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An approach combining enzymatic inhibition and untargeted metabolomics through molecular networking was employed to search for human recombinant full-length protein tyrosine phosphatase 1B ( h PTP1 B 1 - 400 ) inhibitors from a collection of 66 mangrove-associated fungal taxa. This strategy prioritized two Aspergillus strains (IQ-1612, section Circumdati , and IQ-1620, section Nigri ) for further studies. Chemical investigation of strain IQ-1612 resulted in the isolation of a new nonanolide derivative, roseoglobuloside A (1: ), along with two known metabolites (2: and 3: ), whereas strain IQ-1620 led to the isolation of four known naphtho-γ-pyrones and one known diketopiperazine (4: -8: ). Of all isolates, compounds 2, 3: , and 7: showed a marked inhibitory effect on h PTP1B 1 - 400 with an IC 50 value < 20 µM, while 6: showed moderate inhibition with IC 50 of 65 µM. Compounds 1: and 8: were inactive at a concentration of 100 µM, whereas 4: and 5: demonstrated significant inhibition at 20 µM. The structure of 1: was established by comprehensive spectroscopic analysis, and its relative and absolute configuration was assigned based on NOE correlations and by comparison of calculated and experimental ECD curves. Molecular docking indicated that these molecules primarily bind to two different allosteric sites, thereby inducing conformational changes that impact enzymatic activity., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Glycosyltransferases catalyze the transfer of a glycoside group to a wide range of acceptor compounds to produce glycoconjugates with diverse biological and pharmacological activities. The present work reports the identification and biochemical characterization of Nicotiana tabacum UGT89A2 glycosyltransferase (NtUGT89A2). The enzyme is a monomer in solution that catalyzes the O-β-glucosylation of di- and tri-hydroxylated and chlorinated derivatives of benzoic acid. NtUGT89A2 has a preference for 2,5-dihydroxybenzoic acid (2,5-DHBA) over 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,4-dihydroxybenzoic acid (2,4-DHBA). Other substrates that can be used by NtUGT89A2 include 3,4,5-trihydroxybenzoic acid and chlorinated derivatives such as 2-chloro-5-hydroxybenzoic acid (2-Cl-5-HBA). The substrates of NtUGT89A2 were identified by thermal stability experiments, where we observed a maximum increase of the thermal denaturation midpoint (T m ) of 10 °C in the presence of 2,5-DHBA and UDP-glucose. On the other hand, the highest specific activity was obtained with 2,5-DHBA (225 ± 1.7 nkat/mg). Further characterization revealed that the enzyme has a micromolar affinity for its substrates. Notably, the enzyme retains full activity after incubation at 70 °C for 1 h. These results provide a basis for future functional and structural studies of NtUGT89A2., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Chemical-biological efforts to increase the diversity of duclauxin ( 1 )-like molecules for medicinal chemistry purposes unveiled the reactivity of duclauxin ( 1 ) toward amines and alcohols. To expand the compound class, a semisynthetic strategy conjugating amines to duclauxin ( 1 ) was employed. Insights gained from this approach led to the hypothesis that certain duclauxin-like "natural products" such as talaromycesone B ( 2 ), bacillisporin G ( 3 ), xenoclauxin ( 4 ), bacillisporins F ( 5 / 6 ), bacillisporins J ( 8 / 9 ), bacillisporins I ( 12 / 13 ), and verruculosin A ( 38 ) may be isolation artifacts rather than enzymatic products. Further experimentation, involving adsorption of 1 onto silica gel, resulted in the production of 2 - 6 . To gain insights into the conditions that generate such molecules, one-step reactions under mild conditions were set. Outcomes from both experiments confirmed that duclauxin-like molecules are generated via nonenzymatic reactions. This article presents analytical evidence, indicating that these molecules originate from 1 , with the epimeric mixture of bacillisporins J ( 8 and 9 ) acting as the primary intermediate.

Duclauxin ( 1 ) from Talaromyces sp. IQ-313 was reported as a putative allosteric modulator of human recombinant protein tyrosine phosphatase 1B (400 amino acids) ( h PTP1B 1-400 ), a validated target for the treatment of type II diabetes. Based on these findings, a one-strain-many-compound (OSMAC) experiment on the IQ-313 strain generated derivatives 5a , 6 , and 7 . Moreover, a one-/two-step semisynthetic approach guided by docking toward h PTP1B 1-400 produced 38 analogs, a series (A) incorporating a lactam functionalization at C-1 ( 8a - 15a , 36a , and 37a ) and a series (B) containing a lactam at C-1 and an extra unsaturation between C-7 and C-8 ( 5b , 11b - 37b ). In vitro evaluation and structure-activity relationship (SAR) analysis revealed that analogs from the B series are up to 10-fold more active than 1 and derivatives from the A series. Furthermore, duclauxin ( 1 ) and 36b were assessed for their potential acute toxicity, estimating their LD 50 to be higher than 300 mg/kg. Moreover, 36b significantly reduced glycemia in an insulin tolerance test in mice, suggesting that its mechanism of action is through the PTP1B inhibition.

