A comparison of eugenol and menthol on encapsulation characteristics with water-soluble quaternized β-cyclodextrin grafted chitosan

Cyclodextrin-based metal-organic frameworks transforming drug delivery

Cyclodextrin-based metal-organic frameworks (CD-MOFs) are gaining traction in the realm of drug delivery due to their inherent versatility and potential to amplify drug efficacy, specificity, and safety. This article explores the predominant preparation techniques for CD-MOFs, encompassing methods like vapor diffusion, microwave-assisted, and ultrasound hydrothermal approaches. Native CD-MOFs present compelling advantages in drug delivery applications. They can enhance drug loading capacity, stability, solubility, and bioavailability by engaging in diverse interactions with drugs, including host-guest, hydrogen bonding, and electrostatic interactions. Beyond their inherent properties, CD-MOFs can be customized as drug carriers through two primary strategies: co-crystallization with functional components and surface post-modifications. These tailored modifications pave the way for controlled release manners. They allow for slow and sustained drug release, as well as responsive releases triggered by various factors such as pH levels, glutathione concentrations, or specific cations. Furthermore, CD-MOFs facilitate targeted delivery strategies, like pulmonary or laryngeal delivery, enhancing drug delivery precision. Overall, the adaptability and modifiability of CD-MOFs underscore their potential as a versatile platform for drug delivery, presenting tailored solutions that cater to diverse biomedical and industrial needs.

Masculinization of Red Tilapia (Oreochromis spp.) Using 17α-Methyltestosterone-Loaded Alkyl Polyglucosides Integrated into Nanostructured Lipid Carriers

The aim of the present study was to optimize a masculinization platform for the production of all-male red tilapia fry by oral administration of 30 and 60 ppm of MT and alkyl polyglucoside nanostructured lipid carriers (APG-NLC) loaded with MT, respectively, for 14 and 21 days. The characterization, encapsulation efficiency and release kinetics of MT in lipid-based nanoparticles were assessed in vitro. The results showed that the MT-loaded nanoparticles were spherical, ranging from 80 to 125 nm in size, and had a negative charge with a narrow particle distribution. The APG-NLC loaded with MT provided higher physical stability and encapsulation efficacy than the NLC. The release rate constants of MT from MT-NLC and MT-APG-NLC were higher than those of free MT, which is insoluble in aqueous media. There was no significant difference in survival between the fish administered MT or the those fed orally with MT-APG-NLC fish. According to the logistic regression analysis, the sex reversal efficacy of MT-APG-NLC (30 ppm) and MT (60 ppm), resulted in significantly higher numbers of males after 21 days of treatment compared with the controls. The production cost of MT-APG-NLC (30 ppm) after 21 days of treatment was reduced by 32.9% compared with the conventional MT treatment group (60 ppm). In all the treatments, the length-weight relationship (LWR) showed negatively allomeric growth behavior (b < 3), with a relative condition factor (K_n) of more than 1. Therefore, MT-APG-NLC (30 ppm) would seem to be a promising, cost-effective way to reduce the dose of MT used for the masculinization of farmed red tilapia.

Menthol carbonates as potent antiparasitic agents: synthesis and in vitro studies along with computer-aided approaches

Introduction

Despite the number of deaths and the significant economic and social costs associated with Chagas, Leishmaniasis and Malaria diseases worldwide, available drugs are limited and have serious side effects and high toxicity for the patient. Therefore, there is an urgent need for safe, low-cost, and effective treatments. Natural products are an important source of bioactive compounds and there is current interest in finding natural bioactive molecules that can be used for treating these parasitic diseases. In the present study we proposed to evaluate the in vitro antiparasitic activity of new menthol derivatives against Trypanosoma cruzi, Leishmania braziliensis and Plasmodium falciparum; moreover, we propose to explore their mode of action through in silico approaches.

Material and methods

A series of carbonate prodrugs (1–9) were synthesized from menthol with different aliphatic alcohols. Spectroscopic techniques were used to confirm the structures of the synthesized compounds. The cytotoxicity of the compounds was assessed using U-937 cells. In vitro trypanocidal, leishmanicidal and antiplasmodial activity were evaluated using a T. cruzi, L. braziliensis and P. falciparum organism, respectively. In addition, in silico studies were also performed through molecular dynamics simulations and MM-PBSA analysis.

