Vo Thi Dieu Trang

Background: Mycophenolic acid (MPA) is an IMPDH inhibitor used clinically as an immunosuppressant, but its antiproliferative potency is offset by immune toxicity. We previously identified marine-derived MPA analogues as candidate estrogen receptor α (ERα) ligands. Here, we tested whether penicacid G (PG), a C-4′-oxidized MPA derivative from the marine fungus Penicillium sp. 1901NT-2.53.1, exerts ERα-dependent antiproliferative activity against ER-positive breast cancer cells. Methods: Molecular targets were predicted with TargetNet and OCHEM QSAR models; ERα binding was modeled by docking (PDB 3UUD) and 100 ns molecular dynamics. Cytotoxicities of PG, 4′-hydroxy-MPA, and MPA were determined in MCF-7, MDA-MB-231, H9c2, and MonoMac-1 cells. ERα dependence was interrogated by 4-hydroxytamoxifen (4-OHT) competition, clonogenic assay, ERα monomer/dimer analysis, qPCR of ER-regulated transcripts, cell-cycle flow cytometry, and LINCS L1000 analysis. Results: PG docked into the ERα ligand-binding pocket (−7.7 kcal/mol) and remained stably bound over 100 ns. PG reduced MCF-7 viability at 1 μM (−19.4%) without affecting MDA-MB-231, H9c2, or MonoMac-1 cells (IC50 > 100 μM) and inhibited MCF-7 colony formation (IC50 3.1 μM). Its effect was attenuated by 4-OHT and accompanied by altered ERα monomer/dimer ratios, rapid PHB2 upregulation, and IGFBP4 suppression, indicating ERα pathway engagement. In contrast, MPA inhibited both cancer cell lines, was not blocked by 4-OHT, and its LINCS L1000 profile suggests indirect antagonism of ER-dependent transcription secondary to nucleotide depletion. Conclusions: Penicacid G is an ERα-engaging MPA analogue that selectively impairs ER-positive breast cancer cell proliferation while sparing monocytic immune cells, representing a promising ERα-targeted lead scaffold.

The aim of this study was to investigate the metabolites in Aspergillus subramanianii 1901NT-1.40.2 extract using UPLC-MS, isolate and elucidate the structure of individual compounds, and study the antimicrobial and cytotoxic activities of the isolated compounds. The structures of two previously unreported ergostane triterpenoid aspersubrin A (1) and pyrazine alkaloid ochramide E (2) were established using NMR and HR ESI-MS. The absolute configuration of 1 was determined using quantum chemical calculations. Moreover, the known polyketides sclerolide (3) and sclerin (4); the indolediterpene alkaloid 10,23-dihydro-24,25-dehydroaflavinine (5); the bis-indolyl benzenoid alkaloids kumbicin D (6), asterriquinol D dimethyl ether (7), petromurin C (8); and the cyclopentenedione asterredione (9) were isolated. The effects of compounds 3-9 on the growth and biofilm formation of the yeast-like fungus Candida albicans and the bacteria Staphylococcus aureus and Escherichia coli were investigated. Compounds 5 and 6 inhibited C. albicans growth and biofilm formation at an IC₅₀ of 7–10 µM. Moreover, the effects of compounds 3-9 on non-cancerous H9c2 cardiomyocytes, HaCaT keratinocytes, MCF-10A breast epithelial cells, and breast cancer MCF-7 and MDA-MB-231 cells were also investigated. Compound 8 (10 µM) significantly decreased the viability of MCF-7 cells, inhibited colony formation, and arrested cell cycle progression and proliferation in monolayer culture. Moreover, 8 significantly decreased the area of MCF-7 3D spheroids by approximately 30%. A competitive test with 4-hydroxytamoxyfen and molecular docking showed that estrogen receptors (ERβ more than ERα) were involved in the anticancer effect of petromurin C (8).