Natural product reisolation is a bottleneck when discovering new bioactive chemical entities from nature. To overcome this issue, multi-informative approaches integrating several layers of data have been applied with promising results. In this study, integration of taxonomy, nontargeted metabolomics, and bioactivity information resulted in the selection of Scytalidium sp. IQ-074 and Diaporthe sp. IQ-053 to isolate new natural products active against h PTP1B 1-400 and repurpose others as antibiotics. Strain IQ-074 was selected based on the hypothesis that investigating poorly studied and highly metabolic taxa could lead to the isolation of new chemical entities. A chemical investigation of IQ-074 resulted in the isolation of papyracillic acid A ( 14 ), 7-deoxypapyracillic acid A ( 15a and 15b ), and linear polyketides scytalpolyols A-D ( 16 - 19 ). Compound 17 inhibited h PTP1B 1-400 with a half-maximal inhibitory concentration of 27.0 ± 1.7 μM. Diaporthe sp. IQ-053 was selected based on its antibacterial properties against pathogenic strains. Its chemical investigation yielded dothiorelones A ( 20 ) and I ( 21) , cytosporones B ( 22 ) and C ( 23 ), pestalotiopsone B ( 24 ), and diaporthalasin ( 25 ). Compounds 22 and 25 inhibited the growth of Staphylococcus aureus and Staphylococcus epidermidis 42R and moderately inhibited the growth of Acinetobacter baumannii A564, a pandrug-resistant bacterium.

Fungus-growing ants depend on a fungal mutualist that can fall prey to fungal pathogens. This mutualist is cultivated by these ants in structures called fungus gardens. Ants exhibit weeding behaviors that keep their fungus gardens healthy by physically removing compromised pieces. However, how ants detect diseases of their fungus gardens is unknown. Here, we applied the logic of Koch's postulates using environmental fungal community gene sequencing, fungal isolation, and laboratory infection experiments to establish that Trichoderma spp. can act as previously unrecognized pathogens of Trachymyrmex septentrionalis fungus gardens. Our environmental data showed that Trichoderma are the most abundant noncultivar fungi in wild T. septentrionalis fungus gardens. We further determined that metabolites produced by Trichoderma induce an ant weeding response that mirrors their response to live Trichoderma . Combining ant behavioral experiments with bioactivity-guided fractionation and statistical prioritization of metabolites in Trichoderma extracts demonstrated that T. septentrionalis ants weed in response to peptaibols, a specific class of secondary metabolites known to be produced by Trichoderma fungi. Similar assays conducted using purified peptaibols, including the two previously undescribed peptaibols trichokindins VIII and IX, suggested that weeding is likely induced by peptaibols as a class rather than by a single peptaibol metabolite. In addition to their presence in laboratory experiments, we detected peptaibols in wild fungus gardens. Our combination of environmental data and laboratory infection experiments strongly support that peptaibols act as chemical cues of Trichoderma pathogenesis in T. septentrionalis fungus gardens.

Compounds derived from natural sources have been major contributors to the area of cancer chemotherapy for decades. As part of an ongoing effort to discover anticancer drug leads from tropical plants, a large-scale collection of Glycosmis ovoidea Pierre (Rutaceae), was made at Nui Chua National Park, Vietnam. Activity-guided fractionation of the chloroform-soluble fractions led to the isolation of nine coumarins, including the new compound, 1-(7-methoxy-2-oxo-2H-chromen-8-yl)-3-methyl-1-oxobut-2-en-2-yl (S)-2-methylbutanoate (1). An close analogue of 1, namely, kincuongin (2), was deemed as non-cytotoxic (IC 50  > 10 μM) against five different cancer cell lines. However, co-administration of kimcuongin (2) showed an approximately 100 times potentiation of the MCF-7 breast cancer cell cytotoxicity of the previously reported flavonoid, 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (10). To provide a mechanistic basis for the cancer cell line inhibition enhancement observed, an initial in silico study on compound 10 indicated that it interacts with isoforms of the NF-κB complex. In a confirmatory western blot experiment conducted, kimcuongin (2) was found to potentiate the effects of flavone 10 in inhibiting both NF-κB and PARP-1. In vivo investigations using a zebrafish (Danio rerio) model showed that compounds 2, 3, 5, and 6 did not exhibit any discernible toxicity at concentrations up to 50 μM., Competing Interests: Declaration of Competing Interest The authors declared no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The discovery of novel antimicrobials has significantly slowed down over the last three decades. At the same time, humans rely increasingly on antimicrobials because of the progressive antimicrobial resistance in medical practices, human communities, and the environment. Data mining is currently considered a promising option in the discovery of new antibiotics. Some of the advantages of data mining are the ability to predict chemical structures from sequence data, anticipation of the presence of novel metabolites, the understanding of gene evolution, and the corroboration of data from multiple omics technologies. This review analyzes the state-of-the-art for data mining in the fields of bacteria, fungi, and plant genomic data, as well as metabologenomics. It also summarizes some of the most recent research accomplishments in the field, all pinpointing to innovation through uncovering and implementing the next generation of antimicrobials., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Protein tyrosine phosphatase 1B (PTP1B) is an active target for developing drugs to treat type II diabetes, obesity, and cancer. However, in the past, research programs targeting this enzyme focused on discovering inhibitors of truncated models (hPTP1B 1-282 , hPTP1B 1-298 , or hPTP1B 1-321 ), losing valuable information about the ligands' mechanism of inhibition and selectivity. Nevertheless, finding an allosteric site in hPTP1B 1-321 , and the full-length (hPTP1B 1-400 ) protein expression, have shifted the strategies to discover new PTP1B inhibitors. Accordingly, as part of a research program directed at finding non-competitive inhibitors of hPTP1B 1-400 from Pezizomycotina, the extract of Penicillium sp. (IQ-429) was chemically investigated. This study led to xanthoepocin (1) isolation, which was elucidated by means of spectroscopic and spectrometric data. The absolute configuration of 1 was determined to be 7R8S9R7'R8'S9'R by comparing the theoretical and experimental ECD spectra and by GIAO-NMR DP4 + statistical analysis. Xanthoepocin (1) inhibited the phosphatase activity of hPTP1B 1-400 (IC 50 value of 8.8 ± 1.0 µM) in a mixed type fashion, with k i and αk i values of 5.5  and 6.6 μM, respectively. Docking xanthoepocin (1) with a homologated model of hPTP1B 1-400 indicated that it binds in a pocket different from the catalytic triad at the interface of the N and C-terminal domains. Molecular dynamics (MD) simulations showed that 1 locks the WPD loop of hPTP1B 1-400 in a closed conformation, avoiding substrate binding, products release, and catalysis, suggesting an allosteric modulation triggered by large-scale conformational and dynamics changes. Intrinsic quenching fluorescence experiments indicated that 1 behaves like a static quencher of hPTP1B 1-400 (K SV  = 1.1 × 10 5 M -1 ), and corroborated that it binds to the enzyme with an affinity constant (k a ) of 3.7 × 10 5 M -1 . Finally, the drug-likeness and medicinal chemistry friendliness of 1 were predicted with SwissADME., (Copyright © 2021 Elsevier Inc. All rights reserved.)

