The Nicotiana tabacum UGT89A2 enzyme catalyzes the glycosylation of di- and trihydroxylated benzoic acid derivatives.

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-ß-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 (Tm) 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.

Antivirulence and antipathogenic activity of Mayan herbal remedies against Pseudomonas aeruginosa.

ETHNOPHARMACOLOGICAL RELEVANCE: The Yucatan Peninsula has a privileged wealth of vascular plants with which various Mayan herbal formulations have been developed. However, studies on their antipathogenic and antivirulence properties are scarce. AIM OF THE STUDY: Identify antivirulence properties in Mayan herbal remedies and determine their antipathogenic capacity in burn wounds infected with Pseudomonas aeruginosa. MATERIALS AND METHODS: An ethnobotanical study was conducted in Mayan communities in central and southern Quintana Roo, Mexico. Furthermore, the antipathogenic capacity of three Mayan herbal remedies was analyzed using an animal model of thermal damage and P. aeruginosa infection. Antivirulence properties were determined by inhibiting phenotypes regulated by quorum sensing (pyocyanin, biofilm, and swarming) and by the secretion of the ExoU toxin. The chemical composition of the most active herbal remedy was analyzed using molecular network analysis. RESULTS: It was found that topical administration of the remedy called "herbal soap" (HS) for eleven days maintained 100% survival of the animals, reduced establishment of the bacteria in the burn and prevented its systemic dispersion. Although no curative effect was recorded on tissue damaged by HS treatment, its herbal composition strongly reduced swarming and ExoU secretion. Through analysis of Molecular Networks, it was possible to carry out a global study of its chemical components, and identify the family of oxindole monoterpenoid alkaloids and carboline and tetrahydropyrididole alkaloids. In addition, flavonols, flavan-3-ols, and quinic acid derivatives were detected. CONCLUSIONS: The antipathogenic and antivirulence capacity of ancient Mayan remedies makes them a potential resource for developing new antibacterial therapies to treat burns infected by P. aeruginosa.

Synthesis, antibiofilm activity and molecular docking of N-acylhomoserine lactones containing cinammic moieties.

We prepared a series of cinnamoyl-containing furanones by an affordable and short synthesis. The nineteen compounds hold a variety of substituents including electron-donating, electron-withdrawing, bulky and meta-substituted phenyls, as well as heterocyclic rings. Compounds showed antibiofilm activity in S. aureus, K. pneumoniae and, more pronounced, against P. aeruginosa. The disruption of quorum sensing (QS) was tested using the violacein test and molecular docking predicted the antagonism of LasR as a plausible mechanism of action. The trimethoxylated and diene derivatives showed the best antibiofilm and anti-QS properties, thus becoming candidates for further modifications.

Harnessing the Reactivity of Duclauxin toward Obtaining hPTP1B1-400 Inhibitors.

Duclauxin (1) from Talaromyces sp. IQ-313 was reported as a putative allosteric modulator of human recombinant protein tyrosine phosphatase 1B (400 amino acids) (hPTP1B1-400), 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 hPTP1B1-400 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 LD50 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.

Integrating Taxonomic and Chemical Diversity of Mangrove-Associated Ascomycetes to Discover or Repurpose Bioactive Natural Products.

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 hPTP1B1-400 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 hPTP1B1-400 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.

Absolute configuration and protein tyrosine phosphatase 1B inhibitory activity of xanthoepocin, a dimeric naphtopyrone from Penicillium sp. IQ-429.

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 (hPTP1B1-282, hPTP1B1-298, or hPTP1B1-321), losing valuable information about the ligands' mechanism of inhibition and selectivity. Nevertheless, finding an allosteric site in hPTP1B1-321, and the full-length (hPTP1B1-400) 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 hPTP1B1-400 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 hPTP1B1-400 (IC50 value of 8.8 ± 1.0 µM) in a mixed type fashion, with ki and αki values of 5.5  and 6.6 µM, respectively. Docking xanthoepocin (1) with a homologated model of hPTP1B1-400 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 hPTP1B1-400 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 hPTP1B1-400 (KSV = 1.1 × 105 M-1), and corroborated that it binds to the enzyme with an affinity constant (ka) of 3.7 × 105 M-1. Finally, the drug-likeness and medicinal chemistry friendliness of 1 were predicted with SwissADME.

