Effect of Co-Surfactants on Properties and Bactericidal Activity of Cu2O and Hybrid Cu2O/Ag Particles.

Nanomaterials based on metal oxides, especially Cu2O, have received much attention in recent years due to the many unique properties of the surface plasmon resonance they provide. The report presented the co-precipitation method, a simple preparation method to produce Cu2O oxide particles. In addition, to improve the unique antibacterial properties of Cu2O, a proposed method is to attach Ag nanoparticles to the surface of Cu2O particles. The Cu2O and Cu2O-Ag particles were synthesized based on redox reactions using ascorbic acid (LAA) as a reducing agent. Moreover, in this experiment, two surfactants, polyethylene glycol 6000 (PEG 6000) and sodium dodecyl sulfate (SDS), were added during the manufacturing process to create particle samples and particle combinations with better properties than the original sample. Changes in the characteristics and properties of particle samples are determined by many different physical and chemical methods such as ultraviolet-visible spectroscopy (UV-Vis), infrared spectroscopy (IR), noise X-ray radiation (XRD), scanning electron microscope (SEM), dynamic light scattering (DLS), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). Finally, the activity against bacteria, including E. coli and S. aureus, was also tested using the agar well diffusion method to determine the zone of inhibition. The results improved the particle size value, which decreased by half to 200 nm when two additional surfactants, PEG and SDS, were added. In addition, the antibacterial ability has also been shown to increase significantly when the diameter of the bacterial inhibition zone increased significantly, reaching values of 20 mm (Cu2O/Ag/SDS) and 32 mm (Cu2O/Ag/PEG) for the E. coli bacterial strain. The initial test sample was only about 14 mm in size. The S. aureus bacterial strain also had a similar improvement trend after adding Ag to the Cu2O surface with the appearance of two surfactants, SDS and PEG. The inhibition zone diameter values reached the optimal value at 36 mm in the Cu2O/Ag/PEG particle combination sample compared to only the initial 26 mm in the Cu2O particle sample. Finally, the particle samples are added to the acrylic emulsion paint film to evaluate the changes. Positive results were obtained, such as improvement in adhesion (1.22 MPa), relative hardness (240/425), and sand drop resistance (100 L/mil) in the Cu2O/Ag/PEG particle combination sample, which showed the correctness and accuracy of the research.

Study on the compatibility between pharmaceutical excipient polyethylene glycol 6000 and antiepileptic active pharmaceutical ingredients levetiracetam / 中国药师

Objective To investigate the compatibility between antiepileptic active pharmaceutical ingredient(API)levetiracetam and binder polyethylene glycol 6000,and provide a basis for evaluating and ensuring the safety of drugs.Methods Levetiracetam and polyethylene glycol 6000 from different producers were mixed in a certain proportion,and placed under different conditions according to the test method of stability influencing factors.The compatibility of levetiracetam and polyethylene glycol 6000 was analyzed by differential scanning calorimetry and HPLC,respectively,and the thermal variations,changes of levetiracetam appearance and related substances were investigated.Results After being placed under high humidity(relative humidity of 90％)and light(4 500 Lx)for 10 days,the compatibility between API and pharmaceutical excipients was proved good,while under the conditions of high temperature of 50℃ and 60℃,polyethylene glycol 6000 interacted with levetiracetam,resulting in the growth of levetiracetam related substances including impurity A and total amount of impurities,along with the production of two unknown impurities.Polyethylene glycol 6000 from different producers and different batches had different effects on the related substances of levetiracetam.Conclusion There is a risk of compatibility between levetiracetam and polyethylene glycol 6000 under elevated temperatures,and it is recommended that preparation producers optimize product prescriptions and improve the quality and safety of drugs.

Ecological roles of secondary metabolites of Saposhnikovia divaricata in adaptation to drought stress.

