p-Terphenyls as Anti-HSV-1/2 Agents from a Deep-Sea-Derived Penicillium sp

Fluorescent octahydrophenazines as novel inhibitors against herpes simplex viruses

A new series of racemic fluorescent octahydrophenazines (rac-PZ1-11) have been designed and synthesized via the efficient nucleophilic aromatic substitution (SNAr) of tetrafluorobenzenedinitriles (1a-c) and racemic cyclohexane-1,2-diamines (rac-2a and b). The bioactivities of these racemic rac-PZs (20 μM) against herpes simplex virus type-1 (HSV-1) were evaluated by the relative cell viability of Vero cells infected with HSV-1. It was found that rac-PZ3 shows much higher anti-HSV-1 activity than others, with EC50 = 9.2 ± 1.4 μM. Further investigation into the anti-HSV activities of rac-PZ3 and its enantiomers RR- and SS-PZ3 indicates that rac-PZ3 can also efficiently inhibit HSV-2 and even ACV-resistant HSV-2 (EC50 = 11.0 ± 2.3 and 14.9 ± 2.8 μM, respectively), SS-PZ3 has better activities against HSV-1, HSV-2 and ACV-resistant HSV-2 (EC50 = 4.1 ± 1.1, 5.8 ± 1.0 and 7.9 ± 1.2 μM, respectively), but RR-PZ3 has almost no antiviral activities. The primary mechanism study indicates that rac-PZ3 efficiently reverses the HSV-1/2-induced cytopathic effect and suppresses the expression of viral mRNA and proteins. In addition, rac-, RR- and SS-PZ3 possess excellent fluorescence properties with almost the same emission wavelength and high fluorescence quantum yields (ΦF = 90.3-92.3 % in cyclohexane solutions and 54.4-57.3 % in solids) and can target endoplasmic reticulum and cell membrane. The efficient anti-HSV bioactivities and excellent fluorescence of PZ3 prove its potential applications in antiviral therapy and biological imaging.

Discovery of Oxidized p-Terphenyls as Phosphodiesterase 4 Inhibitors from Marine-Derived Fungi

Four new p-terphenyl derivatives, talaroterphenyls A-D (1-4), together with three biosynthetically related known ones (5-7), were obtained from the mangrove sediment-derived Talaromyces sp. SCSIO 41412. Compounds 1-3 are rare p-terphenyls, which are completely substituted on the central benzene ring by oxygen atoms; this is the first report of their isolation from natural sources. Their structures were elucidated through NMR spectroscopy, HRESIMS, and X-ray diffraction. Genome sequence analysis revealed that 1-7 were biosynthesized from tyrosine and phenylalanine, involving four key biosynthetic genes (ttpB-ttpE). These p-terphenyls (1-7) and 36 marine-derived terphenyl analogues (8-43) were screened for phosphodiesterase 4 (PDE4) inhibitory activities, and 1-5, 14, 17, 23, and 26 showed notable activities with IC50 values of 0.40-16 μM. The binding pattern of p-terphenyl inhibitors 1-3 with PDE4 were explored by molecular docking analysis. Talaroterphenyl A (1), with a low cytotoxicity, showed obvious anti-inflammatory activity in LPS-stimulated RAW264.7 cells. Furthermore, in the TGF-β1-induced medical research council cell strain-5 (MRC-5) pulmonary fibrosis model, 1 could down-regulate the expression levels of FN1, COL1, and α-SMA significantly at concentrations of 5-20 μM. This study suggests that the oxidized p-terphenyl 1, as a marine-derived PDE4 inhibitor, could be used as a promising antifibrotic agent.

Neuroprotective azaphilones from a deep-sea derived fungus Penicillium sp. SCSIO41030

Ten azaphilones including one pair of new epimers and three new ones, penineulones A-E (1-5) with the same structural core of angular deflectin, were obtained from a deep-sea derived Penicillium sp. SCSIO41030 fermented on a liquid medium. Their structures including absolute configurations were elucidated using chiral-phase HPLC analysis, extensive NMR spectroscopic and HRESIMS data, ECD and NMR calculations, and by comparing NMR data with literature data. Biological assays showed that the azaphilones possessed no antitumor and anti-viral (HSV-1/2) activities at concentrations of 5.0 μM and 20 μM, respectively. In addition, azaphilones 8 and 9 showed neuroprotective effects against Aβ25-35-induced neurotoxicity in primary cultured cortical neurons at a concentration of 10 μM. Azaphilones 8 and 9 dramatically promoted axonal regrowth against Aβ25-35-induced axonal atrophy. Our study indicated that azaphilones could be promising lead compounds for neuroprotection.

