Two Birds with one Stone: Dual-mode immunoassay constructed using a novel emitter ethylene glycol-induced perylene diimide and a multifunctional ANS probe

Perylene diimide (PDI) is a readily reducible electron-deficient dye that exhibits strong photoluminescent properties, providing new opportunities for synthesizing novel electrochemiluminescence (ECL) emitters. In this study, ethylene glycol (EG) was used to induce the self-assembly of PDI supramolecules for the preparation of ultrathin EG-PDI nanosheets characterized by low crystallinity and weak stacking interaction. Notably, EG-PDI integrates luminescent and catalytic functions into one device, accelerating the interfacial electron transfer and the faster charge transfer kinetics of EG-PDI with K2S2O8. Furthermore, the narrow band gap of EG-PDI facilitates its excitation at an ultra-low potential (-0.3 V). To improve the efficiency of tumor marker analysis, multifunctional Au nanostars (ANS) was introduced both as an energy acceptor of the ECL system and a probe for the photothermal system. Dual-mode immunoassay have demonstrated superior analytical performance in detecting alpha-fetoprotein (AFP), meeting the requirements of modern clinical diagnostics in resource-limited environments.

Computational and experimental validation of phthalocyanine and hypericin as effective SARS-CoV-2 fusion inhibitors

Phthalocyanine and hypericin have been previously identified as possible SARS-CoV-2 Spike glycoprotein fusion inhibitors through a virtual screening procedure. In this paper, atomistic simulations of metal-free phthalocyanines and atomistic and coarse-grained simulations of hypericins, placed around a complete model of the Spike embedded in a viral membrane, allowed to further explore their multi-target inhibitory potential, uncovering their binding to key protein functional regions and their propensity to insert in the membrane. Following computational results, pre-treatment of a pseudovirus expressing the SARS-CoV-2 Spike protein with low compounds concentrations resulted in a strong inhibition of its entry into cells, suggesting the activity of these molecules should involve the direct targeting of the viral envelope surface. The combination of computational and in vitro results hence supports the role of hypericin and phthalocyanine as promising SARS-CoV-2 entry inhibitors, further endorsed by literature reporting the efficacy of these compounds in inhibiting SARS-CoV-2 activity and in treating hospitalized COVID-19 patients.Communicated by Ramaswamy H. Sarma.

Potential therapeutic effects of Chinese herbal medicine in postpartum depression: Mechanisms and future directions

ETHNOPHARMACOLOGICAL RELEVANCE

Postpartum depression (PPD) is a common psychiatric disorder in women after childbirth. Per data from epidemiologic studies, PPD affects about 5%-26.32% of postpartum mothers worldwide. Biological factors underlying this condition are multiple and complex and have received extensive inquiries for the roles they play in PPD. Chinese herbal medicine (CHM), which is widely used as a complementary and alternative therapy for neurological disorders, possesses multi-component, multi-target, multi-access, and low side effect therapeutic characteristics. CHM has already shown efficacy in the treatment of PPD, and a lot more research exploring the mechanisms of its potential therapeutic effects is being conducted.

AIM OF THE REVIEW

This review provides an in-depth and comprehensive overview of the underlying mechanisms of PPD, as well as samples the progress made in researching the potential role of CHM in treating the disorder.

MATERIALS AND METHODS

Literature was searched comprehensively in scholarly electronic databases, including PubMed, Web of Science, Scopus, CNKI and WanFang DATA, using the search terms "postpartum depression", "genetic", "hormone", "immune", "neuroinflammation", "inflammation", "neurotransmitter", "neurogenesis", "brain-gut axis", "traditional Chinese medicine", "Chinese herbal medicine", "herb", and an assorted combination of these terms.

RESULTS

PPD is closely associated with genetics, as well as with the hormones, immune inflammatory, and neurotransmitter systems, neurogenesis, and gut microbes, and these biological factors often interact and work together to cause PPD. For example, inflammatory factors could suppress the production of the neurotransmitter serotonin by inducing the regulation of tryptophan-kynurenine in the direction of neurotoxicity. Many CHM constituents improve anxiety- and depression-like behaviors by interfering with the above-mentioned mechanisms and have shown decent efficacy clinically against PPD. For example, Shen-Qi-Jie-Yu-Fang invigorates the neuroendocrine system by boosting the hormone levels of hypothalamic pituitary adrenal (HPA) and hypothalamic pituitary gonadal (HPG) axes, regulating the imbalance of Treg/T-helper cells (Th) 17 and Th1/Th2, and modulating neurotransmitter system to play antidepressant roles. The Shenguiren Mixture interferes with the extracellular signal-regulated kinase (ERK) pathway to enhance the number, morphology and apoptosis of neurons in the hippocampus of PPD rats. Other herbal extracts and active ingredients of CHM, such as Paeoniflorin, hypericin, timosaponin B-III and more, also manage depression by remedying the neuroendocrine system and reducing neuroinflammation.

CONCLUSIONS

The pathogenesis of PPD is complex and diverse, with the main pathogenesis not clear. Still, CHM constituents, like Shen-Qi-Jie-Yu-Fang, the Shenguiren Mixture, Paeoniflorin, hypericin and other Chinese Medicinal Formulae, active monomers and Crude extracts, treats PPD through multifaceted interventions. Therefore, developing more CHM components for the treatment of PPD is an essential step forward.

Hypericin emulsomes combined with hollow microneedles as a non-invasive photodynamic platform for rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a joint-destructive autoimmune disease that severely affects joint function. Despite the variability of treatment protocols, all of them are associated with severe side effects that compromise patient compliance. The main aim of the current study is to prepare localized effective RA treatment with reduced side effects by combining nanoencapsulation, photodynamic therapy (PDT) and hollow microneedles (Ho-MNs) to maximize the pharmacological effects of hypericin (HYP). To attain this, HYP-loaded emulsomes (EMLs) were prepared, characterized and administered through intradermal injection using AdminPen™ Ho-MNs combined with PDT in rats with an adjuvant-induced RA model. The prepared EMLs had a spherical shape and particle size was about 93.46 nm with an absolute entrapment efficiency. Moreover, confocal imaging indicated the interesting capability of Ho-MNs to deposit the HYP EMLs to a depth reaching 1560 µm into the subcutaneous tissue. In vivo, study results demonstrated that the group treated with HYP EMLs through Ho-MNs combined with PDT had no significant differences in joint diameter, TNF-α, IL1, HO-1, NRF2 and SD levels compared with the negative control group. Similarly, rats treated with the combination of HYP EMLs, Ho-MNs and PDT showed superior joint healing efficacy compared with the groups treated with HYP EMLs in dark, HYP ointment or HYP in microneedles in histopathological examination. These findings highlight the promising potential of photoactivated HYP EMLs when combined with Ho-MNs technology for RA management. The presented therapeutic EMLs-MNs platform could serve as a powerful game-changer in the development of future localized RA treatments.

Synthetic Biology-based Construction of Unnatural Perylenequinones with Improved Photodynamic Anticancer Activities

The construction of structural complexity and diversity of natural products is crucial for drug discovery and development. To overcome high dark toxicity and poor photostability of natural photosensitizer perylenequinones (PQs) for photodynamic therapy, herein, we aim to introduce the structural complexity and diversity to biosynthesize the desired unnatural PQs in fungus Cercospora through synthetic biology-based strategy. Thus, we first elucidate the intricate biosynthetic pathways of class B PQs and reveal how the branching enzymes create their structural complexity and diversity from a common ancestor. This enables the rational reprogramming of cercosporin biosynthetic pathway in Cercospora to generate diverse unnatural PQs without chemical modification. Among them, unnatural cercosporin A displays remarkably low dark toxicity and high photostability with retention of great photodynamic anticancer and antimicrobial activities. Moreover, it is found that, unlike cercosporin, unnatural cercosporin A could be selectively accumulated in cancer cells, providing potential targets for drug development. Therefore, this work provides a comprehensive foundation for preparing unnatural products with customized functions through synthetic biology-based strategies, thus facilitating drug discovery pipelines from nature.

Supersensitive detection of lincomycin with an ECL aptasensor based on the synergistic integration of gold-functionalized upconversion nanoparticles and thiolated 3,4,9,10-perylene tetracarboxylic acid

In this work, the supersensitive and selective determination of lincomycin (Lin) was achieved using a novel electroluminescent (ECL) aptasensor based on the synergistic integration of gold functionalized upconversion nanoparticles (UCNPs) and thiolated 3,4,9,10-perylene tetracarboxylic acid (PTCA). The integration of two luminophores of UCNPs and PTCA combined the merits of the cathodoluminescence stability of UCNPs and the high quantum yield of PTCA, which significantly promoted the ECL signal and analytical performance of the proposed sensor. The introduction of gold nanoparticles in UCNPs can not only improve the conductivity and ECL performance of UCNPs but also cause them to easily integrate with thiolated PTCA (t-PTCA) via an Au-S bond. The ECL signal of UCNPs@Au/t-PTCA/GCE was almost twice as strong as that of t-PTCA/GCE and tenfold higher than that of UCNPs@Au/GCE. Because of the non-conductive protein of the Lin aptamer, the ECL intensity of apt/UCNPs@Au/t-PTCA/GCE noticeably decreased. In the presence of Lin, the aptamer was pulled down from the sensing interface, resulting in the recovery of the ECL intensity of the sensor. Under optimal conditions, our proposed sensor can quantify the concentration of Lin in the range from 1.0 × 10-15 to 1.0 × 10-7 M with a low detection limit of 2.4 × 10-16 M (S/N = 3), exhibiting high sensitivity and specificity for the determination of Lin.

