Preparation and Characterization of Butachlor/(2-Hydroxypropyl)-β-cyclodextrin Inclusion Complex: Improve Soil Mobility and Herbicidal Activity and Decrease Fish Toxicity

Inhibition of the p62-Nrf2-GPX4 Pathway Confers Sensitivity to Butachlor-Induced Splenic Macrophage Ferroptosis

Butachlor is widely used in agriculture around the world and therefore poses environmental and public health hazards due to persistent and poor biodegradability. Ferroptosis is a type of iron-mediated cell death controlled by glutathione (GSH) and GPX4 inhibition. P62 is an essential autophagy adaptor that regulates Keap1 to activate nuclear factor erythroid 2-related factor 2 (Nrf2), which effectively suppresses lipid peroxidation, thereby relieving ferroptosis. Here, we found that butachlor caused changes in splenic macrophage structure, especially impaired mitochondrial morphology with disordered structure, which is suggestive of the occurrence of ferroptosis. This was further confirmed by the detection of iron metabolism, the GSH system, and lipid peroxidation. Mechanistically, butachlor suppressed the protein level of p62 and promoted Keap1-mediated degradation of Nrf2, which results in decreased GPX4 expression and accelerated splenic macrophage ferroptosis. These findings suggest that targeting the p62-Nrf2-GPX4 signaling axis may be a promising strategy for treating inflammatory diseases.

A general supramolecular adjuvant for pesticides based on host-guest recognition

BACKGROUND

Pesticides are indispensable in agriculture and can effectively improve the yields and quality of crops. Due to their weak water solubility, most pesticides need to be dissolved by adding solubilizing adjuvants. In this work, based on molecular recognition of the macrocyclic host, we developed a novel supramolecular adjuvant, called sulfonated azocalix[4]arene (SAC4A), which significantly improves the water solubility of pesticides.

RESULTS

SAC4A presents multiple advantages, including high water solubility, strong binding affinity, universality, and simple preparation. SAC4A showed an average binding constant value of 1.66 × 105  M-1 for 25 pesticides. Phase solubility results indicated that SAC4A increased the water solubility of pesticides by 80-1310 times. The herbicidal, fungicidal, and insecticidal activities of supramolecular formulations were found to be superior to those of technical pesticides, and the herbicidal effects were even better than those of commercial formulations.

CONCLUSION

Overall results revealed the potential of SAC4A to improve the solubility and effectiveness of pesticides, providing a new development idea for the application of adjuvants in agriculture. © 2023 Society of Chemical Industry.

Assembled Bisphenol A with cyclic oligosaccharide as the controlled release complex to reduce risky effects

Herein, in order to improve the bioavailability of a non-biodegradable pollutant, inclusion complexation procedures had been used to develop better formulations of this pollutant, Bisphenol A (BPA). In our research, an inclusion complex (IC) of β-cyclodextrin (β-CD) with BPA was formed to investigate the effect of β-CD on the water solubility, anti-oxidant, anti-bacterial activity, toxicity, and thermal stability of BPA. UV-Vis and other spectrometric methods such as NMR, FTIR, and XRD indicated the molecular mechanism of interactions between β-CD and BPA, which was further hypothesized using molecular modeling to confirm preliminary results. Studies of TGA and DSC demonstrated that encapsulation boosted the thermal stability of BPA. This research also makes predictions about BPA's release behavior when CT-DNA is present. In vitro testing of the IC's antibacterial activities showed that it outperformed pure BPA. The in silico study was found to have a considerable decrease in toxicity level for IC compared to pure BPA. Therefore, β-CD-encapsulated BPA can lessen toxicity by raising antioxidant levels. Additionally, as its antibacterial activity increases, it may be employed therapeutically. Thus, this discovery of creating BPA formulations with controlled release and/or protective properties allows for a more logical application of BPA by reducing its hazardous effects through boosting its efficacy.

Exploring inclusion complex of an anti-cancer drug (6-MP) with β-cyclodextrin and its binding with CT-DNA for innovative applications in anti-bacterial activity and photostability optimized by computational study

The co-evaporation approach was used to examine the host-guest interaction and to explore the cytotoxic and antibacterial properties of an important anti-cancer medication, 6-mercaptopurine monohydrate (6-MP) with β-cyclodextrin (β-CD). The UV-Vis investigation confirmed the inclusion complex's (IC) 1 : 1 stoichiometry and was also utilized to oversee the viability of this inclusion process. FTIR, NMR, and XRD, among other spectrometric techniques, revealed the mechanism of molecular interactions between β-CD and 6-MP which was further hypothesized by DFT to verify tentative outcomes. TGA and DSC studies revealed that 6-MP's thermal stability increased after encapsulation. Because of the protection of drug 6-MP by β-CD, the formed IC was found to have higher photostability. This work also predicts the release behavior of 6-MP in the presence of CT-DNA without any chemical changes. An evaluation of the complex's antibacterial activity in vitro revealed that it was more effective than pure 6-MP. The in vitro cytotoxic activity against the human kidney cancer cell line (ACHN) was also found to be significant for the IC (IC₅₀ = 4.18 μM) compared to that of pure 6-MP (IC₅₀ = 5.49 μM). These findings suggest that 6-MP incorporation via β-CD may result in 6-MP stability and effective presentation of its solubility, cytotoxic and antibacterial properties.