Saposhnikovia divaricata is a traditional Chinese herb that mainly grows in arid grasslands and strongly adapts to various stresses. Drought is not only a major abiotic stress factor but also a typical feature conducive to producing high-quality medicinal material. The present study investigated by treating S. divaricata plants with polyethylene glycol (PEG-6000). Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) identified 146 compounds from the roots of S. divaricata, among which seven primary metabolites and 28 secondary metabolites showed significant changes after drought treatment. UV-Vis spectrophotometer detected the activity of antioxidant enzymes and the content of superoxide anion (O2 -.) and malondialdehyde (MDA). The differential primary metabolites revealed that drought promotes glycolysis, reducing primary metabolism and enhancing secondary metabolism. Meanwhile, the differential secondary metabolites showed an increase in the content of compounds upstream of the secondary metabolic pathway, and other glycosides and increased that of the corresponding aglycones. The activities of antioxidant enzymes and the content of O2 -. and MDA shown different changes duing the drought treatment. These observations indicate that drought promotes the biosynthesis and transformation of the secondary metabolites and activity of antioxidant enzymes, improving plant adaptability. The present study also analyzed a few primary and secondary metabolites of S. divaricata under different degrees and durations of drought and speculated on the metabolic pathways in an arid environment. The findings indicate the biological nature, diversity, and complexity of secondary metabolites and the mechanisms of plant adaptation to ecological stress.

Physical Characterization and In Vitro Evaluation of Dissolution Rate from Cefpodoxime Proxetil Loaded Self Solidifying Solid SNEDDS.

BACKGROUND: Cefpodoxime Proxetil (CPD) is a broad-spectrum cephalosporin indicated in respiratory and urinary tract infections. CPD is a BCS class IV drug with pH-dependent solubility and has poor bioavailability. This study investigated the challenges of developing ternary components based on solid SNEDDS of CPD for in vitro dissolution rate enhancement and self-solidifying behaviour. METHODS: Tween 80, Transcutol and PEG6000 were employed as surfactants, solvents and solidifiers for a base of ternary components to develop self-solidifying solid SNEDDS, respectively. Ternary phase diagrams were used to characterize solidifying behaviour of ternary components in different proportions. S-SNEDDS formulations were drawn on the solidification areas available in the phase diagram and characterized for IR, XRD, DSC and in vitro drug release in various pH media. RESULTS: Ternary components for the preparation of self-solidifying solid SNEDDS were selected based on drug solubility. FTIR and DSC characterization studies ruled out any drug interaction between CPD and components chosen to prepare S-SNEDDS. CPD was transformed from a crystalline into an amorphous state in ternary dispersions as revealed from XRD data. Optimized formulation (S-S 1) demonstrated more than 95% of drug release irrespective of the pH environments of the medium. Calculation of dissolution efficiency and similarity factors indicate that S SNEDDS resulted in a higher drug dissolution rate over binary dispersion (p<0.01). The stability studies showed that the S SNEDDS were stable in performances and CPD assay. CONCLUSION: The present investigation provides an alternative approach for enhancing the CPD dissolution rate using self-solidifying solid SNEDDS exhibited solidification behaviour at ambient temperature conditions and drug loading, which could be exploited over conventional dosage form.

Optimized MALDI-TOF MS Strategy for Characterizing Polymers.

In recent years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) plays an essential role in the analysis of polymers. To acquire a more reliable strategy for polymer profiling, we characterized four representative polymers including polyethylene glycol 6000, polyvinylpyrrolidone K12, polymer polyol KPOP-5040, and polyether polyol DL-4000. The preparation methods of these four polymer samples have been optimized from six aspects, including matrix, cationization reagent, solvent, mixing ratio of cationization reagent to polymer, mixing ratio of matrix to polymer, and laser intensity. After investigating the effects of seven commonly used matrices on the ionization efficiency of four polymers, trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene] malononitrile (DCTB) was found to be the only matrix suitable for the analysis of all the four polymers. Our experimental results suggested that different polymers showed a certain preference for different cationization reagents. For example, the polymer polyol KPOP-5040 was suitable for sodium iodide as the cationization reagent, while polyvinylpyrrolidone K12 was more suitable for silver trifluoroacetate (AgTFA). For the choice of solvent, tetrahydrofuran is a reagent with rapid evaporation and a wide range of dissolution which can achieve the best results for the analysis of four polymers. The optimized method was successfully applied to the identification of DSPE-PEG-NH2 with different polymerized degrees. This MALDI-TOF strategy potentially provided the supplementary function through the polymer's application in biomedical and visible probing.

Nitrogen application and osmotic stress antagonistically affect wheat seed germination and seedling growth.