Mechanisms of hepatocellular toxicity associated with the components of St. John's Wort extract hypericin and hyperforin in HepG2 and HepaRG cells

St. John's Wort preparations are used for the treatment of mild to moderate depression. They are usually well tolerated but can cause adverse reactions including liver toxicity in rare cases. To date, the mechanism(s) underlying the hepatotoxicity of St. John's Wort extracts are poorly investigated. We studied the hepatocellular toxicity of hypericin and hyperforin as the two main ingredients of St. John's Wort extracts in HepG2 and HepaRG cells and compared the effects to citalopram (a synthetic serotonin uptake inhibitor) with a special focus on mitochondrial toxicity and oxidative stress. In HepG2 cells, hypericin was membrane-toxic at 100 µM and depleted ATP at 20 µM. In HepaRG cells, ATP depletion started at 5 µM. In comparison, hyperforin and citalopram were not toxic up to 100 µM. In HepG2 cells, hypericin decreased maximal respiration starting at 2 µM and mitochondrial ATP formation starting at 10 µM but did not affect glycolytic ATP production. Hypericin inhibited the activity of complex I, II and IV of the electron transfer system and caused mitochondrial superoxide accumulation in cells. The protein expression of mitochondrial superoxide dismutase 2 (SOD2) and thioredoxin 2 (TRX2) and total and reduced glutathione decreased in cells exposed to hypericin. Finally, hypericin diminished the mitochondrial DNA copy number and caused cell necrosis but not apoptosis. In conclusion, hypericin, but not hyperforin or citalopram, is a mitochondrial toxicant at low micromolar concentrations. This mechanism may contribute to the hepatotoxicity occasionally observed in susceptible patients treated with St. John's Wort preparations.

A Self-Assembly-Induced Exciton Delocalization Strategy for Converting a Perylene Diimide Derivative from a Type-II to Type-I Photosensitizer

Type-I photosensitizers have shown advantages in addressing the shortcomings of traditional oxygen-dependent type-II photosensitizers for the photodynamic therapy (PDT) of hypoxic tumors. However, developing type-I photosensitizers is yet a huge challenge because the type-II energy transfer process is much faster than the type-I electron transfer process. Herein, from the fundamental point of view, an effective approach is proposed to improve the electron transfer efficiency of the photosensitizer by lowering the internal reorganization energy and exciton binding energy via self-assembly-induced exciton delocalization. An example proof is presented by the design of a perylene diimide (PDI)-based photosensitizer (PDIMp) that can generate singlet oxygen (1O2) via a type-II energy transfer process in the monomeric state, but induce the generation of superoxide anion (O2˙-) via a type-I electron transfer process in the aggregated state. Significantly, with the addition ofcucurbit[6]uril (CB[6]), the self-assembled PDIMp can convert back to the monomeric state via host-guest complexation and consequently recover the generation of 1O2. The biological evaluations reveal that supramolecular nanoparticles (PDIMp-NPs) derived from PDIMp show superior phototherapeutic performance via synergistic type-I PDT and mild photothermal therapy (PTT) against cancer under either normoxia or hypoxia conditions.

[Determination of 13 chemical components of Epimedii Folium in pharmacopoeia by UPLC method combined with quantitative analysis of multicomponents by single-marker]

The quantitative analysis of multicomponents by single-marker(QAMS) was established for 13 chemical components of Epimedii Folium, including neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ, so as to investigate the feasibility and accuracy of this method in evaluating the quality of Epimedii Folium materials from different origins and different varieties. Through the scientific and accurate investigation of the experimental method, the external standard method was used to determine the content of 13 chemical components in epimedium brevieornu. At the same time, icariin was used as the internal standard, and the relative correction factors of icariin with neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ were established, respectively. The contens of neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuosideⅠ in Epimedii Folium were calculated by QAMS. Finally, the difference between the measured value and the calculated value was compared to verify the accuracy and scientific nature of QAMS in the determination. The relative correction factor of each component had better repeatability, and there was no significant difference between the results of the external standard method and those of QAMS. With icariin as the internal standard, QAMS simultaneously determining neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ can be used for quantitative analysis of Epimedii Folium.

The evaluation of four nano-formulations loaded-Elsinochrome A on characteristics and in vitro cytotoxicity effect

Elsinochrome A (EA) is a naturally occurring photosensitizer with potential applications in photodynamic therapy (PDT) for various malignancies. Despite its promising therapeutic properties, the poor solubility of EA hampers its effective utilization in clinical settings. To circumvent this limitation, we engineered four distinct nano-formulations: PLGA/EA nanoparticles (NPs), CMC-PLGA/EA NPs, mPEG-PCL/EA nanomicelles (NMs), and LHP-CHOL/EA nanoliposomes (NLs), all designed to enhance the solubility of EA. A comparative evaluation of these formulations, based on metrics such as particle size, Zeta potential, drug loading efficiency, and encapsulation efficiency, identified PLGA/EA NPs and mPEG-PCL/EA NMs as the most efficacious candidates. Subsequent in vitro investigations into the drug release kinetics under varying pH conditions and the impact on cell viability and apoptosis in A549 and MCF-7 cell lines were conducted. Remarkably, the maximum drug release for PLGA/EA NPs and mPEG-PCL/EA NMs was recorded at 62.5% and 70.8% in an acidic environment (pH 5.7), respectively. Upon exposure to 460 nm light, PLGA/EA NPs induced a significant reduction in A549 cell viability to 13.8% and an apoptosis rate of 93.8%, whereas mPEG-PCL/EA NMs elicited a decrease in MCF-7 cell viability to 12.8% and an apoptosis rate of 73.0%.

Hypericin blocks the function of HSV-1 alkaline nuclease and suppresses viral replication

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum L. has a long history in many countries of being used as a herbal medicine. It is also widely used in Chinese herbal medicine for the treatment of infections. Hypericin, a main component extracted from Hypericum perforatum L., has attracted the attention of many researchers for its remarkable antiviral, antitumor and antidepressant effects.

AIM OF THE STUDY

To find plant molecules that inhibit the alkaline nuclease (AN) of herpes simplex virus type 1 (HSV-1) and suppress viral replication.

MATERIALS AND METHODS

Bioinformatics methods were used to determine which compounds from a variety of natural compounds in our laboratory interact with AN. By this means we predicted that hypericin may interact with AN and suppress HSV-1 replication. Experiments were then carried out to verify whether hypericin inhibits the bioactivity of AN. The Pichia pastoris expression system was used to obtain recombinant AN. The exonuclease and endonuclease activity of AN treated with hypericin were tested by electrophoresis. Immunohistochemical staining of the HSV-1 nucleocapsids was used to find out whether hypericin inhibits the intracellular function of AN. Real-time PCR and western blotting analysis were performed to test viral gene expression and viral protein synthesis. The extent of viral replication inhibited by hypericin was determined by a plaque assay and a time of addition assay.

RESULTS

Recombinant AN was obtained by Pichia pastoris expression system. The exonuclease and endonuclease activity of recombinant AN were inhibited by hypericin in the electrophoresis assay. Hypericin showed no inhibitory effect on BeyoZonase™ Super Nuclease or DNase I. T5 Exonuclease activity was inhibited partially by10 μM hypericin, and was completely suppressed by 50 μM hypericin. Hind Ⅲ was inhibited by hypericin at concentrations greater than 100 μM, but EcoR I, BamH I, and Sal I were not inhibited by hypericin. HSV-1 nucleocapsids gathered in the nucleus when the viruses were treated with hypericin. Plaque formation was significantly reduced by hypericin (EC₅₀ against HSV-1 F is 2.59 ± 0.08 μM and EC₅₀ against HSV-1 SM44 is 2.94 ± 0.10 μM). UL12, ICP27, ICP8, gD, and UL53 gene expression (P < 0.01, 4.0 μM hypericin treated group vs control group) and ICP4 (P < 0.05, 6.0 μM hypericin treated group vs control group), ICP8 and gD (P < 0.05, 2.0 μM hypericin treated group vs control group) protein synthesis were inhibited by hypericin. In the time of addition assay, HSV-1 was suppressed by hypericin in the early stages of viral replication. Hypericin exhibits potent virucidal activity against HSV-1 and inhibits the adsorption and penetration of HSV-1.

CONCLUSION

Hypericin inhibits the bioactivity of AN and suppresses HSV-1 replication. The data revealed a novel mechanism of the antiherpetic effect of hypericin.

Fullerene-Perylenediimide (C60-PDI) Based Systems: An Overview and Synthesis of a Versatile Platform for Their Anchor Engineering

An overview of the different covalent bonding synthetic strategies of two electron acceptors leading to fullerene-perylenediimide (C₆₀-PDI)-based systems, essentially dyads and triads, is presented, as well as their more important applications. To go further in the development of such electron and photoactive assemblies, an original aromatic platform 5-benzyloxy-3-formylbenzoic acid was synthesized to graft both the PDI dye and the fullerene C₆₀. This new C₆₀-PDI dyad exhibits a free anchoring phenolic function that could be used to attach a third electro- and photoactive unit to study cascade electron and/or energy transfer processes or to obtain unprecedented side-chain polymers in which the C₆₀-PDI dyads are attached as pendant moieties onto the main polymer chain. This C₆₀-PDI dyad was fully characterized, and cyclic voltammetry showed the concomitant reduction process onto both C₆₀ and PDI moieties at identical potential. A quasi-quantitative quenching of fluorescence was demonstrated in this C₆₀-PDI dyad, and an intramolecular energy transfer was suggested between these two units. After deprotection of the benzyloxy group, the free hydroxyl functional group of the platform was used as an anchor to reach a new side-chain methyl methacrylate-based polymer in which the PDI-C₆₀ dyad units are located as pendants of the main polymer chain. Such polymer which associates two complementary acceptors could find interesting applications in optoelectronics and in particular in organic solar cells.

