Chemical Analysis and Antidiabetic Potential of a Decoction from Stevia serrata Roots.

A decoction of the roots (31.6-316 mg/kg) from Stevia serrata Cav. (Asteraceae) as well as the main component (5-150 mg/kg) showed hypoglycemic and antihyperglycemic effects in mice. The fractionation of the active extract led to the isolation of dammaradiene acetate (1), stevisalioside A (2), and three new chemical entities characterized by spectroscopic methods and named stevisaliosides B-D (3-5). Glycoside 2 (5 and 50 mg/kg) decreased blood glucose levels and the postprandial peak during oral glucose and insulin tolerance tests in STZ-hyperglycemic mice. Compounds 1-5 were tested also against PTP1B1-400 and showed IC50 values of 1180.9 ± 0.33, 526.8 ± 0.02, 532.1 ± 0.03, 928.2 ± 0.39, and 31.8 ± 1.09 µM, respectively. Compound 5 showed an IC50 value comparable to that of ursolic acid (IC50 = 30.7 ± 0.00 µM). Docking studies revealed that 2-5 and their aglycones bind to PTP1B1-400 in a pocket formed by the C-terminal region. The volatilome of S. serrata was characterized by a high content of (E)-longipinene, spathulenol, guaiadiene, seychellene, and aromandendrene. Finally, a UHPLC-UV method was developed and validated to quantify the content of 2 in the decoction of the plant.

Antidiabetic Potential of a Trimeric Anthranilic Acid Peptide Isolated from Malbranchea flocciformis.

Compound 3, a trimeric anthranilic acid peptide, and another three metabolites were isolated from an organic extract from the culture medium of Malbranchea flocciformis ATCC 34530. The chemical structure proposed previously for 3 was unequivocally assigned via synthesis and X-ray diffraction analysis. Tripeptide 3 showed insulinotropic properties by decreasing the postprandial peak in healthy and hyperglycemic mice. It also increased glucose-induced insulin secretion in INS-1E at 5 µM, specifically at higher glucose concentrations. These results revealed that 3 might act as an insulin sensitizer and a non-classical insulin secretagogue. Altogether, these findings are in harmony with the in vivo oral glucose tolerance test and acute oral hypoglycemic assay. Finally, the chemical composition of the extract was established by the Global Natural Products Social Molecular Network platform. Phylogenetic analysis using the internal transcribed spacer region revealed that M. flocciformis ATCC 34530 is related to the Malbrancheaceae.

Antimicrobial and antibiofilm activity of fungal metabolites on methicillin-resistant Staphylococcus aureus (ATCC 43300) mediated by SarA and AgrA.

Methicillin-resistant Staphylococcus aureus (MRSA) increases its antibiotic resistance by forming biofilms. Natural products (NP) or specialized metabolites have demonstrated their ability to decrease the virulence and pathogenesis of MRSA infections by inhibiting biofilm formation. The present study evaluated the antimicrobial and antibiofilm potential against MRSA of a small library of fungal NP isolated from Mexican biodiversity. The most potent antibacterial activity was observed for myrotecisin B, epiequisetin, equisetin, stachybotrolide acetate, monorden A, zearalenone, fuscin, and fusarubin. On the other hand, epifiscalin C, fiscalin C, dimethylglyotoxin, aspernolide B, and butyrolactones I and IV inhibited the biofilm formation without decreasing bacterial growth. To determine the putative mechanism of action of these compounds, docking analyses were performed against SarA and AgrA proteins, targets known to regulate biofilm production in MRSA. Overall, the results demonstrate that fungal NP may act as potential antibiofilm agents for treating MRSA infections.

Parasitological and molecular characterization of Trypanosoma cruzi of triatomines and mammals from endemic areas for Chagas disease in Venezuela.

