Enhancing Effect Of Chitosan Research Articles

Effect of Chitosan Molecules on Paraquat Herbicidal Efficacy under Simulated Rainfall Conditions

Unexpected rainfall before herbicide absorption by plants can wash away herbicides from plant tissue surfaces, which may reduce the herbicidal efficacy and increase the adverse effects on nontarget organisms and the environment, including water networks. The objective of this study was the evaluation of the effect of chitosan on paraquat efficacy under simulated rainfall conditions. Simulated rainfall within 3 h after paraquat application decreased its herbicidal efficacy. A mixture of paraquat (280 g a.i./ha) and chitosan (0.05% w/v) significantly increased the herbicidal efficacy against Ageratum conyzoides L. (21% increase), Borreria alata Aubl. (15%) and Paspalum conjugatum Bergius (8%) under the rainfall conditions. The chemical structure of chitosan may contribute to the penetration of paraquat into plant tissues. However, a mixture of paraquat and chitosan did not affect the herbicidal efficacy against Imperata cylindrica (L.) Beauv. The morphological characteristics of I. cylindrica may interfere with the enhancement effect of chitosan. Chitosan is a degradable, nontoxic and easily available and low-cost material made from crustacean shells. These results suggest that chitosan may increase paraquat efficacy against some noxious weed species under rainfall conditions, which may reduce the risk of paraquat contamination into the environment. Therefore, the application of herbicides with chitosan may provide the economic and environmental benefits. Chitosan may enhance the efficacy of other herbicides under unexpected rainfall conditions; however, this possibility requires further investigation.

Enhancing effect of chitosan on methylene blue-mediated photodynamic therapy against C. albicans: A study in planktonic growth, biofilms, and persister cells

Chitosan (CS) is a natural polymer extracted from the exoskeleton of crustaceans. Due to its cationic structure, CS has been studied as a possible enhancer of antimicrobial photodynamic therapy (aPDT). The objective was to evaluate the association of CS with methylene blue (MB)-mediated aPDT on Candida albicans, investigating its effects on planktonic growth, biofilms, and cells persistent to fluconazole. The ability of CS to interfere with MB absorption by Candida cells was also evaluated. For the assays, planktonic cells of C. albicans were cultivated for 24 h, and the biofilms were formed for 48 h. For the induction of persister cells, C. albicans was cultivated with high concentration of fluconazole for 48 h. Treatments were performed with MB, CS or MB+CS, followed by irradiation with LED (660 nm ). As results, aPDT with MB (300 µm) reduced the planktonic cells by 1.6 log10 CFU, while the MB+CS association led to a reduction of 4.8 log10 CFU. For aPDT in biofilms, there was a microbial reduction of 2.9 log10 CFU for the treatment with MB (600 µm) and 5.3 log10 CFU for MB+CS. In relation to persister cells, the fungal reductions were 0.4 log10 CFU for MB and 1.5 log10 CFU for MB+CS. In the absorption assays, the penetration of MB into Candida cells was increased in the presence of CS. It was concluded that CS enhanced the antimicrobial activity of aPDT in planktonic growth, biofilms, and persister cells of C. albicans, probably by facilitating the penetration of MB into fungal cells.

Modified glutinous rice starch-chitosan composite films for buccal delivery of hydrophilic drug

The fabrication and characterization of ball-milling modified glutinous rice starch (MGRS):chitosan (CS) composite films were demonstrated. Effect of CS ratios (2:1, 1:1, 1:2 MGRS:CS) on the film properties was investigated. Lidocaine hydrochloride was used as a model hydrophilic drug. ATR-FTIR confirmed hydrogen bond formation between MGRS and CS. XRD indicated an amorphous state of all fabricated films. The uniform and comparable thickness, weight, and drug contents of all fabricated films were obtained. The presence of CS did not affect the mucoadhesiveness of MGRS films. The increase in tensile strength and decreases in elongation and folding endurance were observed with 1:2 MGRS:CS films. The film swelling and drug release decreased with the CS ratio. Drug permeation across porcine mucosa indicated the enhancement effect of CS, whereby the permeation flux of 1:2 MGRS:CS composite increased by 3 folds. In conclusion, the MGRS:CS composite could be useful for buccal delivery of hydrophilic drug.

Determination of picogram quantities of chlortoluron in soil samples by luminol–chitosan chemiluminescence system

Based on the enhancing effect of chitosan (CS) on luminol-dissolved oxygen chemiluminescence (CL) reaction, a flow injection (FI) luminol-CS CL system was established. It was found that the increase of CL intensity was proportional to the concentrations of CS ranging from 0.7 to 10.0 μmol l(-1). In the presence of chlortoluron (CTU), the CL intensity of luminol-CS system could be obviously inhibited and the decrements of CL intensity were linearly proportional to the logarithm of CTU concentrations ranging from 0.01 to 70.0 ng ml(-1), giving the limit of detection 3.0 pg ml(-1) (3σ). At a flow rate of 2.0 ml min(-1), the whole process including sampling and washing could be accomplished within 36 s, offering a sample throughput of 100 h(-1). The proposed FI-CL method was successfully applied to the determination of CTU in soil samples with recoveries ranging from 95.0 % to 105.3 % and the relative standard deviations (RSDs) of less than 4.0 %.