Association between falls and cardiovascular diseases in the geriatric population.

Objective: To determine the association of cardiovascular diseases with falls in the geriatric population. Methods: Original, Transversal and analytical study. Elderly patients who attend the external consultation of the Geriatrics service, older than 65 years, with falls history, perform comprehensive geriatric assessment to indentify causes of falls in the period from March 2018 to June 2019. We perform measures of central tendency, chi-square test X2 for qualitative variables, we performed linear regression model. Results: A total of 669 patients were included, the analysis shows association with frailty [OR 1.65 (95% CI 1.37-3.77), p <0.05], Heart Failure [OR 1.02, (95% CI, 0.68 - 1.54), p < 0.05 ], the logistic regression analysis with the variables (Fragility, SAH, es: DM2, AMI, Stroke, AF, postural hypotensive syncope, Hypothyroidism, Dyslipidemia, and HF) shows that the probability of falling is 57%. Conclusion: Cardiovascular diseases have a high prevalence in the population studied and increase the risk of falls. Individually analyzed cardiovascular diseases do not show an association with the syndrome of falls in the elderly, except for frailty, which proved to be an independent factor that increases the risk of falls with an OR 1.65. When analyzing them together, the risk of falling increases up to 57%. It is necessary to correctly identify and treat cardiovascular diseases in the elderly.

Objetivo: Determinar la asociación de las caídas con las enfermedades cardiovasculares en la población geriátrica. Métodos: Estudio original, transversal y analítico. Se incluyó a los pacientes que acuden a la consulta externa del Servicio de Geriatría, mayores de 65 años, con antecedentes de caídas, se realizó una evaluación geriátrica integral para identificar las causas de las caídas en el periodo de marzo de 2018 a junio de 2019. Realizamos medidas de tendencia central, chi cuadrada (prueba c2) para variables cualitativas, realizamos modelo de regresión lineal. Resultados: Se incluyeron un total de 669 pacientes. El análisis muestra asociación con fragilidad (odds ratio [OR]: 1.65; intervalo de confianza del 95% [IC 95%]: 1.37-3.77); p < 0.05]), insuficiencia cardiaca (OR: 1.02; IC 95%: 0.68-1.54); p < 0.05). El análisis de regresión logística con las variables fragilidad, HAS, DM2, IAM, EVC, FA, síncope por hipotensión ortostática, hipotiroidismo, dislipidemia e insuficiencia cardiaca (IC) muestra que la probabilidad de caídas es del 57%. Conclusión: Las enfermedades cardiovasculares tienen una alta prevalencia en la población estudiada y aumentan el riesgo de caídas. Las enfermedades cardiovasculares analizadas individualmente no muestran una asociación con el síndrome de caídas en los ancianos, a excepción de la fragilidad, que resultó ser un factor independiente que aumenta el riesgo de caídas con una OR de 1.65. Al analizarlas juntas, el riesgo de caídas se incrementa en un 57%. Es necesario identificar y tratar correctamente las enfermedades cardiovasculares en los ancianos.

Association between falls and cardiovascular diseases in the geriatric population / Asociación entre caídas y enfermedades cardiovasculares en los ancianos

Abstract Objective: To determine the association of cardiovascular diseases with falls in the geriatric population. Methods: Original, Transversal and analytical study. Elderly patients who attend the external consultation of the Geriatrics service, older than 65 years, with falls history, perform comprehensive geriatric assessment to indentify causes of falls in the period from March 2018 to June 2019. We perform measures of central tendency, chi-square test X2 for qualitative variables, we performed linear regression model. Results: A total of 669 patients were included, the analysis shows association with frailty [OR 1.65 (95% CI 1.37-3.77), p <0.05], Heart Failure [OR 1.02, (95% CI, 0.68 - 1.54), p < 0.05 ], the logistic regression analysis with the variables (Fragility, SAH, es: DM2, AMI, Stroke, AF, postural hypotensive syncope, Hypothyroidism, Dyslipidemia, and HF) shows that the probability of falling is 57%. Conclusion: Cardiovascular diseases have a high prevalence in the population studied and increase the risk of falls. Individually analyzed cardiovascular diseases do not show an association with the syndrome of falls in the elderly, except for frailty, which proved to be an independent factor that increases the risk of falls with an OR 1.65. When analyzing them together, the risk of falling increases up to 57%. It is necessary to correctly identify and treat cardiovascular diseases in the elderly.

