Biological evaluation of sulfonate and sulfate analogues of lithocholic acid: A bioisosterism-guided approach towards the discovery of potential sialyltransferase inhibitors for antimetastatic study.

The naturally occurring bile acid lithocholic acid (LCA) has been a crucial core structure for many non-sugar-containing sialyltranferase (ST) inhibitors documented in literature. With the aim of elucidating the impact of the terminal carboxyl acid substituent of LCA on its ST inhibition, in this present study, we report the (bio)isosteric replacement-based design and synthesis of sulfonate and sulfate analogues of LCA. Among these compounds, the sulfate analogue SPP-002 was found to selectively inhibit N-glycan sialylation by at least an order of magnitude, indicating a substantial improvement in both potency and selectivity when compared to the unmodified parent bile acid. Molecular docking analysis supported the stronger binding of the synthetic analogue in the enzyme active site. Treatment with SPP-002 also hampered the migration, adhesion, and invasion of MDA-MB-231 cells in vitro by suppressing the expression of signaling proteins involved in the cancer metastasis-associated integrin/FAK/paxillin pathway. In totality, these findings offer not only a novel structural scaffold but also valuable insights for the future development of more potent and selective ST inhibitors with potential therapeutic effects against tumor cancer metastasis.

Innate immune response restarts adaptive immune response in tumors.

The imbalance of immune response plays a crucial role in the development of diseases, including glioblastoma. It is essential to comprehend how the innate immune system detects tumors and pathogens. Endosomal and cytoplasmic sensors can identify diverse cancer cell antigens, triggering the production of type I interferon and pro-inflammatory cytokines. This, in turn, stimulates interferon stimulating genes, enhancing the presentation of cancer antigens, and promoting T cell recognition and destruction of cancer cells. While RNA and DNA sensing of tumors and pathogens typically involve different receptors and adapters, their interaction can activate adaptive immune response mechanisms. This review highlights the similarity in RNA and DNA sensing mechanisms in the innate immunity of both tumors and pathogens. The aim is to enhance the anti-tumor innate immune response, identify regions of the tumor that are not responsive to treatment, and explore new targets to improve the response to conventional tumor therapy and immunotherapy.

A neutral rhenium-biimidazole complex for the selective recognition of fluoride ions.

The neutral rhenium(I)-biimidazole complex [Re(CO)3(biimH)(1,4-NVP)] (1) was designed and synthesized by a one-pot reaction of Re2(CO)10, 2,2'-biimidazole (biimH2) and 4-(1-naphthylvinyl)pyridine (1,4-NVP). The structure of 1 was characterized by various spectroscopic techniques including IR, 1H NMR, FAB-MS, and elemental analysis and further confirmed by a single-crystal X-ray diffraction analysis. The mononuclear complex 1, a relatively simple structure with an octahedral geometry, is comprised of facial-arranged carbonyl groups, one chelated biimH monoanion, and one 1,4-NVP. Complex 1 shows the lowest energy absorption band at around 357 nm and an emission band at 408 nm in THF. The luminescent characteristics of 1 combined with the hydrogen bonding ability of the partially coordinated monoionic biimidazole ligand permits the complex to selectively recognize fluoride ions (F-) in the presence of other halides through a dramatic luminescence enhancement. The recognition mechanism of 1 can be convincingly explained in terms of H-bond formation and proton abstraction upon the addition of F- ions by 1H and 19F NMR titration experiments. The electronic properties of 1 were further supported by time dependent density functional theory (TDDFT) computational studies.

A critical overview of current progress for COVID-19: development of vaccines, antiviral drugs, and therapeutic antibodies.

The novel coronavirus disease (COVID-19) pandemic remains a global public health crisis, presenting a broad range of challenges. To help address some of the main problems, the scientific community has designed vaccines, diagnostic tools and therapeutics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The rapid pace of technology development, especially with regard to vaccines, represents a stunning and historic scientific achievement. Nevertheless, many challenges remain to be overcome, such as improving vaccine and drug treatment efficacies for emergent mutant strains of SARS-CoV-2. Outbreaks of more infectious variants continue to diminish the utility of available vaccines and drugs. Thus, the effectiveness of vaccines and drugs against the most current variants is a primary consideration in the continual analyses of clinical data that supports updated regulatory decisions. The first two vaccines granted Emergency Use Authorizations (EUAs), BNT162b2 and mRNA-1273, still show more than 60% protection efficacy against the most widespread current SARS-CoV-2 variant, Omicron. This variant carries more than 30 mutations in the spike protein, which has largely abrogated the neutralizing effects of therapeutic antibodies. Fortunately, some neutralizing antibodies and antiviral COVID-19 drugs treatments have shown continued clinical benefits. In this review, we provide a framework for understanding the ongoing development efforts for different types of vaccines and therapeutics, including small molecule and antibody drugs. The ripple effects of newly emergent variants, including updates to vaccines and drug repurposing efforts, are summarized. In addition, we summarize the clinical trials supporting the development and distribution of vaccines, small molecule drugs, and therapeutic antibodies with broad-spectrum activity against SARS-CoV-2 strains.

