With the restricted use of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), a number of alternatives to PFOS and PFOA have attracted great interest. Most of the alternatives are still characterized by persistence, bioaccumulation, and a variety of toxicity. Due to the production and use of these substances, they can be detected in the atmosphere, soil and water body. They affect human health through several exposure pathways and especially enter the gut by drinking water and eating food, which results in gut toxicity. In this review, we summarized the effects of PFOS, PFOA and 9 alternatives on pathological changes in the gut, the disruption of physical, chemical, biological and immune barriers of the intestine, and the gut-organ axis. This review provides a valuable understanding of the gut toxicity of PFOS, PFOA and their alternatives as well as the human health risks of emerging contaminants.

Development of secure and efficient drug delivery systems to overcome physicochemical challenges in cancer clinical treatment is one of the most active fields, and novel drug carriers are actively sought. In this work, the successful synthesis of amphiphilic chitosan derivatives containing pyridine cations and folic acid (TMACMCF) was confirmed by FTIR and 1H NMR spectroscopy. The critical micelle concentration (CMC) of TMACMCF was studied, and the results indicated that it possessed a relatively low CMC (0.186 mg/mL). Self-assembled nanoparticles (TMACMCF-ADM NPs) for the entrapment and delivery of adriamycin (ADM) were synthesized based on TMACMCF, and the morphology, particle size, zeta potential, sustained release performance, antioxidant and antitumor activities, and cytotoxicity were investigated. The particle size of TMACMCF-ADM NPs was 163.79±7.31 nm, and the morphology observed by SEM and TEM showed spherical or oval particles. TMACMCF-ADM NPs showed excellent entrapment of ADM with entrapment efficiency and drug loading efficiency of 65.04±1.20% and 22.73±0.40%, respectively. The release performance results showed that in vitro release profiles of ADM from NPs exhibited pH-sensitive controlled and sustained release properties. The assay of antioxidant activity exhibited that TMACMCF-ADM NPs possessed significantly improved scavenging ability against three kinds of radicals (Superoxide-radical, DPPH radical, and ABTS radical). Moreover, the assay of antitumor activity by CCK-8 test exhibited that nanoparticles led to statistically significant enhancement in inhibition index for four kinds of cancer cells (BGC-823, MCF-7, HEPG-2, and A549). This work provides a promising carrier for secure and effective entrapment and delivery of ADM.

Abnormalities in vascular smooth muscle cells (VSMCs) are pivotal in the pathogenesis of cardiovascular pathologies such as atherosclerosis and hypertension. Scutellarin (Scu), a flavonoid derived from marigold flowers, exhibits a spectrum of biological activities including anti-inflammatory, antioxidant, antitumor, immunomodulatory and antimicrobial effects. Notably, Scu has demonstrated the capacity to mitigate vascular endothelial damage and prevent atherosclerosis via its antioxidative properties. Nevertheless, the influence of Scu on the formation of VSMC-derived foam cells remains underexplored. In this study, Scu was evidenced to efficaciously attenuate oleic acid (OA)-induced lipid accumulation and the upregulation of adipose differentiation-associated protein Plin2 in a dose- and time-responsive manner. We elucidated that Scu effectively diminishes OA-provoked VSMC foam cell formation. Further, it was established that Scu pretreatment augments the protein expression of LC3B-II and the mRNA levels of Map1lc3b and Becn1, concurrently diminishing the protein levels of the NLRP3 inflammasome compared to the OA group. Activation of autophagy through rapamycin attenuated NLRP3 inflammasome protein expression, intracellular lipid droplet content and Plin2 mRNA levels. Scu also counteracted the OA-induced decrement of LC3B-II levels in the presence of bafilomycin-a1, facilitating the genesis of autophagosomes and autolysosomes. Complementarily, in vivo experiments revealed that Scu administration substantially reduced arterial wall thickness, vessel wall cross-sectional area, wall-to-lumen ratio and serum total cholesterol levels in comparison to the high-fat diet model group. Collectively, our findings suggest that Scu attenuates OA-induced VSMC foam cell formation through the induction of autophagy and the suppression of NLRP3 inflammasome activation.