Peniditerpenoids A and B: Oxidized Indole Diterpenoids with Osteoclast Differentiation Inhibitory Activity from a Mangrove-Sediment-Derived Penicillium sp

An unprecedented di-seco-indole diterpenoid, peniditerpenoid A (1), and a rare N-oxide-containing indole diterpenoid derivative, peniditerpenoid B (2), together with three known ones (3-5), were obtained from the mangrove-sediment-derived fungus Penicillium sp. SCSIO 41411. Their structures were determined by the analysis of spectroscopic data, quantum chemical calculations, and X-ray diffraction analyses. Peniditerpenoid A (1) inhibited lipopolysaccharide-induced NF-κB with an IC50 value of 11 μM and further effectively prevented RANKL-induced osteoclast differentiation in bone marrow macrophages. In vitro studies demonstrated that 1 exerted significant inhibition of NF-κB activation in the classical pathway by preventing TAK1 activation, IκBα phosphorylation, and p65 translocation. Furthermore, 1 effectively reduced the level of NFATc1 activation, resulting in the attenuation of osteoclast differentiation. Our findings suggest that 1 holds promise as an inhibitor with significant potential for the treatment of diseases related to osteoporosis.

New piperazine derivatives helvamides B-C from the marine-derived fungus Penicillium velutinum ZK-14 uncovered by OSMAC (One Strain Many Compounds) strategy

Four extracts of the marine-derived fungus Penicillium velutinum J.F.H. Beyma were obtained via metal ions stress conditions based on the OSMAC (One Strain Many Compounds) strategy. Using a combination of modern approaches such as LC/UV, LC/MS and bioactivity data analysis, as well as in silico calculations, influence metal stress factors to change metabolite profiles Penicillium velutinum were analyzed. From the ethyl acetate extract of the P. velutinum were isolated two new piperazine derivatives helvamides B (1) and C (2) together with known saroclazin A (3) (4S,5R,7S)-4,11-dihydroxy-guaia-1(2),9(10)-dien (4). Their structures were established based on spectroscopic methods. The absolute configuration of helvamide B (1) as 2R,5R was determined by a combination of the X-ray analysis and by time-dependent density functional theory (TD-DFT) calculations of electronic circular dichroism (ECD) spectra. The cytotoxic activity of the isolated compounds against human prostate cancer PC-3 and human embryonic kidney HEK-293 cells and growth inhibition activity against yeast-like fungi Candida albicans were assayed.

Novel Bioactive Natural Products from Marine-Derived Penicillium Fungi: A Review (2021-2023)

Marine-derived Penicillium fungi are productive sources of structurally unique and diverse bioactive secondary metabolites, representing a hot topic in natural product research. This review describes structural diversity, bioactivities and statistical research of 452 new natural products from marine-derived Penicillium fungi covering 2021 to 2023. Sediments are the main sources of marine-derived Penicillium fungi for producing nearly 56% new natural products. Polyketides, alkaloids, and terpenoids displayed diverse biological activities and are the major contributors to antibacterial activity, cytotoxicity, anti-inflammatory and enzyme inhibitory capacities. Polyketides had higher proportions of new bioactive compounds in new compounds than other chemical classes. The characteristics of studies in recent years are presented.