Hypericin and its anticancer effects: From mechanism of action to potential therapeutic application

BACKGROUND

Emerging studies indicate that hypericin has diverse pharmacological actions and exhibits potential for treatment of various types of cancer.

PURPOSE

The current review evaluates the pharmacological activity, associated molecular mechanism, and therapeutic application of hypericin as an anticancer agent according to the most recent state of knowledge with special emphasis on clinical trials and safety profile.

METHOD

This review follows The Preferred Reporting Items for Systematic Reviews criteria. Various databases, including PubMed, Scopus and Science Direct, were used to search and collect relevant literature. The major keywords used included the following: cancer, distribution, property, signaling pathway, pharmacological effect, treatment, prevention, in vitro and in vivo studies, toxicity, bioavailability, and clinical trials.

RESULTS

One hundred three articles met the established inclusion and exclusion criteria. Hypericin has shown anticancer activity against the expansion of several cell types including breast cancer, cervical cancer, colorectal cancer, colon cancer, hepatocellular carcinoma, stomach carcinoma, leukemia, lung cancer, melanoma, and glioblastoma cancer. Hypericin exerts its anticancer activity by inhibiting pro-inflammatory mediators, endothelial growth factor, fibroblast growth factor, cell adhesion, angiogenesis, and mitochondrial thioredoxin. It has also been shown to cause an increase in the levels of caspase-3 and caspase-4, arrest the cell cycle at metaphase leading to cancer cell apoptosis, and affect various protein and gene expression patterns.

CONCLUSION

Hypericin exhibits significant inhibitory activity against various types of in vitro and in vivo cancer models. However, well-designed, high quality, large-scale and multi-center randomized clinical studies are required to establish the safety and clinical utility of hypericin in cancer patients.

Naturally Occurring Partially Reduced Perylenequinones from Fungi

This Review provides a critical analysis of the literature covering the naturally occurring partially reduced perylenequinones (PQs) from fungi without carbon substituents (which can be named class A perylenequinones) and discusses their structures, stereochemistry, biosynthesis, and biological activities as appropriate. Perylenequinones are natural pigments with a perylene skeleton produced by certain fungi, aphids, some plants, and animal species. These compounds display several biological activities, e.g., antimicrobial, anti-HIV, photosensitizers, cytotoxic, and phytotoxic. It describes 36 fungal PQs and cites 81 references, covering from 1956 to August 2022.

Efficacy and Safety of Topical Hypericin Photodynamic Therapy for Early-Stage Cutaneous T-Cell Lymphoma (Mycosis Fungoides): The FLASH Phase 3 Randomized Clinical Trial

Importance

Given that mycosis fungoides-cutaneous T-cell lymphoma (MF/CTCL) is chronic, there is a need for additional therapies with minimal short- and long-term adverse effects. Topical synthetic hypericin ointment, 0.25%, activated with visible light is a novel, nonmutagenic photodynamic therapy (PDT).

Objectives

To determine the efficacy and safety of topical synthetic hypericin ointment, 0.25%, activated with visible light as a nonmutagenic PDT in early-stage MF/CTCL.

Design, Settings, and Participants

This was a multicenter, placebo-controlled, double-blinded, phase 3 randomized clinical trial (FLASH study) conducted from December 2015 to November 2020 at 39 academic and community-based US medical centers. Participants were adults (≥18 years) with early-stage (IA-IIA) MF/CTCL.

Interventions

In cycle 1, patients were randomized 2:1 to receive hypericin or placebo to 3 index lesions twice weekly for 6 weeks. In cycle 2, all patients received the active drug for 6 weeks to index lesions. In cycle 3 (optional), both index and additional lesions received active drug for 6 weeks.

Main Outcomes and Measures

The primary end point was index lesion response rate (ILRR), defined as 50% or greater improvement in modified Composite Assessment of Index Lesion Severity (mCAILS) score from baseline after 6 weeks of therapy for cycle 1. For cycles 2 and 3, open label response rates were secondary end points. Adverse events (AEs) were assessed at each treatment visit, after each cycle, and then monthly for 6 months. Data analyses were performed on December 21, 2020.

Results

The study population comprised 169 patients (mean [SD] age, 58.4 [16.0] years; 96 [57.8%] men; 120 [72.3%] White individuals) with early-stage MF/CTCL. After 6 weeks of treatment, hypericin PDT was more effective than placebo (cycle 1 ILRR, 16% vs 4%; P = .04). The ILRR increased to 40% in patients who received 2 cycles of hypericin PDT (P < .001 vs cycle 1 hypericin) and to 49% after 3 cycles (P < .001 vs cycle 1 hypericin). Significant clinical responses were observed in both patch and plaque type lesions and were similar regardless of age, sex, race, stage IA vs IB, time since diagnosis, and number of prior therapies. The most common treatment-related AEs were mild local skin (13.5%-17.3% across cycles 1-3 vs 10.5% for placebo in cycle 1) and application-site reactions (3.2%-6.9% across cycles 1-3 vs 4% for placebo in cycle 1). No drug-related serious AEs occurred.

Conclusion and Relevance

The findings of this randomized clinical trial indicate that synthetic hypericin PDT is effective in early-stage patch and plaque MF/CTCL and has a favorable safety profile.

Trial Registration

ClinicalTrials.gov Identifier: NCT02448381.

A perylenediimide modified SiO2@TiO2 yolk-shell light-responsive nanozyme: Improved peroxidase-like activity for H2O2 and sarcosine sensing

Although light-responsive nanozyme have been widely used in colorimetric sensing, some limitations such as poor catalytic activity, low detection efficiency, and unclear structure-activity relationships remain unresolved. Herein, we prepared an excellent light-responsive peroxidase (POD) mimic, perylenediimide (PDI-OH) modified SiO₂ @TiO₂ yolk-shell spheres (SiO₂ @TiO₂/PDI-OH), based on DFT-assisted design. The experiment and DFT calculation revealed that the enhanced POD-like activity was mainly attributed to a suitable built-in electric field among adjacent PDI-OH molecules on the surface of the SiO₂ @TiO₂ and the unique yolk-shell structure with more reaction sites of SiO₂ @TiO₂. Consequently, the highly selective and ultrasensitive detection of H₂O₂ is achieved with a detection limit (LOD) of 7.6 × 10^-8M. Further, the selective detection of sarcosine with LOD of 1.2 × 10^-7 M was also achieved by introducing sarcosine oxidase (SOx). This colorimetric assay is successfully applied to selectively detect H₂O₂ and sarcosine levels in real samples. Controlled response time, anti-interference, and the robustness of the developed colorimetric sensor are the key advantages. And the present work firstly clarifies the effect of PDIs substituents on the POD-like activity of light-responsive nanozymes and provided new guidelines to develop high-performance nanozymes for hazardous substances detection.

Thermoresponsive Liposomes for Photo-Triggered Release of Hypericin Cyclodextrin Inclusion Complex for Efficient Antimicrobial Photodynamic Therapy

Antimicrobial strategies with high efficacy against bacterial infections are urgently needed. The development of effective therapies to control bacterial infections is still a challenge. Herein, near-infrared (NIR)-activated thermosensitive liposomes (TSL) were loaded with the NIR-dye 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide (DiR) and the water-soluble hypericin (Hyp) β-cyclodextrin inclusion complex (Hyp-βCD). DiR and Hyp-βCD loaded thermosensitive liposomes (DHβCD-TSL) are functionalized for photothermal triggered release and synergistic photodynamic therapy to eliminate the gram-positive Staphylococcus saprophyticus. The dually active liposomes allow the production of heat and singlet oxygen species with the help of DiR and Hyp, respectively. The elevated temperature, generated by the NIR irradiation, irreversibly damages the bacterial membrane, increases the permeation, and melts the liposomes via a phase-transition mechanism, which allows the release of the Hyp-βCD complex. The photodynamic effect of Hyp-βCD eradicates the bacterial cells owing to its toxic oxygen species production. DHβCD-TSL measured the size of 130 nm with an adequate encapsulation efficiency of 81.3% of Hyp-βCD. They exhibited a phase transition temperature of 42.3 °C, while they remained stable at 37 °C, and 44% of Hyp-βCD was released after NIR irradiation (T > 47 °C). The bacterial viability dropped significantly after the synergistic treatment (>4 log₁₀), indicating that the NIR-activated TSL have immense therapeutic potential to enhance the antibacterial efficacy. The liposomes showed good biocompatibility, which was confirmed by the cellular viability of mouse fibroblasts (L929).

