclear factor kappa B (NF‑κB); the results showed that curcumin and its three metabolites significantly inhibited LPS‑mediated upregulation of iNOS and COX‑2 as well as NF‑κB activation. However, curcumin exerted a more potent effect on LPS‑stimulated RAW 264.7 cells compared to that of its three metabolites, of which tetrahydrocurcuim was found to be the most pharmacologically active. In conclusion, the results of the present study demonstrated that curcumin and its major metabolites inhibited the LPS‑induced inflammatory response via the mechanism of inhibiting NF‑κB translocation to the nucleus.

Dual pH/redox responsive and CD44 receptor targeting hybrid nano-chrysalis based on new oligosaccharides of hyaluronan conjugates

A smart hybrid microenvironment-mediated dual pH/redox-responsive polymeric nanoparticles combined with inorganic calcium phosphate (CaP) was fabricated, which we term as armored nano-chrysalis inspired by butterfly pupa. The nano-chrysalis has an inner core composed of specially designed oligosaccharides of hyaluronan (oHA) targeting CD44 receptor. The inner core has two functions, i.e., the dual pH/redox responsive polymeric conjugate and the fluorescent curcumin-prodrug function. The prepared nano-chrysalis possessed a smaller size (102.5±4.6nm) than the unarmored nano-chrysalis (122.5±6.6nm). Interestingly, while the nano-chrysalis were stable under pH 7.4, when incubated under the tumor acidic conditions (pH 6.5) the outer CaP armor would dissolve in a pH-dependent, sustained manner. Moreover, nano-chrysalis was demonstrated to present the most effective antitumor efficacy than other formulations. This study provides a promising smart nano-carrier platform to enhance the stability, decrease the side effects, and improve the therapeutic efficacy of anticancer drugs.

Novel multicore niosomes based on double pH-sensitive mixed micelles for Ginsenoside Rh2 delivery

Abstract In this study, we report the novel double pH-sensitive mixed micelles to fabricate multicore niosomes for drug delivery. The double pH-sensitive mixed micelles (PMM) were prepared with different pH-sensitive polymers, mPEG2000-Hz-CHEMS and mPEG2000-IS (2:1 w/w). Ginsenoside Rh2-loaded DPMM was mixed with Pluronic F-68, in the aqueous medium, and multicore niosomes were fabricated. The size of multicore niosomes were around 100–300 nm with a high encapsulation efficiency of G-Rh2. The G-Rh2-MCN could release encapsulated G-Rh2 with an accelerated rate under lower pH conditions with lower cytotoxicity and good antitumor efficacy.

In vivo evaluation of novel ketal-based oligosaccharides of hyaluronan micelles as multifunctional CD44 receptor-targeting and tumor pH-responsive carriers

In this report, the oligosaccharides of hyaluronan (oHA)-histidine-menthone 1,2-glycerol ketal (MGK) (oHM) carried pH-sensitive MGK as hydrophobic moieties and oHA as the target of the CD44 receptor. The oHM could self-assemble, with a diameter of 65 nm. The cellular uptake, indicated by the fluorescent signals, was higher at 4 h. The ex vivo imaging indicated that micelles have a longer blood circulation, beyond 5 h. The fluorescence intensity of the micelles in the liver and spleen was much higher from 5 to 24 h. The CD44 receptor-targeting, indicated by the fluorescence signals of A549 and MDA-MB-231 group, were higher than those of the HepG2 and the control.

Acylation of Exenatide by Glycolic Acid and its Anti-Diabetic Activities in db/db Mice

ABSTRACTPurposeTo prepare acylated exenatide analogues and investigate their biological properties for guiding the development of PLGA formulations of exenatide.MethodsThe acylated exenatide analogues were prepared by reaction with glycolic acid (GA), one constitutional unit of PLGA, and characterized by HPLC-MS/MS and Circular Dichroism (CD). The pharmacokinetic properties and anti-diabetic activities were studied in SD rats and db/db mice, respectively.ResultsStructural characterizations of the acylated products showed that one to four glycolic acids (GAs) were connected to the primary amine groups of exenatide, and there was a conversion of α-helix to β-sheet to some extent. Pharmacokinetic studies in SD rats revealed that acylated exenatides had a similar Tmax with that of the prototype drug, whereas the Cmax and the AUC values of the adducts were significantly decreased. Biological activity tests demonstrated that exenatide and acylated exenatide analogues had similar in vivo antidiabetic activities in terms of controlling blood glucose concentration, HbA1c level, body weight and food intake.ConclusionsThese findings suggest that GA conjugated exenatide had no influence on the peptide efficacy, therefore it’s not necessary to inhibit exenatide acylation in PLGA formulations during the peptide release process.

Co-encapsulation of curcumin and resveratrol into novel nutraceutical hyalurosomes nano-food delivery system based on oligo-hyaluronic acid-curcumin polymer

In this work, in order to enhance the stability, bioavailability and antioxidant activity of insoluble antioxidants used into juice, yoghourt and nutritional supplements, the oligo-hyalurosomes nano-delivery system (CRHs) based on oligo-hyaluronic acid -curcumin (oHC) polymer loaded curcumin(Cur) and resveratrol (Res) was fabricated with new nanotechnolgy. The rosy biodegradable amphiphilic oHC polymer was successfully synthesized and used to fabricate the hyalurosomes containing both Cur and Res, called CRHs. The CRHs can spontaneously self-assemble into nano-sized spherical shape of average particle size 134.5±5.1nm and Zeta potential -29.4±1.2 at pH 7.4 PBS conditions. In vitro gastrointestinal release test showed a perfect stability and outstanding sustained release character. Moreover, compared to the single formulations and liposomes, CRHs showed a dose-dependent manner with a higher radical scavenging activity. Therefore, the novel CRHs nano-food manifested the hopeful properties for the new effective gastrointestinal formulation and promising new nano-food delivery system in the use of juice, yoghourt and nutritional supplements.