Resumen Objetivo: Determinar la asociación de las caídas con las enfermedades cardiovasculares en la población geriátrica. Métodos: Estudio original, transversal y analítico. Se incluyó a los pacientes que acuden a la consulta externa del Servicio de Geriatría, mayores de 65 años, con antecedentes de caídas, se realizó una evaluación geriátrica integral para identificar las causas de las caídas en el periodo de marzo de 2018 a junio de 2019. Realizamos medidas de tendencia central, chi cuadrada (prueba c2) para variables cualitativas, realizamos modelo de regresión lineal. Resultados: Se incluyeron un total de 669 pacientes. El análisis muestra asociación con fragilidad (odds ratio [OR]: 1.65; intervalo de confianza del 95% [IC 95%]: 1.37-3.77); p < 0.05]), insuficiencia cardiaca (OR: 1.02; IC 95%: 0.68-1.54); p < 0.05). El análisis de regresión logística con las variables fragilidad, HAS, DM2, IAM, EVC, FA, síncope por hipotensión ortostática, hipotiroidismo, dislipidemia e insuficiencia cardiaca (IC) muestra que la probabilidad de caídas es del 57%. Conclusión: Las enfermedades cardiovasculares tienen una alta prevalencia en la población estudiada y aumentan el riesgo de caídas. Las enfermedades cardiovasculares analizadas individualmente no muestran una asociación con el síndrome de caídas en los ancianos, a excepción de la fragilidad, que resultó ser un factor independiente que aumenta el riesgo de caídas con una OR de 1.65. Al analizarlas juntas, el riesgo de caídas se incrementa en un 57%. Es necesario identificar y tratar correctamente las enfermedades cardiovasculares en los ancianos.

Protein tyrosine phosphatase 1B inhibitors from the fungus Malbranchea albolutea.

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 IC50's ranging from 19 to 129 µM (ursolic acid IC50 = 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.

Dimeric phenalenones from Talaromyces sp. (IQ-313) inhibit hPTP1B1-400: Insights into mechanistic kinetics from in vitro and in silico studies.

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 (PTP1B1-300), missing valuable information about the mechanisms of inhibition, and selectivity of ligands. The present study describes the biochemical characterization of a full-length PTP1B (hPTP1B1-400), as well as the description of phenalenones 1-4 and ursolic acid (5) as allosteric modulators. Compounds 1-5 showed inhibitory potential on hPTP1B1-400, with IC50 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 hPTP1B1-400. 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 hPTP1B1-400, as well as the changes to its rigidity when bound to 1, 4, and 5.

Hydroxy-neo-Clerodanes and 5,10-seco-neo-Clerodanes from Salvia decora.

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 hPTP1B1-400 (human protein tyrosine phosphatase) inhibitors, where 7 showed the best activity, with an IC50 value in the lower µM range. Additionally, compound 7 was evaluated as an α-glucosidase inhibitor. The affinity constant of the 7-hPTP1B1-400 complex was determined by quenching fluorescence experiments (ka = 1.3 × 104 M-1), while the stoichiometry ratio (1:1 protein-ligand) was determined by a continuous variation method.

Structural Elucidation of Malonylcommunol and 6ß-Hydroxy-trans-communic Acid, Two Undescribed Diterpenes from Salvia cinnabarina. First Examples of Labdane Diterpenoids from a Mexican Salvia Species.

The aerial parts of Salvia cinnabarina afforded two undescribed labdane diterpenoids 1 and 2 (malonylcommunol and 6ß-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 ß-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.

Tetradecanoic Acids With Anti-Virulence Properties Increase the Pathogenicity of Pseudomonas aeruginosa in a Murine Cutaneous Infection Model.