Engineered extracellular vesicles efficiently deliver CRISPR-Cas9 ribonucleoprotein (RNP) to inhibit herpes simplex virus1 infection in vitro and in vivo

Extracellular vesicles (EVs) have recently emerged as a promising delivery platform for CRISPR/Cas9 ribonucleoproteins (RNPs), owing to their ability to minimize off-target effects and immune responses. However, enhancements are required to boost the efficiency and safety of Cas9 RNP enrichment within EVs. In response, we employed the Fc/Spa interaction system, in which the human Fc domain was fused to the intracellular domain of PTGFRN-Δ687 and anchored to the EV membrane. Simultaneously, the B domain of the Spa protein was fused to the C domain of cargos such as Cre or spCas9. Due to the robust interaction between Fc and Spa, this method enriched nearly twice the amount of cargo within the EVs. EVs loaded with spCas9 RNP targeting the HSV1 genome exhibited significant inhibition of viral replication in vitro and in vivo. Moreover, following neuron-targeting peptide RVG modification, the in vivo dosage in neural tissues substantially increased, contributing to the clearance of the HSV1 virus in neural tissues and exhibiting a lower off-target efficiency. These findings establish a robust platform for efficient EV-based SpCas9 delivery, offering potential therapeutic advantages for HSV1 infections and other neurological disorders.

Identifying Marine-Derived Tanzawaic Acid Derivatives as Novel Inhibitors against Osteoclastogenesis and Osteoporosis via Downregulation of NF-κB and NFATc1 Activation

To discover novel osteoclast-targeting antiosteoporosis leads from natural products, we identified 40 tanzawaic acid derivatives, including 22 new ones (1-8, 14-19, 27-32, 37, and 38), from the South China Sea mangrove-derived fungus Penicillium steckii SCSIO 41025. Penicisteck acid F (2), one of the new derivatives showing the most potent NF-κB inhibitory activity, remarkably inhibited osteoclast generation in vitro. Mechanistically, 2 reduced RANKL-induced IκBα degradation, NF-κB p65 nuclear translocation, the activation and nuclear translocation of NFATc1, and the relevant mRNA expression. NF-κB p65 could be a potential molecular target for 2, which has been further determined by the cellular thermal shift assay, surface plasmon resonance, and the gene knock-down assay. Moreover, 2 could also alleviate osteoporosis in ovariectomized mice by reducing the quantities of osteoclasts. Our finding offered a novel potential inhibitor of osteoclastogenesis and osteoporosis for further development of potent antiosteoporosis agents.

Anti-herpes simplex virus activities and mechanisms of marine derived compounds

Herpes simplex virus (HSV) is the most widely prevalent herpes virus worldwide, and the herpetic encephalitis and genital herpes caused by HSV infection have caused serious harm to human health all over the world. Although many anti-HSV drugs such as nucleoside analogues have been ap-proved for clinical use during the past few decades, important issues, such as drug resistance, toxicity, and high cost of drugs, remain unresolved. Recently, the studies on the anti-HSV activities of marine natural products, such as marine polysaccharides, marine peptides and microbial secondary metabolites are attracting more and more attention all over the world. This review discusses the recent progress in research on the anti-HSV activities of these natural compounds obtained from marine organisms, relating to their structural features and the structure-activity relationships. In addition, the recent findings on the different anti-HSV mechanisms and molecular targets of marine compounds and their potential for therapeutic application will also be summarized in detail.

p-Terphenyl and Diphenyl Ether Derivatives from the Marine-Derived Fungus Aspergillus candidus HM5-4

Two undescribed p-terphenyl derivatives, asperterphenylcins A-B (1-2), and two undescribed diphenyl ether derivatives, asperdiphenylcins A-B (3-4), together with three previously described p-terphenyl derivatives-4″-deoxyterprenin (5), terphenyllin (6), and 3″-hydroxyterphenyllin (7)-were obtained from the solid-rice culture of the marine-derived fungus Aspergillus candidus HM5-4, which was isolated from sponges from the South China Sea. Their structures were elucidated by HRESIMS data and NMR spectroscopic analysis. Compound 1 showed a strong inhibitory effect on Neoscytalidium dimidiatum, with an inhibition circle diameter of 31.67 ± 2.36 mm at a concentration of 10.0 µg/disc. Compounds 5 and 7 displayed cytotoxic activity against human chronic myeloid leukemia cells (K562), human liver cancer cells (BEL-7402), human gastric cancer cells (SGC-7901), human non-small cell lung cancer cells (A549) and human HeLa cervical cancer cells, with IC50 values ranging from 3.32 to 60.36 µM, respectively. Compounds 2, 6 and 7 showed potent inhibitory activity against α-glucosidase, with IC50 values of 1.26 ± 0.19, 2.16 ± 0.44 and 13.22 ± 0.55 µM, respectively.