Results

The assay revealed that most of the compounds were highly active against intracellular amastigotes of T. cruzi and L. braziliensis, and had moderate activity against the total forms of P. falciparum. Compound 2 was one of the drugs that showed a high selectivity index (SI) for the three organisms evaluated. The prediction of the ADME properties suggests that all the compounds have drug-like molecular properties and the probability to be lead candidates. Finally, molecular dynamics simulations, and MM-PBSA studies indicate that menthol at the substrate binding site of TcDHODH, LbDHODH and PfDHODH is structurally stable in the same order as the natural substrate; also, interactions of menthol with residues involved in the inhibition of TcDHODH and PfDHODH proteins were predicted.

Conclusions

The present study demonstrates that menthol prodrugs are promising antiparasitic agents; however, the mechanisms of action proposed in this study need to be experimentally verified by future enzymatic assays.

Enhanced stability and controlled release of menthol using a β-cyclodextrin metal-organic framework

Menthol inclusion complexes (ICs) have addressed a range of opportunities in food applications due to their volatile resistance. However, previous protocols used for their synthesis give low yields and high industrial application costs. In the present investigation, metal-organic frameworks based on β-cyclodextrin (β-CD-MOF) have been prepared for the molecular encapsulation of menthol. Menthol/β-CD-MOF-IC was synthesized under the optimized parameters, after which release behavior was studied. In this optimized manner, a higher menthol capacity was obtained in which the menthol content and encapsulation efficiency were 27.1 and 30.6%, respectively. Compared with menthol/β-CD-IC, menthol/β-CD-MOF-IC is resistant to high temperature, but sensitive to moisture. In a simulated oral release experiment, the rate of menthol release from different samples followed the order of: pure menthol > β-CD > β-CD-MOF, which can be attributed to two mechanisms: non-specific binding and site preference. We propose that β-CD-MOF can be used as a promising delivery system for aroma compounds.

Precision release systems of food bioactive compounds based on metal-organic frameworks: synthesis, mechanisms and recent applications

Controlled release (CR) systems have become a powerful platform for accurate and effective delivery of bioactive compounds (BCs). Metal-organic frameworks (MOFs) are one of the best BCs-loaded carriers for CR systems. In the review, the principles and methods of the design and synthesis of MOFs-CR systems are summarized in detail, the encapsulation of BCs by MOFs and CR mechanisms are explored, and their biological toxicity and biocompatibility are highlighted and applications in the food industry are discussed. In addition, current challenges in this field and possible future development directions are also presented. MOFs have been proven to encapsulate BCs effectively, including gaseous and solid molecules, and control the release of BCs through spontaneous diffusion or stimulus-response. The solubility, stability and biocompatibility of BCs encapsulated by MOFs are greatly improved, which expands their applications in foods. The effective CR of BCs by MOFs-CR systems is beneficial to assist in maintaining or even improving the quality and safety of food, reduce the BCs usage while increasing the bioavailability. Low- or non-biotoxic MOFs, especially bio-MOFs, show greater application prospects in the food industry.

Antibacterial Effect of Dihydromyricetin on Specific Spoilage Organisms of Hybrid Grouper

This study aimed to investigate the mechanism of antibacterial activity level inhibition of dihydromyricetin (DMY) against specific spoilage bacteria of grouper. Firstly, the specific spoilage bacteria of grouper in the cold storage process are Pseudomonas antarctica (P. antarctica), which are selected by calculating the spoilage metabolite yield factor. It was determined that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of DMY against grouper spoilage bacteria were 2.0 mg/mL and 6.4 mg/mL, respectively. DMY was added to the matrix of chitosan and sodium alginate, and DMY emulsions of different concentrations (0 MIC, 1 MIC, 2 MIC, 4 MIC) were prepared and characterized by differential calorimetry methods. Through analyzing cell permeability, enzyme activity, and images of the confocal laser scanning microscope (CLSM), we further studied the antibacterial mechanism of DMY emulsion on specific spoilage bacteria. The results showed that, with the increase of DMY concentration in the treatment group, the leakage of nucleic acid and protein increased significantly, the activity of ATPase and three critical enzymes in the Embden-Meyerhof-Parnas (EMP) pathway decreased significantly, and the activity of AKPase did not decrease significantly, . The metabolic activity and viability are reduced considerably. Analysis of the above results shows that DMY inhibits the growth and reproduction of P. antarctica by interfering with the metabolic activity of bacteria and destroying the function of bacterial cell membranes but has no inhibitory effect on the activity of AKPase. This study proves that DMY could be an effective and natural antibacterial agent against specific spoilage bacteria in aquatic products.