Atmospheric nitrogen (N) deposition (AtNiDe) and drought stress (DS) have strongly affected plant growth. However, previous research has primarily focused on the effects of AtNiDe with various levels and DS on plant growth (especially seed germination and seedling growth). This study aimed to evaluate the single and combined effects of AtNiDe with four types (compounds: NH4-N, NO3-N, CO(NH2)2-N, and a mixture of the three types of N) and DS (three levels: control, low, and high) on wheat seed germination and seedling growth. The AtNiDe treatment increased wheat seed germination and seedling growth. Mixed N exerted a greater positive effect on wheat seed germination and seedling growth than single N forms. Organic N also had a greater positive effect on wheat seed germination and seedling growth than reduced inorganic N. The DS treatment decreased wheat seed germination and seedling growth. The AtNiDe treatment alleviated the adverse effects of DS on wheat seed germination and seedling growth. Mixed N had the greatest effect on alleviating the adverse effects of DS on wheat seed germination and seedling growth. Thus, AtNiDe and DS antagonistically affected wheat seed germination and seedling growth. NOVELTY STATEMENT This study assessed the single and combined effects of atmospheric nitrogen deposition with four types and drought stress at three levels on wheat seed germination and seedling growth. Generally, nitrogen and drought antagonistically affected wheat seed germination and seedling growth.

A multifunctional CeO2@SiO2-PEG nanoparticle carrier for delivery of food derived proanthocyanidin and curcumin as effective antioxidant, neuroprotective and anticancer agent.

The nanoparticle systems could effectively overcome the drug delivery challenges of food bioactive compounds. In this study, a novel and effective multifunctional PEG modified CeO2@SiO2 nanoparticle (CSP-NPs) system was successfully fabricated. Food derived proanthocyanidin (PAC) and curcumin (Cur) were loaded onto CSP-NPs and formed as PAC-NPs and Cur-NPs. Fourier transform Infrared spectra, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and dynamic light scattering were used to characterize the prepared NPs. CSP-NPs, PAC-NPs and Cur-NPs displayed spherical shape with about 35-45 nm size. The bioactivity analysis revealed that CSP-NPs system could effectively deliver PAC and Cur to exhibit strong antioxidant activity, potent neuroprotective effect against Aß1-42-mediated toxicity in PC-12 cells (recovered cell viability from 57.5% to 81.0% at the dose of 25 µg/mL) and effective antiproliferative effects on HepG2 and Hela cells. Besides, all prepared nanoparticles (0-100 µg/ml) used in this study showed no significant toxicity on cell models of antioxidative and neuroprotective activities, excepting for cancer cells, suggesting that these nanoparticles had the potential of being utilized in drug delivery. Therefore, CSP-NPs might be a promising delivery system for hydrophilic molecule proanthocyanidin and hydrophobic molecule curcumin against the oxidative damage, neurodegenerative diseases and cancer, which could facilitate the application of food derived nutrients in functional foods industry.

Indigenous plant species and invasive alien species tend to diverge functionally under heavy metal pollution and drought stress.

The functional similarity between indigenous plant species (IPS) and invasive alien species (IAS) governs the invasion process of successful IAS because IPS and coexisting IAS suffer alike or even same ecological selection pressures. The aggravated condition created by heavy metal pollution (HMP) and drought stress may generate a noticeable impact on the invasive competitiveness and invasion process of IAS possibly via the variations in the functional similarity between IPS and IAS. Consequently, it is necessary to illumine the functional similarity between IPS and IAS under HMP and drought stress to clarify the mechanisms underlying the successful invasion of IAS. This study aims to estimate the functional similarity between IPS Amaranthus tricolor L. and IAS A. retroflexus L. under the condition with the alone and combined effects of HMP with different kinds (e.g., Cu and Pb) and drought stress [simulated by polyethylene glycol-6000 (PEG) solution]. HMP notably declines A. tricolor growth but has no remarkable effect on A. retroflexus growth. A. retroflexus displays a strong competitive intensity than A. tricolor under HMP. Further, HMP makes a greater stress intensity on A. tricolor growth than A. retroflexus growth. Therefore, HMP can accelerate A. retroflexus invasion. A. retroflexus displays a poor competitive intensity under drought stress. Thus, drought stress can hinder A. retroflexus invasion. However, drought stress causes a greater stress intensity on A. tricolor growth than A. retroflexus growth. Thus, the continued drought stress may converse the adverse effects of drought stress on A. retroflexus invasion potentially. The two Amaranthus species tend to diverge functionally under the combined HMP and drought stress. Further, A. retroflexus shows a strong competitive intensity than A. tricolor under the combined HMP and drought stress. Moreover, the combined HMP and drought stress induces a greater stress intensity on A. tricolor growth than A. retroflexus growth. Thus, the combined HMP and drought stress can facilitate A. retroflexus invasion. Meanwhile, the competitiveness for sunlight acquisition and leaf photosynthetic capacity may play a key role in the successful invasion of A. retroflexus under the combined HMP and drought stress.