From solid rice-based cultures of Malbranchea albolutea, three undescribed ardeemins and sartoryglabrins analogs were discovered and named alboluteins A-C. 1H-Indole-3-carbaldehyde, and anthranilic acid were also isolated. 1D and 2D-NMR techniques, as well as DFT-calculated chemical shifts, allowed characterizing alboluteins A-C. Testing these compounds against PTP1B indicated their inhibitory activity with IC 50 's ranging from 19 to 129 μM (ursolic acid IC 50  = 29.8 μM, positive control). Kinetic analysis revealed that albolutein C behaved as a non-competitive inhibitor. Docking studies of alboluteins A-C into the crystal structure of PTP1B (PDB ID: 1T49) predicted that all compounds prefer to bind at the allosteric site of the enzyme, with Ki values of 2.02 × 10 -4 , 1.31 × 10 -4 , and 2.67 × 10 -4  mM, respectively. Molecular dynamic studies indicated that the active compounds remained tied to the enzyme with good binding energy., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Protein tyrosine phosphatase 1B (PTP1B) is a validated target for developing antiobesity, antidiabetic and anticancer drugs. Over the past years, several inhibitors of PTP1B have been discovered; however, none has been approved by the drug regulatory agencies. Interestingly, the research programs focused on discovering PTP1B inhibitors typically use truncated structures of the protein (PTP1B 1-300 , 1-300 amino acids), leading to the loss of valuable information about the inhibition and selectivity of ligands and repeatedly misleading the optimization of putative drug leads. Up to date, only six inhibitors of the full-length protein (hPTP1B 1-400 ), with affinity constants ranging from 1.3 × 10 4 to 3.3 × 10 6 M -1 , have been reported. Towards the discovery of new ligands of the full-length human PTP1B (hPTP1B 1-400 ) from natural sources, herein we describe the isolation of a γ-lactone (1, butyrolactone I) from the fungus Aspergillus terreus, as well as the semisynthesis, inhibitory properties (in vitro and in silico), and the structure-activity relationship of a set of butyrolactone derivatives (1 and 2, and 6-12) as hPTP1B 1-400 inhibitors, as well as the affinity constant (k a  = 2.2 × 10 5 M -1 ) of the 1-hPTP1B 1 - 400 complex, which was determined by fluorescence quenching experiments, after the inner filter effect correction., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background/aim: This study aimed to uncover the effects of (+)-betulin on the NF-κB-apoptotic pathway in MDA-MB-231 cells, and determine its toxicity and protein expression in vivo., Materials and Methods: Cell cytotoxicity and toxicity were determined using the SRB assay and a zebrafish model, respectively. Western blot, mitochondrial transmembrane potential (MTP), and computational modeling analysis were performed., Results: (+)-betulin inhibited the growth of MDA-MB-231 cells, but did not induce toxicity in zebrafish. (+)-Betulin inhibited the activity of NF-κB p65 in silico and in vitro. In cells, (+)-betulin down-regulated NF-κB p50 and 65, IKKα and β, ICAM-1 and bcl-2 expressions. Cell co-treatment with (+)-betulin and TNFα increased the (+)-betulin cytotoxic potential. Moreover, (+)-betulin induced the loss of MTP. Furthermore, (+)-betulin, in zebrafish, down-regulated the expression of NF-κB p65, IKKα, ΙΚΚβ and procaspase-3., Conclusion: The results contribute to the understanding of the mode of action on apoptosis induction by inhibiting NF-κB pathway in MDA-MB-231 cells., (Copyright © 2020 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Thirteen compounds were isolated from the methanolic extract of the leaves of Androcymbium palaestinum Baker (Colchicaceae). Of these, three were new, two were new natural products, and eight were known. The new isolated compounds were (+)-1-demethylandrocine (5), (-)-andropalaestine (8), and (+)-2-demethyl-β-lumicolchicone (10), while the new natural products were (+)-O-methylkreysigine-N-oxide (3) and (+)-O,O-dimethylautumnaline (9). Moreover, two known compounds are reported for the first time from this species, specifically (-)-colchicine (11) and (-)-3-demethyldemecolcine (13). The structures of the isolated compounds were elucidated using a series of spectroscopic and spectrometric techniques, principally HRESIMS, 1D-NMR ( 1 H and 13 C NMR) and 2D-NMR (COSY, edited-HSQC, and HMBC). ECD spectroscopy was used for assigning the absolute configurations of compounds 3, 5, and 10. The cytotoxic activities of the isolated compounds were evaluated using the MDA-MB-435 (melanoma), MDA-MB-231 (breast), and OVCAR3 (ovary) cancer cell lines. Compound 11 was the most potent against all tested cell lines, with IC 50 values of 12, 95 and 23 nM, respectively., Competing Interests: Declaration of Competing Interest All the authors have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Recently, the isolation and elucidation of a series of polyhydroxyanthraquinones were reported from an organic extract of a solid phase culture of an endophytic fungus, Penicillium restrictum (strain G85). One of these compounds, ω -hydroxyemodin (1: ), showed promising quorum-sensing inhibition against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) in both in vitro and in vivo models. The initial supply of 1: was 19 mg, and this amount needed to be scaled by a factor of 30 to 50 times, in order to generate material for further in vivo studies. To do so, improvements were implemented to enhance both the fermentation of the fungal culture and the isolation of this compound, with the target of generating > 800 mg of study materials in a period of 13 wk. Valuable insights, both regarding chemistry and mycology, were gained during the targeted production of 1: on the laboratory-scale. In addition, methods were modified to make the process more environmentally friendly by judicious choice of solvents, implementing procedures for solvent recycling, and minimizing the use of halogenated solvents., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