It is estimated that 6-7 million people worldwide are infected with Trypanosoma cruzi, the parasite that causes Chagas disease. In Venezuela, Chagas disease remains a public health problem. In this work, T. cruzi isolates from six species of triatomines and mammals of the orders Didelphimorphia and Xenarthra, captured in rural communities of Monagas, underwent parasitological and molecular characterization. A total of 471 triatomines and 17 mammals were captured, with a natural infection rate of 41.4% and 70.6%, respectively. In the male NMRI mouse model used for parasitological characterization (prepatent period, parasitemia curve, mouse mortality, and tissular parasitism), T. cruzi isolates exhibited high lethality due to their pronounced virulence, irrespective of the parasite load in each mouse, resulting in a mortality rate of 75%. Among the vector isolates, in the mouse model, only 2 out of 6 remained alive, while the rest perished during the evaluation. Conversely, the isolates from mammals proved fatal for all the inoculated mice. All isolates were identified as belonging to DTU TcI, based on the molecular markers such as the intergenic region of the miniexon, D7 divergent domain of the 24Sα rDNA, size-variable domain of the 18S rDNA, and hsp60-PCR-RFLP-EcoRV. This study demonstrates the presence of vectors and mammalian reservoirs naturally infected with T. cruzi in communities of Monagas, the 9th largest and 9th most populous state in Venezuela. This situation represents a neglected epidemiological problem demanding urgent attention and imperative health care intervention.

Metabolomic Diversity in Microbial Mats Under Different Environmental Conditions: A Tool to Test Microbial Ecosystem Chemical Change.

Microbial mats are microbial communities capable of recycling the essential elements of life and considered to be the oldest evidence of microbial communities on Earth. Due to their uniqueness and limited sampling material, analyzing their metabolomic profile in different seasons or conditions is challenging. In this study, microbial mats from a small pond in the Cuatro Cienegas Basin in Coahuila, Mexico, were collected in wet and dry seasons. In addition to these samples, mesocosm experiments from the wet samples were set. These mats are elastic and rise after heavy rainfall by forming gas domes structures known as "Archean domes", by the outgassing of methanogenic bacteria, archaea, and sulfur bacteria. Extracts from all mats and mesocosms were subjected to untargeted mass spectrometry-based metabolomics and molecular networking analysis. Interestingly, each mat showed high chemical diversity that may be explained by the temporal dynamic processes in which they were sampled.

Starch degradation in the bean fruit pericarp is characterized by an increase in maltose metabolism.

The bean fruit pericarp accumulates a significant amount of starch, which starts to be degraded 20 days after anthesis (DAA) when seed growth becomes exponential. This period is also characterized by the progressive senescence of the fruit pericarp. However, the chloroplasts maintained their integrity, indicating that starch degradation is a compartmentalized process. The process coincided with a transient increase in maltose and sucrose levels, suggesting that ß-amylase is responsible for starch degradation. Starch degradation in the bean fruit pericarp is also characterized by a large increase in starch phosphorylation, as well as in the activities of cytosolic disproportionating enzyme 2 (DPE2, EC 2.4.1.25) and glucan phosphorylase (PHO2, EC 2.4.1.1). This suggests that the rate of starch degradation in the bean fruit pericarp 20 DAA is dependent on the transformation of starch to a better substrate for ß-amylase and the increase in the rate of cytosolic metabolism of maltose.

Biological Dark Matter Exploration using Data Mining for the Discovery of Antimicrobial Natural Products.

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.

New Terpenoids from the Corticioid Fungus Punctularia atropurpurascens and their Antimycobacterial Evaluation.

Chemical investigation of Punctularia atropurpurascens strain HM1 (Punctulariaceae), a corticioid isolated from a decorticated piece of Quercus bark collected in Bosque de Tlalpan, Mexico City, led to the isolation of a new drimane, 1-α-hydroxy-isodrimenine (1: ) and a new tetrahydroxy kauranol, 16-hydroxy-phlebia-nor-kauranol (2: ), together with the known N-phenylacetamide (3: ). Structures of all compounds were elucidated by spectroscopic and spectrometric methods, and the absolute configuration of 1: and 2: was confirmed via single-crystal X-ray crystallography. The isolated compounds showed modest antimycobacterial activity.

Freshwater Fungi as a Source of Chemical Diversity: A Review.

