Antibiofilm activity of polyethylene glycol-quercetin nanoparticles-loaded gelatin-N,O-carboxymethyl chitosan composite nanogels against Staphylococcus epidermidis.

BACKGROUND: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. OBJECTIVES: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. METHODS: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. RESULTS: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. CONCLUSIONS: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

Enhanced Cellular Delivery of Tildipirosin by Xanthan Gum-Gelatin Composite Nanogels.

Tildipirosin has no significant inhibitory effect on intracellular bacteria because of its poor membrane permeability. To this end, tildipirosin-loaded xanthan gum-gelatin composite nanogels were innovatively prepared to improve the cellular uptake efficiency. The formation of the nanogels via interactions between the positively charged gelatin and the negatively charged xanthan gum was confirmed by powder X-ray diffraction and Fourier transform infrared. The results indicate that the optimal tildipirosin composite nanogels possessed a 3D network structure and were shaped like a uniformly dispersed ellipse, and the particle size, PDI, and ζ potential were 229.4 ± 1.5 nm, 0.26 ± 0.04, and -33.2 ± 2.2 mV, respectively. Interestingly, the nanogels exhibited gelatinase-responsive characteristics, robust cellular uptake via clathrin-mediated endocytosis, and excellent sustained release. With those pharmaceutical properties provided by xanthan gum-gelatin composite nanogels, the anti-Staphylococcus aureus activity of tildipirosin was remarkably amplified. Further, tildipirosin composite nanogels demonstrated good biocompatibility and low in vivo and in vitro toxicities. Therefore, we concluded that tildipirosin-loaded xanthan gum-gelatin composite nanogels might be employed as a potentially effective gelatinase-responsive drug delivery for intracellular bacterial infection.

On-demand release of enrofloxacin-loaded chitosan oligosaccharide-oxidized hyaluronic acid composite nanogels for infected wound healing.

In this study, enrofloxacin (ENR) was encapsulated by oxidized hyaluronic acid (OHA) containing aldehyde groups and chitosan oligosaccharide (COS) containing amino groups through Schiff's base reaction to achieve on-demand release in the micro-environment (pH 5.5 and HAase) of bacterial-infected wounds (Escherichia coli and Staphylococcus aureus). The formation mechanism, physicochemical characterization, responsive release performance, in vitro and in vivo antimicrobial activities, and in vivo regeneration in full-thickness wounds in a bacterial-infected mouse model of the ENR nanogels were systematically studied. According to the single-factor experiment and Design-Expert software, the optimized formula was 3.8 mg/ml COS, 0.5 mg/ml OHA, and 0.3 mg/ml ENR, respectively. The mean particle diameter, polydispersity index, zeta potential, loading capacity, and encapsulation efficiency were 35.6 ± 1.7 nm, -6.7 ± 0.5 mV, 0.25 ± 0.02, 30.4 % ± 1.3 %, and 76.3 % ± 2.6 %, respectively. The appearance, optical microscopy images, SEM, TEM, PXRD, and FTIR showed that the ENR nanogels were successfully prepared. The ENR nanogels exhibited obvious pH and HAase-responsiveness by swelling ratios and in vitro release and had stronger antibacterial activity with time-dependent and concentration-dependent effects, as well as accelerating infected wound healing. In vitro and in vivo biosafety studies suggested the great promise of ENR nanogels as biocompatible wound dressings for infected wounds.

Pattern and control of biomass allocation across global forest ecosystems.

The underground part of a tree is an important carbon sink in forest ecosystems. Understanding biomass allocation between the below- and aboveground parts (root:shoot ratios) is necessary for estimation of the underground biomass and carbon pool. Nevertheless, large-scale biomass allocation patterns and their control mechanisms are not well identified. In this study, a large database of global forests at the community level was compiled to investigate the root:shoot ratios and their responses to environmental factors. The results indicated that both the aboveground biomass (AGB) and belowground biomass (BGB) of the forests in China (medians 73.0 Mg/ha and 17.0 Mg/ha, respectively) were lower than those worldwide (medians 120.3 Mg/ha and 27.7 Mg/ha, respectively). The root:shoot ratios of the forests in China (median = 0.23), however, were not significantly different from other forests worldwide (median = 0.24). In general, the allocation of biomass between the belowground and aboveground parts was determined mainly by the inherent allometry of the plant but also by environmental factors. In this study, most correlations between root:shoot ratios and environmental factors (development parameter, climate, altitude, and soil) were weak but significant (p < .01). The allometric model agreed with the trends observed in this study and effectively estimated BGB based on AGB across the entire database.