Heteronemin and Tetrac Induce Anti-Proliferation by Blocking EGFR-Mediated Signaling in Colorectal Cancer Cells.

Overexpressed EGFR and mutant K-Ras play vital roles in therapeutic resistance in colorectal cancer patients. To search for an effective therapeutic protocol is an urgent task. A secondary metabolite in the sponge Hippospongia sp., Heteronemin, has been shown to induce anti-proliferation in several types of cancers. A thyroxine-deaminated analogue, tetrac, binds to integrin αvß3 to induce anti-proliferation in different cancers. Heteronemin- and in combination with tetrac-induced antiproliferative effects were evaluated. Tetrac enhanced heteronemin-induced anti-proliferation in HT-29 cells (KRAS WT CRC) and HCT-116 cells (KRAS MT CRC). Heteronemin and tetrac arrested cell cycle in different phases. Combined treatment increased the cell accumulation in sub-G1 and S phases. The combined treatment also induced the inactivation of EGFR signaling and downregulated the phosphorylated ERK1/2 protein in both cell lines. Heteronemin and the combination showed the downregulation of the phosphorylated and total PI3K protein in HT-29 cells (KRAS WT CRC). Results by NanoString technology and RT-qPCR revealed that heteronemin and combined treatment suppressed the expression of EGFR and downstream genes in HCT-116 cells (KRAS MT CRC). Heteronemin or combined treatment downregulated genes associated with cancer progression and decreased cell motility. Heteronemin or the combined treatment suppressed PD-L1 expression in both cancer cell lines. However, only tetrac and the combined treatment inhibited PD-L1 protein accumulation in HT-29 cells (KRAS WT CRC) and HCT-116 cells (KRAS MT CRC), respectively. In summary, heteronemin induced anti-proliferation in colorectal cancer cells by blocking the EGFR-dependent signal transduction pathway. The combined treatment further enhanced the anti-proliferative effect via PD-L1 suppression. It can be an alternative strategy to suppress mutant KRAS resistance for anti-EGFR therapy.

Heteronemin and tetrac derivatives suppress non-small cell lung cancer growth via ERK1/2 inhibition.

The most common cancer, lung cancer, causes deaths worldwide. Most lung cancer patients have non-small cell lung carcinomas (NSCLCs) with a poor prognosis. The chemotherapies frequently cause resistance therefore search for new effective drugs for NSCLC patients is an urgent and essential issue. Deaminated thyroxine, tetraiodothyroacetic acid (tetrac), and its nano-analogue (NDAT) exhibit antiproliferative properties in several types of cancers. On the other hand, the most abundant secondary metabolite in the sponge Hippospongia sp., heteronemin, shows effective cytotoxic activity against different types of cancer cells. In the current study, we investigated the anticancer effects of heteronemin against two NSCLC cell lines, A549 and H1299 cells in vitro. Combined treatment with heteronemin and tetrac derivatives synergistically inhibited cancer cell growth and significantly modulated the ERK1/2 and STAT3 pathways in A549 cells but only ERK1/2 in H1299 cells. The combination treatments induce apoptosis via the caspases pathway in A549 cells but promote cell cycle arrest via CCND1 and PCNA inhibition in H1299 cells. In summary, these results suggest that combined treatment with heteronemin and tetrac derivatives could suppress signal transduction pathways essential for NSCLC cell growth. The synergetic effects can be used potentially as a therapeutic procedure for NSCLC patients.

Increased activation of the caudate nucleus and parahippocampal gyrus in Parkinson's disease patients with dysphagia after repetitive transcranial magnetic stimulation: a case-control study.