Chitosan and its derivatives as drug penetration enhancers

The review deals with the penetration enhancement properties of chitosan and its derivatives for oral, nasal, buccal and vaginal drug delivery applications. Penetration enhancement through the ocular epithelium and through the skin are beyond the scope of this paper. Extensive experimental evidence has been given of the absorption enhancement properties of chitosan with regard to hydrophilic molecules of different molecular weights. The mechanisms involved in the enhancement effect of chitosan are different depending on whether the epithelia are endowed with tight junctions (intestinal and nasal) or lack tight junctions (buccal and vaginal). Chitosan and its derivatives, when applied in solution to the mucosal site, are capable of facilitating the paracellular route by opening the tight junctions or by interacting with extra-cellular matrix components. The added value of chitosan nanocarriers in promoting drug absorption is also considered. Nanocarriers are capable of being internalized by cells in different areas, thus promoting drug transport. Moreover their mucoadhesive properties and their ability to protect macromolecular drugs from degradation indirectly contribute to enhancing absorption.

Effects of chitosan on serum cytokine levels in elderly subjects

This study was done to evaluate the immune enhancing activity of health function food, chitosan by clinical study. To evaluate the effect of chitosan on serum cytokine levels in elderly adults, 5.1 g/day of chitosan was administrated to volunteers (age range 74 approximately 86, mean 80 +/- 3 year old) for 8 weeks. This study was IRB approved and all patients gave informed consent prior to examination. The clinical study showed that the increase of IL-2, IL-12, and TNF-alpha production were a little greater in chitosan administered group as in the control group but there were no significant differences. In the safety study with blood biochemical test, it has been shown that all safety parameters in liver were in normal ranges. Also there were no significant changes in the values of the electrolytes, blood lipids profiles, glucose levels and leucocytes number. With these results we have not found any safety problems after the administration of chitosan for 8 weeks. In this study, there was a tendency of immune enhancing effect of chitosan at the experimental dose, which is generally used. More intense clinical study will be needed to confirm statistical significance.

Enhancing effect of chitosan on nasal absorption of salmon calcitonin in rats: comparison with hydroxypropyl- and dimethyl-β-cyclodextrins

Two types of chitosan, i.e. the free amine (CS J) and the glutamate salt (CS G), were evaluated for their enhancing effect on in vivo nasal absorption of salmon calcitonin (sCT) in rats. The results were subsequently compared with β-cyclodextrins, one of the most commonly studied enhancers. Solutions containing sCT and chitosan (0–1.25% w/v) in isotonic phosphate buffers (IPB; pH 3.0–6.0) were nasally administered at the dose of 10 IU/kg. The plasma calcium lowering effect in each sCT-treated rat was determined by calculating the total percent decrease in plasma calcium (% D). CS J showed an increase in % D as the solution pH was decreased in accordance with the increased ionization and hydration of the free amine chitosan at the more acidic pH. However, CS G showed an increase in % D with increasing pH, with maximum hypocalcemic effect observed at pH 6.0. At their optimal pH (4.0 for CS J and 6.0 for CS G), the absorption enhancing effect of both chitosans was concentration dependent from 0.25 to 1.0% and leveled off at 1.25%. Using specific RIA, the absolute bioavailability of sCT after comparison with i.v. administration was determined to be 2.45, 1.91, and 1.22% for 1% CS J, 5% dimethyl-β-cyclodextrin (DM-β-CD) and control group (intranasal (in) sCT alone), respectively. Although the absolute nasal bioavailability seemed to be low when compared to the i.v. administration, the inclusion of 1% CS J resulted in two-fold increase in the AUC 0–180 of plasma sCT relative to that of the control group. Addition of 5% DM-β-CD also led to 1.56-fold increase in absorption over the control group. All the enhancers showed significant absorption enhancement ( P<0.05) with the highest effect observed with CS J. In conclusion, cationic polymer chitosan may have promising potential as a safe and effective nasal absorption enhancer of sCT.

Enhancing effect of chitosan on peptide drug delivery across buccal mucosa

The buccal mucosa represents a potentially important topical route for delivery of peptide or protein drugs with some unique advantages such as the avoidance of hepatic first-pass metabolism and the acidity and protease activity encountered in the gastrointestinal tract. However, the bioavailabilities or relative potencies of intraorally administered peptides are usually quite low, unless permeabilizers are employed. Chitosan, a mucopolysaccharide of marine origin, has been claimed to act both as a bioadhesive and permeabilizer, making it a candidate system for mucosal drug delivery. In this study, the enhancement effect of chitosan in gel form for oral mucosa was investigated with a large bioactive peptide, transforming growth factor- β (TGF- β). Chitosan gel was prepared at 2% concentration in dilute lactic acid and TGF- β was incorporated into the gel. The effect of chitosan as a permeabilizer was determined by measuring the flux of TGF- β across porcine oral mucosa in an in vitro system. The localization of TGF- β within the oral mucosa was determined by horizontal sectioning and counting. Chitosan was found to exert a marked permeabilizing effect on buccal mucosa for peptide drug.

EFFECTS OF CHITOSAN ON GELLING PROPERTIES OF LOW QUALITY SURIMI

ABSTRACT In order to produce a strong and elastic gel from low quality walleye pollock surimi, use of chitosan was examined. The strength of gels was nearly doubled by the addition of 1.5% chitosan when salted surimi pastes were set below 25C. In contrast, chitin did not cause any changes in the physical texture of gels. When salted surimi pastes containing 1.5% chitosan were set at 20C, a large decrease in the proportion of myosin heavy chain was observed with a concomitant increase in components with molecular weights heavier than myosin heavy chain. Since the addition of EGTA, an inhibitor of transglutaminase, to surimi reduced gel strength and minimized myosin heavy chain polymerization, it is suggested that the enhancing effect ofchitosan on the gel formation of walleye pollock surimi could be due to the activity of the endogenous transglutaminase known to be present in this surimi.