Marine natural products

Metabolomic Analysis and Antiviral Screening of a Marine Algae Library Yield Jobosic Acid (2,5-Dimethyltetradecanoic Acid) as a Selective Inhibitor of SARS-CoV-2

Current small-molecule-based SARS-CoV-2 treatments have limited global accessibility and pose the risk of inducing viral resistance. Therefore, a marine algae and cyanobacteria extract library was screened for natural products that could inhibit two well-defined and validated COVID-19 drug targets, disruption of the spike protein/ACE-2 interaction and the main protease (Mpro) of SARS-CoV-2. Following initial screening of 86 extracts, we performed an untargeted metabolomic analysis of 16 cyanobacterial extracts. This approach led to the isolation of an unusual saturated fatty acid, jobosic acid (2,5-dimethyltetradecanoic acid, 1). We confirmed that 1 demonstrated selective inhibitory activity toward both viral targets while retaining some activity against the spike-RBD/ACE-2 interaction of the SARS-CoV-2 omicron variant. To initially explore its structure-activity relationship (SAR), the methyl and benzyl ester derivatives of 1 were semisynthetically accessed and demonstrated acute loss of bioactivity in both SARS-CoV-2 biochemical assays. Our efforts have provided copious amounts of a fatty acid natural product that warrants further investigation in terms of SAR, unambiguous determination of its absolute configuration, and understanding of its specific mechanisms of action and binding site toward new therapeutic avenues for SARS-CoV-2 drug development.

Antitumor aspochalasin and antiviral benzofuran derivatives from a marine-derived fungus Aspergillus sp. SCSIO41032

Chemical investigation of the EtOAc extract of a deep-sea derived fungus Aspergillus sp. SCSIO41032 resulted in the isolation of ten known compounds, including eight aspochalasins. Their structures were elucidated by using extensive NMR spectroscopic, mass spectrometric and single crystal X-ray diffraction analysis. The detailed crystallographic data for structures 1, 2, and 4, along with the relative configurations of aspochalasin E (3) determined by its acetonide derivative were reported for the first time. The results of antitumor and antiviral activities showed that 3 displayed moderate antitumor activities against 22Rv1, PC-3, A549, and HCT-15 cell lines with IC50 values ranged from 5.9 ± 0.8 to 19.0 ± 7.7 μM, and 9 exhibited moderate antiviral activities against HSV-1/2 with EC50 values of 9.5 ± 0.5 and 5.4 ± 0.6 μM, respectively. Plate clone formation assays results indicated that 3 inhibited the 22Rv1, PC-3 cells growth in a dose-dependent manner.

Bioactive Alkaloids from the Mangrove-Derived Fungus Nigrospora oryzae SYSU-MS0024

Chemical investigation of marine fungus Nigrospora oryzae SYSU-MS0024 cultured on solid-rice medium led to the isolation of three new alkaloids, including a pair of epimers, nigrosporines A (1) and B (2), and a pair of enantiomers, (+)-nigrosporine C (+)-3, and (-)-nigrosporine C (-)-3, together with eight known compounds (4-11). Their structures were elucidated based on extensive mass spectrometry (MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopic analyses and compared with data in the literature. The absolute configurations of compounds 1-3 were determined by a combination of electronic circular dichroism (ECD) calculations, Mosher's method, and X-ray single-crystal diffraction technique using Cu Kα radiation. In bioassays, compound 2 exhibited moderate inhibition on NO accumulation induced by lipopolysaccharide (LPS) on BV-2 cells in a dose-dependent manner at 20, 50, and 100 μmol/L and without cytotoxicity in a concentration of 100.0 μmol/L. Moreover, compound 2 also showed moderate acetylcholinesterase (AChE) inhibitory activities with IC50 values of 103.7 μmol/L. Compound 5 exhibited moderate antioxidant activity with EC50 values of 167.0 μmol/L.

Cytotoxic and Antibacterial Meroterpenoids Isolated from the Marine-Derived Fungus Talaromyces sp. M27416

Three novel meroterpenoids, taladrimanins B-D (1-3), were isolated from the marine-derived fungus Talaromyces sp. M27416, alongside three biogenetically related compounds (4-6). We delineated taladrimanin B's (1) structure using HRESIMS and NMR, confirmed its configuration via quantum chemical NMR analysis and DP4+ methodology, and verified it through X-ray crystallography. ECD calculations determined the absolute configuration of compound 1, while comparative NMR and ECD analyses elucidated the absolute configurations of 2 and 3. These compounds are drimane-type meroterpenoids with a C10 polyketide unit (8R-configuration). We proposed a biosynthetic pathway and noted that compound 1 showed cytotoxic activity against MKN-45 and 5637 cell lines and selective antibacterial effects against Staphylococcus aureus CICC 10384.

Chemical Constituents and Biological Activities of Bruguiera Genus and Its Endophytes: A Review

The genus Bruguiera, a member of the Rhizophoraceae family, is predominantly found in coastal areas as a mangrove plant, boasting a rich and diverse community of endophytes. This review systematically compiled approximately 496 compounds derived from both the Bruguiera genus and its associated endophytes, including 152 terpenoids, 17 steroids, 16 sulfides, 44 alkaloids and peptides, 66 quinones, 68 polyketides, 19 flavonoids, 38 phenylpropanoids, 54 aromatic compounds, and 22 other compounds. Among these, 201 compounds exhibited a spectrum of activities, including cytotoxicity, antimicrobial, antioxidant, anti-inflammatory, antiviral, antidiabetic, insecticidal and mosquito repellent, and enzyme inhibitory properties, etc. These findings provided promising lead compounds for drug discovery. Certain similar or identical compounds were found to be simultaneously present in both Bruguiera plants and their endophytes, and the phenomenon of their interaction relationship was discussed.

Rapid discovery of a new antifoulant: From in silico studies targeting barnacle chitin synthase to efficacy against barnacle settlement

Due to the adverse environmental impacts of toxic heavy metal-based antifoulants, the screening of environmentally friendly antifoulants has become important for the development of marine antifouling technology. Compared with the traditional lengthy and costly screening method, computer-aided drug design (CADD) offers a promising and efficient solution that can accelerate the screening process of green antifoulants. In this study, we selected barnacle chitin synthase (CHS, an important enzyme for barnacle settlement and development) as the target protein for docking screening. Three CHS genes were identified in the barnacle Amphibalanus amphitrite, and their encoded proteins were found to share a conserved glycosyltransferase domain. Molecular docking of 31,561 marine natural products with AaCHSs revealed that zoanthamine alkaloids had the best binding affinity (-11.8 to -12.6 kcal/mol) to AaCHSs. Considering that the low abundance of zoanthamine alkaloids in marine organisms would limit their application as antifoulants, a marine fungal-derived natural product, mycoepoxydiene (MED), which has a similar chemical structure to zoanthamine alkaloids and the potential for large-scale production by fermentation, was selected and validated for stable binding to AaCHS2L2 using molecular docking and molecular dynamics simulations. Finally, the efficacy of MED in inhibiting cyprid settlement of A. amphitrite was confirmed by a bioassay that demonstrated an EC50 of 1.97 μg/mL, suggesting its potential as an antifoulant candidate. Our research confirmed the reliability of using AaCHSs as antifouling targets and has provided insights for the efficient discovery of green antifoulants by CADD.

