Chemical Constituents and Anticancer Activities of Marine-Derived Fungus Trichoderma lixii.

The fungal genus Trichoderma is a rich source of structurally diverse secondary metabolites with remarkable pharmaceutical properties. The chemical constituents and anticancer activities of the marine-derived fungus Trichoderma lixii have never been investigated. In this study, a bioactivity-guided investigation led to the isolation of eleven compounds, including trichodermamide A (1), trichodermamide B (2), aspergillazine A (3), DC1149B (4), ergosterol peroxide (5), cerebrosides D/C (6/7), 5-hydroxy-2,3-dimethyl-7-methoxychromone (8), nafuredin A (9), and harzianumols E/F (10/11). Their structures were identified by using various spectroscopic techniques and compared to those in the literature. Notably, compounds 2 and 5-11 were reported for the first time from this species. Evaluation of the anticancer activities of all isolated compounds was carried out. Compounds 2, 4, and 9 were the most active antiproliferative compounds against three cancer cell lines (human myeloma KMS-11, colorectal HT-29, and pancreas PANC-1). Intriguingly, compound 4 exhibited anti-austerity activity with an IC50 of 22.43 µM against PANC-1 cancer cells under glucose starvation conditions, while compound 2 did not.

Proposal for structure revision of pinofuranoxin A through total syntheses of stereoisomers.

The relative configuration of the epoxide functionality in pinofuranoxin A (1), α-alkylidene-ß-hydroxy-γ-methyl-γ-butyrolactone with trans-epoxy side chain isolated by Evidente et al. in 2021, was revised by DFT-based spectral reinvestigations and stereo-controlled synthesis. The present investigation demonstrates the difficulty of the configurational elucidation of the stereogenic centers on the conformationally flexible acyclic side-chains. Sharpless's enantioselective epoxidations and dihydroxylations were quite effective in the reinvestigations of the configurations. As our syntheses made all diastereomers available, these would be quite effective in the next structure-biological activity relationship studies.

First Total Syntheses of Beauvericin A and allo-Beauvericin A.

The first total syntheses of beauvericin A and allo-beauvericin A were achieved. N-Methyl-l-phenylalanine, (2R)-hydroxylvaleric acid, and (2R,3S)- or (2R,3R)-2-hydroxy-2-methylpentanoic acid were linked and cyclized to form the target natural products. The structure of synthetic beauvericin A was confirmed by X-ray crystallographic analysis. NMR data of the synthetic beauvericins were identical with those of the reported natural products. These results secure the structures of natural products, as originally proposed in the isolation studies.

Impact of multiple H/D replacements on the physicochemical properties of flurbiprofen.

Although deuterium incorporation into pharmaceutical drugs is an attractive way to expand drug modalities, their physicochemical properties have not been sufficiently examined. This study focuses on examining the changes in physicochemical properties between flurbiprofen (FP) and flurbiprofen-d8 (FP-d8), which was successfully prepared by direct and multiple H/D exchange reactions at the eight aromatic C-H bonds of FP. Although the effect of deuterium incorporation was not observed between the crystal structures of FP and FP-d8, the melting point and heat of fusion of FP-d8 were lower than those of FP. Additionally, the solubility of FP-d8 increased by 2-fold compared to that of FP. Calculation of the interaction energy between FP/FP-d8 and water molecules using the multi-component density functional theory method resulted in increased solubility of FP-d8. These novel and valuable findings regarding the changes in physicochemical properties triggered by deuterium incorporation can contribute to the further development of deuterated drugs.

Cytotoxic activity of cordycepin produced by marine-derived fungus Emericella sp. against HT29 human colon cancer cell lines.

Colorectal cancer accounted for the third most common cancer in the world. The search for new drug candidates that can be used for colorectal cancer treatment from marine-derived fungi, Emericella sp. The present study was performed to isolate the cytotoxic compound from Emericella sp. The isolation method was carried out by using a combination of chromatographic techniques to afford compound 1. The cytotoxic activity and the exosome production property were determined by using proliferation and luciferase assay against HT29 CD63 Nluc cells, respectively. The chemical structure of compound 1 was identified as cordycepin based on spectroscopy methods such as mass spectrometry and nuclear magnetic resonance (1D and 2D NMR) analyses and comparison with authentic spectral data. The biological activity assay showed that cordycepin exhibited cytotoxic activity with an IC50 value of 92.05 µM through proliferation assay, and also inhibited the exosome production by luciferase assay with an IC50 value of 86.47 µM. Cordycepin was isolated from culture broth Emericella sp., exhibiting moderate cytotoxic activity and inhibitory activity of exosome production. Thus, cordycepin is a potential compound to be investigated further for its exosome production inhibition activity for further use as an anticancer lead compound.