A critical biological event that contributes to the appearance and progress of cancer and diabetes is the reversible phosphorylation of proteins, a process controlled by protein tyrosine-kinases (PTKs) and protein tyrosine-phosphatases (PTPs). Within the PTPs, PTP1B has gained significant interest since it is a validated target in drug discovery. Indeed, several PTP1B inhibitors have been developed, from both, synthesis and natural products. However, none have been approved by the FDA, due to their poor selectivity and/or pharmacokinetic properties. One of the most significant challenges to the discovery of PTP1B inhibitors (in vitro or in silico) is the use of truncated structures (PTP1B 1-300 ), missing valuable information about the mechanisms of inhibition, and selectivity of ligands. The present study describes the biochemical characterization of a full-length PTP1B (hPTP1B 1-400 ), as well as the description of phenalenones 1-4 and ursolic acid (5) as allosteric modulators. Compounds 1-5 showed inhibitory potential on hPTP1B 1-400 , with IC 50 values ranging from 12.7 to 82.1 µM. Kinetic studies showed that 1 and 5 behave as mixed and non-competitive inhibitors, respectively. Circular dichroism experiments confirmed that 1 and 5 induced conformational changes to hPTP1B 1-400 . Further insights into the structure of hPTP1B1 -400 were obtained from a homology model, which pointed out that the C-terminus (residues 301-400) is highly disordered. Molecular docking with the homologated model suggested that compounds 1 and 3-5 bind to the C-terminal domain, likely inducing conformational changes on the protein. Docking positions of compounds 1, 4, and 5 were refined with molecular dynamics simulations. Importantly, these simulations confirmed the high flexibility of the C-terminus of hPTP1B 1-400 , as well as the changes to its rigidity when bound to 1, 4, and 5., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Preliminary analysis of the mass spectrometric (MS) and NMR spectroscopic data of the primary fractions from the biologically active extract of Salvia decora revealed spectra that are characteristic for neo -clerodane-type diterpenoids. MS-guided isolation of the bioactive fractions led to the isolation of three new chemical entities, including two hydroxy- neo -clerodanes ( 1 and 2 ) and one acylated 5,10- seco - neo -clerodane ( 3 ), along with three known diterpenoids ( 4 - 6 ), ursolic acid ( 7 ), and eupatorin ( 8 ). The structures of the new compounds were established by analysis of the 1D and 2D NMR and MS data, whereas their absolute configuration was deduced using a combination of experimental and theoretical ECD data and confirmed by X-ray crystallography ( 1 and 4 ). Furthermore, compounds 1 , 3 , 4 , and 6 - 8 were evaluated as h PTP1B 1-400 (human protein tyrosine phosphatase) inhibitors, where 7 showed the best activity, with an IC 50 value in the lower μM range. Additionally, compound 7 was evaluated as an α-glucosidase inhibitor. The affinity constant of the 7 - h PTP1B 1-400 complex was determined by quenching fluorescence experiments ( k a = 1.3 × 10 4 M -1 ), while the stoichiometry ratio (1:1 protein-ligand) was determined by a continuous variation method.

