Talaromides A-C, Bioactive Cyclic Heptapeptides from Talaromyces siglerae Isolated from a Marine Sponge.

Three new cyclic heptapeptides, talaromides A-C (1-3), were isolated from cultures produced by the fungus Talaromyces siglerae (Ascomycota), isolated from an unidentified sponge. The structures, featuring an unusual proline-anthranilic moiety, were elucidated by analysis of spectroscopic data and chemical transformations, including the advanced Marfey's method and GITC derivatization. Talaromides A and B inhibited migration activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

Cavomycins A-C, Linear Oligomer Depsipeptides from an Annelid-Associated Streptomyces cavourensis.

Three unique linear oligomeric depsipeptides, designated as cavomycins A-C (1-3), were identified from Streptomyces cavourensis, a gut bacterium associated with the annelid Paraleonnates uschakovi. The structures of these depsipeptides were determined through a combination of spectroscopic methods and chemical derivatization techniques, including methanolysis, the modified Mosher's method, advanced Marfey's methods, and phenylglycine methyl ester derivatization. The unique dipeptidyl residue arrangements in compounds 1-3 indicate that they are not degradation products of valinomycin. Compound 2 and its methylation derivative 2a exhibited antiproliferative activity against PANC-1 pancreatic cancer cells with IC50 values of 1.2 and 1.7 µM, respectively.

Anithiactin D, a Phenylthiazole Natural Product from Mudflat-Derived Streptomyces sp., Suppresses Motility of Cancer Cells.

Anithiactin D (1), a 2-phenylthiazole class of natural products, was isolated from marine mudflat-derived actinomycetes Streptomyces sp. 10A085. The chemical structure of 1 was elucidated based on the interpretation of NMR and MS data. The absolute configuration of 1 was determined by comparing the experimental and calculated electronic circular dichroism (ECD) spectral data. Anithiactin D (1) significantly decreased cancer cell migration and invasion activities at a concentration of 5 µM via downregulation of the epithelial-to-mesenchymal transition (EMT) markers in A549, AGS, and Caco-2 cell lines. Moreover, 1 inhibited the activity of Rho GTPases, including Rac1 and RhoA in the A549 cell line, suppressed RhoA in AGS and Caco-2 cell lines, and decreased the mRNA expression levels of some matrix metalloproteinases (MMPs) in AGS and Caco-2 cell lines. Thus 1, which is a new entity of the 2-phenylthiazole class of natural products with a unique aniline-indole fused moiety, is a potent inhibitor of the motility of cancer cells.

Ulmus macrocarpa Hance trunk bark extracts inhibit RANKL-induced osteoclast differentiation and prevent ovariectomy-induced osteoporosis in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulmus macrocarpa Hance (UmH) bark has been traditionally utilized for medicinal purposes. The bark extract of this plant has diverse health benefits, and its potential role in enhancing bone health is of distinct interest, particularly when considering the substantial health and economic implications of bone-related pathologies, such as osteoporosis. Despite the compelling theoretical implications of UmH bark in fortifying bone health, no definitive evidence at the in vivo level is currently available, thus highlighting the innovative and as-yet-unexplored potential of this field of study. AIM OF THE STUDY: Primarily, our study aims to conduct a meticulous analysis of the disparity in the concentration of active compounds in the UmH root bark (Umrb) and trunk bark (Umtb) extracts and confirm UmH bark's efficacy in enhancing bone health in vivo, illuminating the cellular mechanisms involved. MATERIALS AND METHODS: The Umrb and Umtb extracts were subjected to component analysis using high-performance liquid chromatography and then assessed for their inhibitory effects on osteoclast differentiation through the TRAP assay. An ovariectomized (OVX) mouse model replicates postmenopausal conditions commonly associated with osteoporosis. Micro-CT was used to analyze bone structure parameters, and enzyme-linked immunosorbent assay and staining were used to assess bone formation markers and osteoclast activity. Furthermore, this study investigated the impact of the extract on the expression of pivotal proteins and genes involved in bone formation and resorption using mouse bone marrow-derived macrophages (BMMs). RESULTS: The findings of our study reveal a significant discrepancy in the concentration of active constituents between Umrb and Umtb, establishing Umtb as a superior source for promoting bone health. I addition, a standardized pilot-scale procedure was conducted for credibility. The bone health benefits of Umtb were verified using an OVX model. This validation involved the assessment of various parameters, including BMD, BV/TV, and BS/TV, using micro-CT imaging. Additionally, the activation of osteoblasts was evaluated by Umtb by measuring specific factors such as ALP, OCN, OPG in blood samples and through IHC staining. In the same investigations, diminished levels of osteoclast differentiation factors, such as TRAP, NFATc1, were also observed. The observed patterns exhibited consistency in vitro BMM investigations. CONCLUSIONS: Through verification at both in vitro levels using BMMs and in vivo levels using the OVX-induced mouse model, our research demonstrates that Umtb is a more effective means of improving bone health in comparison to Umrb. These findings pave the way for developing health-functional foods or botanical drugs targeting osteoporosis and other bone-related disorders and enhance the prospects for future research extensions, including clinical studies, in extract applications.