Anti-Mycobacterial N-(2-Arylethyl)quinolin-3-amines Inspired by Marine Sponge-Derived Alkaloid.

The synthesis and evaluation of simplified analogs of marine sponge-derived alkaloid 3-(phenethylamino)demethyl(oxy)aaptamine were performed to develop novel anti-mycobacterial substances. Ring truncation of the tricyclic benzo[de][1,6]-naphthyridine skeleton effectively weakened the cytotoxicity of the natural product, and the resulting AC-ring analog exhibited good anti-mycobacterial activity. A structure-activity relationship (SAR) study, synthesizing and evaluating some analogs, demonstrated the specificity and importance of the N-(2-arylethyl)quinolin-3-amine skeleton as a promising scaffold for anti-mycobacterial lead compounds.

Design, Synthesis, and Monoamine Oxidase B Selective Inhibitory Activity of N-Arylated Heliamine Analogues.

Monoamine oxidase B (MAO-B) metabolizes monoamines such as dopamine regarding neural transmission and controls its level in the mammalian's brain. When MAO-B metabolizes dopamine abnormally, normal neurotransmission does not occur, and central nervous system disorders such as Parkinson's disease may develop. Although several MAO inhibitors have been developed, most of them have no selectivity between monoamine oxidase A (MAO-A) and MAO-B, or they work irreversibly against the enzyme. This report describes the first case of screening of N-arylated heliamine derivatives to develop novel MAO-B selective inhibitors that can be synthesized concisely by microwave-assisted Pd nanoparticle-catalyzed Buchwald-Hartwig amination. We discovered that the derivatives 4h, 4i, and 4j display inhibitory activity against MAO-B with IC50 values of 1.55, 13.5, and 5.08 µM, respectively.

Gamma-Glutamylcysteine Production Using Phytochelatin Synthase-Like Enzyme Derived from Nostoc sp. Covalently Immobilized on a Cellulose Carrier.

Gamma-glutamylcysteine (γ-EC) is an intermediate generated in the de novo synthesis of glutathione (GSH). Recent studies have revealed that the administration of γ-EC shows neuroprotective effects against oxidative stress in age-related disorders and chronic diseases like Alzhiemer's disease in model animals, which is not expected function in GSH. A phytochelatin synthase-like enzyme derived from Nostoc sp. (NsPCS) mediates γ-EC synthesis from GSH. To achieve low-cost and stable commercial level supply, the availability of immobilized NsPCS for γ-EC production was investigated in this study. Among the tested immobilization techniques, covalent binding to the cellulose carrier was most effective, and could convert GSH completely to γ-EC without decreasing the yield. The stable conversion of γ-EC from 100 mM GSH was achieved by both batch repeated and continuous reactions using the immobilized NsPCS on cellulose sheet and column shape monolith, respectively. The immobilization of NsPCS on those carriers is promising alternative technique for high-yielding and cost-effective production of γ-EC on its commercial applications.

Single-step construction of an acetoxypyrroloindole skeleton via tandem iodocyclization/acetoxylation of indoles.

A method for the synthesis of C3a acetoxy hexahydropyrrolo[2,3-b]indole derivatives via a PhI(OAc)2/nBu4NI mediated tandem iodocyclization/acetoxylation has been developed. The newly developed synthetic strategy features the single-step assembly of various C3a acetoxylated tetrahydropyrrole-, tetrahydrofuran-, and lactone-fused indolines under mild reaction conditions, which enabled efficient asymmetric synthesis of (-)-protubonine B.

Oridonin suppresses particulate-induced NLRP3-independent IL-1α release to prevent crystallopathy in the lung.

The human body is exposed to various particulates of industrial, environmental, or endogenous origin. Invading or intrinsic particulates can induce inflammation by aberrantly activating the immune system, thereby causing crystallopathies. When immune cells such as macrophages phagocytose the particulates, their phagolysosomal membranes undergo mechanical damage, eventually leading to pyroptotic cell death accompanied by the release of inflammatory cytokines, including interleukin (IL)-1α and IL-1ß. The nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is responsible for particulate-induced IL-1ß release and is therefore regarded as a potential therapeutic target for inflammation-mediated crystallopathies. However, IL-1α is released after particulate stimulation in an NLRP3 inflammasome-independent manner and plays a critical role in disease development. Therefore, drugs that exert potent anti-inflammatory effects by comprehensively suppressing particulate-induced responses, including IL-1ß release and IL-1α release, should be developed. Here, we found that oridonin, a diterpenoid isolated from Isodon japonicus HARA, strongly suppressed particulate-induced cell death, accompanied by the release of IL-1α and IL-1ß in mouse and human macrophages. Oridonin reduced particulate-induced phagolysosomal membrane damage in macrophages without affecting phagocytosis of particulates. Furthermore, oridonin treatment markedly suppressed the symptoms of silica particle-induced pneumonia, which was attributed to the release of IL-1α independently of NLRP3. Thus, oridonin is a potential lead compound for developing effective therapeutics for crystallopathies attributed to NLRP3-dependent as well as NLRP3-independent inflammation.