Natural products as potential lead compounds to develop new antiviral drugs over the past decade

Virus infection has been one of the main causes of human death since the ancient times. Even though more and more antiviral drugs have been approved in clinic, long-term use can easily lead to the emergence of drug resistance and side effects. Fortunately, there are many kinds of metabolites which were produced by plants, marine organisms and microorganisms in nature with rich structural skeletons, and they are natural treasure house for people to find antiviral active substances. Aiming at many types of viruses that had caused serious harm to human health in recent years, this review summarizes the natural products with antiviral activity that had been reported for the first time in the past ten years, we also sort out the source, chemical structure and safety indicators in order to provide potential lead compounds for the research and development of new antiviral drugs.

A potential anti-HIV-1 compound, Q308, inhibits HSV-2 infection and replication in vitro and in vivo

HSV-2 is a common human pathogen worldwide that causes genital herpes. Due to the lack of an effective HSV-2 vaccine in the foreseeable future, there is an urgent need to develop effective, safe and affordable anti-HSV-2 agents. Our previous studies confirmed that a small-molecule compound, Q308, effectively inhibits the reactivation of latent HIV and might be developed as an anti-HIV-1 agent. Patients infected with HSV-2 are generally more susceptible to HIV-1 infection than normal humans. In this study, we found that Q308 treatment had strong inhibitory activity against both HSV-2 and acyclovir-resistant HSV-2 strains in vitro and reduced the viral titers in tissue. And this treatment effectively ameliorated the cytokine storm and pathohistological changes caused by HSV-2 infection in HSV-2-infected mice. Unlike nucleoside analogs such as acyclovir, Q308 inhibited post-viral entry events by attenuating the synthesis of viral proteins. Furthermore, Q308 treatment blocked HSV-2-induced PI3K/AKT phosphorylation due to its inhibition on viral infection and replication. Overall, Q308 treatment exhibits potent anti-HSV-2 activity by inhibiting viral replication both in vitro and in vivo. Q308 is a promising lead compound for the development of new anti-HSV-2/HIV-1 therapies, particularly against acyclovir-resistant HSV-2 strains.

Tanzawaic Acid Derivatives from the Marine-Derived Penicillium steckii as Inhibitors of RANKL-Induced Osteoclastogenesis

Seven new tanzawaic acid derivatives, steckwaic acids E-K (1-7), and one new benzene derivate (8), together with seven known tanzawaic acid analogues (9-16) were isolated from the marine algicolous fungus Penicillium steckii SCSIO 41040. The structures and absolute configurations of these new compounds (1-8) were determined by spectroscopic analyses, X-ray diffraction, and comparison of ECD spectra to calculations. Compounds 2, 10, and 15 inhibited lipopolysaccharide (LPS)-induced nuclear factor kappa-B (NF-κB) with IC₅₀ values of 10.4, 18.6, and 15.2 μM, respectively. Compound 2 could suppress the receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation in bone marrow macrophage cells (BMMCs). To the best of our knowledge, this is the first report of osteoclastogenesis inhibitory activity for tanzawaic acid derivatives.

Structurally various p-terphenyls with neuraminidase inhibitory from a sponge derived fungus Aspergillus sp. SCSIO41315

Guided by Global Natural Products Social molecular networking, 14 new p-terphenyl derivatives, asperterphenyls A-N (1-14), together with 20 known p-terphenyl derivatives (15-34), were obtained from a sponge derived fungus Aspergillus sp. SCSIO41315. Among them, new compounds 2-8 and 15-17 were ten pairs of enantiomers. Comprehensive methods such as chiral-phase HPLC analysis, ECD calculations and X-ray diffraction analysis were applied to determine the absolute configurations. Asperterphenyls B (2) and C (3) represented the first reported natural p-terphenyl derivatives possessing a dicarboxylic acid system. Asperterphenyl A (1) displayed neuraminidase inhibitory activity with an IC₅₀ value of 1.77 ± 0.53 µM and could efficiently inhibit infection of multiple strains of H1N1 with IC₅₀ values from 0.67 ± 0.28 to 1.48 ± 0.60 µM through decreasing viral plaque formation in a dose-dependent manner, which suggested that asperterphenyl A (1) might be exploited as a potential antiviral compound in the pharmaceutical fields.