Central composite designed solid dispersion for dissolution enhancement of fluvastatin sodium by kneading technique.

Aim: This research is focused on enhancing aqueous solubility and dissolution of fluvastatin sodium (FSS) through solid dispersion (FSS-SD) production using polyethylene glycol 6000 and polyvinyl pyrollidone K-30 by kneading technique. Methodology & results: Central composite design explored the influence of polyethylene glycol 6000 and polyvinyl pyrollidone K-30 on T50% and Q90. The aqueous saturation solubility of FSS (8.7 ± 1.12 µg/ml) was amplified 20-fold in FSS-SD (179 ± 4.16 µg/ml). Cumulative drug release from FSS and optimized FSS-SD were 27.49 and 87.4% within 90 min, respectively. Conclusion: FSS-SD production using kneading technique offers great prospective in maximizing FSS's solubility and dissolution.

Profiles of endogenous phytohormones and expression of some hormone-related genes in Scots pine and Norway spruce seedlings under water deficit.

Different plant hormones are involved in plant adaptation to water deficit. In comparison to angiosperms, little is known about the impact of drought on the pool of phytohormones in gymnosperms. Therefore, we studied the effect of polyethylene glycol-induced water deficit on the changes in content of different phytohormones in Scots pine and Norway spruce seedlings, which are known for their different strategies of adaptation to water deficit. The following hormone classes were analysed: cytokinins, auxins, jasmonates, salicylic and benzoic acids, and 1-aminocyclopropane-1-carboxylic acid (an ethylene precursor). No consistent reaction to water stress was observed for the content of well-known stress-related hormones - salicylic acid and jasmonates. In contrast, drought induced a dose-dependent accumulation of cytokinins in pine needles, with less profound changes in spruce needles. The most prominent changes were observed for 1-aminocyclopropane-1-carboxylic acid content, which increased several-fold in spruce roots and pine needles under water deficit. Water-deficit-induced changes in the contents of cytokinins and 1-aminocyclopropane-1-carboxylic acid were accompanied by the differential regulation of genes involved in the metabolism of these hormones. Possible links between changes in hormone pools and the adaptation of seedlings to water deficit are discussed.

A rapid synergistic cloud point extraction for nine alkylphenols in water using high performance liquid chromatography and fluorescence detection.

A rapid synergistic cloud point extraction for nine alkylphenols coupled with high performance liquid chromatography and fluorescence detection was developed. The non-ionic surfactant polyethylene glycol 6000 (PEG 6000) was selected as the extractant. Acetonitrile was used as a revulsant and synergistic reagent with Na2SO4 to lower the cloud point temperature of extractant to room temperature. These two reagents allowed a cloudy solution to form without heating. The affecting factors were optimized by multiple response optimization with a Box-Behnken design and the desirability function. The optimum conditions found were PEG 6000, 4% (m/v); acetonitrile, 1.5 mL; Na2SO4, 0.6 mol L-1; no pH adjustment or bathing and dilution; centrifugation for 3 min at 3500 rpm and less 8 min for the throughout sample pretreatment procedure. The extraction efficiencies of the nine alkylphenols ranged from 91.4% to 99.5%. These values varied by less than 2.78% from those predicted by the multiple response optimization model. Good linearity (r > 0.994) was obtained in the ranges of 0.6-200 µg L-1 for eight alkylphenols and 1.8-600 µg L-1 for nonylphenol. Simultaneously, the method showed low limit of detection (0.17-0.39 µg L-1) and excellent repeatability at 50 µg L-1 for eight alkylphenols and 150 µg L-1 for nonylphenol (Intraday and Interday of RSD <4.98%, n = 6). The proposed method was successfully applied to determination of the nine alkylphenols in environmental water samples with good recoveries (95.2-106%) and precision values (RSD <5.51%, spiked two levels of 10 and 100 µL of mixed standard, respectively).