Repetitive transcranial magnetic stimulation (rTMS) has been shown to effectively improve impaired swallowing in Parkinson's disease (PD) patients with dysphagia. However, little is known about how rTMS affects the corresponding brain regions in this patient group. In this case-control study, we examined data from 38 PD patients with dysphagia who received treatment at Beijing Rehabilitation Medicine Academy, Capital Medical University. The patients received high-frequency rTMS of the motor cortex once per day for 10 successive days. Changes in brain activation were compared via functional magnetic resonance imaging in PD patients with dysphagia and healthy controls. The results revealed that before treatment, PD patients with dysphagia showed greater activation in the precentral gyrus, supplementary motor area, and cerebellum compared with healthy controls, and this enhanced activation was weakened after treatment. Furthermore, before treatment, PD patients with dysphagia exhibited decreased activation in the parahippocampal gyrus, caudate nucleus, and left thalamus compared with healthy controls, and this activation increased after treatment. In addition, PD patients with dysphagia reported improved subjective swallowing sensations after rTMS. These findings suggest that swallowing function in PD patients with dysphagia improved after rTMS of the motor cortex. This may have been due to enhanced activation of the caudate nucleus and parahippocampal gyrus. The study protocol was approved by the Ethics Committee of Beijing Rehabilitation Hospital of Capital Medical University (approval No. 2018bkky017) on March 6, 2018 and was registered with Chinese Clinical Trial Registry (registration No. ChiCTR 1800017207) on July 18, 2018.

Sialyltransferase Inhibitors for the Treatment of Cancer Metastasis: Current Challenges and Future Perspectives.

Potent, cell-permeable, and subtype-selective sialyltransferase inhibitors represent an attractive family of substances that can potentially be used for the clinical treatment of cancer metastasis. These substances operate by specifically inhibiting sialyltransferase-mediated hypersialylation of cell surface glycoproteins or glycolipids, which then blocks the sialic acid recognition pathway and leads to deterioration of cell motility and invasion. A vast amount of evidence for the in vitro and in vivo effects of sialyltransferase inhibition or knockdown on tumor progression and tumor cell metastasis or colonization has been accumulated over the past decades. In this regard, this review comprehensively discusses the results of studies that have led to the recent discovery and development of sialyltransferase inhibitors, their potential biomedical applications in the treatment of cancer metastasis, and their current limitations and future opportunities.

Antidepressant effect of electroacupuncture on modulating the expression of c-Fos/AP-1 through the JNK signaling pathway.

The effectiveness and safety of electroacupuncture (EA) for depression have been identified by abundant clinical trials and experimental findings. The c-Jun-NH(2)-terminal kinase (JNK) signaling pathway is considered to be involved in the antidepressant mechanism of EA. However, the antidepressant effect of EA via modulating the expression of c-Fos/activator protein-1 (AP-1) under the condition of JNK inhibition remains unexplored. In this study, we investigated the antidepressant effect and possible mechanism of EA in regulating the expression of c-Fos/AP-1 under the condition of JNK inhibition by SP600125 in rats exposed to chronic unpredictable mild stress (CUMS). The depression-like behaviors were evaluated by the body weight, sucrose preference test (SPT), and open field test (OFT). The expression levels of c-Jun in the hypothalamus, c-Fos in the pituitary gland, and c-Fos and AP-1 in the serum of CUMS induced rat model of depression were detected by ELISA. The results indicated that treatment with EA and fluoxetine can reverse the CUMS-induced depression-like behaviors in rats and can up-regulate the expression levels of c-Jun in the hypothalamus, c-Fos in the pituitary gland, and c-Fos and AP-1 in the serum. Of note, the data demonstrated that SP600125, the inhibitor of JNK signaling pathway, can exert synergistic effect with EA in regulating CUMS-induced abnormal activation of the JNK signaling pathway. The antidepressant effect of EA might be mediated by modulating the expression of c-Fos/AP-1.

Sialyltransferase Inhibitors Suppress Breast Cancer Metastasis.

We report the synthesis and evaluation of a series of cell-permeable and N- versus O-selective sialyltransferase inhibitors. Inhibitor design entailed the functionalization of lithocholic acid at C(3) and at the cyclopentane ring side chain. Among the series, FCW34 and FCW66 were shown to inhibit MDA-MB-231 cell migration as effectively as ST3GALIII-gene knockdown did. FCW34 was shown to inhibit tumor growth, reduce angiogenesis, and delay cancer cell metastasis in animal models. Furthermore, FCW34 inhibited vessel development and suppressed angiogenic activity in transgenic zebrafish models. Our results provide clear evidence that FCW34-induced sialyltransferase inhibition reduces cancer cell metastasis by decreasing N-glycan sialylation, thus altering the regulation of talin/integrin/FAK/paxillin and integrin/NFκB signaling pathways.