The aerial parts of Salvia cinnabarina afforded two undescribed labdane diterpenoids 1 and 2 (malonylcommunol and 6β-hydroxy- trans -communic acid) along with two known labdane diterpenoids, trans -communic acid ( 3 ) and trans -communol ( 4 ). Additionally, seven known metabolites were also isolated; two isopimarane diterpenoids 5 and 6 , two sesquiterpenoids identified as β-eudesmol ( 7 ) and cryptomeridiol ( 8 ), and three aromatic compounds identified as phthalic acid ( 9 ), a mixture of tyrosol fatty acid esters ( 10 ) and the flavone salvigenine ( 11 ). While compounds compounds 1 - 3 showed significant inhibition of yeast α-glucosidase, compounds 2 , 3 and 7 had no anti-inflammatory activity in the edema model induced by TPA. This paper is not only the first report on a wild population of Salvia cinnabarina , but also of the presence of labdane-type diterpenoids in a Mexican Salvia sp.

Prostate cancer (PCa) deaths are typically the result of metastatic castration-resistant PCa (mCRPC). Recently, enzalutamide (Enz), an oral androgen receptor inhibitor, was approved for treating patients with mCRPC. Invariably, all PCa patients eventually develop resistance against Enz. Therefore, novel strategies aimed at overcoming Enz resistance are needed to improve the survival of PCa patients. The role of exosomes in drug resistance has not been fully elucidated in PCa. Therefore, we set out to better understand the exosome's role in the mechanism underlying Enz-resistant PCa. Results showed that Enz-resistant PCa cells (C4-2B, CWR-R1, and LNCaP) secreted significantly higher amounts of exosomes (2-4 folds) compared to Enz-sensitive counterparts. Inhibition of exosome biogenesis in resistant cells by GW4869 and dimethyl amiloride strongly decreased their cell viability. Mechanistic studies revealed upregulation of syntaxin 6 as well as its increased colocalization with CD63 in Enz-resistant PCa cells compared to Enz-sensitive cells. Syntaxin 6 knockdown by specific small interfering RNAs in Enz-resistant PCa cells (C4-2B and CWR-R1) resulted in reduced cell number and increased cell death in the presence of Enz. Furthermore, syntaxin 6 knockdown significantly reduced the exosome secretion in both Enz-resistant C4-2B and CWR-R1 cells. The Cancer Genome Atlas analysis showed increased syntaxin 6 expressions associated with higher Gleason score and decreased progression-free survival in PCa patients. Importantly, IHC analysis showed higher syntaxin 6 expression in cancer tissues from Enz-treated patients compared to Enz naïve patients. Overall, syntaxin 6 plays an important role in the secretion of exosomes and increased survival of Enz-resistant PCa cells., (© 2019 Wiley Periodicals, Inc.)

Cuautepestalorin (4), a 7,8-dihydrochromene-oxoisochromane adduct bearing a spiro-polycyclic (6/6/6/6/6/6) ring system, along with its putative biosynthetic precursors, cytosporin M (1), cytosporin N (2), and oxopestalochromane (3), were isolated from the bioactive extract of Pestalotiopsis sp. using a combination of molecular networking and dereplication techniques. Their structures were elucidated using a set of spectroscopic, spectrometric, chiroptical (experimental and theoretical), and X-ray crystallography data. Compounds 3 and 4 exhibited modest potency when evaluated in vitro as α-glucosidase inhibitors.

Current treatment options for bacterial infections are dependent on antibiotics that inhibit microbial growth and viability. These approaches result in the evolution of drug-resistant strains of bacteria. An anti-infective strategy that is less likely to lead to the development of resistance is the disruption of quorum sensing mechanisms, which are involved in promoting virulence. The goal of this study was to identify fungal metabolites effective as quorum sensing inhibitors. Three new prenylated diresorcinols (1-3), along with two known compounds, (4 R) -regiolone and decarboxycitrinone, were isolated from a freshwater fungus (Helotiales sp.) from North Carolina. Their structures were assigned on the basis of HRESIMS and NMR experiments. The structure of compound 1 was confirmed via X-ray diffraction analysis, and its absolute configuration was established by TDDFT-ECD and optical rotation calculations. Compounds 1-3 suppressed quorum sensing in a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA), with IC 50 values ranging from 0.3 to 12.5 μM. These compounds represent potential leads in the development of antivirulence therapeutics.