The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method. The method resulted in nanogels with low polydispersity index, small particle size, and positive zeta potential values, indicating the good stability of the nanogels. Compared to hydroxypropyl trimethyl ammonium chloride chitosan-Doxorubicin HCl-sodium tripolyphosphate (HACC-D-TPP) nanogel, the benzimidazole-chitosan quaternary ammonium salt-Doxorubicin HCl-sodium tripolyphosphate (BIMIXHAC-D-TPP) nanogel show higher drug encapsulation efficiency and loading capacity (BIMIXHAC-D-TPP 93.17 ± 0.27% and 31.17 ± 0.09%), with acid-responsive release profiles and accelerated release in vitro. The hydroxypropyl trimethyl ammonium chloride chitosan-sodium tripolyphosphate (HACC-TPP), and benzimidazole-chitosan quaternary ammonium salt-sodium tripolyphosphate (BIMIXHAC-TPP) nanogels demonstrated favorable antioxidant capability. The assay of cell viability, measured by the MTT assay, revealed that nanogels led to a significant reduction in the cell viability of two cancer cells: the human lung adenocarcinoma epithelial cell line (A549) and the human breast cancer cell line (MCF-7). Furthermore, the BIMIXHAC-D-TPP nanogel was 2.96 times less toxic than DOX.HCl to the mouse fibroblast cell line (L929). It was indicated that the BIMIXHAC-based nanogel with enhanced antioxidant and antitumor activities and acidic-responsive release could serve as a potential nanocarrier.

Caries is a destructive condition caused by bacterial infection that affects the hard tissues of the teeth, significantly reducing the quality of life for individuals. Photothermal therapy (PTT) offers a noninvasive and painless treatment for caries, but the use of unsafe laser irradiance limits its application. To address this challenge, we prepared nanoparticles of silver ion-doped Prussian blue (AgPB), which was encased within cationic guar gum (CG) to form the antibacterial PTT hydrogel CG-AgPB with a photothermal conversion efficiency of 34.4%. When exposed to an 808 nm laser at a power density of 0.4 W/cm(2), the hydrogel readily reached a temperature of over 50 degrees C in just 3 min, synchronized by the discharge of Ag+ ions from the interstitial sites of AgPB crystals, resulting in broad-spectrum and synergistic antibacterial activities (>99%) against individual oral pathogens (Streptococcus sanguinis, Streptococcus mutans, and Streptococcus sobrinus) and pathogen-induced biofilms. In vivo, CG-AgPB-mediated PTT demonstrated a capability to profoundly reduce the terminal number of cariogenic bacteria to below 1% in a rat model of caries. Given the outstanding biocompatibility, injectability, and flushability, this CG-AgPB hydrogel may hold promise as a next-generation oral hygiene adjunct for caries management in a clinical setting.

pH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs.

Dry eye disease (DED) is a multifactorial ocular surface disorder mutually promoted by reactive oxygen species (ROS) and ocular surface inflammation. NLRP3 is the key regulator for inducing ocular surface inflammation in DED. However, the mechanism by which ROS influences the bio-effects of NLRP3, and the consequent development of DED, largely remains elusive. In the present study, we uncovered that robust ROS can oxidate mitochondrial DNA (ox-mtDNA) along with loss of mitochondria compaction causing the cytosolic release of ox-mtDNA and subsequent co-localization with cytosolic NLRP3, which can promote the activation of NLRP3 inflammasome and stimulate NLRP3-mediated inflammation. Visomitin (also known as SkQ1), a mitochondria-targeted anti-oxidant, could reverse such a process by in situ scavenging of mitochondrial ROS. To effectively deliver SkQ1, we further developed a novel mitochondria-targeted SkQ1 nanoparticle (SkQ1 NP) using a charge-driven self-assembly strategy. Compared with free SkQ1, SkQ1 NPs exhibited significantly higher cytosolic- and mitochondrial-ROS scavenging activity (1.7 and 1.9 times compared to levels of the free SkQ1 group), thus exerting a better in vitro protective effect against H2O2-induced cell death in human corneal epithelial cells (HCECs). After topical administration, SkQ1 NPs significantly reduced in vivo mtDNA oxidation, while suppressing the expressions of NLRP3, Caspase-1, and IL-1β, which consequently resulted in better therapeutic effects against DED. Results suggested that by efficiently scavenging mitochondrial ROS, SkQ1 NPs could in situ inhibit DED-induced mtDNA oxidation, thus blocking the interaction of ox-mtDNA and NLRP3; this, in turn, suppressed NLRP3 inflammasome activation and NLRP3-mediated inflammatory signaling. Results suggested that SkQ1 NPs have great potential as a new treatment for DED.