As their name indicates, freshwater fungi occur on submerged substrates in fresh water habitats. This review brings together the chemical diversity and biological activity of 199 of the 280 known freshwater fungal metabolites published from 1992 to 2020, representing at least seven structural classes, including polyketides, phenylpropanoids, terpenoids, meroterpenoids, alkaloids, polypeptides, and monosaccharides. In addition to describing what they are, where they are found, and what they do, we also discuss strategies for the collection, isolation, and identification of fungi from freshwater habitats, with the goal of enhancing chemists' knowledge of several mycological principles. We anticipate that this review will provide a springboard for future natural products studies from this fascinating but underexplored group of Ascomycota.

Toxicokinetics of temephos after oral administration to adult male rats.

Temephos (Tem) is the larvicide of choice to control mosquito transmission of dengue, Zika, and chikungunya. The toxicokinetic and toxicological information of temephos is very limited. The aim of this work was to determine the toxicokinetics and dosimetry of temephos and its metabolites. Male Wistar rats were orally administered temephos (300 mg/kg) emulsified with saline solution and sacrificed over time after dosing. Temephos and its metabolites were analyzed in blood and tissues by high performance liquid chromatography-diode array detector. At least eleven metabolites were detected, including temephos-sulfoxide (Tem-SO), temephos-oxon (Tem-oxon), temephos-oxon-sulfoxide (Tem-oxon-SO), temephos-oxon-SO-monohydrolyzed (Tem-oxon-SO-OH), 4,4´-thiodiphenol, 4,4´-sulfinyldiphenol, and 4,4´-sulfonyldiphenol or bisphenol S (BPS). The mean blood concentrations of temephos were fitted to a one-compartment model for kinetic analysis. At 2 h, the peak was reached (t1/2 abs = 0.38 h), and only trace levels were detected at 36 h (t1/2 elim = 8.6 h). Temephos was detected in all tissues and preferentially accumulated in fat. Temephos-sulfone-monohydrolyzed (Tem-SO2-OH) blood levels remained constant until 36 h and gradually accumulated in the kidney. Tem-oxon was detected in the brain, liver, kidney, and fat. Clearance from the liver and kidney were 7.59 and 5.52 ml/min, respectively. These results indicate that temephos is well absorbed, extensively metabolized, widely distributed and preferentially stored in adipose tissue. It is biotransformed into reactive metabolites such as Tem-oxons, Tem-dioxons, and BPS. Tem-SO2-OH, the most abundant metabolite of temephos, could be used as an exposure biomarker for toxicokinetic modeling. These results could provide critical insight into the dosimetry and toxicity of temephos and its metabolites.

Coumarins, dihydroisocoumarins, a dibenzo-α-pyrone, a meroterpenoid, and a merodrimane from Talaromyces amestolkiae.

Chemical investigation of an organic extract of a fungus isolated from submerged wood collected from fresh water (strain G173), identified as a Talaromyces amestolkiae (Eurotiales; Trichocomaceae), led to the isolation of three coumarins, three dihydroisocoumarins, a dibenzo-α-pyrone, a meroterpenoid, and a merodrimane. Three of the isolated compounds, namely 7-chloropestalasin A (3), 4-hydroxyaspergillumarin (6), and ent-thailandolide B (9) were new. The structures were elucidated using a combination of spectroscopic and spectrometric techniques. The absolute configurations of 2, 3, 5, and 6 were established via a modified Mosher's ester method, whereas for 9 a combination of TDDFT ECD and ORD calculations were employed. Compounds 1-9 were evaluated for antimicrobial activity against a group of bacteria and fungi.

A Meta-Omics Analysis Unveils the Shift in Microbial Community Structures and Metabolomics Profiles in Mangrove Sediments Treated with a Selective Actinobacterial Isolation Procedure.