Cercosporin-bioinspired photoinactivation of harmful cyanobacteria under natural sunlight via bifunctional mechanisms

Harmful cyanobacterial blooms (HCBs), mainly caused by eutrophication, have deleterious impacts on water resources and pose a great threat to human health and natural ecosystems. Thus, an environmentally-friendly method to inhibit HCBs is urgently needed. Learning from nature, herein, natural product cercosporin, produced by the fungi Cercospora to damage plant cells under natural sunlight, was developed as a powerful photosensitive algicidal reagent to inhibit HCBs. Microcystis aeruginosa could be severely inactivated by 20 μM cercosporin in 36 h with 95% inhibition ratio under 23 W compact fluorescent light irradiation. Further mechanism investigation showed that algal cell walls and membranes along with the antioxidant and photosynthetic systems were damaged via two mechanisms, those being, reactive oxygen species generation and cell adsorption. More importantly, the practical applicability of cercosporin was demonstrated by its effectiveness in a 2 L-scale photoinactivation experiment using cyanobacterial blooms from Taihu Lake, China under natural sunlight with a lower dosage of cercosporin (7.5 μM). This study established the bifunctional mechanisms by which cercosporin inactivates HCBs, opening design possibilities for the development of novel photosensitive algicidal reagents to control HCBs.

Hypericin-mediated photodynamic therapy enhances gemcitabine induced Capan-2 cell apoptosis via inhibiting NADPH level

OBJECTIVES

The combination of gemcitabine (Gem) and hypericin (HY) enhances the apoptosis of Capan-2 cells, providing a promising option for the treatment of pancreatic cancer. Our study further explored the cytotoxic mechanism of HY combined with chemotherapy drugs on pancreatic cancer.

METHODS

The proliferation rate of the cells assayed with the MTT method. The ROS (reactive oxygen species) levels of each treatment were evaluated by DCFH-DA oxidisation methods. The activity of glutathione reductase and the levels of reduced glutathione (GSH) and oxidised glutathione (GSSG) were assessed using assay kits. The expression levels of apoptosis-related proteins were analysed by western blotting.

KEY FINDINGS

The activity of glucose-6-phosphate dehydrogenase (G6PDH), a key enzyme of the pentose phosphate pathway, significantly decreased in Gem + HY groups, however, the ROS level enhanced accompanying with GSH depleting, mitochondrial membrane depolarisation and cytochrome C release. Gem + HY inhibits the expression of Bcl-2 but stimulates Bax level, triggering caspase activation and PARP cleavage and thus promoted apoptosis of Capan-2 cells.

CONCLUSIONS

We demonstrated that Gem combined HY-PDT could inhibit the proliferation of Capan-2 cells and induce cell apoptosis. HY-PDT combined with Gem had a great potential on pancreatic cancer treatment clinically.

Development of new and validated HPTLC methods for the qualitative and quantitative analysis of hyperforin, hypericin and hyperoside contents in Hypericum species

PURPOSE

Hypericum perforatum L. (St. John's wort) is a medicinally important member of Hypericaceae. Many pharmacological activities have been mostly attributed to its hyperforin, hypericin and/or hyperoside contents. Therefore, qualitative and quantitative determinations of these ingredients are essential to justify the beneficial effects of St. John's wort on health. In the European Pharmacopoeia, the TLC and HPLC methods were given for this purpose. High performance thin layer chromatography (HPTLC) has recently become increasingly used as a suitable technique for analysing herbal drugs. This study aims to develop new and validated HPTLC methods to analyse these active components in different Hypericum spp. to find other suitable species to replace the official plant.

METHODS

Three different mobile phases were developed: n-hexane-ethyl acetate (8:2) for hyperforin analysis, toluene-chloroform-ethyl acetate-formic acid (8:5:3.5:0.6) for hypericin analysis and ethyl acetate-formic acid-acetic acid-water (15:2:2:1) for hyperoside analysis. These newly developed and validated HPTLC systems were further applied to determine their concentrations in different Hypericum species.

RESULTS

Hyperforin concentration was found between 6.40 to 26.40 mg/g only in H. triquetrifolium, H. scabrum and two H. perforatum samples; hypericin was detected between 0.81 and 1.41 mg/g only in H. bithynicum, H. perfoliatum, H. triquetrifolium and two H. perforatum samples; and hyperoside was identified in all tested specimens ranging from 1.01 to 9.73 mg/g. The new HPTLC methods developed and validated in the present study may ensure reliable results for the qualification and quantification of hyperforin, hypericin and hyperoside contents in Hypericum species.

Biosynthesis of titanium dioxide nanoparticles using Hypericum perforatum and Origanum vulgare extracts and their main components, hypericin and carvacrol as promising antibacterial agents

OBJECTIVE

To evaluate the anti-bacterial activities of titanium dioxide (TiO) nanoparticles of Origanum (O.) vulgare and Hypericum (H.) perforatum extracts, carvacrol and hypericin against Staphylococcus (S.) aureus.

METHODS

In this study, TiOnanoparticles of O. vulgare and H. perforatum extracts, carvacrol and hypericin, were prepared and their antibacterial effects were evaluated against Staphylococcus (S.) aureus. In this study, scanning electron microscope, fourier transform infrared spectrometer, atomic force microscopy, dynamic light scattering and zeta potential were used to investigate the structure of synthesized drugs.

RESULTS

Anti-bacterial activity of synthesized NPs was tested by minimum inhibitory concentration (MIC), minimum bactericidal concentration and disc diffusion method. MICs of TiO-NPs synthesized using O. vulgare, H. perforatum, carvacrol and hypericin and TiO were obtained 250, 62.5, 250, and 250, and 500 μg/mL, respectively. The MBCs for all of these were obtained 1000 μg/mL.

CONCLUSION

Green-synthesized of TiO nanoparticles provides a promising approach to the use of O. vulgare and H. perforatum, carvacrol and hypericin as novel agents and safer antibacterial compounds, especially anti-S. aureus compounds.

The Interaction of Hypericin with SARS-CoV-2 Reveals a Multimodal Antiviral Activity

Hypericin is a photosensitizing drug that is active against membrane-enveloped viruses and therefore constitutes a promising candidate for the treatment of SARS-CoV-2 infections. The antiviral efficacy of hypericin is largely determined by its affinity toward viral components and by the number of active molecules loaded on single viruses. Here we use an experimental approach to follow the interaction of hypericin with SARS-CoV-2, and we evaluate its antiviral efficacy, both in the dark and upon photoactivation. Binding to viral particles is directly visualized with fluorescence microscopy, and a strong affinity for the viral particles, most likely for the viral envelope, is measured spectroscopically. The loading of a maximum of approximately 30 molecules per viral particle is estimated, despite with marked heterogeneity among particles. Because of this interaction, nanomolar concentrations of photoactivated hypericin substantially reduce virus infectivity on Vero E6 cells, but a partial effect is also observed in dark conditions, suggesting multiple mechanisms of action for this drug.

L-Arginine enhanced perylenequinone production in the endophytic fungus Shiraia sp. Slf14(w) via NO signaling pathway

Perylenequinones (PQ) are natural polyketides used as anti-microbial, -cancers, and -viral photodynamic therapy agents. Herein, the effects of L-arginine (Arg) on PQ biosynthesis of Shiraia sp. Slf14(w) and the underlying molecular mechanism were investigated. The total content of PQ reached 817.64 ± 72.53 mg/L under optimal conditions of Arg addition, indicating a 30.52-fold improvement over controls. Comparative transcriptome analysis demonstrated that Arg supplement promoted PQ precursors biosynthesis of Slf14(w) by upregulating the expression of critical genes associated with the glycolysis pathway, and acetyl-CoA and malonyl-CoA synthesis. By downregulating the expression of genes related to the glyoxylate cycle pathway and succinate dehydrogenase, more acetyl-CoA flow into the formation of PQ. Arg supplement upregulated the putative biosynthetic gene clusters for PQ and activated the transporter proteins (MFS and ABC) for exudation of PQ. Further studies showed that Arg increased the gene transcription levels of nitric oxide synthase (NOS) and nitrate reductase (NR), and activated NOS and NR, thus promoting the formation of nitric oxide (NO). A supplement of NO donor sodium nitroprusside (SNP) also confirmed that NO triggered promoted biosynthesis and efflux of PQ. PQ production stimulated by Arg or/and SNP can be significantly inhibited upon the addition of NO scavenger carboxy-PTIO, NOS inhibitor N_ω-nitro-L-arginine, or soluble guanylate cyclase inhibitor NS-2028. These results showed that Arg-derived NO, as a signaling molecule, is involved in the biosynthesis and regulation of PQ in Slf14(W) through the NO-cGMP-PKG signaling pathway. Our results provide a valuable strategy for large-scale PQ production and contribute to further understanding of NO signaling in the fungal metabolite biosynthesis. KEY POINTS: • PQ production of Shiraia sp. Slf14(w) was significantly improved by L-arginine addition. • Arginine-derived NO was firstly reported to be involved in the biosynthesis and regulation of PQ. • The NO-cGMP-PKG signaling pathway was proposed for the first time to participate in PQ biosynthesis.