Asteltoxin inhibits extracellular vesicle production through AMPK/mTOR-mediated activation of lysosome function.

Cancer cells secrete aberrantly large amounts of extracellular vesicles (EVs) including exosomes, which originate from multivesicular bodies (MVBs). Because EVs potentially contribute to tumor progression, EV inhibitors are of interest as novel therapeutics. We screened a fungal natural product library. Using cancer cells engineered to secrete luciferase-labeled EVs, we identified asteltoxin, which inhibits mitochondrial ATP synthase, as an EV inhibitor. Low concentrations of asteltoxin inhibited EV secretion without inducing mitochondrial damage. Asteltoxin attenuated cellular ATP levels and induced AMPK-mediated mTORC1 inactivation. Consequently, MiT/TFE transcription factors are translocated into the nucleus, promoting transcription of lysosomal genes and lysosome activation. Electron microscopy analysis revealed that the number of lysosomes increased relative to that of MVBs and the level of EVs decreased after treatment with asteltoxin or rapamycin, an mTORC1 inhibitor. These findings suggest that asteltoxin represents a new type of EV inhibitor that controls MVB fate.

Fungicide Activity of Culture Extract from Kocuria palustris 19C38A1 against Fusarium oxysporum.

Secondary metabolites of actinomycetes are a potential source of bioactive compounds in the agricultural sector. This study aimed to determine the fungicidal properties of extracts of marine organism-derived actinomycetes. Actinomycetes were isolated from marine organisms using agar media with 1% colloidal chitin in artificial seawater. Then, the isolates were cultured on liquid media with 1% colloidal chitin in artificial seawater under static conditions for 14 days. The culture was extracted, the fungicide properties were evaluated using the microtiter 96-well plate method, and the influence of inhibition was visualized using apotome and SEM. Finally, the active extract was analyzed using LCMSMS. In the present study, 19 actinomycetes were isolated from marine organisms, and the isolates were examined with regard to their antifungal activities. Of these nineteen isolates, the isolate 19C38A1 was picked out from the rest. Hence, it showed significant control towards F. oxysporum. The prospective strain 19C38A1 was determined to be Kocuria palustris 19C38A1. The extract 19C38A1 was shown to cause damage to cell integrity, indicated by the shrinking form, and inhibited germination in the F. oxysporum; subsequently, the chemical characteristics of the compound produced by the potential isolate 19C38A1 indicated the presence of benzimidazole compounds in the active fraction of C38BK2FA. These results indicate that actinomycetes derived from marine organisms near the coast of Oluhuta, Tomini Bay, Gorontalo, related to strain 19C38A1, are not widely known as sources of valuable fungicides. This preliminary information is important, as it can be used as a basis for further development in the search for fungicides derived from marine actinomycetes.

Study of the Structure-Activity Relationship of an Anti-Dormant Mycobacterial Substance 3-(Phenethylamino)Demethyl(oxy)aaptamine to Create a Probe Molecule for Detecting Its Target Protein.

The current tuberculosis treatment regimen is long and complex, and its failure leads to relapse and emergence of drug resistance. One of the major reasons underlying the extended chemotherapeutic regimen is the ability of Mycobacterium tuberculosis to attain a dormant state. Therefore, the identification of new lead compounds with chemical structures different from those of conventional anti-tuberculosis drugs is essential. The compound 3-(phenethylamino)demethyl(oxy)aaptamine (PDOA, 1), isolated from marine sponge of Aaptos sp., is known as an anti-dormant mycobacterial substance, and has been reported to be effective against the drug resistant strains of M. tuberculosis. However, its target protein still remains unclear. This study aims to clarify the structure-activity relationship of 1 using 15 synthetic analogues, in order to prepare a probe molecule for detecting the target protein of 1. We succeeded in creating the compound 15 with a photoaffinity group that retained antimicrobial activity, which proved to be a suitable probe molecule for identifying the target protein of 1.