Marine natural products

Covering: January to December 2021This review covers the literature published in 2021 for marine natural products (MNPs), with 736 citations (724 for the period January to December 2021) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1425 in 416 papers for 2021), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the number of authors, their affiliations, domestic and international collection locations, focus of MNP studies, citation metrics and journal choices is discussed.

Binding of Vialinin A and p-Terphenyl Derivatives to Ubiquitin-Specific Protease 4 (USP4): A Molecular Docking Study

The para-terphenyl derivative vialinin A (Vi-A), isolated from Thelephora fungi, has been characterized as a potent inhibitor of the ubiquitin-specific protease 4 (USP4). Blockade of USP4 contributes to the anti-inflammatory and anticancer properties of the natural product. We have investigated the interaction of Vi-A with USP4 by molecular modeling, to locate the binding site (around residue V98 within the domain in USP segment) and to identify the binding process and interaction contacts. From this model, a series of 32 p-terphenyl compounds were tested as potential USP4 binders, mainly in the vialinin, terrestrin and telephantin series. We identified 11 compounds presenting a satisfactory USP4 binding capacity, including two fungal products, vialinin B and aurantiotinin A, with a more favorable empirical energy of USP4 interaction (ΔE) than the reference product Vi-A. The rare p-terphenyl aurantiotinin A, isolated from the basidiomycete T. aurantiotincta, emerged as a remarkable USP4 binder. Structure-binding relationships have been identified and discussed, to guide the future design of USP4 inhibitors based on the p-terphenyl skeleton. The docking study should help the identification of other protease inhibitors from fungus.

Anti-inflammatory and anticancer p-terphenyl derivatives from fungi of the genus Thelephora

Fungi from the genus Thelephora have been exploited to identify bioactive compounds. The main natural products characterized are para-terphenyl derivatives, chiefly represented by the lead anti-inflammatory compound vialinin A isolated from species T. vialis and T. terrestris. Different series of p-terphenyls have been identified, including vialinins, ganbajunins, terrestrins, telephantins and other products. Their mechanism of action is not always clearly identified, and different potential molecule targets have been proposed. The lead vialinin A functions as a protease inhibitor, efficiently targeting ubiquitin-specific peptidases USP4/5 and sentrin-specific protease SENP1 which are prominent anti-inflammatory and anticancer targets. Protease inhibition is coupled with a powerful inhibition of the cellular production of tumor necrosis factor TNFα. Other mechanisms contributing to the anti-inflammatory or anti-proliferative action of these p-terphenyl compounds have been invoked, including the formation of cytotoxic copper complexes for derivatives bearing a catechol central unit such vialinin A, terrestrin B and telephantin O. These p-terphenyl compounds could be further exploited to design novel anticancer agents, as evidenced with the parent compound terphenyllin (essentially found in Aspergillus species) which has revealed marked antitumor and anti-metastatic effects in xenograft models of gastric and pancreatic cancer. This review shed light on the structural and functional diversity of p-terphenyls compounds isolated from Thelephora species, their molecular targets and pharmacological properties.

Aromatic Acids and Leucine Derivatives Produced from the Deep-Sea Actinomycetes Streptomyceschumphonensis SCSIO15079 with Antihyperlipidemic Activities

Six new aromatic acids (1–6) and three new leucine derivatives containing an unusual oxime moiety (7–9) were isolated and identified from the deep-sea-derived actinomycetes strain Streptomyces chumphonensis SCSIO15079, together with two known compounds (10–11). The structures of 1–9 including absolute configurations were determined by detailed NMR, MS, and experimental and calculated electronic circular dichroism spectroscopic analyses. Compounds 1–9 were evaluated for their antimicrobial and cytotoxicity activities, as well as their effects on intracellular lipid accumulation in HepG2 cells. Compounds 3 and 4, with the most potent inhibitory activity on intracellular lipid accumulation at 10 μM, were revealed with potential antihyperlipidemic effects, although the mechanism needs to be further studied.