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

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.

Cycloartane triterpenoids and their glycosides from the rhizomes of Cimicifuga foetida.

A phytochemical study on the rhizomes of Cimicifuga foetida resulted in the isolation of two new cycloartane triterpenoids (1 and 2), eight new cycloartane glycosides (3-10), and six known cycloartane glycoside analogues (11-16). The structures of 1-10 were determined by application of spectroscopic methods, with the absolute configuration of 1 determined by X-ray crystallography. Compounds 1-6, as three pairs of epimers at C-10 and C-24, belong to a seven-membered-ring variant of 9,10-seco-9,19-cycloartane triterpenoids, and glycosides 3-10 were found to be 3-O-ß-D-xylopyranosides. The cytotoxicity of the isolates was evaluated against five selected human tumor cell lines, and the known compounds 15 and 16 showed cytotoxicity against the hepatocellular carcinoma SMMC-7721 cell line with IC50 values of 5.5 and 6.3 µM, respectively.

Ocotillol Enhanced the Antitumor Activity of Doxorubicin via p53-Dependent Apoptosis.

The use of doxorubicin (Dox) was severely constrained by dose-dependent side effects, which might be attenuated by combining a "sensitizer" to decrease its cumulative dosage. In this study, it was investigated whether ocotillol could enhance the antiproliferation activity of Dox. MTT assays and xenograft tumor model were firstly conducted to evaluate the effect of ocotillol on the antitumor activity of Dox. Flow cytometry and Hoechst staining assays were then performed to assess cell apoptosis. Western blot and real-time PCR were finally used to detect the expression of p53 and its target genes. Our results showed ocotillol to enhance Dox-induced cell death in p53 wild-type cancer cells. Compared with Dox alone, Dox with ocotillol (Dox-O) could induce much more cell apoptosis and activate p53 to a much greater degree, which in turn markedly increased expression of proapoptosis genes. The enhanced cytotoxic activity was partially blocked by pifithrin- α , which might be through attenuating the increased apoptosis. Furthermore, ocotillol significantly increased the antitumor activity of Dox in A549 xenograft tumor in nude mice. These findings indicated that ocotillol could potentiate the cytotoxic effect of Dox through p53-dependent apoptosis and suggested that coadministration of ocotillol with Dox might be a potential therapeutic strategy.

Cardioprotective Effects of 20(S)-Ginsenoside Rh2 against Doxorubicin-Induced Cardiotoxicity In Vitro and In Vivo.

Doxorubicin (DOX) is considered as one of the best antineoplastic agents. However, its clinical use is restricted by its associated cardiotoxicity, which is mediated by the production of reactive oxygen species. In this study, 20(S)-ginsenoside Rh2 (Rh2) was explored whether it had protective effects against DOX-induced cardiotoxicity. In vitro study on H9C2 cell line, as well as in vivo investigation in one mouse and one rat model of DOX-induced cardiomyopathy, was carried out. The results showed that pretreatment with Rh2 significantly increased the viability of DOX-injured H9C2 cells. In the mouse model, Rh2 could suppress the DOX-induced release of the cardiac enzymes into serum and improved the occurred pathological changes through ameliorating the decreased antioxidant biomolecules and the cumulated lipid peroxidation malondialdehyde in heart tissues. In the rat model, Rh2 could attenuate the change of ECG resulting from DOX administration. Furthermore, Rh2 enhanced the antitumor activity of DOX in A549 cells. Our findings thus demonstrated that Rh2 pretreatment could effectively alleviate heart injury induced by DOX, and Rh2 might act as a novel protective agent in the clinical usefulness of DOX.

Cytotoxic constituents from the skin of the toad Bufo bufo gargarizans.

To study the chemical composition of the skin of Bufo bufo gargarizans, various chromatographic methods were used in the isolation procedures and the structures of isolated compounds were determined based on NMR and MS analysis. As a result, two new compounds were isolated from its ethanolic extract and characterized as N-[2-hydroxy-2-(4-hydroxyphenyl)ethyl]-N-methylurea (1) and 19-oxocinobufotalin 3-adipoylarginine ester (2), together with 11 known compounds. Isolated bufadienolides showed significant inhibition effect against human hepatocellular carcinoma cell line SMMC-7721 in vitro.

