Hypericin: A natural anthraquinone as promising therapeutic agent

New polycyclic polyprenylated acylphloroglucinols with antidepressant activities from Hypericum perforatum L

Six new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperidiones A-F (1-6), were obtained from Hypericum perforatum L. Their structures were characterized via extensive spectroscopic analyses, the circular dichroism data of the in situ formed [Mo2(OCOCH3)4] complexes, the nuclear magnetic resonance calculation with DP4 + probability analysis, and the calculated electronic circular dichroism (ECD) spectra. Compounds 1-6 are bicyclic polyprenylated acylphloroglucinols with a major bicyclo[3.3.1]nonane-2,4,9-trione skeleton. Notably, compound 1 is a rare PPAP with a hydroperoxy group, and a plausible biosynthetic pathway for 1 was proposed. Compounds 4 and 6 exhibited significant neuroprotective effects under 10 μM against corticosterone (CORT)-injured SH-SY5Y cells. Furthermore, compound 4 demonstrated a noteworthy antidepressant effect at the dose of 5 mg/kg in the tail suspension test (TST) of mice, which was equivalent to 5 mg/kg of fluoxetine. And it potentially exerted an antidepressant effect through the hypothalamic-pituitary-adrenal (HPA) axis.

Photodynamic antibacterial research on hypericin-loaded PEGylated mesoporous silica delivery system

In this study, a novel drug delivery system (MSN-PEG-Hypericin) was successfully fabricated using tetraethyl orthosilicate and 3-aminopropyltriethoxysilane as raw materials, and the PEGylation of the prepared aminated mesoporous silica and grafting of hypericin onto the carrier were further conducted to obtain MSN-PEG-Hypericin. The successful preparation of MSN-PEG-Hypericin was characterized by several physical-chemical techniques. Furthermore, the MSN-PEG-Hypericin system increased the ability of hypericin to generate reactive oxygen species (ROS) in vitro. The cytotoxicity assay and hemolysis analysis showed that MSN-PEG-Hypericin had good biocompatibility. For antibacterial studies, the irradiation time and incubation time of photodynamic therapy (PDT) for S. aureus and E. coli were respectively 8 min and 8 h, and the concentrations of hypericin were 2.5 and 5 μg/mL. The result of triphenyl tetrazolium chloride assay indicated that MSN-PEG-Hypericin had stronger photodynamic antibacterial activity than free hypericin, and S. aureus was more sensitive to PDT than E. coli, which was related to their cell structural differences. The antibacterial mechanism study indicated that the generated ROS could destroy the bacterial structures and cause bacterial death due to the leakage of the contents. The MSN-PEG-Hypericin system prepared in this study had potential application prospects in the antibacterial field.

Taming the storm: potential anti-inflammatory compounds targeting SARS-CoV-2 MPro

In severe COVID-19 cases, an exacerbated inflammatory response triggers a cytokine storm that can worsen the prognosis. Compounds with both antiviral and anti-inflammatory activities show promise as candidates for COVID-19 therapy, as they potentially act against the SARS-CoV-2 infection regardless of the disease stage. One of the most attractive drug targets among coronaviruses is the main protease (MPro). This enzyme is crucial for cleaving polyproteins into non-structural proteins required for viral replication. The aim of this review was to identify SARS-CoV-2 MPro inhibitors with both antiviral and anti-inflammatory properties. The interactions of the compounds within the SARS-CoV-2 MPro binding site were analyzed through molecular docking when data from crystallographic structures were unavailable. 18 compounds were selected and classified into five different superclasses. Five of them exhibit high potency against MPro: GC-376, baicalein, naringenin, heparin, and carmofur, with IC50 values below 0.2 μM. The MPro inhibitors selected have the potential to alleviate lung edema and decrease cytokine release. These molecules mainly target three critical inflammatory pathways: NF-κB, JAK/STAT, and MAPK, all previously associated with COVID-19 pathogenesis. The structures of the compounds occupy the S1/S2 substrate binding subsite of the MPro. They interact with residues from the catalytic dyad (His41 and Cys145) and/or with the oxyanion hole (Gly143, Ser144, and Cys145), which are pivotal for substrate recognition. The MPro SARS-CoV-2 inhibitors with potential anti-inflammatory activities present here could be optimized for maximum efficacy and safety and be explored as potential treatment of both mild and severe COVID-19.

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.