Oxidative trimerization of indoles via water-assisted visible-light photoredox catalysis and the study of their anti-cancer activities.

Incorporation of water has been revealed to successfully facilitate visible-light photoredox catalysis of indole leading to increased production of C2-quaternary indolinone. The water-promoted photoreaction of indole under catalyst-free conditions by a household compact fluorescence light was also demonstrated. The antiproliferative activity of the synthesized indolinones was evaluated against three human cancer cell lines.

Metformin therapy and cognitive dysfunction in patients with type 2 diabetes: A meta-analysis and systematic review.

BACKGROUND: Type 2 diabetes (T2D) is a risk factor for cognitive dysfunction. The relationship between metformin therapy and cognitive function in patients with T2D is unknown. Therefore, we determined the relationship between metformin therapy and cognitive function in patients with T2D using a meta-analysis. METHODS: We systematically searched the Cochrane library, PubMed, and Embase to identify studies showing correlations, and we calculated hazard ratios (HRs). RESULTS: We identified 10 studies including 254,679 participants. Metformin significantly reduced the occurrence of cognitive dysfunction in patients with T2D (HR 0.90; 95% CI [0.88, 0.92]). Compared with other hypoglycemic drugs, sulfonylureas also improved cognitive dysfunction (HR 0.92; 95% CI [0.88, 0.95]). Thiazolidinediones gave no statistically significant improvement in cognitive dysfunction (HR 0.97; 95% CI [0.87, 1.07]). The use of insulin aggravated cognitive dysfunction (HR 1.34; 95% CI [1.24, 1.43]). In the subgroup analysis of various regions controlling for age, gender, education, diabetes course, complications, metformin administration and dosage, and follow-up time, metformin significantly improved cognitive dysfunction in patients in the Americas and Europe (HR 0.69; 95% CI [0.63, 0.74]), (HR 0.71; 95% CI [0.66, 0.76], respectively), while metformin did not significantly improve cognitive dysfunction in Asian patients (HR 0.99; 95% CI [0.96, 1.01]). CONCLUSIONS: Metformin significantly improved cognitive dysfunction in patients with T2D. Sulfonylureas also improved cognitive dysfunction. Thiazolidinediones had no significant effect on cognitive dysfunction. The use of insulin aggravated cognitive dysfunction. Metformin improved cognitive dysfunction more significantly in patients in the Americas and Europe than in Asia.

Benzenesulfonamide Derivatives as Calcium/Calmodulin-Dependent Protein Kinase Inhibitors and Antiviral Agents against Dengue and Zika Virus Infections.

Emerging and resurging mosquito-borne flaviviruses are an important public health challenge. The increased prevalence of dengue virus (DENV) infection has had a significant socioeconomic impact on epidemic countries. The recent outbreak of Zika virus (ZIKV) has created an international public health emergency because ZIKV infection has been linked to congenital defects and Guillain-Barré syndrome. To develop potentially prophylactic antiviral drugs for combating these acute infectious diseases, we have targeted the host calcium/calmodulin-dependent kinase II (CaMKII) for inhibition. By using CaMKII structure-guided inhibitor design, we generated four families of benzenesulfonamide (BSA) derivatives for SAR analysis. Among these substances, N-(4-cycloheptyl-4-oxobutyl)-4-methoxy-N-phenylbenzenesulfonamide (9) showed superior properties as a lead CaMKII inhibitor and antiviral agent. BSA 9 inhibited CaMKII activity with an IC50 value of 0.79 µM and displayed EC50 values of 1.52 µM and 1.91 µM against DENV and ZIKV infections of human neuronal BE(2)C cells, respectively. Notably, 9 significantly reduced the viremia level and increased animal survival time in mouse-challenge models.

Antiangiogenic Effect of Isomalyngamide A Riboside CY01 in Breast Cancer Cells via Inhibition of Migration, Tube Formation and pVEGFR2/pAKT Signals.