Synthesis and biological evaluation of cajaninstilbene acid and amorfrutins A-D as cytotoxic agents against human pancreatic carcinoma PANC-1 cells.

A concise synthesis of cajaninstilbene acid was achieved in 7 steps from (E)-3,5-dimethoxystilbene in 8.6% overall yield via the Claisen rearrangement of an aryl reverse-prenyl ether as the key step. Cytotoxic activities against human pancreatic carcinoma PANC-1 cells of cajaninstilbene acid and amorfrutins A-D were also evaluated.

Reactivity of γ-glutamyl-cysteine with intracellular and extracellular glutathione metabolic enzymes.

Gamma-glutamyl-cysteine (γ-EC) is a precursor of glutathione (GSH) biosynthesis. We investigated whether it functions as a substrate for three intracellular and one extracellular GSH metabolic enzymes, which mediate the antioxidant defence function of GSH. Among them, glutathione peroxidase, glutathione S-transferase and γ-glutamyl transferase (GGT) exhibited substrate specificity for γ-EC, whereas glutathione reductase did not. The specificities of γ-EC and its disulphide form to GGT were comparable to GSH and its oxidized form, GSSG respectively. These results indicate that they can supply GSH constituent amino acids, glutamate, cysteine and cystine through degradation by GGT. γ-EC may contribute valuable antioxidant defence properties as a food and cosmetic additive.

A New Tetracyclic Bromopyrrole-Imidazole Derivative through Direct Chemical Diversification of Substances Present in Natural Product Extract from Marine Sponge Petrosia (Strongylophora) sp.

Chemical diversification of substances present in natural product extracts can lead to a number of natural product-like compounds with a better chance of desirable bioactivities. The aim of this work was to discover unprecedented chemical conversion and produce new compounds through a one-step reaction of substances present in the extracts of marine sponges. In this report, a new unnatural tetracyclic bromopyrrole-imidazole derivative, rac-6-OEt-cylindradine A (1), was created from a chemically diversified extract of the sponge Petrosia (Strongylophora) sp. We also confirmed that 1 originated from naturally occurring (-)-cylindradine A (2) via a new reaction pattern. Moreover, (-)-dibromophakellin (3) and 4,5-dibromopyrrole-2-carboxylic acid (4), as well as 2, were reported herein for the first time in this genus. Studies on the possible reaction mechanism and bioactivities were also conducted. The results indicate that the direct chemical diversification of substances present in natural product extracts can be a speedy and useful strategy for the discovery of new compounds.

In vitro study on α-amylase and α-glucosidase inhibitory activities of a new stigmastane-type steroid saponin from the leaves of Vernonia amygdalina.

Using various chromatographic separations, four compounds, including one new steroid saponin named vernoamyoside E (1), were isolated from the leaves of the Vietnamese medicinal plant Vernonia amygdalina Delile (Asteraceae). Their structures were established by spectroscopic methods such as 1D- and 2D-NMR, HR-ESI-MS, and HPLC analysis. The inhibitory activities against α-glucosidase and α-amylase of the isolated compounds from V. amygdalina were reported for the first time. The results indicated that compound 1 significantly inhibited both against α-amylase and α-glucosidase activity.

Mitochondrial Targeting in an Anti-Austerity Approach Involving Bioactive Metabolites Isolated from the Marine-Derived Fungus Aspergillus sp.

The tumor microenvironment is a nutrient-deficient region that alters the cancer cell phenotype to aggravate cancer pathology. The ability of cancer cells to tolerate nutrient starvation is referred to as austerity. Compounds that preferentially target cancer cells growing under nutrient-deficient conditions are being employed in anti-austerity approaches in anticancer drug discovery. Therefore, in this study, we investigated physcion (1) and 2-(2',3-epoxy-1',3',5'-heptatrienyl)-6-hydroxy-5-(3-methyl-2-butenyl) benzaldehyde (2) obtained from a culture extract of the marine-derived fungus Aspergillus species (sp.), which were isolated from an unidentified marine sponge, as anti-austerity agents. The chemical structures of 1 and 2 were determined via spectroscopic analysis and comparison with authentic spectral data. Compounds 1 and 2 exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions, with IC50 values of 6.0 and 1.7 µM, respectively. Compound 2 showed higher selective growth-inhibitory activity (505-fold higher) under glucose-deficient conditions than under general culture conditions. Further analysis of the mechanism underlying the anti-austerity activity of compounds 1 and 2 against glucose-starved PANC-1 cells suggested that they inhibited the mitochondrial electron transport chain.