Molecular Nanoarchitectonics of Natural Photosensitizers and Their Derivatives Nanostructures for Improved Photodynamic Therapy

Natural photosensitizers (PSs) and their derivatives have drawn ever-increasing attention in photodynamic therapy (PDT) for their wild range of sources, desirable biocompatibility, and good photosensitivity. Nevertheless, many factors such as poor solubility, high body clearance rate, limited tumor targeting ability, and short excitation wavelengths severely hinder their applications in efficient PDT. In recent years, fabricating nanostructures by utilizing molecular assembly technique is proposed to solve these problems. This technique is easy to put into effect, and the assembled nanostructures could improve the physical properties of the PSs so as to meet the requirement of PDT. In this concept, we focus on the construction of natural PSs and their derivatives nanostructures through molecular assembly technique to enhance PDT efficacy (Figure 1). Furthermore, current challenges and future perspectives of natural PSs and their derivatives for efficient PDT are discussed.

Immunomodulatory Effect of Hypericin-Mediated Photodynamic Therapy on Oral Cancer Cells

In 2020, there were 377,713 new oral and lip cancer diagnoses and 177,757 deaths. Oral cancer is a malignancy of the head and neck region, and 90% of cases are squamous cell carcinomas (OSCCs). One of the alternative methods of treating pre-cancerous lesions and oral cancer is photodynamic therapy (PDT). In addition to the cytotoxic effect, an important mechanism of PDT action is the immunomodulatory effect. This study used the OSCC (SCC-25) cell line and the healthy gingival fibroblast (HGF-1) line. A compound of natural origin-hypericin (HY)-was used as the photosensitizer (PS). The HY concentrations of 0-1 µM were used. After two hours of incubation with PS, the cells were irradiated with light doses of 0-20 J/cm2. The MTT test determined sublethal doses of PDT. Cell supernatants subjected to sublethal PDT were assessed for interleukin 6 (IL-6), soluble IL-6 receptor alpha (sIL-6Ralfa), sIL-6Rbeta, IL-8, IL-10, IL-11 IL-20, IL-32, and Pentraxin-3 using the Bio-Plex ProTM Assay. The phototoxic effect was observed starting with a light dose of 5 J/cm2 and amplified with increasing HY concentration and a light dose. HY-PDT affected the SCC-25 cell secretion of sIL-6Rbeta, IL-20, and Pentraxin-3. HY alone increased IL-8 secretion. In the case of HGF-1, the effect of HY-PDT on the secretion of IL-8 and IL-32 was found.

A promising natural anthraquinones mediated by photodynamic therapy for anti-cancer therapy

BACKGROUND

Experimental studies emphasize the therapeutic potential of plant-derived photosensitizers used in photodynamic therapy. Moreover, several in vitro and in vivo research present the promising roles of less-known anthraquinones that can selectively target cancer cells and eliminate them after light irradiation. This literature review summarizes the current knowledge of chosen plant-based-photosensitizers in PDT to show the results of emodin, aloe-emodin, parietin, rubiadin, hypericin, and soranjidiol in photodynamic therapy of cancer treatment and describe the comprehensive perspective of their role as natural photosensitizers.

METHODS

Literature searches of chosen anthraquinones were conducted on PubMed.gov with keywords: "emodin", "aloe-emodin", "hypericin", "parietin", "rubiadin", "soranjidiol" with "cancer" and "photodynamic therapy".

RESULTS

According to literature data, this review concentrated on all existing in vitro and in vivo studies of emodin, aloe-emodin, parietin, rubiadin, soranjidiol used as natural photosensitizers emphasizing their effectiveness and detailed mechanism of action in anticancer therapy. Moreover, comprehensive preclinical and clinical studies on hypericin reveal that the above-described substances may be included in the phototoxic treatment of different cancers.

CONCLUSIONS

Overall, this review presented less-known anthraquinones with their promising molecular mechanisms of action. It is expected that in the future they may be used as natural PSs in cancer treatment as well as hypericin.

Traditional Chinese medicines and natural products targeting immune cells in the treatment of metabolic-related fatty liver disease

MAFLD stands for metabolic-related fatty liver disease, which is a prevalent liver disease affecting one-third of adults worldwide, and is strongly associated with obesity, hyperlipidemia, and type 2 diabetes. It encompasses a broad spectrum of conditions ranging from simple liver fat accumulation to advanced stages like chronic inflammation, tissue damage, fibrosis, cirrhosis, and even hepatocellular carcinoma. With limited approved drugs for MAFLD, identifying promising drug targets and developing effective treatment strategies is essential. The liver plays a critical role in regulating human immunity, and enriching innate and adaptive immune cells in the liver can significantly improve the pathological state of MAFLD. In the modern era of drug discovery, there is increasing evidence that traditional Chinese medicine prescriptions, natural products and herb components can effectively treat MAFLD. Our study aims to review the current evidence supporting the potential benefits of such treatments, specifically targeting immune cells that are responsible for the pathogenesis of MAFLD. By providing new insights into the development of traditional drugs for the treatment of MAFLD, our findings may pave the way for more effective and targeted therapeutic approaches.