BACKGROUND: To block the metastatic and angiogenic pathways during the tumor progression arouses considerable pharmacological interests in the development of anticancer drugs. OBJECTIVE: To develop alternative antiangiogenic and antimetastic agents, we designed and prepared a series of nature inspired isomalyngamide A analogs containing ribose conjugate with 1,2-diaminoethane or 1,3- diaminopropane linkers (1-8). METHODS: The target glycosylated isomalyngamide A analogs 1-8 were constructed through condensation of the malonic acids 16-19 and the corresponding aminoethoxyl ribosides 20 and 21, using HBTU/DIPEA as the coupling agent. The cell growth inhibition assay, cell migration assay, transwell invasion assay, adhesion assay, tube formation assay and western blot analysis were used to validate the biological actions of compounds. RESULTS: The most effective compound, isomalyngamide A riboside 1 (CY01), possessing a D-ribose core structure and a 1,3-diaminopropane linker, showed significant suppression of MDA-MB-231 cell migration and inhibited tube formation of Human Umbilical Vascular Endothelial Cells (HUVECs) in a dose-dependent manner. Effect of the latter is comparable to that of sorafenib, an orally active multikinase inhibitor and an inhibitor of angiogenesis. CY01 also showed slight inhibition on collagen type IV- and laminin-mediated cell adhesion. These actions may be regulated through the blockade of the VEGF/VEGFR2 signaling pathway by inhibiting the VEGF induced phosphorylation of p-VEGFR2 and p-AKT. CONCLUSION: In this effort, we have discovered synthetic and glycosylated marine metabolites which may serve as an alternative antiangiogenic and antimetastic agent during multitherapy.

[Study on quality standard of gypenosides extract and Gypenosides Tablets].

In response to no national standard for Gynostemma pentaphyllum, a market survey was carried out, and 17 batches of gypenosides extract and 29 batches of Gypenosides Tablets on the market were collected. With gypenoside A as an index, the TLC qualitative identification and HPLC quantitative evaluation method of gypenosides extract and tablets was established. Based on the determination results of 17 batches of gypenosides extract and 29 batches of Gypenosides Tablets, the quality standards of gypenosides extract and tablets were formulated respectively, so as to give suggestions for improving the quality standards of gypenosides extract and tablets. Compared with the existing ministerial standards, the qualitative identification and quantitative detection of specific components were added, in order to provide scientific basis and suggestions for the revision of the quality standard of gypenosides extract and tablet preparation.

Primary thoracic neuroblastoma in an adult: A rare case report.

RATIONALE: Neuroblastoma is one of the most common malignant tumors in childhood, which mainly occurs in adrenal glands and peripheral sympathetic nerve system. Neuroblastoma occurring in adulthood is rare, and adults with neuroblastoma arising from thorax are exceedingly rare. A case of neuroblastoma that originated from thorax was reported, and was treated by resection operation. PATIENT CONCERNS: A 46-year-old woman was admitted to our hospital with left side chest pain for 5 days. Laboratory examinations were all normal. Chest computerized tomogram (CT) showed a lesion with clear boundary that was located at the left dorsal pleura. The nature of the mass was heterogeneous, showing slight heterogeneous enhancement after contrast and there was no obvious necrosis. DIAGNOSES: Based on the morphologic and immunohistochemical features, the tumor diagnosis was favorable for neuroblastoma. INTERVENTIONS: A resection operation was carried out. OUTCOMES: Three years postoperative, no sign of recurrence or metastasis has been observed. LESSONS: Primary neuroblastoma in adulthood is rare and has poor prognosis. Resection can be an important treatment option, and combining with other methods like chemotherapy, stem cell transplantation, the survival rate may be improved.

Liposomal Irinotecan for Treatment of Colorectal Cancer in a Preclinical Model.

Colorectal cancer (CRC) is the most frequently diagnosed cancer and leading cause of cancer-related deaths worldwide. Because of the use of first-line CRC treatments, such as irinotecan (IRI), is hindered by dose-limiting side effects, improved drug delivery systems may have major clinical benefits for CRC treatment. In this study, we generate and characterize liposomal irinotecan (Lipo-IRI), a lipid-based nanoparticle, which shows excellent bioavailability and pharmacokinetics. Additionally, this formulation allows IRI to be maintained in active form and prolongs its half-life in circulation compared to IRI in solution. Compared with IRI statistically, the level of prostaglandin E2 (PGE2) in colonic tissue decreases, and Bifidobacterium spp. (beneficial intestinal microbiota) content increases in the Lipo-IRI-treated group. Moreover, no damage is observed by the hematoxylin and eosin staining of the normal tissue samples from the Lipo-IRI-treated group. In a xenograft mouse model, CRC tumors shrink markedly following Lipo-IRI treatment, and mice receiving a targeted combination of Lipo-IRI and liposomal doxorubicin (Lipo-Dox) extend their survival rate significantly. Overall, our results demonstrate that this formulation of Lipo-IRI shows a great potential for the treatment of colorectal cancer.