Amphiphilic low molecular weight chitosan-lipoic acid (LC-LA) conjugates with different degrees of substitution (DS) of LA were synthesized by N, N'‑carbonyldiimidazole (CDI) catalysis to self-assemble into redox-sensitive micelles. Critical micelle concentration (CMC), size, zeta potential, biocompatibility and redox-sensitive behavior of blank micelles were investigated. The results indicated that blank micelles with low CMC, nanoscale size and positive zeta potential showed excellent biocompatibility and redox-sensitive behavior. Doxorubicin (Dox) loaded micelles were prepared by encapsulating Dox into blank micelles. The loading ability, trigger-release behavior, antitumor activity and cellular uptake of Dox loaded micelles were studied. The results demonstrated that Dox loaded micelles with superior loading ability exhibited redox-trigger behavior, strong antitumor activity and increased cellular uptake efficiency against A549 cell. Besides, the effect of DS of LA on above properties was estimated. An increase in DS of LA reduced the CMC and cumulative release amount of Dox, but improved the loading efficiency, antitumor activity, and cellular uptake of Dox loaded micelles, which resulted from stronger interaction of hydrophobic groups in micelles with the DS of LA increased. Overall, self-assembled LC-LA micelles with good biosecurity and redox-sensitive behavior hold promising application prospects in Dox delivery and improving cancer therapeutic effect of Dox.

Natural polysaccharides are abundant and renewable resource, but their applications are hampered by limited biological activity. Chemical modification can overcome these drawbacks by altering their structure. Three series of polysaccharide derivatives with coumarins were synthesized to obtain polysaccharide derivatives with enhanced biological activity. The biological activities were tested, including antioxidant property, antifungal property, and antibacterial property. Based on the results, the inhibitory properties of the coumarin-polysaccharide derivatives were significantly improved over the raw polysaccharide. The IC50 of the inhibition of DPPH, ABTS•+, and superoxide (O2•-) radical-scavenging was 0.06-0.15 mg/mL, 2.3-15.9 μg/mL, and 0.03-0.25 mg/mL, respectively. Compared with the raw polysaccharides, coumarin- polysaccharide derivatives exhibited higher efficacy in inhibiting the growth of tested phytopathogens, showing inhibitory indices of 60.0-93.6 % at 1.0 mg/mL. Chitosan derivatives with methyl and chlorine (Compound 10B and 10C) exhibited significant antibacterial activity against S. aureus (MIC = 31.2 μg/mL), E. coli (MIC = 7.8 μg/mL), and V. harveyi (MIC = 15.6 μg/mL), respectively. The results of the cytotoxicity assay showed no observed cytotoxicity when the RAW 264.7 cells were incubated with the synthesized polysaccharide derivatives at the tested concentrations.

Based on the chroman-4-one ROR1 inhibitor ARI-1, two new series of 4H-pyrido[1,2-a]pyrimidin-4-one derivatives were designed and synthesized, and their biological activities were investigated.In vitro biological activity assays showed that compound 10b exhibited the best antiproliferation activity against H1975 (IC50 = 0.572 μM), which was superior to the lead compound ARI-1 (IC50 = 3.51 μM).Compound 10b also dose-dependently induced G0/G1 phase block and apoptosis.In addition, 10b exhibited inhibitory activity against ROR1 and modulated the ROR1 signaling pathway in a dose-dependent manner to exert anticancer activity.In conclusion, our data suggest that 10b may be a new lead compound for further development of ROR1 inhibitors as anti-cancer agents.