Mimicking Nonribosomal Peptides from the Marine Actinomycete Streptomyces sp. H-KF8 Leads to Antimicrobial Peptides

Microorganisms within the marine environment have been shown to be very effective sources of naturally produced antimicrobial peptides (AMPs). Several nonribosomal peptides were identified based on genome mining predictions of Streptomyces sp. H-KF8, a marine Actinomycetota isolated from a remote Northern Chilean Patagonian fjord. Based on these predictions, a series of eight peptides, including cyclic peptides, were designed and chemically synthesized. Six of these peptides showed antimicrobial activity. Mode of action studies suggest that two of these peptides potentially act on the cell membrane via a novel mechanism allowing the passage of small ions, resulting in the dissipation of the membrane potential. This study shows that though structurally similar peptides, determined by NMR spectroscopy, the incorporation of small sequence mutations results in a dramatic influence on their bioactivity including mode of action. The qualified hit sequence can serve as a basis for more potent AMPs in future studies.

Shikimate-Derived Meroterpenoids from the Ascidian-Derived Fungus Amphichorda felina SYSU-MS7908 and Their Anti-Glioma Activity

Glioma is a clinically heterogeneous type of brain tumor with a poor prognosis. Current treatment approaches have limited effectiveness in treating glioma, highlighting the need for novel drugs. One approach is to explore marine natural products for their therapeutic potential. In this study, we isolated nine shikimate-derived diisoprenyl-cyclohexene/ane-type meroterpenoids (1-9), including four new ones, amphicordins A-D (1-4) from the ascidian-derived fungus Amphichorda felina SYSU-MS7908, and further semisynthesized four derivatives (10-13). Their structures were extensively characterized using 1D and 2D NMR, modified Mosher's method, HR-ESIMS, NMR and ECD calculations, and X-ray crystallography. Notably, amphicordin C (3) possesses a unique benzo[g]chromene (6/6/6) skeleton in this meroterpenoid family. In an anti-glioma assay, oxirapentyn A (7) effectively inhibited the proliferation, migration, and invasion of glioma cells and induced their apoptosis. Furthermore, an in silico analysis suggested that oxirapentyn A has the potential to penetrate the blood-brain barrier. These findings highlight the potential of oxirapentyn A as a candidate for the development of novel anti-glioma drugs.

Distinct emissions of biogenic volatile organic compounds from temperate benthic taxa

INTRODUCTION

Biogenic volatile organic compounds (BVOCs) are emitted by all organisms as intermediate or end-products of metabolic processes. Individual BVOCs perform important physiological, ecological and climatic functions, and collectively constitute the volatilome-which can be reflective of organism taxonomy and health. Although BVOC emissions of tropical benthic reef taxa have recently been the focus of multiple studies, emissions derived from their temperate counterparts have never been characterised.

OBJECTIVES

Characterise the volatilomes of key competitors for benthic space among Australian temperate reefs.

METHODS

Six fragments/fronds of a temperate coral (Plesiastrea versipora) and a macroalga (Ecklonia radiata) from a Sydney reef site were placed within modified incubation chambers filled with seawater. Organism-produced BVOCs were captured on thermal desorption tubes using a purge-and-trap methodology, and were then analysed using GC × GC - TOFMS and multivariate tests.

RESULTS

Analysis detected 55 and 63 BVOCs from P. versipora and E. radiata respectively, with 30 of these common between species. Each taxon was characterised by a similar relative composition of chemical classes within their volatilomes. However, 14 and 10 volatiles were distinctly emitted by either E. radiata or P. versipora respectively, including the halogenated compounds iodomethane, tribromomethane, carbon tetrachloride and trichloromonofluoromethane. While macroalgal cover was 3.7 times greater than coral cover at the sampling site, P. versipora produced on average 17 times more BVOCs per cm2 of live tissue, resulting in an estimated contribution to local BVOC emission that was 4.7 times higher than E. radiata.

CONCLUSION

Shifts in benthic community composition could disproportionately impact local marine chemistry and affect how ecosystems contribute to broader BVOC emissions.

Isolation and Identification of Culturable Bacteria from South China Seawater and Preliminary Screening of Marine Biocontrol Bacteria

Marine microorganisms have evolved special metabolic pathways to produce numerous bioactive substances with novel structures and unique functions. This study analyzed the diversity of culturable bacteria in marine water samples from the South China Sea and screened the isolated bacteria with pathogenic fungi. A total of 200 culturable strains of 72 different bacteria were obtained from 56 water samples from the South China Sea. They belonged to three phyla and four classes, namely Gammaproteobacteria, Alphaproteobacteria, Bacilli and Actinomycetia. Bacilli was the dominant class, comprising up to 59.72%, followed by Gammaproteobacteria (20.83%). Bacillus, Pseudomonas, Paenibacillus and Rhizobium were the most dominant genera. Among these strains, HY-88 and HY-91 encoding BamC, FenB and PKSI genes were selected and identified as Bacillus subtilis. The respective inhibition rates of the HY-88 caused by plate confrontation against Magnaporthe grisea, Fusarium oxysporum, Botrytis cinerea, anthrax and Botrytis cinerea were 90.91%, 54.29%, 52.17% and 51.72%, in comparison with HY-91 86.36%, 48.57%, 47.83% and 34.48%. In addition, the supernatant of HY-88 showed a lesion inhibition rate of 74.5%, which was significantly higher than HY-91 (60.55%). In addition, HY-88 and HY-91 showed strong antifungal activity to Colletotrichum viniferum on detached Shine Muscat grapes. Tolerance tests showed that the HY-88 and HY-91 grew at 10-40 °C, 7-10% NaCl and pH 3-11. HY-88 and HY-91 could inhibit various fungal plant diseases, which lays a foundation for the development of new biopesticides.

Multi-omics Data Reveal the Effect of Sodium Butyrate on Gene Expression and Protein Modification in Streptomyces

Streptomycetes possess numerous gene clusters and the potential to produce a large amount of natural products. Histone deacetylase (HDAC) inhibitors play an important role in the regulation of histone modifications in fungi, but their roles in prokaryotes remain poorly understood. Here, we investigated the global effects of the HDAC inhibitor, sodium butyrate (SB), on marine-derived Streptomycesolivaceus FXJ 8.021, particularly focusing on the activation of secondary metabolite biosynthesis. The antiSMASH analysis revealed 33 secondary metabolite biosynthetic gene clusters (BGCs) in strain FXJ 8.021, among which the silent lobophorin BGC was activated by SB. Transcriptomic data showed that the expression of genes involved in lobophorin biosynthesis (ge00097-ge00139) and CoA-ester formation (e.g., ge02824), as well as the glycolysis/gluconeogenesis pathway (e.g., ge01661), was significantly up-regulated in the presence of SB. Intracellular CoA-ester analysis confirmed that SB triggered the biosynthesis of CoA-ester, thereby increasing the precursor supply for lobophorin biosynthesis. Further acetylomic analysis revealed that the acetylation levels on 218 sites of 190 proteins were up-regulated and those on 411 sites of 310 proteins were down-regulated. These acetylated proteins were particularly enriched in transcriptional and translational machinery components (e.g., elongation factor GE04399), and their correlations with the proteins involved in lobophorin biosynthesis were established by protein-protein interaction network analysis, suggesting that SB might function via a complex hierarchical regulation to activate the expression of lobophorin BGC. These findings provide solid evidence that acetylated proteins triggered by SB could affect the expression of genes involved in the biosynthesis of primary and secondary metabolites in prokaryotes.