Nano-Diamino-Tetrac (NDAT) Enhances Resveratrol-Induced Antiproliferation by Action on the RRM2 Pathway in Colorectal Cancers.

Cancer resistance to chemotherapeutic agents is a major issue in the management of cancer patients. Overexpression of the ribonucleotide reductase regulatory subunit M2 (RRM2) has been associated with aggressive cancer behavior and chemoresistance. Nano-diamino-tetrac (NDAT) is a nanoparticulate derivative of tetraiodothyroacetic acid (tetrac), which exerts anticancer properties via several mechanisms and downregulates RRM2 gene expression in cancer cells. Resveratrol is a stilbenoid phytoalexin which binds to a specific site on the cell surface integrin αvß3 to trigger cancer cell death via nuclear translocation of COX-2. Here we report that resveratrol paradoxically activates RRM2 gene expression and protein translation in colon cancer cells. This unanticipated effect inhibits resveratrol-induced COX-2 nuclear accumulation. RRM2 downregulation, whether achieved by RNA interference or treatment with NDAT, enhanced resveratrol-induced COX-2 gene expression and nuclear uptake which is essential to integrin αvß3-mediated-resveratrol-induced antiproliferation in cancer cells. Elsewhere, NDAT downregulated resveratrol-induced RRM2 expression in vivo but potentiated the anticancer effect of the stilbene. These findings suggest that RRM2 appears as a cancer cell defense mechanism which can hinder the anticancer effect of the stilbene via the integrin αvß3 axis. Furthermore, the antagonistic effect of RRM2 against resveratrol is counteracted by the administration of NDAT.

Liposomal paclitaxel induces fewer hematopoietic and cardiovascular complications than bioequivalent doses of Taxol.

Paclitaxel (PTX) exhibits potent antineoplastic activity against various human malignancies; however, clinical application must overcome the inherent hydrophobicity of this molecule. The commercialized Taxol formulation utilizes Cremophor EL (CrEL)/ethanol as a solvent to stabilize and dispense PTX in an aqueous solution. However, adverse CrEL­induced hypersensitivity reactions have been reported in ~30% of recipients, and 40% of patients receiving premedication may also experience this adverse effect. Therefore, the development of a CrEL-free delivery system is crucial, in order to fully exploit the therapeutic efficacy of PTX. In the present study, a novel liposomal PTX (lipo­PTX) formulation was optimized with regards to encapsulation rate and long­term stability, arriving at a molar constituent ratio of soybean phosphatidylcholine:cholesterol:N-(carbonyl-methoxy-poly-ethylene glycol 2000)­1,2­distearoyl­sn-glycero­3-phosphoethanolamine, sodium salt:PTX at 95:2:1:2. Comparable doses of lipo­PTX and Taxol were bioequivalent in terms of therapeutic efficacy in xenograft tumor models. However, the systemic side effects, including hematopoietic toxicity, acute hypersensitivity reactions and cardiac irregularities, were significantly reduced in lipo­PTX­treated mice compared with those infused with reference formulations of PTX. In conclusion, the present study reported that lipo­PTX exhibited a higher therapeutic index than clinical PTX formulations.

Aggregation-induced emission enhancement of anthracene-derived Schiff base compounds and their application as a sensor for bovine serum albumin and optical cell imaging.

Three anthracene-based Schiff base complexes, R1-R3 (R1 = (E)-N´-((anthracen-10-yl)methylene)benzohydrazide; R2 = (E)-1-((anthracen-10-yl)methylene)-4-phenylsemicarbazide; and R3 = (E)-1-((anthracen-10-yl)methylene)-4-phenylthiosemicarbazide) were synthesized from 9-anthracenecarboxaldehyde, benzohydrazide, 4-phenylsemicarbazide and 4-phenylthiosemi-carbazide respectively, and characterized by various spectral techniques. The absorption spectral characteristics of R1-R3 were bathochromically tuned to the visible region by extending the π conjugation. These target compounds were weakly fluorescent in tetrahydrofuran (THF) solution because of rapid isomerization of the C=N double bond in the excited state. However, the aqueous dispersion of R1-R3 in the THF/water mixture by the gradual addition of water up to 90% resulted in an increase in the fluorescence intensity mainly due to aggregation-induced emission enhancement (AIEE) properties. The formation of nanoaggregates of R1-R3 were confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The compounds R1-R3 are ideal probes for the fluorescence sensing of bovine serum albumin (BSA) and breast cancer cells by optical cell imaging.