Silk Sericin-Polylactide Protein-Polymer Conjugates as Biodegradable Amphiphilic Materials and Their Application in Drug Release Systems

Silk sericin (SS) is a byproduct of silk production. In order to transform it into value-added products, sericin can be used as a biodegradable and pH-responsive building block in drug delivery materials. To this end, amphiphilic substances were synthesized via the conjugation of hydrophobic polylactide (PLA) to the hydrophilic sericin using a bis-aryl hydrazone linker. PLA was esterified with a terephthalaldehydic acid to obtain aromatic aldehyde terminated PLA (PLA-CHO). In addition, lysine groups of SS were modified with the linker succinimidyl-6-hydrazino-nicotinamide (S-HyNic). Then, both macromolecules were mixed to form the amphipilic protein-polymer conjugate in buffer-DMF solution. The formation of bis-aryl hydrazone linkages was confirmed and quantified by UV-vis spectroscopy. SS-PLA conjugates self-assembled in water into spherical multicompartment micelles with a diameter of around 100 nm. Doxorubicin (DOX) was selected as a model drug for studying the pH-dependent drug release from SS-PLA nanoparticles. The release rate of the encapsulated drug was slower than that of the free drug and dependent on pH, faster at pH 5.0, and it resulted in a larger cumulative amount of drug released than at physiological pH of 7.4. The SS-PLA conjugate of high PLA branches showed smaller particle size and lower loading capacity than the one with low PLA branches. Both SS-PLA conjugates had negligible cytotoxicity, whereas after loading with DOX, the SS-PLA micelles were highly toxic for the human liver carcinoma immortalized cell line HepG2. Therefore, the SS-based biodegradable amphiphilic material showed great potential as a drug carrier for cancer therapy.

Encapsulation of menthol into cyclodextrin metal-organic frameworks: Preparation, structure characterization and evaluation of complexing capacity

Cyclodextrin (CD)-metal-organic frameworks (MOFs) are developed as a new type of food-acceptable multi-porous material, which shows a great potential for controlled volatile compound release. This study aimed to synthesize CD-MOFs from potassium nitrate, crystallized with α-cyclodextrin (α-CD), β-CD or γ-CD, and their complex capacities were further evaluated using menthol encapsulation. Compared with CD, all the CD-MOFs had highly ordered crystal structures and more regular shapes. β-CD-MOF showed better thermal stability, with an initial thermal degradation temperature of 253 °C, higher than the other two CD-MOFs. The CD-MOFs were used for menthol encapsulation and the resulting menthol concentration within the inclusion complexes (ICs) was determined. The menthol concentration in ICs followed the order: β-CD-MOF > β-CD > γ-CD-MOF > γ-CD > α-CD ≥ α-CD-MOF. The menthol content and encapsulation efficiency of β-CD-MOF were 21.76% (w/w) and 22.54% (w/w) respectively, significantly higher than those of other reported solid materials, such as amylose, CD and V-type starch.

Carboxymethyl β-cyclodextrin grafted carboxymethyl chitosan hydrogel-based microparticles for oral insulin delivery