Decoding the molecular mechanism of stypoldione against breast cancer through network pharmacology and experimental validation

Breast cancer is the primary factor contributing to female mortality worldwide. The incidence has overtaken lung cancer. It is the most difficult illness due to its heterogeneity and is made up of several subtypes, including Luminal A and B, basal-like, Her-2 overexpressed and TNBC. Amongst different breast carcinoma subtypes, TNBC is the most deadly breast cancer subtype. The hostile nature of TNBC is mainly attributed to its lack of three hormonal receptors and hence lack of targeted therapy. Furthermore, the current diagnostic options like radiotherapy, surgery and chemotherapy render unsuccessful due to recurrence, treatment side effects and drug resistance. The majority of anticancer drugs come from natural sources or is developed from them, making nature a significant source of many medicines. Marine-based constituents such as nucleotides, proteins, peptides, and amides are receiving a lot of interest in the field of cancer treatment due to their bioactive properties. The role of stypoldione in this study as a prospective treatment for breast carcinoma was examined, and we sought to comprehend the molecular means/pathways this chemical employs in breast carcinoma. The most promising possibility for an anti-cancer treatment is stypoldione, a marine chemical produced from the brown alga Stypopodium zonale. We investigated stypoldione's mode of action in breast cancer using the network pharmacology method, and we confirmed our research by using a number of computational tools, including UALCAN, cBioportal, TIMER, docking, and simulation. The findings revealed 92 common targets between the chemical and breast cancer target network. Additionally, we found that stypoldione targets a number of unregulated genes in breast cancer, including: ESR1, HSP90AA1, CXCL8, PTGS2, APP, MDM2, JAK2, KDR, LCK, GRM5, MAPK14, KIT, and several signaling pathways such as FOXO signaling pathway, VEGF pathway, calcium signaling pathway, MAPK/ERK pathway and Neuroactive ligand-receptor interaction. The examined medication demonstrated a strong affinity for the major targets, according to a docking analysis. The best hit compound produced a stable protein-ligand pair, as predicted by molecular dynamics simulations. Our results are supported by the fact that when in-vitro assays were done on melanoma using stypoldione compound it was found that its mechanisms of action involved the PI3K/mTOR/Akt and NF-kB pathways. This study was set out to inspect the possible value of stypoldione as a breast cancer cure and to get a deeper understanding of the molecular mechanisms by which this drug acts on breast cancer.

Hepialiamides A-C: Aminated Fusaric Acid Derivatives and Related Metabolites with Anti-Inflammatory Activity from the Deep-Sea-Derived Fungus Samsoniella hepiali W7

A systematic investigation combined with a Global Natural Products Social (GNPS) molecular networking approach, was conducted on the metabolites of the deep-sea-derived fungus Samsoniella hepiali W7, leading to the isolation of three new fusaric acid derivatives, hepialiamides A-C (1-3) and one novel hybrid polyketide hepialide (4), together with 18 known miscellaneous compounds (5-22). The structures of the new compounds were elucidated through detailed spectroscopic analysis. as well as TD-DFT-based ECD calculation. All isolates were tested for anti-inflammatory activity in vitro. Under a concentration of 1 µM, compounds 8, 11, 13, 21, and 22 showed potent inhibitory activity against nitric oxide production in lipopolysaccharide (LPS)-activated BV-2 microglia cells, with inhibition rates of 34.2%, 30.7%, 32.9%, 38.6%, and 58.2%, respectively. Of particularly note is compound 22, which exhibited the most remarkable inhibitory activity, with an IC50 value of 426.2 nM.

Antiproliferative effect of natural and semisynthetic polyethers from Laurencia viridis

Squalene-derived polyethers are a unique class of compounds that display a great diversity of structures and a broad array of bioactivities, among which its notable antiproliferative activity stands out against various types of cancer cell lines. In this study, eighteen triterpene squalene-derived polyethers, including twelve natural products and six synthetic derivatives, obtained from the red alga Laurencia viridis Gil-Rodríguez & Haroun were screened for their antiproliferative activity against six cancer cell lines: A549, HBL-100, HeLa, SW1573, T-47D, and WiDr; and a structure-activity relationship (SAR) study was established.

Discovery of anti-neuroinflammatory agents from 1,4,5,6-tetrahydrobenzo[2,3]oxepino[4,5-d]pyrimidin-2-amine derivatives by regulating microglia polarization

Neuroinflammation mediated by microglia activation leads to various neurodegenerative and neurological disorders. In order to develop more and better options for this disorders, a series of 3,4-dihydrobenzo[b]oxepin-5(2H)-one derivatives (BZPs, 6-19) and novel 1,4,5,6-tetrahydrobenzo[2,3]oxepino[4,5-d]pyrimidin-2-amine derivatives (BPMs, 20-33) were synthesized and screened the anti-neuroinflamamtion effects. 3,5-bis-trifluoromethylphenyl-substituted BPM 29 showed more potent anti-neuroinflammatory activity and no toxicity to BV2 microglia cells in vitro. 29 significantly reduced the number of M1 phenotype of microglia cells, but significantly increased the number of M2 phenotype of microglia cells in lipopolysaccharide (LPS)-induced BV2 microglia cells. 29 significantly reduced the secretion of inflammatory cytokines (IL-18, IL-1β, TNF-α), but increased the secretion of anti-inflammatory cytokines (IL-10) from LPS-induced BV2 microglia cells. Also, 29 inhibited the NOD-like receptor NLRP3 inflammasome formation, and down-regulated the expression of M2 isoform of pyruvate kinase in LPS-induced BV2 microglia cells. In vivo, 29 reduced the neuroinflammation in cuprizone-induced inflammatory and demyelinating mice by reducing the expression of inducible nitric-oxide synthase, but increased the expression of CD206. Taken together, 29 might be a prospective anti-neuroinflammatory compound for neuroinflammatory and demyelinating disease by alleviating microglia activation.

Deep-sea fungal metabolites as potential inhibitors of glucose-regulatory enzymes: In silico structure-activity analysis

Chronic diabetes mellites related hyperglycemia is a major cause of mortality and morbidity due to further complications like retinopathy, hypertension and cardiovascular diseases. Though several synthetic anti-diabetes drugs specifically targeting glucose-metabolism enzymes are available, they have their own limitations, including adverse side-effects. Unlike other natural or marine-derived pharmacologically important molecules, deep-sea fungi metabolites still remain under-explored for their anti-diabetes potential. We performed structure-based virtual screening of deep-sea fungal compounds selected by their physiochemical properties, targeting crucial enzymes viz., α -amylase, α -glucosidase, pancreatic-lipoprotein lipase, hexokinase-II and protein tyrosine phosphatase-1B involved in glucose-metabolism pathway. Following molecular docking scores and MD simulation analyses, the selected top ten compounds for each enzyme, were subjected to pharmacokinetics prediction based on their AdmetSAR- and pharmacophore-based features. Of these, cladosporol C, tenellone F, ozazino-cyclo-(2,3-dihydroxyl-trp-tyr), penicillactam and circumdatin G were identified as potential inhibitors of α -amylase, α -glucosidase, pancreatic-lipoprotein lipase, hexokinase-II and protein tyrosine phosphatase-1B, respectively. Our in silico data therefore, warrants further experimental and pharmacological studies to validate their anti-diabetes therapeutic potential.