Transient Chemiluminescence Assay for Real-Time Monitoring of the Processes of SO32--Based Advanced Oxidation Reactions

The hydroxyl radical (·OH) is a strong oxidizing agent in situ generated in advanced oxidation processes (AOPs) and crucial for assessing the performances of AOPs toward organic contaminants' degradation. Herein, we developed a specific luminescent probe, APDI (N' N'-di(propylethylenediamine)-perylene-3,4,9,10-tetracarboxylic diimide), to selectively detect ·OH among diverse reactive oxygen species and other radicals. Based on the transient chemiluminescence (TCL) spectra, the in situ concentration profile of ·OH within 0.01 s interval time in classical Fenton reactions and four kinds of SO₃^2--based AOPs was obtained, which provides insights into the high dynamic processes of the whole ·OH generation and consumption processes. Besides, compared with acidic conditions, reduced degradation efficiencies in Fe²⁺-SO₃^2- and Fe²⁺-SO₃^2--H₂O₂ systems were found under neutral conditions. The complete depletion of active free radicals due to SO₂^-̇ radicals generated from Fe²⁺ and SO₃^2- should account most for decreased degradation efficiencies evidenced by a new SO₂* TCL signal discovered in the TCL spectra. In addition, similar phenomena have also been found in other M^(n-1)+-SO₃^2--related AOPs. As SO₃^2- and HSO₃^- often exist naturally in wastewater, more efforts are needed to improve the performance of Fe²⁺-H₂O₂ systems. This discovery has important significance for organic contaminant degradation in a natural environment.

Hypocrellin A exerts antitumor effects by inhibiting the FGFR1 signaling pathway in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer, which is the deadliest form of cancer worldwide. Recent studies have shown that genes in the fibroblast growth factor (FGF) family are highly mutated in lung cancer, and fibroblast growth factor receptor 1 (FGFR1) has been found to be involved in various cancers, including lung cancer, suggesting that FGFR1 is a valid therapeutic target. Hypocrellin A (HA), a molecule with multiple biological activities, has been shown to influence cancer growth, but the specific mechanisms of its antitumor action have not been fully explored.

METHODS

MTT, colony formation, wound healing, transwell cell invasion and EdU cell proliferation assays were performed upon HA treatment of three NSCLC cell lines, H460, PC-9 and H1975. Hoechst 33258 staining and caspase 3 activity assays were carried out to investigate the impact of HA on apoptosis in these cells. Molecular docking and surface plasmon resonance were conducted to assess binding of HA to FGFR1. A mouse tumor model was used to detect the NSCLC-inhibitory ability of HA in vivo.

RESULTS

Through in vitro assays, HA was shown to negatively impact cell viability, migration, invasion and promote apoptosis in three human NSCLC cell line models. HA was shown to bind to FGFR1 and to inhibit its autophosphorylation and the phosphorylation of downstream signaling molecules. Inhibition of tumor growth was also demonstrated in a mouse xenograft tumor model, and no toxic effects of HA treatment were observed.

CONCLUSIONS

HA inhibits the activity of the FGFR1 and STAT3 signaling pathways. HA thus represents a potential new FGFR1-targeted treatment for NSCLC.

Anti-fatigue effect of hypericin in a chronic forced exercise mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum L. is a traditional Chinese medicine used to sooth the liver, relieve depression, reduce body temperature, reduce sweating, and stimulate lactation. HP was extracted from Hypericum perforatum L.

AIM OF STUDY

The antifatigue effects of hypericin were assessed in a series of experiments.

MATERIALS AND METHODS

Six-to eight-week-old male ICR mice were raised in our lab. Mice were subjected to swimming training for 2 h, 6 days/week for 6 weeks. One hour prior to each swimming session, intraperitoneal injection of saline or HP (2 or 4 mg/kg) was performed.

RESULTS

Compared with the fatigue model control group, HP was found to significantly increase the swimming time in forced swimming tests. The molecular mechanisms underlying the antifatigue effects were further revealed by analysing energy metabolism, the oxidant-antioxidant system and the inflammatory response. HP normalized changes in BLA, LDH, BUN, and CK, LG in the liver. In addition, multiple assays have confirmed that HP improved the MDA, T-AOC, GSH-PX and SOD activity, and the relevant signalling pathways involved in the antifatigue effects were clarified. Furthermore, HP improves the expression of pro- and anti-inflammatory cytokines in skeletal muscle.

CONCLUSION

These results suggested that the anti-chronic fatigue effects of HP are likely achieved by normalizing energy metabolism and attenuating oxidative and inflammatory responses. Consequently, this study supports HP use in the clinic to alleviate chronic fatigue.

An NIR Discrete Metallacycle Constructed from Perylene Bisimide and Tetraphenylethylene Fluorophores for Imaging-Guided Cancer Radio-Chemotherapy

To promote the clinical theranostic performances of platinum-based anticancer drugs, imaging capability is urgently desired, and their chemotherapeutic efficacy needs to be upgraded. Herein, a theranostic metallacycle (M) is developed for imaging-guided cancer radio-chemotherapy using perylene bisimide fluorophore (PPy) and tetraphenylethylene-based di-Pt(II) organometallic precursor (TPE-Pt) as building blocks. The formation of this discrete supramolecular coordination complex facilitates the encapsulation of M by a glutathione (GSH)-responsive amphiphilic block copolymer to prepare M-loaded nanoparticles (MNPs). TPE-Pt acts as a chemotherapeutic drug and also an excellent radiosensitizer, thus incorporating radiotherapy into the nanomedicine to accelerate the therapeutic efficacy and overcome drug resistance. The NIR-emission of PPy is employed to detect the intracellular delivery and tissue distribution of MNPs in real time. In vitro and in vivo investigations demonstrate the excellent anticancer efficacy combining chemotherapy and radiotherapy; the administration of this nanomedicine effectively inhibits the tumor growth and greatly extends the survival rate of cisplatin-resistant A2780CIS-tumor-bearing mice. Guided by in vivo fluorescence imaging, radio-chemotherapy is precisely carried out, which facilitates boosting of the therapeutic outcomes and minimizing undesired side effects. The success of this theranostic system brings new hope to supramolecular nanomedicines for their potential clinical translations.

Plasmon-Enhanced Electrochemiluminescence of PTP-Decorated Eu MOF-Based Pt-Tipped Au Bimetallic Nanorods for the Lincomycin Assay

Plasmonic bimetal nanostructures can be employed to amplify electrochemiluminescence (ECL) signals. In this work, a high-performance ECL platform was constructed using a europium metal-organic framework (MOF) as a luminophore and Au-Pt bimetallic nanorods (NRs) as a plasma source. Due to the SPR effect of Au-Pt NRs, the aptasensor exhibits 2.6-fold ECL intensity compared to that of pure polyaniline (PANI)-decorated perylene tetracarboxylic dianhydride (PTCA)/Eu MOF. Moreover, decoration with PTP greatly enhances the conductivity and stability of Eu MOF, resulting in sizeable plasmon-enhanced electrochemical luminescence. The as-designed plasmon-enhanced ECL aptasensor displayed highly sensitive detection for lincomycin (Lin). The as-proposed aptasensor could quantify Lin from 0.1 mg/mL to 0.1 ng/mL with a limit of detection (LOD) of 0.026 ng/mL.

Genomic analysis of Elsinoë arachidis reveals its potential pathogenic mechanism and the biosynthesis pathway of elsinochrome toxin

Elsinochromes (ESCs) are virulence factors produced by Elsinoë arachidis which is the cause of peanut scab. However, the biosynthesis pathway of ESCs in E. arachidis has not been elucidated and the potential pathogenic mechanism of E. arachidis is poorly understood. In this study, we report a high-quality genome sequence of E. arachidis. The size of the E. arachidis genome is 33.18Mb, which is comparable to the Ascomycota genome (average 36.91 Mb), encoding 9174 predicted genes. The self-detoxification family including transporters and cytochrome P450 enzymes were analysis, candidate effectors and cell wall degrading enzymes were investigated as the pathogenicity genes by using PHI and CAZy databases. Additionally, the E. arachidis genome contains 24 secondary metabolism gene clusters, in which ESCB1 was identified as the core gene of ESC biosynthesis. Taken together, the genome sequence of E. arachidis provides a new route to explore its potential pathogenic mechanism and the biosynthesis pathway of ESCs.

Thermosensitive liposomes encapsulating hypericin: Characterization and photodynamic efficiency

The potent photodynamic properties of Hypericin (Hyp) elicit a range of light-dose-dependent anti-tumor activities. However, its low water solubility hampers its broad application. Therefore, the administration of Hyp into biological systems requires drug carriers that would enable sufficient bioavailability. Stimuli-triggered nanocarriers, which are sensitive to endogenous or exogenous stimuli, have become an attractive replacement for conventional therapeutic regimens. Herein, we produced optimized Hyp thermosensitive liposomes (Hyp-TSL), self-assembled from DPPC, DSPC, DSPE-PEG2000. Hyp-TSL displayed a hydrodynamic diameter below 100 nm with an adequate encapsulation efficiency of 94.5 % and good colloidal stability. Hyp-TSL exhibited thermal sensitivity over a narrow range with a phase transition temperature of 41.1 °C, in which liposomal destruction was evident in AFM images after elevated temperature above the phase transition temperature. The uptake of TSL-Hyp into MDA-MB-231 cells was significantly increased with hyperthermic treatment of 42 °C when compared to the uptake at a average physiological temperature of 37 °C. Consequent enhancement of cellular reactive oxygen species was observed after hyperthermic treatment at 42 °C. The half-maximal inhibitory concentration of Hyp TSL was reduced by 3.8 fold after hyperthermic treatment at 42 °C in comparison to treatment at 37 °C. Hyp-TSL were considered safe for intravenous applications as compared by hemocompatibility studies, where coagulation time was <50 s and hemolytic potential was <10%. Conclusively, the enhancement in tumor drug availability correlated with improved therapeutic outcomes.