Fucoidanases are endo-fucoidanases (also known as endo-fucanases) that catalyze hydrolysis of α-glycosidic linkages in fucoidans, a family of sulfated fucose-rich polysaccharides primarily found in the cell walls of brown seaweeds. Fucoidanases are promising tools for producing bioactive fucoidan oligosaccharides for a range of biomedical applications. High sulfation degree has been linked to high bioactivity of fucoidans. In this study, a novel fucoidanase, Fhf2, was identified in the genome of the aerobic, Gram-negative marine bacterium Formosa haliotis. Fhf2 was found to share sequence similarity to known endo-α(1,4)-fucoidanases (EC 3.2.1.212) from glycoside hydrolase family 107. A C-terminal deletion mutant Fhf2∆484, devoid of 484 amino acids at the C-terminus, with a molecular weight of approximately 46 kDa, was constructed and found to be more stable than the full-length Fhf2 protein. Fhf2∆484 showed endo-fucoidanase activity on fucoidans from different seaweed species including Fucus evanescens, Fucus vesiculosus, Sargassum mcclurei, and Sargassum polycystum. The highest activity was observed on fucoidan from F. evanescens. The Fhf2∆484 enzyme was active at 20–45°C and at pH 6–9 and had optimal activity at 37°C and pH 8. Additionally, Fhf2∆484 was found to be calcium-dependent. NMR analysis showed that Fhf2∆484 catalyzed hydrolysis of α(1,4) linkages between L-fucosyl moieties sulfated on C2 (similar to Fhf1 from Formosa haliotis), but Fhf2∆484 in addition released oligosaccharides containing a substantial amount of 2,4-disulfated fucose residues. The data thus suggest that the Fhf2∆484 enzyme could be a valuable candidate for producing highly sulfated oligosaccharides applicable for fucoidan bioactivity investigations.

Vibriosis in farmed animals is a serious threat to aquaculture worldwide. Using probiotics and anti-Vibrio antimicrobial substances in aquaculture systems can be a means of preventing Vibrio infections. Therefore, we aimed to characterize and compare 16 potential anti-Vibrio probiotics (Vi+) isolated from marine sponges and fish intestines collected from the Vietnam Sea, as well as an anti-Vibrio bacteriocin to fully explore their application potentials. 16S rRNA sequencing confirmed all Vi+ to be Bacillus species with different strain variants across two sample types. An obvious antimicrobial spectrum toward Gram-negative bacteria was observed from intestinal Vi+ compared to sponge-associated Vi+. The reason was the higher gene frequency of two antimicrobial compounds, non-ribosomal peptides (NRPS) and polyketide type-I (PKS-I) from intestinal Vi+ (66.7%) than sponge-associated Vi+ (14.3% and 0%, respectively). Additionally, a three-step procedure was performed to purify an anti-Vibrio bacteriocin produced by B. methylotrophicus NTBD1, including (i) solvent extraction of bacteriocin from cells, (ii) hydrophobic interaction chromatography, and (iii) reverse-phase HPLC. The bacteriocin had a molecular weight of ~2–5 kDa, was sensitive to proteolysis and thermally stable, and showed a broad antimicrobial spectrum, all of which are essential properties for promising feed additives. This study provides necessary information of the potential of probiotic Bacillus species with anti-Vibrio antimicrobial properties to study their further use in sustainable aquaculture.

A new lectin from the marine red alga Gracilaria canaliculata (GCL) was isolated by a combination of aqueous ethanol extraction, ethanol precipitation, ion exchange and filtration chromatography. Lectin gave a single band with molecular mass of 22,000 Da in both non-reducing and reducing SDS-PAGE conditions, indicating that GCL is a monomeric protein. The hemagglutination activities of GCL were stable over a wide range of pH from 3 to 10, temperature up 60 oC and not affected by either the presence of EDTA or addition of divalent cations. Lectin GCL had high affinity for N-acetylneuraminic acid through interacting with the acetamido group at equatorial C2 position of these sugar residues, suggesting that GCL is specific for N-acetylneuraminic acid. Furthermore, GCL inhibited the growth of human and shrimp pathogenic bacteria, Staphylococcus aureus and Vibrio alginolyticus, although it did not affect the growth of Escherichia coli, Enterobacter cloace, Vibrio parahaemolyticus and V. harveyi. The red alga G. canaliculata may promise to be a source of valuable lectins for application as antibacterial agents.