This study was aimed at utilizing polysaccharides for the development of effective hydrogel microparticles for oral insulin delivery that has a controlled, and sustained release to enhance paracellular transcellular absorption. Carboxymethyl β-cyclodextrin grafted carboxymethyl chitosan hydrogels (CMCD-g-CMCs) were prepared from carboxymethyl β-cyclodextrin (CMCD) and carboxymethyl chitosan (CMC) using a water-soluble carbodiimide as a crosslinker in the presence of N-hydroxysuccinimide. After synthesis, the hydrogel structures were determined via FT-IR and XRD analyses. The porous structure of hydrogels was confirmed by SEM observations and swelling behaviours. The insulin release behaviours were found to betriggered by pH in vitro. Results showed that insulin was successfully retained inside the hydrogels in the gastric environment and slowly released following passage to intestinal conditions. The stability of the secondary structure of insulin was studied by dichroism circular (CD) and fluorescence (FL) spectrophotometer measurement. There was no significant difference in the secondary structure between the native and released insulin. In vitro studies revealed that the hydrogel microparticles exhibited non-cytotoxicity and were transported across the Caco-2 cell monolayers mainly via the paracellular pathway. In order to examine the effectiveness of hydrogel-based sustained release microparticles in delivering insulin in vivo, we administered different insulin-loaded hydrogel microparticles to diabetic mice. In these studies, we found that the insulin-loaded hydrogel microparticles provided a significant and sustained (ranging from 6 h to 12 h) reduction in the blood glucose levels of diabetic mice compared with subcutaneous injection. Overall, these findings demonstrate that CMCD-g-CMCs may be a promising protein carrier for use in oral drug delivery.

Essential Oils-Loaded Electrospun Biopolymers: A Future Perspective for Active Food Packaging

The growth of global food demand combined with the increased appeal to access different foods from every corner of the globe is forcing the food industry to look for alternative technologies to increase the shelf life. Essential oils (EOs) as naturally occurring functional ingredients have shown great prospects in active food packaging. EOs can inhibit the growth of superficial food pathogens, modify nutritious values without affecting the sensory qualities of food, and prolong the shelf life when used in food packaging as an active ingredient. Since 2016, various reports have demonstrated that combinations of electrospun fibers and encapsulated EOs could offer promising results when used as food packaging. Such electrospun platforms have encapsulated either pure EOs or their complexation with other antibacterial agents to prolong the shelf life of food products through sustained release of active ingredients. This paper presents a comprehensive review of the essential oil-loaded electrospun fibers that have been applied as active food packaging material.

Preparation and characterization of nanoparticles from quaternized cyclodextrin-grafted chitosan associated with hyaluronic acid for cosmetics

Hyaluronic acid (HA, 20–50 kDa) is a hydrophilic macromolecule  with anti-wrinkle effects and moisturizing properties. However, its high molecular weight prevents it from penetrating into the deeper layers of the skin and, thus, limits its benefits to topical effects. Thus, the objective of this study is to prepare nanoparticles of quaternized cyclodextrin-grafted chitosan (QCD-g-CS) associated with HA in different molar ratios of QCD-g-CS and HA. The conjugation of the carboxylic moieties of HA and the amides of QCD-g-CS was confirmed by Fourier-transform infrared spectroscopy. Thus, the system was optimized to create nanoparticles with a small size (235.63 ± 21.89 nm), narrow polydispersity index (0.13 ± 0.02), and zeta potential of 16.07 ± 0.65 mV. The association efficiency and loading efficiency were determined by ultra-performance liquid chromatography as 86.77 ± 0.69% and 10.85 ± 0.09%, respectively. The spherical morphology of the obtained nanoparticles was confirmed by transmission electron microscopy. Moreover, the in-vitro hydrating ability was significantly higher (P < 0.001) than that of bulk HA (3.29 ± 0.41 and 1.71 ± 0.05 g water/g sample, respectively). The safety of these nanoparticles at concentrations in the range of 0.01–0.10 mg/ml was confirmed via tests on human skin fibroblasts. Together, these results demonstrate that the developed nanoparticles are promising for future applications in cosmetics.

Synthesis of Quaternary Ammonium Salts of Chitosan Bearing Halogenated Acetate for Antifungal and Antibacterial Activities