A bioinspired cercosporin/polymethylmethacrylate photocatalyst with high efficiency for decontamination of pharmaceuticals and pathogens

Pharmaceuticals have seriously contaminated aquatic environments and resulted in the formation of drug-tolerant bacteria owing to continuous release and accumulation. Therefore, the development of new methods to simultaneously decompose drugs and disinfect pathogens in an environmental-friendly manner with high efficiency is still in great demand. Bioinspired by the great photosensitivity of natural product cercosporin with the ability to efficiently generate reactive oxygen species (ROS) under natural sunlight and its antibacterial activity, here a novel cercosporin/polymethylmethacrylate (CP/PMMA) photocatalyst was rationally developed by incorporating and restricting cercosporin in a "green" macroporous resin PMMA, which greatly improved the ROS generation efficiency and displayed 97.2-100% photodegradation for broad-spectrum pharmaceuticals, including fluoroquinolones, trimethoprim and chloroquine phosphate, upon 15 W compact fluorescent lamp irradiation. More importantly, this decontamination efficiency was greatly improved, and the decontamination time was substantially shortened in a large-scale assay under natural sunlight. Furthermore, it could inactivate the pathogen Staphylococcus aureus. Overall, this work provides new insight into how a multifunctional photocatalyst could be designed using a natural product and macroporous resins for environmental remediation.

Biodegradable Hypocrellin B nanoparticles coated with neutrophil membranes for hepatocellular carcinoma photodynamics therapy effectively via JUNB/ROS signaling

Hepatocellular carcinoma (HCC) is an inflammation-induced and chemotherapy-resistant common liver cancer, and a major cause of death. Some natural products have been found to be used as photosensitizers in photodynamic therapy of HCC. Due to its specific molecular structure diversities and biological activities, current status of HCC treatment with nature production remains unsatisfactory, owing largely to the toxicity, side effect and inefficiency to drug targeting. Herein, we show a nanoparticle-based broad-spectrum anti-inflammatory strategy that naïve neutrophil membrane-coated PLGA nanoparticles (NM-HB NPs) were constructed for synchronous nearinfrared fluorescence (NIR FL) imaging and photodynamic therapy (PDT) for HCC. Moreover, NM-HB NPs inhibited the expression of JUNB and promoted the ROS production. JUNB depletion enhanced the anti-HCC effect of NM-HB NPs. Importantly, it was shown that NM-HB NPs are well targeted to the tumor site and overcomes the blood circulation and immune elimination in vivo and vitro. In a mouse model of HCC, the neutrophil membrane-coated nanoparticles (NM-HB NPs) show significant therapeutic efficacy by PDT and suppressing tumor tissue increase. All results demonstrated that NM coated HB NPs representing a viable and effective treatment option for HCC.

Surface tailored zein as a novel delivery system for hypericin: Application in photodynamic therapy

Zein is an FDA-approved maize protein featured by its manipulative surface and the possibility of fabrication into nanomaterials. Although extensive research has been carried out in zein-based technology, limited work is available for the application of zein in the field of cancer photodynamic therapy (PDT). In this work, we report zein as a carrier for the natural photosensitizer hypericin in the PDT of hepatocellular carcinoma in vitro. Zein was modified through chemical PEGylation to form PEGylated zein micelles that were compared with two zein nanoparticle formulations physically stabilized by either the lecithin/pluronic mixture or sodium caseinate. FT-IR, ¹HNMR and HP-SEC MALS approaches were employed to confirm the chemical PEGylation of zein. Our developed zein nanoparticles and micelles were further characterized by photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). The obtained results showed relatively smaller sizes and higher encapsulation of hypericin in the micellar zein than the nanoparticle-based formulations. Phototoxicity on hepatocellular carcinoma (HepG2 cells) manifested a dose-dependent toxicity pattern of all designed zein formulations. However, superior cytotoxicity was prominent for the hypericin-based micelles, which was influenced by the higher cellular uptake profile. Consequently, the treated HepG2 cells manifested a higher level of intracellular generated ROS and disruption of mitochondrial membrane potential, which induced apoptotic cell death. Comparatively, the designed hypericin formulations indicated lower phototoxicity profile in murine fibroblast L929 cells reflecting their safety on normal cells. Our investigations suggested that the surface-modified zein could be employed to enhance the delivery of the hydrophobic hypericin in PDT and pave the way for future in vivo and clinical applications in cancer treatment.

Overcoming Aggregation-Induced Quenching by Metal-Organic Framework for Electrochemiluminescence (ECL) Enhancement: Zn-PTC as a New ECL Emitter for Ultrasensitive MicroRNAs Detection

Polycyclic aromatic hydrocarbons (PAHs) as traditional electrochemiluminescence (ECL) luminophores have been widely applied in the analysis field. However, their ECL intensity and efficiency are still limited due to the aggregation-induced quenching (ACQ) effect of PAHs. Hence, to overcome this limitation, we put forward a new strategy to increase the ECL intensity and efficiency by eliminating the ACQ effect of PAHs through the coordinative immobilization of PAHs within metal-organic frameworks (MOFs). As anticipated, the proof-of-concept experiment indicated that the coordinative immobilization of perylene-3,4,9,10-tetracarboxylate (PTC) into a Zn-PTC MOF could distinctly increase the ECL intensity and efficiency compared with H₄PTC aggregates and H₄PTC monomers. The reason for the ECL enhancement of Zn-PTC was that the immobilization of PTC within the MOF effectively amplified the distance between perylene rings of PTC ligands and thus eliminated the ACQ effect. Furthermore, the PTC into Zn-PTC was stacked in an edge-to-edge mode to form J-aggregation, which was also conducive to ECL enhancement. On the basis of the excellent ECL performance, we utilized Zn-PTC as a new ECL emitter combined with exonuclease III-stimulated target cycling and DNAzyme-assisted cycling dual amplification strategies to construct an ECL sensor for microRNA-21 detection, which had a wide signal response (100 aM to 100 pM) with a detection limit of 29.5 aM. Overall, this work represents a new and convenient method to overcome the ACQ effect of PAHs and boost the ECL performance, which opens a new horizon for developing high-performance ECL materials, thus offering more opportunities for building highly sensitive ECL biosensors.

Hypericin Inhibit Alpha-Coronavirus Replication by Targeting 3CL Protease

The porcine epidemic diarrhea virus (PEDV) is an Alphacoronavirus (α-CoV) that causes high mortality in infected piglets, resulting in serious economic losses in the farming industry. Hypericin is a dianthrone compound that has been shown as an antiviral activity on several viruses. Here, we first evaluated the antiviral effect of hypericin in PEDV and found the viral replication and egression were significantly reduced with hypericin post-treatment. As hypericin has been shown in SARS-CoV-2 that it is bound to viral 3CLpro, we thus established a molecular docking between hypericin and PEDV 3CLpro using different software and found hypericin bound to 3CLpro through two pockets. These binding pockets were further verified by another docking between hypericin and PEDV 3CLpro pocket mutants, and the fluorescence resonance energy transfer (FRET) assay confirmed that hypericin inhibits the PEDV 3CLpro activity. Moreover, the alignments of α-CoV 3CLpro sequences or crystal structure revealed that the pockets mediating hypericin and PEDV 3CLpro binding were highly conserved, especially in transmissible gastroenteritis virus (TGEV). We then validated the anti-TGEV effect of hypericin through viral replication and egression. Overall, our results push forward that hypericin was for the first time shown to have an inhibitory effect on PEDV and TGEV by targeting 3CLpro, and it deserves further attention as not only a pan-anti-α-CoV compound but potentially also as a compound of other coronaviral infections.

Visual detection of fluoride based on supramolecular aggregates of perylene diimide in 100% aqueous media

A water-soluble perylene imide derivative (PDI-Glu) was synthesized and their supramolecular aggregates composed of PDI-Glu and Al³⁺ were prepared as a "turn on" fluorometric probe to monitor F^- in a purely aqueous system. Based on an "indicator displacement assay" (IDA) approach, the sensing performance and mechanism of PDI-Glu/Al³⁺ complex toward F^- were investigated by absorption and emission spectra. It was suggested that disassembly of PDI-Glu/Al³⁺ aggregates was promoted by addition of F^- through the competitive binding between Al³⁺ and F^-. The detection limit is 240 nmol/L. This method featured simple preparation, excellent water solubility, adjustable self-assembly performance, ease of observation and operation, and high selectivity and sensitivity. It was used for monitoring F^- in toothpaste and tap water samples with excellent accuracy and recovery. To the best of our knowledge, this is the first water-soluble perylene diimide-based probe for F^- detection in 100% aqueous media. We believe this work could not only extend the sensing scope of water-soluble perylene diimide, but also bring some useful information for the rapid detection of anionic analytes  in aqueous media. The disassembly of supramolecular aggregates of PDI-Glu/Al³⁺ along with significant fluorescence recovery enable a rapid and visual detection of F^- based on an "indicator displacement assay" strategy.

Isothermal kinetics of ethanolic extraction of total hypericin from pre-extracted Hypericum perforatum flowers

INTRODUCTION

Hypericum perforatum L., Hypericaceae (St John's wort) is a highly familiar plant in the medicinal community which recently showed good antiviral activities including against some types of coronavirus.

OBJECTIVE

Establishing the kinetics of isothermal extraction of total hypericin (TH) from the pre-extracted flowers of H. perforatum flowers.