Mangrove sediment ecosystems in the coastal areas of the Yucatan peninsula are unique environments, influenced by their karstic origin and connection with the world's largest underground river. The microbial communities residing in these sediments are influenced by the presence of mangrove roots and the trading chemistry for communication between sediment bacteria and plant roots can be targeted for secondary metabolite research. To explore the secondary metabolite production potential of microbial community members in mangrove sediments at the "El Palmar" natural reserve in Sisal, Yucatan, a combined meta-omics approach was applied. The effects of a cultivation medium reported to select for actinomycetes within mangrove sediments' microbial communities was also analyzed. The metabolome of the microbial communities was analyzed by high-resolution liquid chromatography-tandem mass spectrometry, and molecular networking analysis was used to investigate if known natural products and their variants were present. Metagenomic results suggest that the sediments from "El Palmar" harbor a stable bacterial community independently of their distance from mangrove tree roots. An unexpected decrease in the observed abundance of actinomycetes present in the communities occurred when an antibiotic-amended medium considered to be actinomycete-selective was applied for a 30-day period. However, the use of this antibiotic-amended medium also enhanced production of secondary metabolites within the microbial community present relative to the water control, suggesting the treatment selected for antibiotic-resistant bacteria capable of producing a higher number of secondary metabolites. Secondary metabolite mining of "El Palmar" microbial community metagenomes identified polyketide synthase and non-ribosomal peptide synthetases' biosynthetic genes in all analyzed metagenomes. The presence of these genes correlated with the annotation of several secondary metabolites from the Global Natural Product Social Molecular Networking database. These results highlight the biotechnological potential of the microbial communities from "El Palmar", and show the impact selective media had on the composition of communities of actinobacteria.

Genome Mining and Molecular Networking-Based Metabolomics of the Marine Facultative Aspergillus sp. MEXU 27854.

The marine-facultative Aspergillus sp. MEXU 27854, isolated from the Caleta Bay in Acapulco, Guerrero, Mexico, has provided an interesting diversity of secondary metabolites, including a series of rare dioxomorpholines, peptides, and butyrolactones. Here, we report on the genomic data, which consists of 11 contigs (N50~3.95 Mb) with a ~30.75 Mb total length of assembly. Genome annotation resulted in the prediction of 10,822 putative genes. Functional annotation was accomplished by BLAST searching protein sequences with different public databases. Of the predicted genes, 75% were assigned gene ontology terms. From the 67 BGCs identified, ~60% belong to the NRPS and NRPS-like classes. Putative BGCs for the dioxomorpholines and other metabolites were predicted by extensive genome mining. In addition, metabolomic molecular networking analysis allowed the annotation of all isolated compounds and revealed the biosynthetic potential of this fungus. This work represents the first report of whole-genome sequencing and annotation from a marine-facultative fungal strain isolated from Mexico.

Chemical Diversity and Antimicrobial Potential of Cultivable Fungi from Deep-Sea Sediments of the Gulf of Mexico.

A collection of 29 cultivable fungal strains isolated from deep-sea sediments of the Gulf of Mexico were cultivated under the "one strain, many compounds" approach to explore their chemical diversity and antimicrobial potential. From the 87 extracts tested, over 50% showed antimicrobial activity, and the most active ones were those from cultures grown at 4 °C in darkness for 60 days (resembling deep-sea temperature). PCA analysis of the LC-MS data of all the extracts confirmed that culture temperature is the primary factor in the variation of the 4462 metabolite features, accounting for 21.3% of the variation. The bioactivity-guided and conventional chemical studies of selected fungal strains allowed the identification of several active and specialized metabolites. Finally, metabolomics analysis by GNPS molecular networking and manual dereplication revealed the biosynthetic potential of these species to produce interesting chemistry. This work uncovers the chemical and biological study of marine-derived fungal strains from deep-sea sediments of the Gulf of Mexico.

Analysis of testosterone-hydroxylated metabolites in human urine by ultra high performance liquid chromatography-Mass Spectrometry.

Testosterone regulates the male reproductive system and acts directly or indirectly on nearly all systems during fetal, pubertal and adult life. Testosterone homeostasis depends on its synthesis and degradation. The major biotransformation reactions are hydroxylation by different cytochrome P450 (CYP) isoforms. There are no described methods to determine the profile of testosterone-hydroxylated metabolites in human urine. The aim of this study was to develop an analytical method to determine testosterone-hydroxylated metabolites in human urine using UPLC-MS. Seven testosterone-hydroxylated metabolites, androstenedione, and testosterone, were identified by comparison of their tret and positive electrospray ionization (ESI+) data, with those of analytical standards. The method developed is sensitive, specific, repeatable, and precise. Limits of detection and quantitation for all compounds ranged from 1.360 to 13.054 ng/ml and 4.234-39.679 ng/ml, respectively. The percentages of recovery were between 81.2 and 128.8%. The applicability of the analytical method was confirmed by analysis of urine samples obtained from two groups of healthy men (25-30 and 50-75 years old). All analytes were identified with slightly different metabolites profiles in both groups. In conclusion, the UPLC-MS method developed here was validated for the analysis of testosterone-hydroxylated metabolites in human urine.