In this paper, quaternary ammonium salts of chitosan bearing halogenated acetate, including N,N,N-trimethyl chitosan chloroacetate (TMCSC), N,N,N-trimethyl chitosan dichloroacetate (TMCSDC), N,N,N-trimethyl chitosan trichloroacetate (TMCSTC), and N,N,N-trimethyl chitosan trifluoroacetate (TMCSTF), were prepared via N,N,N-trimethyl chitosan iodide (TMCSI). The obtained chitosan derivatives were characterized by FT-IR, ¹H NMR spectra, 13C NMR spectra, and elemental analysis. Their antifungal property against Fusarium oxysporum f. sp. cucumebrium Owen (F. oxysporum f. sp. cucumebrium Owen), Botrytis cinerea (B. cinerea), and Phomopsis asparagi (P. asparagi) were evaluated by hyphal measurement method at concentrations ranging from 0.08 mg/mL to 0.8 mg/mL. Meanwhile, two common bacteria, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were selected as the model Gram-negative and Gram-positive bacteria to evaluate the antibacterial property of the chitosan derivatives by agar well diffusion method. The results showed that TMCSC, TMCSDC, TMCSTC, and TMCSTF had better antifungal and antibacterial activities than chitosan and TMCSI. In particular, a rule showed that the inhibitory activity decreased in the order: TMCSTF > TMCSTC > TMCSDC > TMCSC > TMCSI > chitosan, which was consistent with the electron-withdrawing property of different halogenated acetate. Apparently, the quaternary ammonium salts of chitosan with stronger electron withdrawing ability possessed relatively greater antifungal and antibacterial activities. This experiment provides a potentially feasible method for the further utilization of chitosan in fields of antifungal and antibacterial biomaterials.

Controllable encapsulation of α-mangostin with quaternized β-cyclodextrin grafted chitosan using high shear mixing

In this study, the inclusion complex formation between α-mangostin and water-soluble quaternized β-CD grafted-chitosan (QCD-g-CS) was investigated. Inclusion complex formation with encapsulation efficiency (%EE) of 5, 15 and 75% can be varied using high speed homogenizer. Tuning %EE plays a role on physicochemical and biological properties of α-mangostin/QCD-g-CS complex. Molecular dynamics simulations indicate that α-mangostin is included within the hydrophobic β-CD cavity and being absorbed on the QCD-g-CS surface, with these results being confirmed by Fourier transform infrared (FTIR) spectroscopy. Probing the release characteristics of the inclusion complex at various %EE (5%, 15% and 75%) in simulated saliva (pH 6.8) demonstrated that α-mangostin release rates were dependent on % EE (order 5% > 15% > 75%). Additionally, higher antimicrobial and anti-inflammation activities were observed for the inclusion complex than those of free α-mangostin due to enhance the solubility of α-mangostin through the inclusion complex with QCD-g-CS.

Formulation of Menthol-Loaded Nanostructured Lipid Carriers to Enhance Its Antimicrobial Activity for Food Preservation

Purpose: Due to the antimicrobial property, menthol have significant potential for food preservation and foodstuff shelf life improvement. Nevertheless, menthol instability, insolubility, and rapid crystallization in aqueous media make it unsuitable for used in food products. This work was aimed to prepare menthol-loaded nanostructured lipid carriers (NLCs) to enhance its antimicrobial activity.

Methods: Morphology, particle size and size distribution, encapsulation efficiency percent (EE%), and physical stability of the optimized formulation, prepared by hot melt homogenization method, were characterized by scanning electron microscopy, particle size analyzing, gas chromatography, and X-ray diffraction (XRD) methods. Minimum inhibitory concentration and minimum bactericidal concentration of menthol-loaded NLCs were evaluated and compared with conventional menthol emulsion against various Gram-positive (Staphylococcus aureus, Bacillus cereus) and Gram-negative bacteria (Escherichia coli), as well as one fungus (Candida albicans).

Results: Menthol-loaded NLCs were spherically shaped nanosized (115.6 nm) particles with narrow size distribution (PDI = 0.2), suitable menthol EE% (98.73%), and appropriate physical stability after 90 days of storage period. XRD results indicated that menthol was in the amorphous form in the nanoparticles matrix. Antibacterial assay results revealed that the menthol-loaded NLCs exhibited significantly higher in vitro antimicrobial property than conventional menthol emulsion. The results also indicated that menthol-loaded NLCs had better effect on fungi than bacteria, and furthermore, antibacterial efficiency on Gram-positive bacteria was higher than Gram-negative bacteria.

Conclusion: In conclusion, NLCs could be a promising carrier for improvement of antimicrobial activity and preservation efficacy of essential oils in foodstuffs.