METHODS

The solvent extraction of TH from the remaining solid residue after the pre-extraction procedure was performed providing isothermal conditions at the temperature of 313 K, 323 K, and 328 K (±1 K) using ethanol as a solvent. The feasibility of mathematical modelling of the isothermal kinetics of TH extraction was explored applying some of the frequently used kinetic models of solvent extraction: first-order reaction model, film theory model, unsteady-state diffusion model, parabolic diffusion model, Elovich's equation. The kinetic complexity was examined using the differential isoconversional method.

RESULTS

The kinetics of isothermal solvent extraction of TH is a kinetic elementary process with the unique rate-determining step. It was found that the kinetics of isothermal extraction of TH can be best described employing the theoretical Jander three-dimensional (3D) diffusional model and its suitability for modelling the investigated extraction was confirmed with statistical parameters [adjusted linear correlation coefficient (R² _adj ) = 0.998-0.999 and the standard error (SE) = 0.005-0.006]. The values of the model kinetic parameters (rate constant (k_M /min^-1 ), activation energy (E_a  = 21.0 ± 4.9 kJ/mol) and pre-exponential factor (lnA = 3.1 ± 2.2 min^-1 ) were calculated.

CONCLUSIONS

Based on the model mechanism of the kinetics of the investigated extraction a new mathematical model is suggested and the controlling step of the overall process was found.

The Effects of Photosensitizing Dyes Fagopyrin and Hypericin on Planktonic Growth and Multicellular Life in Budding Yeast

Naphthodianthrones such as fagopyrin and hypericin found mainly in buckwheat (Fagopyrum spp.) and St. John’s wort (SJW) (Hypericum perforatum L.) are natural photosensitizers inside the cell. The effect of photosensitizers was studied under dark conditions on growth, morphogenesis and induction of death in Saccharomyces cerevisiae. Fagopyrin and hypericin induced a biphasic and triphasic dose response in cellular growth, respectively, over a 10-fold concentration change. In fagopyrin-treated cells, disruptions in the normal cell cycle progression were evident by microscopy. DAPI staining revealed several cells that underwent premature mitosis without budding, a striking morphological abnormality. Flow Cytometric (FC) analysis using a concentration of 100 µM showed reduced cell viability by 41% in fagopyrin-treated cells and by 15% in hypericin-treated cells. FC revealed the development of a secondary population of G1 cells in photosensitizer-treated cultures characterized by small size and dense structures. Further, we show that fagopyrin and the closely related hypericin altered the shape and the associated fluorescence of biofilm-like structures. Colonies grown on solid medium containing photosensitizer had restricted growth, while cell-to-cell adherence within the colony was also affected. In conclusion, the photosensitizers under dark conditions affected culture growth, caused toxicity, and disrupted multicellular growth, albeit with different efficiencies.

In Vitro Screening of Various Bacterially Produced Double-Stranded RNAs for Silencing Cercospora cf. flagellaris Target Genes and Suppressing Cercosporin Production

Cercospora leaf blight (CLB), primarily caused by Cercospora cf. flagellaris, is one of the most important diseases of soybean (Glycine max) in Louisiana. The pathogen produces cercosporin, a nonspecific toxin and an important virulence factor. There are no commercial cultivars with CLB resistance, and the pathogen has developed substantial resistance to the frequently used fungicides. Consequently, alternative methods are needed to manage CLB. One possibility is the RNA interference-based topical application of double-stranded (ds)RNA. The present study addressed the two most critical steps for this novel approach to be practical: inexpensively producing large quantities of dsRNA and identifying the right target genes for silencing. A screening method was developed to compare the effectiveness of Escherichia coli-produced dsRNAs targeting five fungal genes involved in cercosporin production for silencing in liquid culture. As much as 151.6 mg of dsRNA-containing total nucleic acids (TNAs) was produced from 1 liter of E. coli Luria broth culture using the L4440 vector. All tested dsRNAs reduced cercosporin production. However, significant target gene suppression was only detected in the cultures treated with dsRNAs from Avr4 and CTB8. The most potent dsRNA was from Avr4, which reduced 50% of cercosporin production at an estimated TNA concentration of 10.4 µg/ml (half maximal effective concentration [EC₅₀]), and the least potent dsRNA was from HN-2, with an estimated EC₅₀ of 46.7 µg/ml TNA. The present study paves the road for managing CLB under field conditions using dsRNA. Additionally, this approach could be adapted to identify the best dsRNAs to manage other fungal diseases.

Hypericin in photobiological assays: An overview

Hypericin is considered a potent photosensitizer for use in antitumor and antimicrobial photodynamic therapy (PDT). This review presents the primary biological results obtained with hypericin in photodynamic therapy applications, such as photodynamic cancer treatment, photoinactivation of microorganisms (PDI), tissue scarring, and photo diagnosis. We present a compilation of in vitro results that have been published thus far; for these studies, we highlight the hypericin concentration, light dose, and other experimental conditions to evaluate the efficiency of photodynamic treatment like cell death, cell viability, or cell proliferation. The results indicate that different hypericin phototoxicity levels can be observed according to the specific light dose and concentration. Furthermore, it was shown that cellular localization and cell death mechanisms (apoptosis and necrosis) are dependent on the cell type.

Physiological and Transcriptomic Analysis Provide Insight into Low Temperature Enhancing Hypericin Biosynthesis in Hypericum perforatum

Hypericin (Hyp), well-known as an antidepressant, is mainly extracted from Hypericum perforatum. Although Hyp accumulation and biomass are greater at lower compared to higher temperature, the regulation mechanism has not been reported. Here, the physiological characteristics and transcriptome of H. perforatum grown at 15 and 22 °C were determined and analyzed by HPLC and de novo sequencing. The results showed that the stomatal density and opening percentages were 1.1- and 1.4-fold more, and the Hyp content was 4.5-fold greater at 15 °C compared to 22 °C. A total of 1584 differentially expressed genes (DEGs) were observed at 15 versus 22 °C, with 749 characterized genes, 421 upregulated (UR) and 328 downregulated (DR). Based on biological functions, 150 genes were associated with Hyp biosynthesis, plant growth and the stress response, including photosynthesis, carbohydrate metabolism, fatty acids metabolism, cytochrome P450 (CYPs), morpho-physiological traits, heat shock proteins (HSPs), cold-responsive proteins (CRPs) and transcription factors (TFs). The differential expression levels of the master genes were confirmed by qRT-PCR and almost consistent with their Reads Per kb per Million (RPKM) values. This physiological and transcriptomic analyses provided insight into the regulation mechanisms of low temperature enhancing Hyp biosynthesis in H. perforatum.

Lysosome-Instructed Self-Assembly of Amino-Acid-Functionalized Perylene Diimide for Multidrug-Resistant Cancer Cells

Multidrug resistance (MDR) of cancer cells reduces chemotherapeutic efficacy by preventing drug accumulation in the cells through a drug efflux pump and lysosomal sequestration/exocytosis. Herein, to overcome such anticancer resistance, lysosome-targeted self-assembly of perylene diimide (PDI) derivatives is presented as a powerful strategy for effective and selective anticancer therapy. Stimulated by the lysosomal low pH, the amphiphilic PDI derivatives functionalized with amino acids (PDI-AAs) construct fibrous self-assembled structures inside the lysosomes, causing cancer cell apoptosis by lysosomal rupture. In contrast, negligible apoptosis was observed from normal cells by PDI-AA. The agglomerated fibrous assemblies were not removed by lysosomal exocytosis, thereby displaying a 10.7-fold higher anticancer efficacy on MDR cancer cells compared to a doxorubicin chemotherapeutic agent. The MDR-circumventing capability, along with high selectivity toward cancer cells, supports PDI-AAs as potential candidates for the treatment of MDR cancer cells by lysosome-targeted self-assembly.

Photophysical characterization of Hypericin-loaded in micellar, liposomal and copolymer-lipid nanostructures based F127 and DPPC liposomes

Hypericin (Hy) compound presents a high photoactivity in photodynamic therapy (PDT), photodiagnosis and theranostics applications. The maintenance of this compound in monomeric form could undermine the potential benefits of its photophysical and photodynamic activity. In this study, we demonstrated that the Hy formulated in a system based on the use of the F127 copolymer and the 1,2-dipalmitoyl-sn-3-glycerol-phosphatidylcholine (DPPC) as micelles, liposomal vesicles and Copolymer-Lipid coated systems, have improved its photophysical properties for many clinical modalities. Based on the results of the triplet state lifetime values (τ_t), the singlet oxygen quantum yield (Φ_Δ¹O₂), the fluorescence lifetime (τ_F) and the fluorescence quantum yield (Φ_F), all Hy formulations had its photophysical properties described in different models of drug delivery systems (DDS). In addition, the transient spectra profile of those formulations was unaffected by the Hy incorporation process, except for the liposomal system, which demonstrated to be the less stable one by flash photolysis technique. The cytotoxic effects of those formulations were also investigated for CaCo-2 and HaCat cells line. The cytotoxic concentrations for 50% (CC₅₀) were 0.56, 1.05, 1.33 and 4.80 µmol L^-1 for Copolymer-Lipid/Hy, DPPC/Hy, F127/Hy and ethanol/Hy for CaCo-2 cells, respectively, and 0.69, 2.02, 1.45 and 1.16 µmol L^-1 for Copolymer-Lipid/Hy, DPPC/Hy, F127/Hy and ethanol/Hy for HaCat cells, respectively. The F127 copolymer had a significant role in many photophysical parameters determined for Copolymer-Lipid/Hy coated system. Although all those formulations had shown satisfactory results, Copolymer-Lipid/Hy proved to be superior in many aspects, being the most promising formulation for PDT, photodiagnosis and theranostics applications.