Discovery and optimized extraction of the anti-osteoclastic agent epicatechin-7-O-ß-D-apiofuranoside from Ulmus macrocarpa Hance bark.

Ulmus macrocarpa Hance bark (UmHb) has been used as a traditional herbal medicine in East Asia for bone concern diseases for a long time. To find a suitable solvent, we, in this study, compared the efficacy of UmHb water extract and ethanol extract which can inhibit osteoclast differentiation. Compared with two ethanol extracts (70% and 100% respectively), hydrothermal extracts of UmHb more effectively inhibited receptor activators of nuclear factor κB ligand-induced osteoclast differentiation in murine bone marrow-derived macrophages. We identified for the first time that (2R,3R)-epicatechin-7-O-ß-D-apiofuranoside (E7A) is a specific active compound in UmHb hydrothermal extracts through using LC/MS, HPLC, and NMR techniques. In addition, we confirmed through TRAP assay, pit assay, and PCR assay that E7A is a key compound in inhibiting osteoclast differentiation. The optimized condition to obtain E7A-rich UmHb extract was 100 mL/g, 90 °C, pH 5, and 97 min. At this condition, the content of E7A was 26.05 ± 0.96 mg/g extract. Based on TRAP assay, pit assay, PCR, and western blot, the optimized extract of E7A-rich UmHb demonstrated a greater inhibition of osteoclast differentiation compared to unoptimized. These results suggest that E7A would be a good candidate for the prevention and treatment of osteoporosis-related diseases.

Bioactive Piperazic Acid-Bearing Cyclodepsipeptides, Lydiamycins E-H, from an Endophytic Streptomyces sp. Associated with Cinnamomum cassia.

A chemical investigation of the endophytic Streptomyces sp. HBQ95, associated with the medicinal plant Cinnamomum cassia Presl, enabled the discovery of four new piperazic acid-bearing cyclodepsipeptides, lydiamycins E-H (1-4), and one known compound (lydiamycin A). Their chemical structures, including absolute configurations, were defined by a combination of spectroscopic analyses and multiple chemical manipulations. Lydiamycins F-H (2-4) and A (5) exhibited antimetastatic activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

VLDL-VLDLR axis facilitates brown fat thermogenesis through replenishment of lipid fuels and PPARß/δ activation.

In mammals, brown adipose tissue (BAT) is specialized to conduct non-shivering thermogenesis for survival under cold acclimation. Although emerging evidence suggests that lipid metabolites are essential for heat generation in cold-activated BAT, the underlying mechanisms of lipid uptake in BAT have not been thoroughly understood. Here, we show that very-low-density lipoprotein (VLDL) uptaken by VLDL receptor (VLDLR) plays important roles in thermogenic execution in BAT. Compared with wild-type mice, VLDLR knockout mice exhibit impaired thermogenic features. Mechanistically, VLDLR-mediated VLDL uptake provides energy sources for mitochondrial oxidation via lysosomal processing, subsequently enhancing thermogenic activity in brown adipocytes. Moreover, the VLDL-VLDLR axis potentiates peroxisome proliferator activated receptor (PPAR)ß/δ activity with thermogenic gene expression in BAT. Accordingly, VLDL-induced thermogenic capacity is attenuated in brown-adipocyte-specific PPARß/δ knockout mice. Collectively, these data suggest that the VLDL-VLDLR axis in brown adipocytes is a key factor for thermogenic execution during cold exposure.

(+)-Usnic acid and its salts, inhibitors of SARS-CoV-2, identified by using in silico methods and in vitro assay.