Novel Gliclazide Electrosprayed Nano-Solid Dispersions: Physicochemical Characterization and Dissolution Evaluation.

Purpose: In the current study, electrospraying was directed as a novel alternative approach to improve the physicochemical attributes of gliclazide (GLC), as a poorly water-soluble drug, by creating nanocrystalline/amorphous solid dispersions (ESSs). Methods: ESSs were formulated using Eudragit® RS100 and polyethylene glycol (PEG) 6000 as polymeric carriers at various drug: polymer ratios (i.e. 1:5 and 1:10) with different total solution concentrations of 10, 15, and 20% w/v. Morphological, physicochemical, and in-vitro release characteristics of the developed formulations were assessed. Furthermore, GLC dissolution behaviors from ESSs were fitted to various models in order to realize the drug release mechanism. Results: Field emission scanning electron microscopy analyses revealed that the size and morphology of the ESSs were affected by the drug: polymer ratios and solution concentrations. The polymer ratio augmentation led to increase in the particle size while the solution concentration enhancement yielded in a fiber establishment. Differential scanning calorimetry and powder X-ray diffraction investigations demonstrated that the ESSs were present in an amorphous state. Furthermore, the in vitro drug release studies depicted that the samples prepared employing PEG 6000 as carrier enhanced the dissolution rate and the model that appropriately fitted the release behavior of ESSs was Weibull model, where demonstrating a Fickian diffusion as the leading release mechanism. Fourier-transform infrared spectroscopy results showed a probability of complexation or hydrogen bonding, development between GLC and the polymers in the solid state. Conclusion: Hence the electrospraying system avails the both nanosizing and amorphization advantages, therefore, it can be efficiently applied to formulating of ESSs of BCS Class II drugs.

Comparative analysis of abscisic acid levels and expression of abscisic acid-related genes in Scots pine and Norway spruce seedlings under water deficit.

Abscisic acid (ABA) is one of the main participants in the regulation of plant responses to water deficiency. Knowledge of the ABA signal transduction pathways in gymnosperms is rather limited, especially in comparison with those in angiosperms. Seedlings of Scots pine and Norway spruce are known for their contrasting behaviour strategies under water deficit. To characterize the possible role of ABA in these differences, ABA dynamics were investigated under conditions of water deficit in seedlings of these two species. The content of ABA and its catabolites was followed in the roots and needles of seedlings of Pinus sylvestris and Picea abies under conditions of polyethylene glycol (PEG)-induced water deficiency (-0.15 and -0.5 MPa) for 10 days. The expression of the main genes for ABA-biosynthetic enzymes was also analysed. ABA showed more pronounced stress-dependent dynamics in pine roots than in spruce roots, whereas in needles, the response was greater for spruce than pine. The ABA increase during drought was mainly due to de novo synthesis and the shift in the balance between ABA synthesis and catabolism towards synthesis. The ABA-glucosyl ester did not serve as a reserve for the release of free ABA under water deficiency. The expression levels of the main ABA biosynthetic genes showed a weak or no correlation with changes in ABA content under water stress, i.e., the ABA content in the seedlings of both species was not directly linked to the transcript levels of the main ABA biosynthetic genes. Less-pronounced stress-induced changes in ABA in pine needles than in spruce needles may be related to pine seedlings having a less conservative strategy of growth and maintenance of water balance under water deficit.

Determination of the Water Potential Threshold at Which Rice Growth Is Impacted.