Fluorinated organic compounds (FOCs) are difficult to degrade and persistent in the environment due to the strong C-F bond strength. In this context, the applicability of Raney Ni to catalytic hydrodefluorination (HDF) of FOCs under mild conditions remains an important challenge. In this study, the effects of solvent systems and bases on Raney Ni catalyzed HDF reaction were investigated and evaluated with 4-FP using as a model fluo-roaromatic compound (FAC). It was found that the HDF reactivity of 4-FP over Raney Ni increased with the increase of water proportion and polarity of homogeneous ethanol-water solvents, and Raney Ni exhibited highest activity and stability in catalytic HDF of 4-FP in water with appropriate NaOH amount (1.5NaOH) under mild conditions. The mechanisms of these phenomena were clarified with the aid of catalyst characterization (SEM, EDX, and XRD) combined with ICP-OES. The results suggested that water could efficiently dissolve inorganic salt (NaF) produced in situ, which avoided the decrease in the catalytic activity of Raney Ni in the HDF of 4-FP due to the deposition of NaF on the surface of the catalyst. Moreover, the appropriate NaOH amount (1.5NaOH) in water could efficiently avoid the corrosion effect of HF on Raney Ni and eliminate the framework collapse of the catalyst resulted from the corrosion of Al. In water with 1.5NaOH, Raney Ni exhibited the highest activity and stability in catalytic HDF of 4-FP, with a complete conversion of 4-FP for at least 10 times. Based on these studies, an efficient reaction system was developed for Raney Ni catalyzed HDF of 4-FP, which would provide guidance to apply Raney Ni for catalytic HDF of FACs under mild conditions.

Chitooligosaccharide-caffeic acid (COS-CA) conjugates with three different grafting degrees were synthesized by the N, N′-carbonyldiimidazole (CDI) mediated method and used as functional components to prepare antioxidant chitosan-based composite films. The effects of the synthesized conjugates on the physical and biological properties of chitosan-based films, including mechanical property, UV-barrier property, optical, water vapor permeability, thermal stability, degradation behavior in soil, and antioxidant activity, were investigated. Chitosan acetate films with chitooligosaccharide or without other additives were used as the control. The results showed that the incorporation of COS-CA conjugates caused significant increases in mechanical property, color difference, and UV-barrier property without affecting thermal stability of films and endowed the chitosan-based films with excellent DPPH radical scavenging ability and reducing capacity. Moreover, the grafting ratios of caffeic acid in COS-CA conjugates had a noticeable influence on these changes of chitosan-based composite films. Overall, chitosan/COS-CA conjugates composite films with great UV-barrier property and excellent antioxidant activity could be developed as biodegradable antioxidant biomaterials for food packaging.

Ester hydrates, as the intermediates of the esterification between acid and alcohol, are very short-lived and challenging to be trapped. Therefore, the crystal structures of ester hydrates have rarely been characterized. Herein, we present that the mono-deprotonated ester hydrates [CH3OSO2(OH)2]−, serving as the template for the self-assembly of a π-stacked boat-shaped macrocycle (CH3OSO2(OH)2)0.67(CH3OSO3)1.33@{[ClLCoII]6}·Cl4·13CH3OH·9H2O (1) (L = tris(2-benzimidazolylmethyl) amine), can be trapped in the host by multiple NH···O hydrogen bonds. In the solution of CoCl2, L, and H2SO4 in MeOH, HSO4− reacts with MeOH, producing [CH3OSO3]− via the ester hydrate intermediate of [CH3OSO3(OH)2]−. Both the product and the intermediate serve as the template directing the self-assembly of the π-stacked macrocycle, in which the short-lived ester hydrate is firmly trapped and stabilized, as revealed by single-crystal analysis.

Aberrant expression of the phosphatidylinositol 3-kinase (PI3K) signalling pathway is often associated with tumourigenesis, progression and poor prognosis. Hence, PI3K inhibitors have attracted significant interest for the treatment of cancer. In this study, a series of new 6-(imidazo[1,2-a]pyridin-6-yl)quinazoline derivatives were designed, synthesized and characterized by 1H NMR, 13C NMR and HRMS spectra analyses. In the in vitro anticancer assay, most of the synthetic compounds showed submicromolar inhibitory activity against various tumour cell lines, among which 13k is the most potent compound with IC50 values ranging from 0.09 μΜ to 0.43 μΜ against all the tested cell lines. Moreover, 13k induced cell cycle arrest at G2/M phase and cell apoptosis of HCC827 cells by inhibition of PI3Kα with an IC50 value of 1.94 nM. These results suggested that compound 13k might serve as a lead compound for the development of PI3Kα inhibitor.