Recent advances in BCRP-induced breast cancer resistance treatment with marine-based natural products

Breast cancer is the prominent cause of cancer-related death in women globally in terms of incidence and mortality. Despite, recent advances in the management of breast cancer, there are still a lot of cases of resistance to medicines, which is currently one of the biggest problems faced by researchers across the globe. Out of several mechanisms, breast cancer resistance protein (BCRP) arbitrated drug resistance is a major concern. Hormonal, cytotoxic and immunotherapeutic drugs are used in the systemic therapy of breast cancer. It is vital to choose drugs based on the clinical and molecular attributes of the tumor to provide better treatment with greater efficacy and minimal harm. Given the aforementioned necessity, the use of marine flora in treating breast cancer cannot be neglected. The scientists also stressed the value of marine-derived goods in avoiding breast cancer resistance. Future research into the identification of anticancer drugs will heavily draw upon the marine environment's ample supply of marine-derived natural products (MNPs), which have a wide range of biological functions. Cell cycle arrest, induction of apoptosis and anti-angiogenic, anti-proliferative and anti-metastasis actions are all part of their processes. The overview of breast cancer, the mechanisms underlying its resistance, recent clinical trials based on marine-derived products in breast cancer and the use of marine products in the treatment of breast cancer are highlighted in this paper. Moreover, the authors also emphasised the importance of marine-derived products in preventing breast cancer resistance.

A new chromone from Kandelia candel endophytic fungus Aspergillus sp. ZJ-68

One chromone (1), together with four known alkaloids, were isolated from the mangrove endophytic fungus Aspergillus sp. ZJ-68. Their structures were elucidated by a combination of HRESIMS and NMR spectroscopic analyses. Compound 1 showed strong anti-inflammatory activity in vitro by inhibiting nitric oxide (NO) production in lipopolysaccharide-activated RAW264.7 cells with an IC50 value of 4.094 ± 0.8 μM, which was better than positive drug indomethacin (IC50=35.8 ± 0.5 μM).

Marine indole alkaloid diversity and bioactivity. What do we know and what are we missing?

Covering: marine indole alkaloids (n = 2048) and their reported bioactivities up to the end of 2021Despite increasing numbers of marine natural products (MNPs) reported each year, most have only been examined for cytotoxic, antibacterial, and/or antifungal biological activities with the majority found to be inactive in these assays. In this context, why are natural products continuing to be examined in assays they are unlikely to show significant activity in, and what targets might be more useful for expanding knowledge of their biologically relevant chemical space? We have undertaken a meta-analysis of the biological activities for 2048 marine indole alkaloids (MIAs), a diverse sub-class of MNPs reported up to the end of 2021, and this has highlighted that the bioactivity potentials for up to 86% of published MIAs remains underexplored and/or undefined. Although most published MIAs are not cytotoxic or antimicrobial, there is a continued focus on using these assays to evaluate new structurally related analogues. Using cheminformatics analyses, the chemical diversity of the 2048 MIAs were clustered using fragment based fingerprints and their reported bioactivity potency towards specific disease targets was assessed for structure activity trends. These analyses showed that there are groups of MIAs that possess potent and diverse activities and that many analogues, previously tested only in cellular toxicity assays, could be better exploited to generate structure activity relationships associated with leads to treat emerging diseases. A collection of indole drug and drug-lead structures from non-natural sources were also incorporated into the dataset providing complementary bioactivity profiles that were further used to predict underexplored areas of potential new activity and to better direct future testing of MIAs. Our findings clearly suggest the biological evaluation of MIAs continues to be conducted on a narrow range of bioassays and disease targets, and that shifting the focus to non-toxic disease targets should provide expanded knowledge of biologically relevant chemical space aimed at maximising the potential of MIAs for drug discovery.

Biosynthesis of the fungal nonribosomal peptide penilumamide A and biochemical characterization of a pterin-specific adenylation domain

We report the characterization of the penilumamide biosynthetic cluster from Aspergillus flavipes CNL-338. In vitro reconstitution experiments demonstrated that three nonribosomal peptide synthetases are required for constructing the tripeptide and studies with dissected adenylation domains allowed for the first biochemical characterization of a domain that selects a pterin-derived building block.

In silico identification of deep-sea fungal alkaloids as potential inhibitors of SARS-CoV-2, Delta and Omicron spikes

Aim: Virtual screening of deep-sea fungal metabolites against SARS-CoV-2 Delta and Omicron spikes as potential antivirals. Materials & methods: Deep-sea fungal alkaloids (n ≥ 150) were evaluated against SARS-CoV-2, Delta and Omicron spikes, using various in silico approaches, including Admet scores, physiochemical properties, molecular docking (MD) and MD simulation (150 ns). Results: The test alkaloids complied with Admet scores and physiochemical properties within acceptable ranges, and followed Lipinski's rule of five. Of these, Cladosporium sphaerospermum-derived cladosin K (tetramate alkaloid) for SARS-CoV-2, Cystobasidium laryngis-derived saphenol (phenazine alkaloid) for Delta and Chaetomium globosum-derived chaetoglobosin E (quinoline alkaloid) for Omicron were identified as potential spike-inhibitors. Conclusion: Our data therefore, strongly warrants further experimental validations of cladosin K, saphenol and chaetoglobosin E, especially against the Omicron and Delta spikes.

Secondary metabolites from Aspergillus terreus F6-3, a marine fungus associated with Johnius belengerii

Two new terrein derivatives asperterreinones A-B (1-2), one new octahydrocoumarin derivative (±)-asperterreinin A (6), along with seventeen known compounds, were isolated from Aspergillus terreus F6-3, a marine fungus associated with Johnius belengerii. The structures of 1, 2, and 6 were established on the basis of 1D and 2D NMR, mass spectroscopy, comparative electronic circular dichroism (ECD) spectra analysis, density functional theory calculation of 13C NMR, and DP4+ probability analysis. Among all the isolates, eurylene (7), a constituent of the Malaysian medicinal plant Eurycoma longifolia, was obtained from a microbial source for first time. In the in vitro bioassay, 11 and 13 showed potent inhibitory activity against the Escherichia coli β-glucuronidase (EcGUS) with IC50 values of 27.75 ± 0.73 and 17.73 ± 0.81 μM, respectively. It was the first time that questinol (11) and (±)-aspertertone B (13) were reported as potent EcGUS inhibitors.

Antibacterial and antibiofilm activity of extracts from sponge-associated bacterial endophytes

Sponges forms association with many bacteria that serve as sources of new bioactive compounds. The compounds are produced in response to environmental and nutritional conditions of the environment that enable them to protect their host from colonization. In this study, three sponge bacterial endophytes were isolated, identified, and subjected to solvent extraction processes. The identified bacteria are Bacillus amyloquifaciens, Bacillus paramycoides, and Enterobacter sp. The bacteria were cultured in two different fermentation media with varying nutritional composition for the extraction process. The extracts were evaluated for antibacterial and antibiofilm activity against microfouling bacteria and the chemical composition of each extract was analyzed via gas chromatography-mass spectrometry (GC-MS). The extract from the endophytes shows varying antibacterial and antibiofilm activity against the tested strains. Several compounds were detected from the extracts including some with known antibacterial/antibiofilm activity. The results showed variations in activity and secondary metabolite production between the extracts obtained under different nutritional composition of the media. In conclusion, this study indicated the role of nutrient composition in the activity and secondary metabolites production by bacteria associated with sponge Also, this study confirmed the role of sponge bacterial endophytes as producers of bioactive compounds with potential application as antifouling (AF) agents.