A new 8,8'-binaphthopyranone (mycopyranone, 1 ) was isolated from a solid fermentation of Phialemoniopsis sp. (fungal strain MSX61662), and the structure was elucidated via analysis of the NMR and HRESIMS data. The axial chirality of 1 was determined to be M by ECD. The central chirality at C-4/C-4' was assigned through a modified Mosher's method, while the absolute configuration at C-3/C-3' was deduced based on analysis of the 3 J H-3-H-4 values and NOESY correlations. Compound 1 was evaluated for its antimicrobial properties against Staphylococcus aureus SA1199 and a clinically relevant methicillin-resistant S. aureus strain (MRSA USA300 LAC strain AH1263). Compound 1 inhibited the growth of both strains in a concentration dependent manner with IC 50 values in the low μM range. Molecular docking indicated that compound 1 binds to the FtsZ (tubulin-like) protein in the same pocket as viriditoxin ( 2 ), suggesting that 1 targets bacterial cell division.

In research focused on the discovery of new chemical diversity from freshwater fungi, a peak library was built and evaluated against a prostate cancer cell line, E006AA-hT, which was derived from an African American, as this population is disproportionately affected by prostate cancer. The chemical study of the bioactive sample accessioned as G858 ( Delitschia sp.) led to the isolation of eight new α -pyrone derivatives (1:  - 7: , and 11: ), as well as the new 3 S* ,4 S* -7-ethyl-4,8-dihydroxy-3,6-dimethoxy-3,4-dihydronaphthalen-1( 2H )-one (15: ). In addition, the known compounds 5-(3- S -hydroxybutyl)-4-methoxy-6-methyl-2 H -pyran-2-one (8: ), 5-(3-oxobutyl)-4-methoxy-6-methyl-2 H -pyran-2-one (9: ), pyrenocine I (10: ), 5-butyl-6-(hydroxymethyl)-4-methoxy-2 H -pyran-2-one (12: ), sporidesmin A (13: ), 6-ethyl-2,7-dimethoxyjuglone (14: ), artrichitin (16: ), and lipopeptide 15G256 ε (17: ) were also obtained. The structures of the new compounds were elucidated using a set of spectroscopic (NMR) and spectrometric (HRMS) methods. The absolute configuration of the most abundant member of each subclass of compounds was assigned through a modified Mosher's ester method. For 15: , the relative configuration was assigned based on analysis of 3 J values. Compounds 1, 2, 5:  - 14, 16: , and 17: were evaluated against the cancer cell line E006AA-hT under hypoxic conditions, where compound 13: inhibited cell proliferation at a concentration of 2.5 µM., Competing Interests: The authors declare no conflict of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

Covering: up to 2018With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets. A comprehensive compilation of historic to present-day cases as well as contemporary and future applications show that addressing the urgent need for a repository of publicly accessible raw NMR data has the potential to transform natural products (NPs) and associated fields of chemical and biomedical research. The call for advancing open sharing mechanisms for raw data is intended to enhance the transparency of experimental protocols, augment the reproducibility of reported outcomes, including biological studies, become a regular component of responsible research, and thereby enrich the integrity of NP research and related fields.

Correction for 'The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research' by James B. McAlpine et al., Nat. Prod. Rep., 2018, DOI: .

A palladium(II) catalyst, in the presence of Selectfluor, enables the efficient and chemoselective transformation of primary amides into nitriles. The amides can be attached to aromatic rings, heteroaromatic rings, or aliphatic side chains, and the reactions tolerate steric bulk and electronic modification. Dehydration of a peptaibol containing three glutamine groups afforded structure-activity relationships for each glutamine residue. Thus, this dehydration can act similarly to an alanine scan for glutamines via synthetic mutation.