The pandemic caused by severe acute respiratory Coronavirus-2 (SARS-CoV-2) has been ongoing for over two years, and treatment for COVID-19, other than monoclonal antibodies, is urgently required. Accordingly, we have investigated the inhibitors of SARS-CoV-2 protein targets by high-throughput virtual screening using a marine natural products database. Considering the calculated molecular properties and availability of the compounds, (+)-usnic acid was selected as a suitable hit. In the in vitro antiviral assay of (+)-usnic acid by the immunofluorescence method, IC50 was 7.99 µM, which is similar to that of remdesivir used as a positive control. The generalized Born and surface area continuum solvation (MM/GBSA) method was performed to find the potent target of (+)-usnic acid, and the Mpro protein showed the most prominent value, -52.05 kcal/mol, among other SARS-CoV-2 protein targets. Thereafter, RMSD and protein-ligand interactions were profiled using molecular dynamics (MD) simulations. Sodium usnate (NaU) improved in vitro assay results with an IC50 of 5.33 µM and a selectivity index (SI) of 9.38. Additionally, when (+)-usnic acid was assayed against SARS-CoV-2 variants, it showed enhanced efficacy toward beta variants with an IC50 of 2.92 µM and SI of 11.1. We report the in vitro anti-SARS-CoV-2 efficacy of (+)-usnic acid in this study and propose that it has the potential to be developed as a COVID-19 treatment if its in vivo efficacy has been confirmed.

Determination of sequence and absolute configuration of peptide amino acids by HPLC-MS/CD-based detection of liberated N-terminus phenylthiohydantoin amino acids.

We report a method for the simultaneous determination of the sequence and absolute configuration of peptide amino acids using a combination of Edman degradation and HPLC-MS/CD. Phenylthiohydantoin (PTH) derivatives of 20 pairs of standard D- and L-amino acids were synthesized by the Edman reaction. The CD spectra of the derivatives revealed that each pair of the PTH derivatives exhibited the absorption with opposite signs at around 270 nm. These standard PTH derivatives showed well-resolved resolution without interference from byproducts in the ion chromatogram and clear positive/negative CD absorptions when subjected on a reversed phase HPLC-MS system coupled with a CD-2095 HPLC detector. This method was applied for the detection of a synthetic pentapeptide and a natural depsipeptide (halicylindramide C). The sequence and configuration of the pentapeptide and up to eight residues of halicylindramide C were successfully analyzed by this method. The amino acid configuration of the pentapeptide was also determined successfully by subjecting its acid hydrolysates to the Edman reaction followed by HPLC-MS/CD.

Flavonoid Glycosides from Ulmus macrocarpa Inhibit Osteoclast Differentiation via the Downregulation of NFATc1.

The aim of this study was to isolate and identify chemical components with osteoclast differentiation inhibitory activity from Ulmus macrocarpa Hance bark. Spectroscopic analyses, including nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD), resulted in the unequivocal elucidation of active compounds such as (2S)-naringenin-6-C-ß-d-glucopyranoside (1), (2R)-naringenin-6-C-ß-d-glucopyranoside (2), (2R,3S)-catechin-7-O-ß-d-xylopyranoside (3), (2R,3S)-catechin-7-O-ß-d-apiofuranoside (6), (2R,3R)-taxifolin-6-C-ß-d-glucopyranoside (7), and (2S,3S)-taxifolin-6-C-ß-d-glucopyranoside (8). Mechanistically, the compounds may exhibit osteoclast differentiation inhibitory activity via the downregulation of NFATc1, a master regulator involved in osteoclast formation. This is the first report of their inhibitory activities on the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation in murine bone marrow-derived macrophages. These findings provide further scientific evidence for the rational application of the genus Ulmus for the amelioration or treatment of osteopenic diseases.

Antibacterial Bicyclic Fatty Acids from a Korean Colonial Tunicate Didemnum sp.

Five new bicyclic carboxylic acids were obtained by antibacterial activity-guided isolation from a Korean colonial tunicate Didemnum sp. Their structures were elucidated by the interpretation of NMR, MS and CD spectroscopic data. They all belong to the class of aplidic acids. Three of them were amide derivatives (1-3), and the other two were dicarboxylic derivatives (4 and 5). The absolute configurations were determined by a bisignate pattern of CD spectroscopy, which revealed that the absolute configurations of amides were opposite to those of dicarboxylates at every stereogenic centers. Compound 2 exhibited the most potent antibacterial activity (MIC, 2 µg/mL).