Rice feeds 50% of the world’s population. Flooding is the most common irrigation system used for growing rice, a practice responsible for a large amount of water loss. Climate changes may affect water availability in irrigated agriculture, and it will be necessary to develop more sustainable irrigation practices. The aim of this work was to determine, in controlled conditions, the threshold when water potential begins to decrease plant growth. Two independent greenhouse experiments were conducted during middle summer and fall, in order to validate the results for high and low evapotranspiration conditions. Rice plants were grown in hydroponics and the water potential was adjusted with polyethylene glycol 6000, varying from −0.04 MPa (control) to −0.19 MPa. Leaf water potential, water use efficiency, leaf area, and root and shoot biomass were evaluated. All assayed parameters decreased as the water potential was decreased. The water potential threshold which starts to negatively affect rice growth was between −0.046 and −0.056 MPa, which are values close to those observed in the field in previous research. The definition of a critical value may help to improve water management in rice cultivation and to maintain productivity.

Lecithin/TPGS-based spray-dried self-microemulsifying drug delivery systems: In vitro pulmonary deposition and cytotoxicity.

The aim of the present work was to develop a new solid self-microemulsifying drug delivery system (SMEDDS) for the pulmonary delivery of the poorly water-soluble anti-cancer drug atorvastatin (AVT). Microemulsion (ME) was first developed using isopropyl myristate (IPM), a combination of 2 biocompatible surfactants: lecithin/d-α-tocopheryl polyethylene glycol succinate (TPGS) and ethanol as co-surfactant. Two types of lecithin with different phosphatidylcholine (PC) contents were compared. Phase diagram, physico-chemical characterization and stability studies were used to investigate ME region. Solid SMEDDS were then prepared by spray-drying the selected ME using a combination of carriers composed of sugars, leucine as dispersibility enhancer with or without polyethylene glycol (PEG) 6000. Yield, flow properties, particle size and in vitro pulmonary deposition were used to characterize the spray-dried powders. Reconstituted MEs were characterized in terms of morphology, particle size and size distribution. In vitro cytotoxicity study was undertaken on lung cancer cell line for the selected MEs and SD-SMEDDS formulae. Results showed that the most satisfactory MEs properties were obtained with 1:3 lecithin/TPGS, 1:1 lecithin/oil and 1:1 surfactant/co-surfactant ratios. A larger ME area was obtained with lecithin containing 100% PC compared to the less expensive lecithin containing 20% PC. By manipulating spray drying parameters, carrier composition and ratio of ME lipids to carrier, microparticles with more than 70% of respirable fraction could be prepared. The ME was efficiently recovered in simulated lung fluid even after removal of alcohol. The concurrent delivery of AVT with TPGS in solid SMEDDS greatly enhanced the cytotoxic activity on lung cancer cells.

Preparation and in vivo and in vitro evaluation of Pulsatilla Saponin D Solid Dispersions / 中草药

Objective: To prepare the solid dispersion of Pulsatilla saponin D (PSD-SD) and evalution its in vivo and in vitro drug release behavior. Methods: The PSD-SD was prepared by solvent method. Three carriers were used in the PSD-SD. Infrared spectroscopy (IR), differential thermal analysis (DSC), and X-ray diffraction (XRD) were used to determine the PSD-SD. Dissolution rates and pharmacokinetic parameters were evaluated in vitro and in vivo characteristics of the PSD-SD. Results: When the PEG 6000 was used as carrier, the solubility of PSD was increased from 2.39 to 7.06 mg/mL, and the cumulative release rate of PSD reached 90% in 60 min, and the bioavailability of PSD was increased to 2.24 times. Conclusion: The solid dispersion prepared PSD can increase the solubility, dissolution rate, and bioavailability.

Isolation and characterization of a buffalograss (Buchloe dactyloides) dehydration responsive element binding transcription factor, BdDREB2.

Dehydration responsive element binding (DREB) transcription factors play an important role in the regulation of stress-related genes. These factors contribute to resistance to different abiotic stresses. In the present study, a novel DREB transcription factor, BdDREB2, isolated from Buchloe dactyloides, was cloned and characterized. The BdDREB2 protein was estimated to have a molecular weight of 28.36kDa, a pI of 5.53 and a typical AP2/ERF domain. The expression of BdDREB2 was involved in responses to drought and salt stresses. Overexpression of BdDREB2 in tobacco showed higher relative water and proline content, and was associated with lower MDA content under drought stress, suggesting that the transgenic tobacco may tolerate drought stress better. Results demonstrate that BdDREB2 may play an important role in the regulation of abiotic stress responses, and mediate many physiological pathways that enhance stress tolerance in plants.