Exploring marine-derived compounds for MET signalling pathway inhibition in cancer: integrating virtual screening, ADME profiling and molecular dynamics investigations

The MET signalling pathway regulates fundamental cellular processes such as growth, division, and survival. While essential for normal cell function, dysregulation of this pathway can contribute to cancer by triggering uncontrolled proliferation and metastasis. Targeting MET activity holds promise as an effective strategy for cancer therapy. Among potential sources of anti-cancer agents, marine organisms have gained attention. In this study, we screened 47,450 natural compounds derived from marine sources within the CMNPD database against the Met crystal structure. By employing HTVS, SP, and XP docking modes, we identified three compounds (CMNPD17595, CMNPD14026, and CMNPD19696) that outperformed a reference molecule in binding affinity to the Met structure. These compounds demonstrated desirable ADME properties. Molecular Dynamics (MD) simulations for 200 ns confirmed the stability of their interactions with Met. Our findings highlight CMNPD17595, CMNPD14026, and CMNPD19696 as potential inhibitors against Met-dependent cancers. Additionally, these compounds offer new avenues for drug development, leveraging their inhibitory effects on Met to combat carcinogenesis.

Rare rhizo-Actinomycetes: A new source of agroactive metabolites

Numerous biotic and abiotic stress in some geographical regions predisposed their agricultural matrix to challenges threatening plant productivity, health, and quality. In curbing these threats, different customary agrarian principles have been created through research and development, ranging from chemical inputs and genetic modification of crops to the recently trending smart agricultural technology. But the peculiarities associated with these methods have made agriculturists rely on plant rhizospheric microbiome services, particularly bacteria. Several bacterial resources like Proteobacteria, Firmicutes, Acidobacteria, and Actinomycetes (Streptomycetes) are prominent as bioinoculants or the application of their by-products in alleviating biotic/abiotic stress have been extensively studied, with a dearth in the application of rare Actinomycetes metabolites. Rare Actinomycetes are known for their colossal genome, containing well-preserved genes coding for prolific secondary metabolites with many agroactive functionalities that can revolutionize the agricultural industry. Therefore, the imperativeness of this review to express the occurrence and distributions of rare Actinomycetes diversity, plant and soil-associated habitats, successional track in the rhizosphere under diverse stress, and their agroactive metabolite characteristics and functionalities that can remediate the challenges associated with agricultural productivity.

Talasteroid, a new withanolide from the marine-derived fungus Talaromyces stollii

A new withanolide, talasteroid (1), and a known steroid (2), along with eight meroterpenoids (3-10), were obtained from the rice culture of the marine-derived fungus Talaromyces stollii HBU-115. The structure of 1 including its absolute configuration was determined by extensive 1 D and 2 D NMR spectroscopy, and single-crystal X-ray diffraction analysis. Compound 1 represents the first withanolide featuring a 4-substituted 2,3-dimethyl-2-butenolide ring in the side chain. The isolated compounds were evaluated for their antimicrobial and antioxidant activities.

Cytotoxic and anti-bacterial evaluation of two new aromatic A-ring steroids isolated from the Red Sea soft coral Dendronephthya spp

A successful column chromatography of a CHCl3/MeOH crude extract of Dendronephthya spp. soft coral led to the isolation of two new aromatic A-ring steroids (1-2), together with three known compounds (3-5). Both 1 and 2 are 19-norsteroids. The chemical structures were elucidated based on extensive 1D, 2D NMR, and EIMS analyses. In cytotoxic bioassays, compounds 1-5 were tested against three cancer cell lines: MCF-7, NCI-1299, and HepG2, with IC50 in the ranges of 22.1-85.4, 26.9-88.7, and 25.9-93.7 μM, respectively. Compounds 1, 2, and 5 showed moderate degrees of inhibition against Escherichia coli and Pseudomonas sp. at 100 and 150 µg/mL, while exhibiting weak inhibition against Bacillus cereus and Staphylococcus aureus at 150 µg/mL.

Dictyota and Canistrocarpus Brazilian Brown Algae and Their Bioactive Diterpenes-A Review

Dictyotaceae algae have gained recognition as prolific producers of diterpenes, which are molecules with significant biotechnological potential. These diterpenes hold immense promise as potential active drug components, making the algae a compelling area of study. The present review aims to present the latest advancements in understanding the biopotential of Brazilian Dictyota and Canistrocarpus brown algae, shedding light on the remarkable diversity and the biological and pharmacological potential of the secondary metabolites they produce. A total of 78 articles featuring 26 distinct diterpenes are reported in this review, with their antiviral potential being the mosthighlighted biological activity. Despite considerable research on these algae and their diterpenes, significant knowledge gaps persist. Consequently, the present review is poised to serve as a pivotal resource for researchers who are actively engaged in the pursuit of active diterpenes beyond the immediate purview. Furthermore, it holds the potential to catalyze an increase in research endeavors centered around these algal species within the geographical confines of the Brazilian coastline. Also, it assumes a critical role in directing future scientific explorations toward a better comprehension of these compounds and their ecological implications.

Emerging pharmaceutical therapies of Ascidian-derived natural products and derivatives

In a growing multidrug-resistant environment, the identification of potential new drug candidates with an acceptable safety profile is a substantial crux in pharmaceutical discovery. This review discusses several aspects and properties of approved marine natural products derived from ascidian sources (phylum Chordata, subphylum Tunicata) and/or their deduced analogues including their biosynthetic origin, (bio)chemical preclinical assessments and known efficacy-safety profiles, clinical status in trials, but also translational developments, opportunities and final conclusions. The review also describes the preclinical assessments of a large number of other ascidian compounds that have not been involved in clinical trials yet. Finally, the emerging research on the connectivity of the ascidian hosts and their independent or obligate symbiotic guests is discussed. The review covers the latest information on the topic of ascidian-derived marine natural products over the last two decades including 2022, with the majority of publications published in the last decade.

Marine-Derived Components: Can They Be a Potential Therapeutic Approach to Parkinson's Disease?

The increase in the life expectancy average has led to a growing elderly population, thus leading to a prevalence of neurodegenerative disorders, such as Parkinson's disease (PD). PD is the second most common neurodegenerative disorder and is characterized by a progressive degeneration of the dopaminergic neurons in the substantia nigra pars compacta (SNpc). The marine environment has proven to be a source of unique and diverse chemical structures with great therapeutic potential to be used in the treatment of several pathologies, including neurodegenerative impairments. This review is focused on compounds isolated from marine organisms with neuroprotective activities on in vitro and in vivo models based on their chemical structures, taxonomy, neuroprotective effects, and their possible mechanism of action in PD. About 60 compounds isolated from marine bacteria, fungi, mollusk, sea cucumber, seaweed, soft coral, sponge, and starfish with neuroprotective potential on PD therapy are reported. Peptides, alkaloids, quinones, terpenes, polysaccharides, polyphenols, lipids, pigments, and mycotoxins were isolated from those marine organisms. They can act in several PD hallmarks, reducing oxidative stress, preventing mitochondrial dysfunction, α-synuclein aggregation, and blocking inflammatory pathways through the inhibition translocation of NF-kB factor, reduction of human tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6). This review gathers the marine natural products that have shown pharmacological activities acting on targets belonging to different intracellular signaling pathways related to PD development, which should be considered for future pre-clinical studies.