Seven new deoxyisoaustamide derivatives (1–7) together with known compounds (8–10) were isolated from the coral-derived fungus Penicillium dimorphosporum KMM 4689. Their structures were established using spectroscopic methods, X-ray diffraction analysis and by comparison with related known compounds. The absolute configurations of some alkaloids were determined based on CD and NOESY data as well as biogenetic considerations. The cytotoxic and neuroprotective activities of some of the isolated compounds were examined and structure-activity relationships were pointed out. New deoxyisoaustamides 4–6 at concentration of 1 µM revealed a statistical increase of PQ(paraquat)-treated Neuro-2a cell viability by 30–39%.

Fucoidans from brown macroalgae are sulfated fucose-rich polysaccharides, that have several beneficial biological activities, including anti-inflammatory and anti-tumor effects. Controlled enzymatic depolymerization of the fucoidan backbone can help produce homogeneous, defined fucoidan products for structure-function research and pharmaceutical uses. However, only a few endo-fucoidanases have been described. This article reports the genome-based discovery, recombinant expression in Escherichia coli, stabilization, and functional characterization of a new bacterial endo-α-(1,4)-fucoidanase, Fhf1, from Formosa haliotis. Fhf1 catalyzes the cleavage of α-(1,4)-glycosidic linkages in fucoidans built of alternating α-(1,3)-/α-(1,4)-linked l-fucopyranosyl sulfated at C2. The native Fhf1 is 1120 amino acids long and belongs to glycoside hydrolase (GH) family 107. Deletion of the signal peptide and a 470 amino acid long C-terminal stretch led to the recombinant expression of a robust, minimized enzyme, Fhf1Δ470 (71 kDa). Fhf1Δ470 has optimal activity at pH 8, 37–40 °C, can tolerate up to 500 mM NaCl, and requires the presence of divalent cations, either Ca²⁺, Mn²⁺, Zn²⁺ or Ni²⁺, for maximal activity. This new enzyme has the potential to serve the need for controlled enzymatic fucoidan depolymerization to produce bioactive sulfated fucoidan oligomers.

Fucoidans from brown macroalgae (brown seaweeds) have different structures and many interesting bioactivities. Fucoidans are classically extracted from brown seaweeds by hot acidic extraction. Here, we report a new targeted enzyme-assisted methodology for fucoidan extraction from brown seaweeds. This enzyme-assisted extraction protocol involves a one-step combined use of a commercial cellulase preparation (Cellic^®CTec2) and an alginate lyase from Sphingomonas sp. (SALy), reaction at pH 6.0, 40 °C, removal of non-fucoidan polysaccharides by Ca²⁺ precipitation, and ethanol-precipitation of crude fucoidan. The workability of this method is demonstrated for fucoidan extraction from Fucus distichus subsp. evanescens (basionym Fucus evanescens) and Saccharina latissima as compared with mild acidic extraction. The crude fucoidans resulting directly from the enzyme-assisted method contained considerable amounts of low molecular weight alginate, but this residual alginate was effectively removed by an additional ion-exchange chromatographic step to yield pure fucoidans (as confirmed by ¹H NMR). The fucoidan yields that were obtained by the enzymatic method were comparable to the chemically extracted yields for both F. evanescens and S. latissima, but the molecular sizes of the fucoidans were significantly larger with enzyme-assisted extraction. The molecular weight distribution of the fucoidan fractions was 400 to 800 kDa for F. evanescens and 300 to 800 kDa for S. latissima, whereas the molecular weights of the corresponding chemically extracted fucoidans from these seaweeds were 10–100 kDa and 50–100 kDa, respectively. Enzyme-assisted extraction represents a new gentle strategy for fucoidan extraction and it provides new opportunities for obtaining high yields of native fucoidan structures from brown macroalgae.