Germination of salt-stressed seeds as related to the ethylene biosynthesis ability in three Stylosanthes species.

Stylosanthes, a genus of tropical forage legume, is known to exhibit good persistence in saline soils, yet mechanisms for regulation of seed germination under salt stress are poorly understood. This study was carried out to evaluate the mode of action of salt stress on seed germination of Stylosanthes. 1-Aminocyclopropane-1-carboxylic acid (ACC) increased ethylene biosynthesis and germination of NaCl-inhibited seeds in a dose-dependent manner. Contents of ACC and germination of Stylosanthes humilis seeds increased following transfer from NaCl solution to deionised water, but not after transfer to l-α-(2-aminoethoxyvinyl)-glycine (AVG) solution, an inhibitor of ethylene biosynthesis. Ethylene biosynthesis was much larger in NaCl-treated seeds of Stylosanthes guianensis than in seeds of S. humilis and Stylosanthes capitata, a fact which was reflected in higher germination rates. S. guianensis seedlings also displayed higher growth and survival rates than S. humilis and S. capitata under salt stress. Moreover, smaller ACC levels, as well as reduced ethylene biosynthesis of S. capitata seeds were accompanied by lower germination under salt stress. In addition, S. capitata seedlings treated with NaCl solutions exhibited relatively lower growth and survival rates in comparison with S. humilis and S. guianensis. Thus, different abilities to synthesize ethylene by S. guianensis, S. humilis and S. capitata seeds explain the differences in tolerance to salt stress of the three species.

Influences of Polyethylene Glycol6000 on the Solubility of m-Nisoldipine / 医药导报

Objective To investigate the influences of polyethylene glycol on the solubility and in vitro dissolution of m-nisoldipine,which could provide guidance for chosing formulations of m-nisoldipine. Methods Solid dispersions of m-nisoldipine were prepared by solvent-melting method with polyethylene glycol6000 matrix. DSC and XRD spectroscopy were applied to identify the solid dispersions. The solubility and in vitro dissolution were detected by UV spectroscopy. Results The DSC and XRD map were different from the crude drug and their physical mixtures. The dissolution rates(13,15,17) were faster(35. 31%,38. 71%,41. 48%) than that of the crude drug(26. 80%),and the dissolution rates of the solid dispersions in the same ratio were higher than the physical mixtures. Conclusion DSC analysis indicated that eutectic compounds were produced by the m-nisoldipine and polyethylene glycol,in which polyethylene glycol6000 acts as a carrier. The solubility and in vitro dissolution of m-nisoldipine can be increased.

Effects of PEG-6000 stress on tanshinones accumulation in hairy roots of Salvia miltiorrhiza / 中草药

Objective: To study the effects of polyethylene glycol-6000 (PEG-6000) stress on the accumulation of tanshinones in hairy roots of Salvia miltiorrhiza. Methods: Agrobacterium rhizogenes ATCC15834 was used to induce the hairy roots of S. miltiorrhiza. After 20 d suspension culture, the PEG-6000 (1.2%, 2.0%, 5.5%, and 10%, respectively) was added into the suspension cultures and at the same time, the contents of tanshinones (including tanshinone I, cryptotanshinone, dihydrotanshinon I, and tanshinone IIA) were quantified by HPLC on day 7. Results: The growth of the hairy roots of S. miltiorrhiza was inhibited by PEG-6000. After PEG-6000 (1.2%, 2.0%, 5.5%, and 10%) treatment, the dry weights of the hairy roots of S. miltiorrhiza were reduced to 75.1%, 83.0%, 76.2%, and 76.1% of the control group, respectively. Addition of PEG-6000 at different levels could significantly increase the yields of four tanshinones in the hairy roots of S. miltiorrhiza. The yields of tanshinone I, cryptotanshinone, dihydrotanshinon I, and tanshinone IIA were significantly increased by 2.0%-5.5%, 1.2%, 2.0%, and 5.5% PEG-6000, respectively. And the tanshinone IIA increased most. Conclusion: PEG-6000 could stimulate the accumulation of tanshinones in the hairy roots of S. miltiorrhiza.