Quinolinones Alkaloids with AChE Inhibitory Activity from Mangrove Endophytic Fungus Penicillium citrinum YX-002

Acetylcholinesterase (AChE) inhibitory activity-guided studies on the mangrove-derived endophytic fungus Penicillium citrinum YX-002 led to the isolation of nine secondary metabolites, including one new quinolinone derivative, quinolactone A (1), a pair of epimers quinolactacin C1 (2) and 3-epi-quinolactacin C1 (3), together with six known analogs (4-9). Their structures were elucidated based on extensive mass spectrometry (MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopic analyses, and compared with data in the literature. The absolute configurations of compounds 1-3 was determined by combination of electronic circular dichroism (ECD) calculations and X-Ray single crystal diffraction technique using CuKα radiation. In bioassays, compounds 1, 4 and 7 showed moderate AChE inhibitory activities with IC50 values of 27.6, 19.4 and 11.2 μmol/L, respectively. The structure-activity relationships (SARs) analysis suggested that the existence of carbonyl group on C-3 and the oxygen atom on the five-membered ring were beneficial to the activity. Molecular docking results showed that compound 7 had a lower affinity interaction energy (-9.3 kcal/mol) with stronger interactions with different sites in AChE activities, which explained its higher activities.

New bisabolane-type sesquiterpenoid from Aspergillus sydowii BTBU20213012

A new bisabolane-type sesquiterpenoid, named (+)-8-dehydroxylaustrosene (1), along with ten known compounds, penicibisabolanes E (2) and G (3), (+)-austrosene (4), (S)-(+)-11-dehydrosydonic acid (5), sydonic acid (6), (7S,11S)-(+)-12-hydroxysydonic acid (7), (-)-(R)-hydroxysydonic acid (8), pseudaboydin A (9), (-)-(7 R,10R)-iso-10-hydroxysydowic acid (10), lumichrome (11), were identified from the fungus Aspergillus sydowii BTBU20213012 isolated from a marine sediment sample from the Western Pacific. The structures of the compounds were identified by HRESIMS and NMR data analysis. Compound 11 showed weak antimicrobial activity against Staphylococcus aureus with MIC value of 200 μg/mL.

Structure-based pharmacophore modeling and DFT studies of Indian Ocean-derived red algal compounds as PI3Kα inhibitors

Phosphoinositide kinases (PIKs) are a type of lipid kinase that acts as an upstream activator of oncogenic signaling. Presently accessible therapeutic compounds have downsides, such as toxicity and dubious efficacy, as well as lengthy treatment durations, which have bred resistance. Here we attempt to screen the Indian Ocean-derived red algal compounds to be used as a promising lead for PI3Kα inhibitor development. Experimental structure of the PI3K alpha Isoform-Specific Inhibitor alpelisib complex-based pharmacophore model was constructed and used as key to mark off the suitable lead compounds from the pool of marine-derived red algal compounds of Indian Ocean. Besides, the study encompasses pharmacophore scaffold screening as well as physicochemical and pharmacokinetic parameter assessment. We employed molecular docking and molecular dynamics simulation to assess the binding type and stability of 21 red algal derivatives. Twelve compounds demonstrated a sustained binding mode within the PI3Kα binding pocket with an optimal protein backbone root-mean-square deviation, also prompted hydrogen bonding throughout the simulations, and also implies that these MNPs have firmly mediated the interaction with prime hinge region residues in the PI3Kα ATP binding pocket. DFT studies revealed that proposed compounds had the greatest occupied molecular orbital electrophilicity index, basicity, and dipole moment, all of which attributed their stability as well as binding affinity at the PI3Kα active site. Our study's findings revealed that CMNPD31054, CMNPD4798, CMNPD27861, CMNPD4799, CMNPD27860, CMNPD9533, CMNPD3732, CMNPD4221, CMNPD31058, CMNPD31052, CMNPD29281, and CMNPD31055 can be used as lead compounds for PI3KΑ isoform inhibitors design.

Marine diterpenoid targets STING palmitoylation in mammalian cells

Natural products are important sources of therapeutic agents and useful drug discovery tools. The fused macrocycles and multiple stereocenters of briarane-type diterpenoids pose a major challenge to total synthesis and efforts to characterize their biological activities. Harnessing a scalable source of excavatolide B (excB) from cultured soft coral Briareum stechei, we generated analogs by late-stage diversification and performed structure-activity analysis, which was critical for the development of functional excB probes. We further used these probes in a chemoproteomic strategy to identify Stimulator of Interferon Genes (STING) as a direct target of excB in mammalian cells. We showed that the epoxylactone warhead of excB is required to covalently engage STING at its membrane-proximal Cys91, inhibiting STING palmitoylation and signaling. This study reveals a possible mechanism-of-action of excB, and expands the repertoire of covalent STING inhibitors.

Natural Products and Biological Activity from Actinomycetes Associated with Marine Algae

Marine natural products have been recognized as the most promising source of bioactive substances for drug discovery research. This review illustrates the diversity of culturable actinobacteria associated with marine algae, their bioactivity and metabolites, and approaches to their isolation and determination of their biological properties. Furthermore, actinobacteria associated with marine algae are presented as a new subject for an extensive investigation to find novel and active natural products, which make them a potentially rich and innovative source for new drug development deserving more attention and exploration.

Isolation and Biological Activity of Iezoside and Iezoside B, SERCA Inhibitors from Floridian Marine Cyanobacteria

Marine cyanobacteria are a rich source of bioactive natural products. Here, we report the isolation and structure elucidation of the previously reported iezoside (1) and its C-31 O-demethyl analogue, iezoside B (2), from a cyanobacterial assemblage collected at Loggerhead Key in the Dry Tortugas, Florida. The two compounds have a unique skeleton comprised of a peptide, a polyketide and a modified sugar unit. The compounds were tested for cytotoxicity and effects on intracellular calcium. Both compounds exhibited cytotoxic activity with an IC₅₀ of 1.5 and 3.0 μΜ, respectively, against A549 lung carcinoma epithelial cells and 1.0 and 2.4 μΜ against HeLa cervical cancer cells, respectively. In the same cell lines, compounds 1 and 2 show an increase in cytosolic calcium with approximate EC₅₀ values of 0.3 and 0.6 μΜ in A549 cells and 0.1 and 0.5 μΜ, respectively, in HeLa cells, near the IC₅₀ for cell viability, suggesting that the increase in cytosolic calcium is functionally related to the cytotoxicity of the compounds and consistent with their activity as SERCA (sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase) inhibitors. The structure-activity relationship provides evidence that structural changes in the sugar unit may be tolerated, and the activity is tunable. This finding has implications for future analogue synthesis and target interaction studies.

Polyketide- and Terpenoid-Derived Metabolites Produced by a Marine-Derived Fungus, Peroneutypa sp

Bioassay-guided investigation of the EtOAc-soluble extract of a culture of the marine-derived fungus Peroneutypa sp. M16 led to the isolation of seven new polyketide- and terpenoid-derived metabolites (1, 2, 4-8), along with known polyketides (3, 9-13). Structures of compounds 1, 2, and 4-8 were established by analysis of spectroscopic data. Absolute configurations of compounds 1, 2, 4, 6, 7, and 8 were determined by the comparison of experimental ECD spectra with calculated CD data. Compound 5 exhibited moderate antiplasmodial activity against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum.