Investigation on detoxication effects of 2-hydroxypropyl-β-cyclodextrin over two halogenated aromatic DBPs 2,4,6-trichlorophenol and 2,4,6-tribromophenol binding with human serum albumin

The health effects of disinfection byproducts (DBPs) in drinking water drew great attention recently. Herein, by using in vitro (fluorescence quenching, UV absorbance, circular dichroism) and in silico (molecular docking) method, binding interactions of two halophenolic DBPs (2,4,6-trichlorophenol [TCP] and 2,4,6-tribromophenol [TBP]) with human serum albumin (HSA) and the influence of hydroxypropyl-beta-cyclodextrin (HPCD) on the interactions were investigated. TCP/TBP could form complexes with HSA mainly by hydrogen bonding, while changing its secondary structure, among which TBP showed more influential effect. Interestingly, the binding constants for halophenol-HSA complexes decreased obviously with the involvement of HPCD. Molecular docking results revealed that HPCD could include TCP/TBP into its cavity and change their original binding sites from subdomain IB to IIA, resulting in a more stable binding system. These findings are beneficial for understanding the toxicity of halophenols inside the human body and indicated that HPCD could be a promising detoxication agent for DBPs.

Enhancement of Dissolving Capacity and Reducing Gastric Mucosa Irritation by Complex Formation of Resibufogenin with β-Cyclodextrin or 2-Hydroxypropyl-β-cyclodextrin

Resibufogenin (RBG) is a natural medicinal ingredient with promising cardiac protection and antitumor activity. However, poor solubility and severe gastric mucosa irritation restrict its application in the pharmaceutical field. In this study, the inclusion complex of RBG with β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared using the co-evaporation method, and the molar ratio of RBG to CD was determined to be approximately 1:2 by continuous variation plot for both CDs. The formation of inclusion complexes between RBG and each CD (RBG/β-CD and RBG/HP-β-CD) was evaluated by phase solubility study, Fourier transform infrared spectroscopy, and thin-layer chromatography. Powder X-ray diffraction and differential scanning calorimetry confirmed drug amorphization and encapsulation in the molecular cage for both CDs. Moreover, the inclusion complexes’ morphologies were observed using scanning electron microscopy. The dissolution rate of the inclusion complexes was markedly improved compared to that of RBG, and the complexes retained their antitumor activity, as shown in the in vitro cytotoxicity assay on a human lung adenocarcinoma cancer (A549) cell line. Moreover, less gastric mucosal irritation was observed for the inclusion complex. Thus, the inclusion complex should be considered a promising strategy for the delivery of poorly water-soluble anticancer agents, such as RBG.

Efficient Persistent Luminescence Tuning Using a Cyclodextrin Inclusion Complex as Efficient Light Conversion Materials

Developing an appropriate method to broaden the color of long persistent luminescence materials has important scientific significance and practical value but remains a great challenge. Herein, we have developed a unique strategy to fine-tune the persistent luminescence using the inclusion complex of rhodamine 6G with (2-hydroxypropyl)-β-cyclodextrin as efficient light conversion materials. The emitting color of the novel persistent luminescence material could be tuned from green to orange by changing the concentration of the light conversion agent. Furthermore, afterglow decay measurements showed that the initial afterglow brightness is 9.65 cd/m², and the initial afterglow brightness gradually decreased as the cyclodextrin inclusion compound coating increased. This design concept introduces a new perspective for broadening the luminescence color of afterglow phosphors, which may open up new opportunities for persistent luminescence materials toward many emerging applications.

Analytical and in silico study of the inclusion complexes between tropane alkaloids atropine and scopolamine with cyclodextrins

Datura stramonium L. (Solanaceae) possesses a rich tropane alkaloids (TAs) spectrum. The plant contains, in particular, the allelopathic compounds scopolamine and atropine, which are poorly soluble in water, thus limiting their use in agrochemical formulations as biocidal and deterrent agents against herbivore insects. The efficacy of the hydrophobic TAs extracts could be increased with the improvement of their dissolution/leaching properties. This is important for improving screening and test performance and for elucidating the activity of environmentally friendly agricultural approaches, with new perspectives for the production and use of those biodegradable insecticidal products. The present study explores the aspects of atropine and scopolamine complexation with cyclodextrin (CDs) through FT-IR and UV–Vis spectroscopies. In addition, the structures of the inclusion complex of atropine, scopolamine and β-CD have been investigated by molecular modeling techniques. The results obtained indicate that β-CDs are a promising carriers for improving the properties of TAs, therefore increasing their application potential in agrochemical formulations.