Effects of bufalin on the proliferation of human lung cancer cells and its molecular mechanisms of action.

Bufalin, a naturally occurring small-molecule compound from Traditional Chinese Medicine (TCM) Chansu showed inhibitory effects against human prostate, hepatocellular, endometrial and ovarian cancer cells, and leukemia cells. However, whether or not bufalin has inhibitory activity against the proliferation of human non-small cell lung cancer (NSCLC) cells is unclear. The aim of this study is to study the effects of bufalin on the proliferation of NSCLC and its molecular mechanisms of action. The cancer cell proliferation was measured by MTT assay. The apoptosis and cell cycle distribution were analyzed by flow cytometry. The protein expressions and phosphorylation in the cancer cells were detected by Western blot analysis. In the present study, we have demonstrated that bufalin suppressed the proliferation of human NSCLC A549 cell line in time- and dose-dependent manners. Bufalin induced the apoptosis and cell cycle arrest by affecting the protein expressions of Bcl-2/Bax, cytochrome c, caspase-3, PARP, p53, p21WAF1, cyclinD1, and COX-2 in A549 cells. In addition, bufalin reduced the protein levels of receptor expressions and/or phosphorylation of VEGFR1, VEGFR2, EGFR and/or c-Met in A549 cells. Furthermore, bufalin inhibited the protein expressions and phosphorylation of Akt, NF-κB, p44/42 MAPK (ERK1/2) and p38 MAPK in A549 cells. Our results suggest that bufalin inhibits the human lung cancer cell proliferation via VEGFR1/VEGFR2/EGFR/c-Met-Akt/p44/42/p38-NF-κB signaling pathways; bufalin may have a wide therapeutic and/or adjuvant therapeutic application in the treatment of human NSCLC.

Studies on cytotoxic constituents from the skin of the toad Bufo bufo gargarizans.

To study the chemical composition of the skin of Bufo bufo gargarizans, many kinds of chromatography methods were used in the isolation procedures, while the structures of isolated compounds were determined on the basis of their NMR and MS spectral analysis. As a result, two new compounds were isolated from its ethanolic extract and characterized as cinobufotalin 3-nonanedioylarginine ester (8) and bufotalin 3-pimeloylarginine ester (14). Furthermore, 13 known compounds were obtained. Isolated bufadienolides showed significant inhibition effect against SMMC-7721 cell lines in vitro.

Inhibitory effects of sesquiterpenes from Saussurea lappa on the overproduction of nitric oxide and TNF-alpha release in LPS-activated macrophages.

Nitric oxide (NO), derived from L-arginine, is produced by two types (constitutive and inducible) of nitric oxide synthase (NOS: cNOS and iNOS). The NO produced in large amounts by the iNOS is known to be responsible for inflammation, the vasodilation, and hypotension observed in septic shock and cancer metastasis. The inhibitors of the overproduction of NO, thus, may be useful candidates for the treatment of inflammatory diseases. We have found that the petroleum ether extract of Saussurea lappa Decne, which is a wild species wildly distributed in India, can strongly inhibit the overproduction of NO in mouse macrophage RAW 264.7 cells. Through bioassay-guided fractionation, 13 sesquiterpenes were isolated from the active petroleum ether extract. Furthermore, another five sesquiterpenes were synthesized by chemical methods. In the present study, their effects on LPS-induced NO production and TNF-alpha release are reported. Compounds 1, 3, 9, 17, and 18 showed significant inhibitory activities on the production of NO and release of TNF-alpha with IC(50) values lower than 1 micromol/l. SAR studies suggest that the exocyclic double bond (Delta(11(13))) is necessary for the inhibitory activities of sesquiterpenes on the NO production.

[Chemical constituents from dried sorophore of cultured Cordyceps militaris].

OBJECTIVE: To investigate the chemical constituents of the dried sorophore of cultured Cordyceps militaris. METHOD: Compounds were isolated and purified by macroporous adsorption resin and silica gel column chromatography. Their chemical structures were elucidated on the basis of physicochemical properties and spectral data (IR, FAB-MS, 1H-NMR and 13C-NMR). RESULT: Nine compounds were isolated and identified as: ergosta-4, 6, 8 (14)-tetraen-3-one (1), citrostadienol (2), tetracosanoic acid 2, 3-dihydroxypropyl ester (3), ergosterol (4), ergosterol peroxide (5), ergosta-7, 22-dien-3beta, 5alpha, 6beta-triol (6), cordycepin (7), adenosine (8), N-(2-hydroxyethyl) adenosine (9), respectively. CONCLUSION: Compounds 1-3, 6, 9 were separated from the sorophore of cultured C. militaris for the first time.