Extraction, Isolation, Characterization, and Bioactivity of Polypropionates and Related Polyketide Metabolites from the Caribbean Region

The Caribbean region is a hotspot of biodiversity (i.e., algae, sponges, corals, mollusks, microorganisms, cyanobacteria, and dinoflagellates) that produces secondary metabolites such as polyketides and polypropionates. Polyketides are a diverse class of natural products synthesized by organisms through a biosynthetic pathway catalyzed by polyketide synthase (PKS). This group of compounds is subdivided into fatty acids, aromatics, and polypropionates such as macrolides, and linear and cyclic polyethers. Researchers have studied the Caribbean region to find natural products and focused on isolation, purification, structural characterization, synthesis, and conducting biological assays against parasites, cancer, fungi, and bacteria. These studies have been summarized in this review, including research from 1981 to 2020. This review includes about 90 compounds isolated in the Caribbean that meet the structural properties of polyketides. Out of 90 compounds presented, 73 have the absolute stereochemical configuration, and 82 have shown biological activity. We expect to motivate the researchers to continue exploring the Caribbean region's marine environments to discover and investigate new polyketide and polypropionate natural products.

New Indole Diketopiperazine Alkaloids from Soft Coral-Associated Epiphytic Fungus Aspergillus versicolor CGF 9-1-2

Two new indole diketopiperazine alkaloids (IDAs), (+)19-epi-sclerotiamide (1) and (-)19-epi-sclerotiamide (2), along with 13 known analogs (3-15), were isolated from a soft coral-associated epiphytic fungus Aspergillus versicolor CGF 9-1-2. The structures of two new compounds were established based on the combination of HR-ESI-MS, 1D and 2D NMR spectroscopy, optical rotation measurements and quantum chemical 13 C-NMR, the absolute configurations were determined by experimental and electronic circular dichroism (ECD) calculations. The results of molecular docking showed that all the compounds had a good binding with TDP1, TDP2, TOP1, TOP2, Ache, NLRP3, EGFR, EGFR L858R, EGFR T790M and EGFR T790/L858. Biological evaluation of compounds 3, 6, 8, 11 showed that 3 exerted a strong inhibitory effect on TDP2 with a rate of 81.72 %.

A propitious role of marine sourced polysaccharides: Drug delivery and biomedical applications

Numerous compounds, with extensive applications in biomedical and biotechnological fields, are present in the oceans, which serve as a prime renewable source of natural substances, further promoting the development of novel medical systems and devices. Polysaccharides are present in the marine ecosystem in abundance, promoting minimal extraction costs, in addition to their solubility in extraction media, and an aqueous solvent, along with their interactions with biological compounds. Certain algae-derived polysaccharides include fucoidan, alginate, and carrageenan, while animal-derived polysaccharides comprise hyaluronan, chitosan and many others. Furthermore, these compounds can be modified to facilitate their processing into multiple shapes and sizes, as well as exhibit response dependence to external conditions like temperature and pH. All these properties have promoted the use of these biomaterials as raw materials for the development of drug delivery carrier systems (hydrogels, particles, capsules). The present review enlightens marine polysaccharides providing its sources, structures, biological properties, and its biomedical applications. In addition to this, their role as nanomaterials is also portrayed by the authors, along with the methods employed to develop them and associated biological and physicochemical properties designed to develop suitable drug delivery systems.

Exploration of fish gut-associated actinobacteria for its antifouling activity

An attempt has been made to screen the fish gut-associated actinobacterial cultures for antifouling compounds. Fifteen morphologically distinct bacterial cultures were recovered from the biofouling samples scraped from the boat surfaces and other maritime structures in the Kovalam beach (Lat. 12.7870°N; Long. 80.2504°E) coastal areas in Tamil Nadu, India. All the bacterial isolates were identified at generic level from which two isolates namely KB6 and KB7 as Staphylococcus sp. were found the exhibit strong biofilm formation. Four actinobacterial strains viz., IM20, PYA9, F8, and SQA4 were evaluated for inhibitory properties against biofouling bacteria using the agar plug method. Strain IM20 which strongly inhibited the biofouling bacteria was chosen as prospective strain for further studies. When compared to submerged fermentation, IM20 produced a high amount of antifouling chemicals on the agar surface fermentation. Among the solvents tested, better extraction of antifouling compounds was seen in ethyl acetate extract. Antifouling compound production by the strain IM20 was found to be influenced by a number of variables such as glucose, fructose, glutamine, malt extract, pH 7 and 9, temperature 30 and 40^° C and NaCl at 2.5% and 5% concentrations. Gas chromatography-mass spectrometry (GC-MS) analysis of the strain IM20 extract revealed the presence of pyrrolo (1,2-a]pyrazine-1,4-dione, hexahydro) in significant amount. In the present study, the fish gut-associated Streptomyces sp. IM20 was identified as an unusual and newly added source for the isolation of antifouling compounds.

Interconvertible Pyridone Alkaloids from the Marine-Derived Fungus Penicillium oxalicum QDU1

Eleven new pyridone alkaloids, penicipyridones A-K (1-11), and three new tetramic acids, tolypocladenols D-F (12-14), were isolated from rice media cultures of the marine-derived fungus Penicillium oxalicum QDU1. Their structures, including absolute configurations, were determined by comprehensive analyses of spectroscopic data, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction data. Interestingly, several of the penicipyridones undergo interconversions between hydroxy and methoxy groups at C-4 in acidic MeOH solution. Furthermore, in an acidic aqueous solution, OH-4 could be replaced by diverse substituent groups. Compounds 1, 4, 5, 8, 10, 11, and 14 exhibited moderate inhibitory effects on NO production in the LPS-induced RAW264.7 macrophages, with IC₅₀ values ranging from 9.2 to 19 μM.

Ferroptosis Inhibitory Compounds from the Deep-Sea-Derived Fungus Penicillium sp. MCCC 3A00126

Two new xanthones (1 and 2) were isolated from the deep-sea-derived fungus Penicillium sp. MCCC 3A00126 along with 34 known compounds (3-36). The structures of the new compounds were established by spectroscopic data. The absolute configuration of 1 was validated by comparison of experimental and calculated ECD spectra. All isolated compounds were evaluated for cytotoxicity and ferroptosis inhibitory activities. Compounds 14 and 15 exerted potent cytotoxicity against CCRF-CEM cells, with IC₅₀ values of 5.5 and 3.5 μM, respectively, whereas 26, 28, 33, and 34 significantly inhibited RSL3-induced ferroptosis, with EC₅₀ values of 11.6, 7.2, 11.8, and 2.2 μM, respectively.

First continuous marine sponge cell line established

The potential of sponge-derived chemicals for pharmaceutical applications remains largely unexploited due to limited available biomass. Although many have attempted to culture marine sponge cells in vitro to create a scalable production platform for such biopharmaceuticals, these efforts have been mostly unsuccessful. We recently showed that Geodia barretti sponge cells could divide rapidly in M1 medium. In this study we established the first continuous marine sponge cell line, originating from G. barretti. G. barretti cells cultured in OpM1 medium, a modification of M1, grew more rapidly and to a higher density than in M1. Cells in OpM1 reached 1.74 population doublings after 30 min, more than twofold higher than the already rapid growth rate of 0.74 population doublings in 30 min in M1. The maximum number of population doublings increased from 5 doublings in M1 to at least 98 doublings in OpM1. Subcultured cells could be cryopreserved and used to inoculate new cultures. With these results, we have overcome a major obstacle that has blocked the path to producing biopharmaceuticals with sponge cells at industrial scale for decades.