Austalide K from the Fungus Penicillium rudallense Prevents LPS-Induced Bone Loss in Mice by Inhibiting Osteoclast Differentiation and Promoting Osteoblast Differentiation.

Osteoporosis is a chronic disease that has become a serious public health problem due to the associated reduction in quality of life and its increasing financial burden. It is known that inhibiting osteoclast differentiation and promoting osteoblast formation prevents osteoporosis. As there is no drug with this dual activity without clinical side effects, new alternatives are needed. Here, we demonstrate that austalide K, isolated from the marine fungus Penicillium rudallenes, has dual activities in bone remodeling. Austalide K inhibits the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and improves bone morphogenetic protein (BMP)-2-mediated osteoblast differentiation in vitro without cytotoxicity. The nuclear factor of activated T cells c1 (NFATc1), tartrate-resistant acid phosphatase (TRAP), dendritic cell-specific transmembrane protein (DC-STAMP), and cathepsin K (CTSK) osteoclast-formation-related genes were reduced and alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), and osteopontin (OPN) (osteoblast activation-related genes) were simultaneously upregulated by treatment with austalide K. Furthermore, austalide K showed good efficacy in an LPS-induced bone loss in vivo model. Bone volume, trabecular separation, trabecular thickness, and bone mineral density were recovered by austalide K. On the basis of these results, austalide K may lead to new drug treatments for bone diseases such as osteoporosis.

Diversity of microbial community and its metabolic potential for nitrogen and sulfur cycling in sediments of Phu Quoc island, Gulf of Thailand.

Although Phu Quoc island, Gulf of Thailand possesses diverse marine and coastal ecosystems, biodiversity and metabolic capability of microbial communities remain poorly investigated. The aim of our study was to evaluate the biodiversity and metabolic potential of sediment microbial communities in Phu Quoc island. The marine sediments were collected from three different areas and analyzed by using 16S rRNA gene-based amplicon approach. A total of 1,143,939 reads were clustered at a 97% sequence similarity into 8,331 unique operational taxonomic units, representing 52 phyla. Bacteria and archaea occupied averagely around 86% and 14%, respectively, of the total prokaryotic community. Proteobacteria, Planctomycetes, Chloroflexi, and Thaumarchaeota were the dominant phyla in all sediments, which were involved in nitrogen and sulfur metabolism. Sediments harboring of higher nitrogen sources were found to coincide with increased abundance of archaeal phylum Thaumarchaeota. Predictive functional analysis showed high abundance prokaryotic genes associated with nitrogen cycling including nifA-Z, amoABC, nirA, narBIJ, napA, nxrAB, nrfA-K, nirBD, nirS, nirK, norB-Z, nlnA, ald, and ureA-J, based on taxonomic groups detected by 16S rRNA sequencing. Although the key genes involved in sulfur cycling were found to be at low to undetectable levels, the other genes encoding for sulfur-related biological processes were present, suggesting that alternative pathways may be involved in sulfur cycling at our study site. In conclusion, our study for the first time shed light on diversity of microbial communities in Phu Quoc island.

A New Thiopeptide Antibiotic, Micrococcin P3, from a Marine-Derived Strain of the Bacterium Bacillus stratosphericus.

A new thiopeptide (micrococcin P3, 1) and a known one (micrococcin P1, 2) were isolated from the culture broth of a marine-derived strain of Bacillus stratosphericus. The structures of both compounds were elucidated using spectroscopic methods, including extensive 1D and 2D NMR analysis, high resolution mass spectrometry (HRMS), and tandem mass spectrometry. Both compounds exhibited potent antibacterial activities against Gram-positive strains with minimum inhibitory concentration (MIC) values of 0.05-0.8 µg/mL and did not show cytotoxicity in the MTT assay up to a concentration of 10 µM. This study adds a new promising member, micrococcin P3, to the family of thiopeptide antibiotics, which shows potential for the development of new antibiotics targeting Gram-positive bacteria.

Endophytic actinomycetes associated with Cinnamomum cassia Presl in Hoa Binh province, Vietnam: Distribution, antimicrobial activity and, genetic features.