Graphic abstract

Caffeine-Cyclodextrin Complexes as Solids: Synthesis, Biological and Physicochemical Characterization

Mechanochemical and in-solution synthesis of caffeine complexes with α-, β-, and γ-cyclodextrins was optimized. It was found that short-duration, low-energy cogrinding, and evaporation (instead of freeze-drying) are effective methods for the formation and isolation of these complexes. The products obtained, their pure components, and their mixtures were examined by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), FT-IR and Raman spectroscopy. Moreover, molecular modeling provided an improved understanding of the association process between the guest and host molecules in these complexes. The complexes were found to exhibit high toxicity in zebrafish (Danio rerio) embryos, in contrast to pure caffeine and cyclodextrins at the same molar concentrations. HPLC measurements of the caffeine levels in zebrafish embryos showed that the observed cytotoxicity is not caused by an increased caffeine concentration in the body of the organism, as the concentrations are similar regardless of the administered caffeine form. Therefore, the observed high toxicity could be the result of the synergistic effect of caffeine and cyclodextrins.

Design, synthesis, crystal structure, and herbicidal activity of novel pyrrolidine-2,4-dione derivatives incorporating an alkyl ether pharmacophore with natural tetramic acids as lead compounds

A series of pyrrolidine-2,4-dione derivatives incorporating a chainlike alkoxyalkyl moiety or substituted phenoxyethyl moiety were designed and synthesized based on natural tetramic acids. Some target compounds showed obvious herbicidal activities.

Supramolecular polyelectrolyte complexes based on cyclodextrin-grafted chitosan and carrageenan for controlled drug release

In the present study, supramolecular polyelectrolyte complexes (SPEC) based on a cyclodextrin-grafted chitosan derivative and carrageenan were prepared and evaluated for controlled drug release. Samples were characterized by FTIR, SEM, and ζ-potential measurements, which confirmed the formation of the polymeric complex. The phenolphthalein test confirmed the presence and availability of inclusion sites from the attached βCD. Silver sulfadiazine was used as the model drug and the association with the SPEC was studied by FTIR and computational molecular modeling, using a semi-empirical method. DRS and TEM analyses have shown that Ag⁺ ions from the drug were reduced to form metallic silver nanostructures. In vitro tests have shown a clear bacterial activity toward Gram-positive bacteria Staphylococcus aureus and Enterococcus durans/hirae and Gram-negative bacteria Klebsiella pneumoniae and Escherichia coli. Finally, this work shows that βCD-chitosan/carrageenan supramolecular polyelectrolyte complexes hold an expressive potential to be applied as a polymer-based system for controlled drug release.

Quantifying the hygroscopic properties of cyclodextrin containing aerosol for drug delivery to the lungs

Aerosol dynamics is important to quantify in drug delivery to the lungs with the aim of delivering therapeutics to a target location and optimising drug efficacy. The macrocycle (2-hydroxypropyl)-β-cyclodextrin (2-HP-β-CD) is thought to alleviate symptoms associated with neurodegenerative diseases when inhaled but the hygroscopic response is not well understood. Here we measure the hygroscopic growth of individual aqueous aerosol containing 2-HP-β-CD in optical tweezers through analysis of morphology-dependent resonances arising in Raman spectra. Droplets are analysed in the size range of 3-5 μm in radius. The evolving radius and refractive index of each droplet are measured in response to change in relative humidity from 98-20% to determine mass and radius based hygroscopic growth factors, and compared with dynamic vapour sorption measurements. Bulk solution refractive index and density measurements were used in accordance with the self-consistent Lorenz-Lorentz rule to determine melt solute and droplet properties. The refractive index of 2-HP-β-CD was determined to be 1.520 ± 0.002 with a density of 1.389 ± 0.005 g cm^-3. To our knowledge, we show the first aerosol measurements of 2-HP-β-CD and determine hygroscopicity. By quantifying the hygroscopic growth and physicochemical properties of 2-HP-β-CD, the impact of aerosol dynamics can be accounted for in tailoring drug formulations and informing models used to predict drug deposition patterns within the respiratory system.

Enhanced Solubility, Stability, and Herbicidal Activity of the Herbicide Diuron by Complex Formation with β-Cyclodextrin

The herbicide diuron is hardly soluble in water and most organic solvents and is usually made into a wettable powder or mixed with soil when used, which causes environmental risk and a reduction in herbicidal efficacy. In this study, the physicochemical properties were changed by using β-cyclodextrin (β-CD) to encapsulate diuron to form an inclusion complex. Some key technologies, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and nuclear magnetic resonance (1H NMR), were used to characterize the inclusion complex. The stoichiometry of the inclusion complex was determined by recording the 1H NMR spectrum or by using a diagram of inclusion ratios. A phase solubility study proved that the formed inclusion complex exhibited higher water solubility. Thermogravimetric analysis (TGA) demonstrated that the formed inclusion complex exhibited better thermal stability. Biological activity studies indicated that the herbicidal activity, in terms of herbicide removal, of the formed inclusion complex was higher than that of the original diuron. In general, the formation of the inclusion complex could reduce the environmental damage caused by diuron and enhance its herbicidal activity, providing an environmentally friendly method for using diuron.