Synthesis of Fluorinated Hydrazinylthiazole Derivatives: A Virtual and Experimental Approach to Diabetes Management

A novel series of fluorophenyl-based thiazoles was synthesized following the Hanztsch method. All of the compounds were initially verified with physical parameters (color, melting point, retardation factor (R _f)), which were further confirmed by several spectroscopic methods, including ultraviolet-visible (UV-visible), Fourier-transform infrared (FTIR), ¹H, ¹³C, ¹⁹F NMR, and high-resolution mass spectrometry (HRMS). The binding interactions of all compounds were studied using a molecular docking simulation approach. Furthermore, each compound was evaluated for its alpha(α)-amylase, antiglycation, and antioxidant potentials. The biocompatibility of all compounds was checked with an in vitro hemolytic assay. All synthesized scaffolds were found biocompatible with minimal lysis of human erythrocytes as compared to the standard Triton X-100. Among the tested compounds, the analogue 3h (IC₅₀ = 5.14 ± 0.03 μM) was found to be a highly potent candidate against α-amylase as compared to the standard (acarbose, IC₅₀ = 5.55 ± 0.06 μM). The compounds 3d, 3f, 3i, and 3k exhibited excellent antiglycation inhibition potential with their IC₅₀ values far less than the standard amino guanidine (IC₅₀ = 0.403 ± 0.001 mg/mL). The antidiabetic potential was further supported by docking studies. Docking studies revealed that all synthesized compounds exhibited various interactions along enzyme active sites (pi-pi, H-bonding, van der Waals) with varied binding energies.

Insights into Common Octopus (Octopus vulgaris) Ink Proteome and Bioactive Peptides Using Proteomic Approaches

The common octopus (Octopus vulgaris) is nowadays the most demanded cephalopod species for human consumption. This species was also postulated for aquaculture diversification to supply its increasing demand in the market worldwide, which only relies on continuously declining field captures. In addition, they serve as model species for biomedical and behavioral studies. Body parts of marine species are usually removed before reaching the final consumer as by-products in order to improve preservation, reduce shipping weight, and increase product quality. These by-products have recently attracted increasing attention due to the discovery of several relevant bioactive compounds. Particularly, the common octopus ink has been described as having antimicrobial and antioxidant properties, among others. In this study, the advanced proteomics discipline was applied to generate a common octopus reference proteome to screen potential bioactive peptides from fishing discards and by-products such as ink. A shotgun proteomics approach by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) using an Orbitrap Elite instrument was used to create a reference dataset from octopus ink. A total of 1432 different peptides belonging to 361 non-redundant annotated proteins were identified. The final proteome compilation was investigated by integrated in silico studies, including gene ontology (GO) term enrichment, pathways, and network studies. Different immune functioning proteins involved in the innate immune system, such as ferritin, catalase, proteasome, Cu/Zn superoxide dismutase, calreticulin, disulfide isomerase, heat shock protein, etc., were found in ink protein networks. Additionally, the potential of bioactive peptides from octopus ink was addressed. These bioactive peptides can exert beneficial health properties such as antimicrobial, antioxidant, antihypertensive, and antitumoral properties and are therefore considered lead compounds for developing pharmacological, functional foods or nutraceuticals.

An overview on the nutritional and bioactive components of green seaweeds

Green seaweed, as the most abundant species of macroseaweeds, is an important marine biological resource. It is a rich source of several amino acids, fatty acids, and dietary fibers, as well as polysaccharides, polyphenols, pigments, and other active substances, which have crucial roles in various biological processes such as antioxidant activity, immunoregulation, and anti-inflammatory response. In recent years, attention to marine resources has accelerated the exploration and utilization of green seaweeds for greater economic value. This paper elaborates on the main nutrients and active substances present in different green seaweeds and provides a review of their biological activities and their applications for high-value utilization.

Graphical abstract

New Bioactive β-Resorcylic Acid Derivatives from the Alga-Derived Fungus Penicillium antarcticum KMM 4685

Five new β-resorcylic acid derivatives, 14-hydroxyasperentin B (1), β-resoantarctines A-C (3, 5, 6) and 8-dehydro-β-resoantarctine A (4), together with known 14-hydroxyasperentin (5′-hydroxyasperentin) (2), were isolated from the ethyl acetate extract of the fungus Penicillium antarcticum KMM 4685 associated with the brown alga Sargassum miyabei. The structures of the compounds were elucidated by spectroscopic analyses and modified Mosher’s method, and the biogenetic pathways for compounds 3–6 were proposed. For the very first time, the relative configuration of the C-14 center of a known compound 2 was assigned via analyses of magnitudes of the vicinal coupling constants. The new metabolites 3–6 were biogenically related to resorcylic acid lactones (RALs); however, they did not possess lactonized macrolide elements in their structures. Compounds 3, 4 and 5 exhibited moderate cytotoxic activity in LNCaP, DU145 and 22Rv1 human prostate cancer cells. Moreover, these metabolites could inhibit the activity of p-glycoprotein at their noncytotoxic concentrations and consequently synergize with docetaxel in p-glycoprotein-overexpressing drug-resistant cancer cells.

Phloroglucinol Inhibits Oxidative-Stress-Induced Cytotoxicity in C2C12 Murine Myoblasts through Nrf-2-Mediated Activation of HO-1

Phloroglucinol is a class of polyphenolic compounds containing aromatic phenyl rings and is known to have various pharmacological activities. Recently, we reported that this compound isolated from Ecklonia cava, a brown alga belonging to the family Laminariaceae, has potent antioxidant activity in human dermal keratinocytes. In this study, we evaluated whether phloroglucinol could protect against hydrogen peroxide (H2O2)-induced oxidative damage in murine-derived C2C12 myoblasts. Our results revealed that phloroglucinol suppressed H2O2-induced cytotoxicity and DNA damage while blocking the production of reactive oxygen species. We also found that phloroglucinol protected cells from the induction of apoptosis associated with mitochondrial impairment caused by H2O2 treatment. Furthermore, phloroglucinol enhanced the phosphorylation of nuclear factor-erythroid-2 related factor 2 (Nrf2) as well as the expression and activity of heme oxygenase-1 (HO-1). However, such anti-apoptotic and cytoprotective effects of phloroglucinol were greatly abolished by the HO-1 inhibitor, suggesting that phloroglucinol could increase the Nrf2-mediated activity of HO-1 to protect C2C12 myoblasts from oxidative stress. Taken together, our results indicate that phloroglucinol has a strong antioxidant activity as an Nrf2 activator and may have therapeutic benefits for oxidative-stress-mediated muscle disease.

New Isocoumarins from the Marine Fungus Phaeosphaeriopsis sp. WP-26

Five new isocoumarins, phaeosphaerins A–E (1–5), were isolated from the fermentation broth of the marine fungus Phaeosphaeriopsis sp. WP-26, along with one known isocoumarin, 6,8-dihydroxy-7-methoxy-3-methylisocoumarin (6), and two known pimarane-type diterpenes, diaportheins A (7) and B (8). Their structures were elucidated via NMR experiments, X-ray diffraction analysis, and comparison of the experimental and computed ECD curves. Compounds 1–7 displayed weak neuroprotective effects against H2O2-induced damage in SH-SY5Y cells. Moreover, compound 8 showed cytotoxicity against BEL-7402, SGC-7901, K562, A549, and HL-60 cell lines.