α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitors from Malbranchea circinata.

During a search for new α-glucosidase and protein tyrosine phosphatase 1B inhibitors from fungal sources, eight new secondary metabolites, including two anthranilic acid-derived peptides (1 and 2), four glycosylated anthraquinones (3-6), 4-isoprenylravenelin (7), and a dimer of 5,8-dihydroxy-4-methoxy-α-tetralone (8), along with four known compounds (9-12), were isolated from solid rice-based cultures of Malbranchea circinata. The structural elucidation of these metabolites was performed using 1D and 2D NMR techniques and DFT-calculated chemical shifts. Compounds 1-3, 9, and 10 showed inhibitory activity to yeast α-glucosidase (αGHY), with IC50 values ranging from 57.4 to 261.3 µM (IC50 acarbose = 585.8 µM). The effect of 10 (10.0 mg/kg) was corroborated in vivo using a sucrose tolerance test in normoglucemic mice. The most active compounds against PTP-1B were 8-10, with IC50 values from 10.9 to 15.3 µM (IC50 ursolic acid = 27.8 µM). Docking analysis of the active compounds into the crystal structures of αGHY and PTP-1B predicted that all compounds bind to the catalytic domains of the enzymes. Together, these results showed that M. circinata is a potential source of antidiabetic drug leads.

Reading and Theory of Mind in Adolescents with Cochlear Implant.

Previous research has shown a possible link between reading comprehension and theory of mind (ToM), but these findings are unclear in adolescents with cochlear implants (CI). In the present study, reading comprehension and ToM were assessed in adolescents with CI and the relation between both skills was also studied. Two sessions were performed on two groups of adolescents aged between 12 and 16 years of age (36 adolescents with CI and 54 participants with typical hearing, TH). They were evaluated by means of a standardized reading battery, a false belief task, and Faux Pas stories. The results indicated that reading and cognitive ToM were more developed in the TH group than in adolescents with CI. However, early-CI and binaural group performance were close to the TH group in narrative and expository comprehension and cognitive ToM. The results also indicated that cognitive ToM and reading comprehension appear to be related in deaf adolescents.

Prenylated Diresorcinols Inhibit Bacterial Quorum Sensing.

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 IC50 values ranging from 0.3 to 12.5 µM. These compounds represent potential leads in the development of antivirulence therapeutics.

Metabolites from the Marine-Facultative Aspergillus sp. MEXU 27854 and Gymnoascus hyalinosporus MEXU 29901 from Caleta Bay, Mexico.

During our ongoing research on fungal strains from unexplored sources, the reinvestigation of the CHCl3-MeOH extract of the marine-facultative Aspergillus sp. MEXU 27854 yielded a new N-methyl cyclic pentapeptide (1) along with known butyrolactone II and PF1233 A. In addition, from the marine-facultative Gymnoascus hyalinosporus MEXU 29901, a new alternariol glucoside, 10-O-[ß-D-(4-methoxyl-glucopyranosyl)]-4-O-methylalternariol (2) and known alternariol 4-O-methyl ether, alternariol and beauvericin, were isolated. The structures of 1 and 2 were established by detailed spectroscopic data, and their absolute configuration was ascertained by Marfey's analysis and HRESIMS-MS/MS data for 1, and by chemical degradation and optical rotation analysis for 2.

Insights in Fungal Bioprospecting in Mexico.

Fungi have consistently been one of the richest sources of natural products, with unprecedented chemical scaffolds and potent biological activities. During the last 20 years, pharmacognosy researchers in Mexico, in collaboration with mycologists, have discovered many novel bioactive fungi natural products and new fungal species. To date, more than 100 bioactive secondary metabolites from 20 fungi from different ecosystems throughout Mexico have been documented in peer-reviewed literature according to Scopus and SciFinder databases. These include compounds from different biosynthetic origins and structural cores with the potential for the development of anticancer, antidiabetic, and/or pesticide agents.