Four new homoisoflavonoids, 7-O-methyl-8-demethoxy-3'-hydroxy-3,9-dihydropunctatin (4), 6-hydroxy-8-demethoxy-4'-O-methyl-3,9-dihydropunctatin (8), 7,4'-O-dimethyl-8-demethoxy-3,3'-dihydroxy-3,9-dihydropunctatin (13), and 7-O-methyl-3-hyroxy-3,9-dihydropunctatin (14) were identified from a chloroform extract of the bulbs of Bellevalia flexuosa, along with 13 known analogues. The structures were determined by analysis of HRMS and NMR data, while ECD spectroscopy enabled the assignment of the absolute configurations of the new compounds 4, 8, 13 and 16. The cytotoxic activities of the isolated compounds (1-17) were evaluated using a panel of human cancer cell lines. Compounds 2 and 7 were the most potent against the MDA-MB-435 (melanoma) cancer cell line with IC 50 values of 1.6 and 2.0 μM, respectively, and were essentially equipotent against the OVCAR3 (ovarian) cancer cell line with IC 50 values of 9.5 and 10.8 μM, respectively. However, compound 7, with an IC 50 value of 3.6 μM, was the most potent against the MDA-MB-231 (breast) cancer cell line., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Peptaibols are an intriguing class of fungal metabolites due both to their wide range of reported bioactivities and to the structural variability that can be generated by the exchange of variable amino acid building blocks. In an effort to streamline the discovery of structurally diverse peptaibols, a mass spectrometry surface sampling technique was applied to screen the chemistry of fungal cultures in situ. Four previously undescribed peptaibols, all containing a rare threonine residue, were identified from a fungal culture (MSX53554), which was identified as Nectriopsis Maire (Bionectriaceae, Hypocreales, Ascomycota). These compounds not only increased the known threonine-containing peptaibols by nearly 20%, but also, the threonine residue was situated in a unique place compared to the other reported threonine-containing peptaibols. After the initial in situ detection and characterization, a large-scale solid fermentation culture was grown. The four peptaibols were isolated and characterized by mass spectrometry. In addition, one of the peptaibols was fully characterized by NMR and amino acid analysis using Marfey's reagent and exhibited moderate in vitro anticancer activity., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Synthetic biological approaches, such as site-directed biosynthesis, have contributed to the expansion of the chemical space of natural products, making possible the biosynthesis of unnatural metabolites that otherwise would be difficult to access. Such methods may allow the incorporation of fluorine, an atom rarely found in nature, into complex secondary metabolites. Organofluorine compounds and secondary metabolites have both played pivotal roles in the development of drugs; however, their discovery and development are often via nonintersecting tracks. In this context, we used the biosynthetic machinery of Trichoderma arundinaceum (strain MSX70741) to incorporate a fluorine atom into peptaibol-type molecules in a site-selective manner. Thus, fermentation of strain MSX70741 in media containing ortho- and meta-F-phenylalanine resulted in the biosynthesis of two new fluorine-containing alamethicin F50 derivatives. The fluorinated products were characterized using spectroscopic (1D and 2D NMR, including 19 F) and spectrometric (HRESIMS/MS n ) methods, and their absolute configurations were established by Marfey's analysis. Fluorine-containing alamethicin F50 derivatives exhibited potency analogous to the nonfluorinated parent when evaluated against a panel of human cancer cell lines. Importantly, the biosynthesis of fluorinated alamethicin F50 derivatives by strain MSX70741 was monitored in situ using a droplet-liquid microjunction-surface sampling probe coupled to a hyphenated system.

The study presented herein constitutes an extensive investigation of constituents in Hydrastis canadensis L. (Ranunculaceae) leaves. It describes the isolation and identification of two previously unknown compounds, 3,4-dimethoxy-2-(methoxycarbonyl)benzoic acid ( 1 ) and 3,5,3'-trihydroxy-7,4'-dimethoxy-6,8- C -dimethyl-flavone ( 2 ), along with the known compounds (±)-chilenine ( 3 ), (2 R )-5,4'-dihydroxy-6- C -methyl-7-methoxy-flavanone ( 4 ), 5,4'-dihydroxy-6,8-di- C -methyl-7-methoxy-flavanone ( 5 ), noroxyhydrastinine ( 6 ), oxyhydrastinine ( 7 ) and 4',5'-dimethoxy-4-methyl-3'-oxo-(1,2,5,6-tetrahydro-4 H -1,3-dioxolo-[4',5':4,5]-benzo[1,2- e ]-1,2-oxazocin)-2-spiro-1'-phtalan ( 8 ). Compounds 3-8 have been reported from other sources, but this is the first report of their presence in H. canadensis extracts. A mass spectrometry based assay was employed to demonstrate bacterial efflux pump inhibitory activity against Staphylococcus aureus for 2 , with an IC 50 value of 180 ± 6 μM. This activity in addition to that of other bioactive compounds such as flavonoids and alkaloids, may explain the purported efficacy of H. canadensis for treatment of bacterial infections. Finally, this report includes high mass accuracy fragmentation spectra for all compounds investigated herein which were uploaded into the Global Natural Products Social molecular networking library and can be used to facilitate their future identification in H. canadensis or other botanicals.

In the field of natural products chemistry, a common question pertains to the authenticity of an isolated compound, i.e. are the interesting side chains biosynthesized naturally or an artefact of the isolation/purification processes? The droplet-liquid microjunction-surface sampling probe (droplet-LMJ-SSP) coupled to a hyphenated system (UPLC-UV-HRESIMS) empowers the analysis of natural product sources in situ , providing data on the biosynthetic timing and spatial distribution of secondary metabolites. In this study the droplet-LMJ-SSP was utilized to validate the authenticity of two new peptaibols ( 2 and 3 ) as biosynthesized secondary metabolites, even though both them had structural features that could be perceived as artefacts. Compounds 2 and 3 were isolated from the scaled up fermentation of Trichoderma arundinaceum (strain MSX70741), along with a new member of the trichobrevin BIII complex ( 1 ), and four known compounds ( 4 - 7 ). The structures of the isolates were established using a set of spectroscopic and spectrometric methods, and their absolute configurations were determined by Marfey's analysis. The cytotoxic activity of compounds 1 , 3 , 4 and 6 was evaluated against a panel of cancer cell lines, where cytotoxic activity in the single digit μM range was observed.