Four new neo-clerodane diterpenoid alkaloids from Scutellaria barbata with cytotoxic activities.

Four new neo-clerodane diterpenoid alkaloids, named scutebarbatines C-F (1-4), were isolated from the whole plants of Scutellaria barbata D. DON. Their structures were elucidated by spectral analyses (UV, IR, FAB-MS, 1D-NMR and 2D-NMR). In vitro, compounds 1-4 showed significant cytotoxic activities against three human cancer cell lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, and gave IC(50) values in the range 3.9-7.8 muM.

neo-Clerodane diterpenoids from Scutellaria barbata with cytotoxic activities.

Three neo-clerodane diterpenoids, named barbatins A-C (1-3), and the neo-clerodane diterpenoid nicotinyl ester, named scutebarbatine B (4), were isolated from the whole plant of Scutellaria barbata D. Don. Their structures were elucidated by spectroscopic analyses (UV, IR, HRFAB-MS, 1D NMR and 2D NMR). In vitro, compounds 1-4 showed significant cytotoxic activities against three human cancer lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, with IC50 values in the range 3.5-8.1 microM.

Neuroprotective effect of 20(S)-ginsenoside Rg3 on cerebral ischemia in rats.

This study was conducted to investigate the neuroprotective effects of 20(S)-ginsenoside Rg3 on focal cerebral ischemia in rats. Middle cerebral artery occlusion (MCAO) model in male Wistar-Kyoto (WKY) rats was employed. The behavioral tests were used to evaluate the damage to central nervous system. The infarct area of brain was assessed in the brain slices stained with 2,3,5-triphenyltetrazolium chloride (TTC). Hydrogen clearance techniques were used to monitor regional cerebral blood flow (rCBF), spectrophotometric assay methods were used to determine the activities of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-Px), contents of malondialdehyde (MDA) and adenosine triphosphate (ATP) of the brain. Furthermore, the respiratory control ratio (RCR=State 3/State 4) was assessed in the brain mitochondria. The results showed that sublingual vein injection of 20(S)-ginsenoside Rg3 at doses of 10 and 5 mg kg(-1), but not 2.5 mg kg(-1) exhibited significant neuroprotective effects on rats against focal cerebral ischemic injury by markedly decreasing neurological deficit scores, reducing the infarct area and enhancing the rCBF compared with the control group. At the same time, 20(S)-ginsenoside Rg3 significantly improved mitochondrial energy metabolism, antagonized decreases in SOD and GSH-Px activities and increase in MDA level induced by cerebral ischemia. All these findings suggest that 20(S)-ginsenoside Rg3 might provide neuroprotection against the cerebral ischemia-induced injury in rat brain through reducing lipid peroxides, scavenging free radicals and improving the energy metabolism.

[Alkaline-degradation products of ginsenosides from leaves and stems of Panax quinquefolium].

AIM: To study the alkaline-degradation products of ginsenosides from leaves and stems of Panax quinquefolium L. METHODS: Isolation and purification were carried out on silica gel and HPLC; the structures of chemical constituents were elucidated by spectral analysis. RESULTS: From the alkaline-degradation products, nine compounds were identified as: 20 (S) -protopanaxadiol (I), 20 (S) -dammar-25 (26)-ene-3beta, 12beta, 20-triol (II), 24 (R) -ocotillol (III), 20 (S) -protopanaxatriol (IV), 20 (S) -dammar-25 (26)-ene-3beta, 6alpha, 12beta, 20-tetrol (V), dammar-20 (21), 24-diene-3beta, 12beta-diol (VI), dammar-20(21), 24-diene-3beta, 6alpha, 12beta-triol (VII), 20 (S), 24 (S) -dammar-25 (26) -ene-3beta, 6alpha, 12beta, 20, 24-pentanol (VIII), 20 (S) -dammar-23-ene-25-hydroperoxyl-3beta, 6alpha, 12beta, 20-tetrol (IX). CONCLUSION: The configuration of C20 position of ginsenosides was not changed by alkaline-degradation. The complete assignments of 1H and 13C NMR chemical shifts of four new compounds V, VII, VIII, IX, were acquired by means of 2D NMR spectra. Compound I showed antitumor effect on human colon carcinoma cells in vitro.