As a reactive intermediate, chloracetyl chitosan oligosaccharide (CACS) can be nucleophilic substituted by some bioactive groups to give novel derivatives of chitosan oligosaccharide (COS). The Schiff bases of pyridine-4-aldehyde are grafted onto CACS to give four COS derivatives in this paper. Specific structural characterization is implemented by fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The degree of substitution (DS) of COS derivatives is quantitatively calculated by ratio of hydrogen proton integral. Their antioxidant property is evaluated using free radical scavenging assay towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals, and the antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is also investigated. The results revealed that the pyridine-4-aldehyde Schiff bases grafted chloracetyl chitosan oligosaccharide derivatives showed better antioxidant activity as well as antibacterial activity than COS and CACS, which may be related to the positive charge of these derivatives. Among all final products, derivative BPCACS with the highest DS has the best bioactivity with scavenging rate of 91.49% for the DPPH assay and inhibition diameter of 39.25 mm for S. aureus inhibitory assay, respectively. These results indicated that COS derivatives with enhanced biological activities could serve as potential biomaterial for antioxidant and antibacterial applications.

Nanoparticles self‐assembled by amphiphilic copolymers for loading hydrophobic molecules are intensively investigated. However, their hydrophobic molecule‐loading capacity is low due to the limitation of hydrophobic groups in these copolymers. In this regard, new lysine oligomer‐based multi‐hydrophobic side chain polymers (MHCPs) are synthesized by polymerization of γ ‐benzyl‐ l glutamate N‐carboxy anhydride initiated by side‐chain primary amino groups in lysine oligomer. Each hydrophobic side chain in MHCPs can be self‐assembled by hydrophobic interaction to form multi‐hydrophobic‐core nanoparticles (MHC‐NPs) with silkworm cocoon‐, grape cluster‐, and butterfly‐like shapes (depending on hydrophobic‐side‐chains lengths). To increase their stability, MHC‐NPs are dually self‐assembled with polyethylene glycol–polyglutamic acid through charge interaction. Each hydrophobic core in MHC‐NPs serves as a carrier for hydrophobic molecules, endowing their nanostructure with high loading capacity. MHC‐NPs are employed to load tacrolimus (also known as FK506), and the loading amount is 18% and the loading efficiency is 80%, which are higher than those of previously reported nanomicelles self‐assembled by linear amphiphilic copolymers. Topical administration of FK506‐loaded nanoparticle (FK506‐NP) can significantly prolong retention of FK506 on the eye surface. FK506‐NP exhibits higher in vivo immunosuppressive effects than free FK506 and commercial FK506 eye drop, as well as a better protective effect against immunotoxicity in the corneal grafts after keratoplasty.

ROR1 and Aurora kinase were overexpressed in various cancers and essential for cell proliferation, survive and metastasis. Pharmaceutical inhibition of ROR1 and Aurora kinase abrogated the activation of downstream signaling and induced cancer cell apoptosis. Hence, ROR1 and Aurora kinase considered as attractive therapeutic targets for the development of anticancer drugs. In the present work, three series of novel 6-(imidazo[1,2-a] pyridin-6-yl)-quinazolin-4(3H)-one derivatives were designed and synthesized via bioisosterism and scaffold-hopping strategies guided by FLF-13, an Aurora kinase inhibitor we discovered earlier. Most of compounds in series 2 and series 3 showed submicromolar to nanomolar inhibitory activity against multiple cancer cell lines. More importantly, compounds 12d and 12f in series 3 showed nanomolar inhibitory activity against all test cancer cells. The most promising compound 12d exhibited potent inhibitory activity against Aurora A and Aurora B with IC50 values of 84.41 nM and 14.09 nM, respectively. Accordingly, compounds 12d induced G2/M phase cell cycle arrest at 24 h and polyploidy at 48 h. It's worth noting that 12d also displayed inhibitory activity against ROR1 and induce cell apoptosis. Furthermore, 12d could significantly inhibit the tumor growth in SH-SY5Y xenograft model with tumor growth inhibitory rate (IR) up to 46.31 % at 10 mg/kg and 52.66 % at 20 mg/kg. Overall, our data suggested that 12d might serve as a promising candidate for the development of therapeutic agents for cancers with aberrant expression of ROR1 and Aurora kinases by simultaneously targeting ROR1 and Aurora kinase.