Purpurin ameliorates D-galactose-induced aging phenotypes in mouse hippocampus by reducing inflammatory responses

Purpurin, an anthraquinone, has potent anti-oxidant and anti-inflammatory effects in various types of brain damage. In a previous study, we showed that purpurin exerts neuroprotective effects against oxidative and ischemic damage by reducing pro-inflammatory cytokines. In the present study, we investigated the effects of purpurin against D-galactose-induced aging phenotypes in mice. Exposure to 100 mM D-galactose significantly decreased cell viability in HT22 cells, and purpurin treatment significantly ameliorated the reduction of cell viability, formation of reactive oxygen species, and lipid peroxidation in a concentration-dependent manner. Treatment with 6 mg/kg purpurin significantly improved D-galactose-induced memory impairment in the Morris water maze test in C57BL/6 mice and alleviated the reduction of proliferating cells and neuroblasts in the subgranular zone of the dentate gyrus. In addition, purpurin treatment significantly mitigated D-galactose-induced changes of microglial morphology in the mouse hippocampus and the release of pro-inflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α. In addition, purpurin treatment significantly ameliorated D-galactose-induced phosphorylation of c-Jun N-terminal kinase and cleavage of caspase-3 in HT22 cells. These results suggest that purpurin can delay aging by reducing the inflammatory cascade and phosphorylation of the c-Jun N-terminal in the hippocampus.

The Role of NQO1 in Ovarian Cancer

Ovarian cancer is one of the most dangerous gynecologic malignancies showing a high fatality rate because of late diagnosis and relapse occurrence due to chemoresistance onset. Several researchers reported that oxidative stress plays a key role in ovarian cancer occurrence, growth and development. The NAD(P)H:quinone oxidoreductase 1 (NQO1) is an antioxidant enzyme that, using NADH or NADPH as substrates to reduce quinones to hydroquinones, avoids the formation of the highly reactive semiquinones, then protecting cells against oxidative stress. In this review, we report evidence from the literature describing the effect of NQO1 on ovarian cancer onset and progression.

An Update on Recent Advances of Photodynamic Therapy for Primary Cutaneous Lymphomas

Primary cutaneous lymphomas are rare non-Hodgkin lymphomas consisting of heterogeneous disease entities. Photodynamic therapy (PDT) utilizing photosensitizers irradiated with a specific wavelength of light in the presence of oxygen exerts promising anti-tumor effects on non-melanoma skin cancer, yet its application in primary cutaneous lymphomas remains less recognized. Despite many in vitro data showing PDT could effectively kill lymphoma cells, clinical evidence of PDT against primary cutaneous lymphomas is limited. Recently, a phase 3 "FLASH" randomized clinical trial demonstrated the efficacy of topical hypericin PDT for early-stage cutaneous T-cell lymphoma. An update on recent advances of photodynamic therapy in primary cutaneous lymphomas is provided.

Effect of Hypericin-Mediated Photodynamic Therapy on the Secretion of Soluble TNF Receptors by Oral Cancer Cells

Squamous cell carcinoma is the most common cancer of the head and neck region. In addition to the classic surgical treatment method, alternative therapy methods are sought. One such method is photodynamic therapy (PDT). In addition to the direct cytotoxic effect, it is essential to determine the effect of PDT on persistent tumor cells. The study used the SCC-25 oral squamous cell carcinoma (OSCC) cell line and the HGF-1 healthy gingival fibroblast line. A compound of natural origin-hypericin (HY)-was used as a photosensitizer (PS) at concentrations of 0-1 µM. After two hours of incubation with the PS, the cells were irradiated with light doses of 0-20 J/cm². The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test was used to determine sublethal doses of PDT. Cell supernatants subjected to sublethal PDT were assessed for soluble tumor necrosis alpha receptors (sTNF-R1, sTNF-R2). The phototoxic effect was observed starting with a light dose of 5 J/cm² and amplified with the increase in HY concentration and light dose. A statistically significant increase in sTNF-R1 secretion by SCC-25 cells was demonstrated after the PDT with 0.5 µM HY and irradiation with 2 J/cm² (sTNF-R1 concentration = 189.19 pg/mL ± 2.60) compared to the control without HY and irradiated with the same dose of light (sTNF-R1 concentration = 108.94 pg/mL ± 0.99). The baseline production of sTNF-R1 was lower for HGF-1 than for SCC-25, and secretion was not affected by the PDT. The PDT had no effect on the sTNF-R2 production in the SCC-25 or HGF-1 lines.