Endophytic microbes associated with medicinal plants are considered to be potential producers of various bioactive secondary metabolites. The present study investigated the distribution, antimicrobial activity and genetic features of endophytic actinomycetes isolated from the medicinal plant Cinnamomum cassia Presl collected in Hoa Binh province of northern Vietnam. Based on phenotypic characteristics, 111 actinomycetes were isolated from roots, stems and leaves of the host plants by using nine selective media. The isolated actinomycetes were mainly recovered from stems (n = 67; 60.4%), followed by roots (n = 29; 26.1%) and leaves (n = 15; 13.5%). The isolates were accordingly assigned into 5 color categories of aerial mycelium, of which gray is the most dominant (n = 42; 37.8%), followed by white (n = 33; 29.7%), yellow (n = 25; 22,5%), red (n = 8; 7.2%) and green (n = 3; 2.7%). Of the total endophytic actinomycetes tested, 38 strains (occupying 34.2%) showed antimicrobial activity against at least one of nine tested microbes and, among them, 26 actinomycetes (68.4%) revealed anthracycline-like antibiotics production. Analysis of 16S rRNA gene sequences deposited on GenBank (NCBI) of the antibiotic-producing actinomycetes identified 3 distinct genera, including Streptomyces, Microbacterium, and Nocardia, among which Streptomyces genus was the most dominant and represented 25 different species. Further genetic investigation of the antibiotic-producing actinomycetes found that 28 (73.7%) and 11 (28.9%) strains possessed genes encoding polyketide synthase (pks) and nonribosomal peptide synthetase (nrps), respectively. The findings in the present study highlighted endophytic actinomycetes from C. cassia Presl which possessed broad-spectrum bioactivities with the potential for applications in the agricultural and pharmaceutical sectors.

Benzophenone Compounds, from a Marine-Derived Strain of the Fungus Pestalotiopsis neglecta, Inhibit Proliferation of Pancreatic Cancer Cells by Targeting the MEK/ERK Pathway.

Pancreatic cancer, which has an extremely poor prognosis, is one of the most fatal human cancers. Chemotherapy is the main palliative treatment for advanced cancer patients and also plays an indispensable role in postoperative treatments for surgical patients. Therefore, there is an urgent need to develop more innovative anticancer drugs to fight against this fatal disease. Here, we investigate the potential of benzophenone derivatives, obtained from a marine-derived strain of the fungus Pestalotiopsis neglecta, as antiproliferative lead compounds for the treatment of pancreatic cancer. The compounds, seven new (1-7) and two known (8 and 9) halogenated benzophenone derivatives, were obtained by bioactivity-guided fractionation from the cultures of Pestalotiopsis neglecta. The structures were defined by spectroscopic methods including X-ray crystallographic analysis. Using the commonly used pancreatic cancer cell line PANC-1, 2 and 4 were found to suppress cell proliferation and induce apoptosis in the low micromolar range of 7.6 and 7.2 µM, respectively. Mechanistically, benzophenone derivatives not only inhibit MEK activity in the cytoplasm but also suppress ERK activity in the cytoplasm and nucleus. An in silico study suggests that benzophenone derivatives could potentially inhibit MEK activity by binding to the allosteric pocket in MEK. Benzophenones could serve as new lead compounds for the treatment of pancreatic cancer.

Austalides, Osteoclast Differentiation Inhibitors from a Marine-Derived Strain of the Fungus Penicillium rudallense.

Four new meroterpenoids, austalides V-X (1-3) and a farnesylated phthalide derivative (4), were isolated from the culture of the marine fungus Penicillium rudallense, together with eight known meroterpenoids derivatives (5-12). Their structures, including absolute configurations, were determined by spectroscopic methods. All of the isolated compounds were evaluated for their inhibitory activities on the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation. Compounds 1, 2, 5-7, and 10 exhibited potent osteoclast differentiation inhibitory activity with ED50 values of 1.9-2.8 µM.

Mycousfurans A and B, Antibacterial Usnic Acid Congeners from the Fungus Mycosphaerella sp., Isolated from a Marine Sediment.

Mycousfurans (1 and 2), two new usnic acid congeners, along with (-)-mycousnine (3), (-)-placodiolic acid (4), and (+)-usnic acid (5), were isolated using high-performance liquid chromatography-ultraviolet (HPLC-UV)-guided fractionation of extracts of Mycosphaerella sp. isolated from a marine sediment. The planar structures of 1 and 2 were elucidated using 1D and 2D NMR spectra. The relative configurations of the stereogenic carbons of 1 and 2 were established via analysis of their nuclear Overhauser spectroscopy (NOESY) spectra, and their absolute configurations were determined using a comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1 and 2 were found to have antibacterial activity, showing moderate activity against Kocuria rhizophila and Staphylococcus aureus.