In order to contribute to the structural basis for rational design of calmodulin (CaM) inhibitors, we analyzed the interaction of CaM with 14 classic antagonists and two compounds that do not affect CaM, using docking and molecular dynamics (MD) simulations, and the data were compared to available experimental data. The Ca(2+)-CaM-Ligands complexes were simulated 20 ns, with CaM starting in the "open" and "closed" conformations. The analysis of the MD simulations provided insight into the conformational changes undergone by CaM during its interaction with these ligands. These simulations were used to predict the binding free energies (ΔG) from contributions ΔH and ΔS, giving useful information about CaM ligand binding thermodynamics. The ΔG predicted for the CaM's inhibitors correlated well with available experimental data as the r(2) obtained was 0.76 and 0.82 for the group of xanthones. Additionally, valuable information is presented here: I) CaM has two preferred ligand binding sites in the open conformation known as site 1 and 4, II) CaM can bind ligands of diverse structural nature, III) the flexibility of CaM is reduced by the union of its ligands, leading to a reduction in the Ca(2+)-CaM entropy, IV) enthalpy dominates the molecular recognition process in the system Ca(2+)-CaM-Ligand, and V) the ligands making more extensive contact with the protein have higher affinity for Ca(2+)-CaM. Despite their limitations, docking and MD simulations in combination with experimental data continue to be excellent tools for research in pharmacology, toward a rational design of new drugs.

Two new compounds, pestalotin 4'-O-methyl-β-mannopyranoside (1) and 3S,4R-(+)-4-hydroxymellein (2), were isolated from an organic extract of a Xylaria feejeensis, which was isolated as an endophytic fungus from Hintonia latiflora. In addition, the known compounds 3S,4S-(+)-4-hydroxymellein (3), 3S-(+)-8-methoxymellein (4), and the quinone derivatives 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione (5), 4S,5S,6S-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-en-1-one (6), and 4R,5R-dihydroxy-3-methoxy-5-methylcyclohexen-2-en-1-one (7) were obtained. The structures of 1 and 2 were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of the stereogenic centers of 1 and 2 was determined using ECD spectroscopy combined with time-dependent density functional theory calculations. In the case of 1, comparison of the experimental and theoretical (3)J6-7 coupling constants provided further evidence for the stereochemical assignments. Compounds 2 and 3 inhibited Saccharomyces cerevisiae α-glucosidase (αGHY), with IC50 values of 441 ± 23 and 549 ± 2.5 μM, respectively. Their activity was comparable to that of acarbose (IC50 = 545 ± 19 μM), used as positive control. Molecular docking predicted that both compounds bind to αGHY in a site different from the catalytic domain, which could imply an allosteric type of inhibition.

Ethnopharmacological Relevance: Artemisia ludoviciana, commonly known as "estafiate", plays an important role in contemporary Mexico for treating several diseases including diabetes. To establish the preclinical efficacy of Artemisia ludoviciana as hypoglycemic and/or antihyperglycemic agent using well-known animal models., Materials and Methods: Acute hypoglycemic as well as oral glucose (OGTT) and sucrose (OSTT) tolerance tests were used to demonstrate the value of the plant for treating diabetes. An essential oil (EO), an organic extract (OE) and an infusion (AE) were assayed in normal and NA-STZ-treated mice. The acute toxicity of the three preparations was analyzed by the Lorke method. The infusion was subjected to conventional phytochemical study using chromatographic conventional procedures. Some of the isolates were evaluated using the same pharmacological assays as well as an enzymatic test. The latter was employed to assess their potential inhibitory effect on yeast α-glucosidase., Results: Oral administration of OE to normal mice significantly decreased blood glucose level only at the dose of 100 mg/kg; in NA-STZ-mice the hypoglycemic effect was observed at the three doses tested (31.6, 100, and 316 mg/kg). The infusion reduced significantly, blood sugar levels only in diabetic mice; the best effect was observed at the dose of 316 mg/kg. The EO was inactive when evaluated in normal mice. Regarding to the antihyperglycemic effect, the best effect was observed with the OE, during the OGTT and OSTT in diabetic mice. The infusion (AE) showed better effects during the OGTT in both normal and diabetic animals at the dose of 100 mg/kg. Finally, the EO was inactive during an OGTT at the three doses tested (31.6, 100, and 316 mg/kg) in diabetic mice. In addition, the results of AE on the enzymatic test using yeast α-glucosidase revealed an inhibition of 45%; this finding was consistent with the results obtained with the same preparation in vivo during an OSTT. Conventional phytochemical analysis of the active AE led to the isolation and characterization of eupatilin (1), jaceosidin (2), arglanin (3), salvinine (4), and 3,5-dicaffeoylquinic acid (5). Biological testing of 1 and 3 revealed their hypoglycemic effect. The hypoglycemic effect of arglanin (3) was attenuated in the presence of nicorandil, which suggested that the lactone behaved as an ATP-K+-channel blocker as glibenclamide. Salvinine (4) turned out to be a mixed α-glucosidase inhibitor, while 3 was inactive., Conclusions: Artemisia ludoviciana preparations showed hypoglycemic and antihyperglycemic effects, which could explain its effectiveness for treating diabetes in contemporary Mexico. Some of the active principles of the plant included compounds 1-5. These compounds seem to be acting synergistically on different molecular targets which involved glucose absorption and insulin liberation., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)