Aurora A (Aurora kinase A), a critical regulator of cell mitosis, is frequently overexpressed in many malignant cancers, and has been considered as a promising drug target for cancer therapy. Likewise, Phosphatidylinositol 3-kinase alpha (PI3K alpha) is also regarded as one of the most important targets in cancer therapy by mediating the cell growth and angiogenesis of various human cancers. In addition, Bromodomain-containing protein 4 (BRD4) modulates oncogene expressions of Myc, Aurora kinase and various RTKs. Recently, accumulating evidences indicated that hyperactivated or abnormally expressed Aurora A, PI3K alpha or BRD4 are closely associated with drug resistance and poor prognosis of non-small cell lung cancer (NSCLC). Hence, simultaneous inhibition of Aurora A, PI3K alpha, and BRD4 is expected to be a new strategy for NSCLC therapy. In this study, we performed further structure optimization of 6-(2-amino-1H-benzo[d]imidazole-6-yl)-quinazolin-4(3H)-one based on previous study to obtain a series of derivatives for discovering potential Aurora A, PI3K alpha and BRD4 multi-targeted inhibitors. MTT assay showed that most of the newly synthesized compounds exhibited an evident anticancer activity against the NSCLC cells. Among them, the IC50 values of the most potent compound 9a were 0.83, 0.26 and 1.02 mu M against A549, HCC827 and H1975 cells, respectively. In addition, 9a markedly inhibited the Aurora A and PI3K alpha kinase activities with IC50 values of 10.19 nM and 13.12 nM. Compound 9a induced G2/M phase arrests and apoptosis of HCC827 cells by simultaneous inhibition of Aurora A/PI3K/ BRD4 signaling pathways. Collectively, our studies suggested that 9a might be a potential multi-targeted inhibitor for NSCLC therapy.

One possible strategy for modulating autophagy is to disrupt the critical protein-protein interactions (PPIs) formed during this process. Our attention is on the autophagy-related 12 (ATG12)-autophagy-related 5 (ATG5)-autophagy-related 16-like 1 (ATG16L1) heterotrimer complex, which is responsible for ATG8 translocation from ATG3 to phosphatidylethanolamine. In this work, we discovered a compound with an (E)-3-(2-furanylmethylene)-2-pyrrolidinone core moiety (T1742) that blocked the ATG5-ATG16L1 and ATG5-TECAIR interactions in the in vitro binding assay (IC50 = 1-2 μM) and also exhibited autophagy inhibition in cellular assays. The possible binding mode of T1742 to ATG5 was predicted through molecular modeling, and a batch of derivatives sharing essentially the same core moiety were synthesized and tested. The outcomes of the in vitro binding assay and the flow cytometry assay of those newly synthesized compounds were generally consistent. This work has validated our central hypothesis that small-molecule inhibitors of the PPIs involving ATG5 can tune down autophagy effectively, and their pharmaceutical potential may be further explored.

In this study, five new chitosan oligosaccharide quaternary ammonium derivatives bearing quinoline are synthesized by reaction between 6-O-chloroacetyl-2-N, N, N-trimethyl quaternary ammonium salt chitosan oligosaccharide (CTCOS, compound 1) and quinoline derivatives. The derivatives are characterized by analytical techniques including Fourier Transform Infrared (FTIR), H-1 Nuclear Magnetic Resonance (H-1 NMR) spectroscopy, and elemental analysis. The obtained results confirm that quinoline groups are successfully introduced into the CTCOS molecule. Meanwhile, the antioxidant activities of the prepared chitosan oligosaccharide derivatives are evaluated in vitro. The experimental results show that the derivatives have excellent free radical scavenging ability. The free radical scavenging abilities are all over 75% at the concentration of 1.6 mg mL(-1). Moreover, antibacterial tests show that derivative 2e has the best antibacterial activities. Its minimum inhibitory concentration (MIC) value and minimum bactericidal concentration (MBC) value against Staphylococcus aureus and Escherichia coli are 0.0625 and 0.03125 mg mL(-1), respectively. In addition, the cytotoxicity of chitosan oligosaccharide and its derivatives is examined by MTT colorimetric assay in RAW 264.7 macrophages, observing that all derivatives are non-cytotoxic. Consequently, the findings indicate that the enhanced antioxidant activity, antibacterial activity, and biocompatibility of these chitosan oligosaccharide derivatives can enlarge the scope of the application of chitosan oligosaccharides, particularly as antioxidant and antibacterial agents in food packaging, pharmaceutical, cosmetics industries, and other fields.