Identification and characterization of Cercospora beticola necrosis-inducing effector CbNip1

Cercospora beticola is a hemibiotrophic fungus that causes cercospora leaf spot disease of sugar beet (Beta vulgaris). After an initial symptomless biotrophic phase of colonization, necrotic lesions appear on host leaves as the fungus switches to a necrotrophic lifestyle. The phytotoxic secondary metabolite cercosporin has been shown to facilitate fungal virulence for several Cercospora spp. However, because cercosporin production and subsequent cercosporin-initiated formation of reactive oxygen species is light-dependent, cell death evocation by this toxin is only fully ensured during a period of light. Here, we report the discovery of the effector protein CbNip1 secreted by C. beticola that causes enhanced necrosis in the absence of light and, therefore, may complement light-dependent necrosis formation by cercosporin. Infiltration of CbNip1 protein into sugar beet leaves revealed that darkness is essential for full CbNip1-triggered necrosis, as light exposure delayed CbNip1-triggered host cell death. Gene expression analysis during host infection shows that CbNip1 expression is correlated with symptom development in planta. Targeted gene replacement of CbNip1 leads to a significant reduction in virulence, indicating the importance of CbNip1 during colonization. Analysis of 89 C. beticola genomes revealed that CbNip1 resides in a region that recently underwent a selective sweep, suggesting selection pressure exists to maintain a beneficial variant of the gene. Taken together, CbNip1 is a crucial effector during the C. beticola-sugar beet disease process.

Axial Chiral Binaphthoquinone and Perylenequinones from the Stromata of Hypocrella bambusae Are SARS-CoV-2 Entry Inhibitors

A new axial chiral binaphtoquinone, hypocrellone (1), and a new perylenequinone, hypomycin F (2), were isolated from the stromata of Hypocrella bambusae, together with five known compounds, 3-7. The structures of 1 and 2 were assigned by spectroscopic and HRESIMS data analyses. The axial chirality of 1 was determined by electronic circular dichroism data analysis, and the absolute configurations of 2 and 3 were determined by X-ray crystallography. The axial chirality of 7 was determined by UV-induced photooxidation from 4. Compounds 1, 4, and 5 showed inhibitory activity against pseudotyped SARS-CoV-2 infection in 293T-ACE2 cells with IC₅₀ values of 0.17, 0.038, and 0.12 μM. Compounds 4 and 5 were also active against live SARS-CoV-2 infection with EC₅₀ values of 0.22 and 0.21 μM, respectively. Further cell-cell fusion assays, surface plasmon resonance assays, and molecular docking studies revealed that 4 and 5 could bind with the receptor-binding domain of SARS-CoV-2 S protein to prevent its interaction with human angiotensin-converting enzyme II receptor. Our results revealed that 4 and 5 are potential SARS-CoV-2 entry inhibitors.

Harvest time affects antioxidant capacity, total polyphenol and flavonoid content of Polish St John's wort's (Hypericum perforatum L.) flowers

The polyphenol content and antioxidant capacity of hyperforin and hypericin-standardized H. perforatum L. extracts may vary due to the harvest time. In this work, ethanol and ethanol-water extracts of air-dried and lyophilized flowers of H. perforatum L., collected throughout a vegetation season in central Poland, were studied. Air-dried flowers extracts had higher polyphenol (371 mg GAE/g) and flavonoid (160 mg CAE/g) content, DPPH radical scavenging (1672 mg DPPH/g), ORAC (5214 µmol TE/g) and FRAP (2.54 mmol Fe2+/g) than lyophilized flowers extracts (238 mg GAE/g, 107 mg CAE/g, 1287 mg DPPH/g, 3313 µmol TE/g and 0.31 mmol Fe2+/g, respectively). Principal component analysis showed that the collection date influenced the flavonoid and polyphenol contents and FRAP of ethanol extracts, and DPPH and ORAC values of ethanol-water extracts. The ethanol extracts with the highest polyphenol and flavonoid content protected human erythrocytes against bisphenol A-induced damage. Both high field and benchtop NMR spectra of selected extracts, revealed differences in composition caused by extraction solvent and raw material collection date. Moreover, we have shown that benchtop NMR can be used to detect the compositional variation of extracts if the assignment of signals is done previously.

Impacts of manganese bio-based nanocomposites on phytochemical classification, growth and physiological responses of Hypericum perforatum L. shoot cultures

We report a new green route for preparing MnO₂/perlite nanocomposites (NCs) by leaf extract of Hypericum perforatum. Characterization of the physicochemical properties of the MnO₂/perlite-NCs was performed using XRD, FESEM, EDX, FT-IR, and DLS techniques. Furthermore, their effects on the phytochemical classification and growth parameters of H. perforatum shoot cultures were assessed. According to the FESEM image, the synthesized spherical MnO₂ nanoparticles on the sheet-like structure of nano-perlite were formed, ranging about 20-50 nm. In addition, based on the EDX spectra, the elemental analysis showed the presence of Carbon, Oxygen, Silicon, Aluminum, and Manganese elements in the as-synthesized MnO₂/perlite-NCs. Biological studies confirmed that nano-perlite and MnO₂/perlite-NCs were non-toxic to H. perforatum shoot cultures and showed positive effects on plant growth in specific concentrations. Overall, phytochemical classification demonstrated that the terpenoids decreased in the evaluated treatments, while hypericin and pseudohypericin were increased in some treatments (25, 50 and 150 mg/L of nano-perlite) relative to control. Metabolomics results suggested that both nano-perlite and MnO₂/perlite-NCs can be used as elicitors and new nanofertilizers for generating some secondary metabolites.

Nanoencapsulated hypericin in P-123 associated with photodynamic therapy for the treatment of dermatophytosis

The antifungal application of photodynamic therapy (PDT) has been widely explored. According to superficial nature of tinea capitis and the facility of application of light sources, the use of nanoencapsulated hypericin in P-123 associated with PDT (P123-Hy-PDT) has been a poweful tool to treat this pathology. Thus, the aim of this study was to evaluate the efficiency of P123-Hy-PDT against planktonic cells and in a murine model of dermatophytosis caused by Microsporum canis. In vitro antifungal susceptibility and in vivo efficiency tests were performed, including a skin toxicity assay, analysis of clinical signs by evaluating score, and photoacoustic spectroscopy. In addition, tissue analyses by histopathology and levels of pro-inflammatory cytokines, such as quantitative and qualitative antifungal assays, were employed. The in vitro assays demonstrated antifungal susceptibility with 6.25 and 12.5 μmol/L P123-Hy-PDI; these experiments are the first that have used this treatment of animals. P123-Hyp-mediated PDT showed neither skin nor biochemical alteration in vivo; it was safe for dermatophytosis treatment. Additionally, the treatment revealed rapid improvement in clinical signs at the site of infection after only three treatment sessions, with a clinical score confirmed by photoacoustic spectroscopy. The mycological reduction occurred after six treatment sessions, with a statistically significant decrease compared with untreated infected animals. These findings showed that P123-Hy-PDT restored tissue damage caused by infection, a phenomenon confirmed by histopathological analysis and proinflammatory cytokine levels. Our results reveal for the first time that P123-Hy-PDT is a promising treatment for tinea capitis and tinea corporis caused by M. canis, because it showed rapid clinical improvement and mycological reduction without causing toxicity.

Biophysical Characterization and Anticancer Activities of Photosensitive Phytoanthraquinones Represented by Hypericin and Its Model Compounds

Photosensitive compounds found in herbs have been reported in recent years as having a variety of interesting medicinal and biological activities. In this review, we focus on photosensitizers such as hypericin and its model compounds emodin, quinizarin, and danthron, which have antiviral, antifungal, antineoplastic, and antitumor effects. They can be utilized as potential agents in photodynamic therapy, especially in photodynamic therapy (PDT) for cancer. We aimed to give a comprehensive summary of the physical and chemical properties of these interesting molecules, emphasizing their mechanism of action in relation to their different interactions with biomacromolecules, specifically with DNA.

A dual thiourea-appended perylenebisimide "turn-on" fluorescent chemosensor with high selectivity and sensitivity for Hg2+ in living cells

Sensing heavy metal ions particularly for the most toxic Hg²⁺ is a long-term pursuit for chemists because of its obvious and extreme harmfulness to both the environment and human health. Herein, a novel 'turn-on' perylenebisimide-thiourea fluorescent probe PBI-BTB is achieved for rapid detection of Hg²⁺ in a DMSO/H₂O (5/1, v/v) solution through a typical Hg²⁺-promoting desulfurization reaction, which has been investigated through Job's plot titration, FT-IR, ¹H NMR and HRMS analysis. A remarkable fluorescence emission enhancement at 540 and 580 nm is observed in the presence of Hg²⁺, which is visible to the naked eye with high selectivity and sensitivity. Moreover, probe PBI-BTB combined strong anti-interference recognition with short response time (< 1 min). The rapid fluorescence response with low limit of detection (0.35 μM) in a wide pH range of 3.0-11.0 makes PBI-BTB a promising candidate for detection of Hg²⁺ without any buffer system. Furthermore, the practicability of probe PBI-BTB upon the Hg²⁺ recognition in human liver cancer cells (HepG-2) has been studied through fluorescent live cell imaging which reveals the probe's low toxicity to organism as well as the favorable cell permeability of PBI-BTB for detecting Hg²⁺ in biological systems.