Blocking virulence is a promising alternative to counteract Pseudomonas aeruginosa infections. In this regard, the phenomenon of cell-cell communication by quorum sensing (QS) is an important anti-virulence target. In this field, fatty acids (FA) have gained notoriety for their role as autoinducers, as well as anti-virulence molecules in vitro, like some saturated FA (SAFA). In this study, we analyzed the anti-virulence activity of SAFA with 12 to18 carbon atoms and compared their effect with the putative autoinducer cis-2-decenoic acid (CDA). The effect of SAFA on six QS-regulated virulence factors and on the secretion of the exoenzyme ExoU was evaluated. In addition, a murine cutaneous infection model was used to determine their influence on the establishment and damage caused by P. aeruginosa PA14. Dodecanoic (lauric, C12:0) and tetradecanoic (myristic, C14:0) acids (SAFA C12-14) reduced the production of pyocyanin by 35-58% at 40 and 1,000 µM, while CDA inhibited it 62% at a 3.1 µM concentration. Moreover, the SAFA C12-14 reduced swarming by 90% without affecting biofilm formation. In contrast, CDA reduced the biofilm by 57% at 3 µM but did not affect swarming. Furthermore, lauric and myristic acids abolished ExoU secretion at 100 and 50 µM respectively, while CDA reduced it by ≈ 92% at 100 µM. Remarkably, the coadministration of myristic acid (200 and 1,000 µM) with P. aeruginosa PA14 induced greater damage and reduced survival of the animals up to 50%, whereas CDA to 500 µM reduced the damage without affecting the viability of the PA14 strain. Hence, our results show that SAFA C12-14 and CDA have a role in regulation of P. aeruginosa virulence, although their inhibition/activation molecular mechanisms are different in complex environments such as in vivo systems.

Cuautepestalorin, a 7,8-Dihydrochromene-Oxoisochromane Adduct Bearing a Hexacyclic Scaffold from Pestalotiopsis sp. IQ-011.

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.

α-Glucosidase Inhibitors from a Xylaria feejeensis Associated with Hintonia latiflora.

Two new compounds, pestalotin 4'-O-methyl-ß-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.

Calmodulin inhibitors from natural sources: an update.

Calmodulin (CaM) plays a central role in regulating a myriad of cellular functions in physiological and pathophysiological processes, thus representing an important drug target. In previous reviews, our group has reported relevant information regarding natural anti-CaM compounds up to 2009. Natural sources continue to provide a diverse and unique reservoir of CaM inhibitors for drug and research tool discovery. This review provides an update of natural products with reported CaM inhibitory properties, which includes around 70 natural products and some synthetic analogues, belonging to different structural classes. Most of these natural inhibitors were isolated from fungi and plants and belong to the stilbenoid, polyketide, alkaloid, and peptide structural classes. These products were discovered mainly using a fluorescence-based method on rationally designed biosensors, which are highly specific, low-cost, and selective and have short reaction times. The effect of several antimitotic drugs on Ca(2+)-hCaM is also described.

Hypoglycemic properties of some preparations and compounds from Artemisia ludoviciana Nutt.

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.

Thielavins A, J and K: α-Glucosidase inhibitors from MEXU 27095, an endophytic fungus from Hintonia latiflora.

Bioassay-guided fractionation of the bio-active organic extract obtained from solid-media culture of MEXU 27095, an endophytic fungus isolated from the Mexican medicinal plant Hintonia latiflora (Rubiaceae), led to separation of three tridepsides which were identified as thielavins A, J and K. All three compounds inhibited Saccharomyces cerevisieae α-glucosidase (αGHY) in a concentration-dependent manner with IC50 values of 23.8, 15.8, and 22.1µM, respectively. Their inhibitory action was higher than that of acarbose (IC50=545µM), used as a positive control. Kinetic analysis established that the three compounds acted as non-competitive inhibitors with ki values of 27.8, 66.2 and 55.4µM, respectively (α=1.0, 1.2, 0.7, respectively); acarbose behaved as competitive inhibitor with a ki value of 156.1µM. Thielavin J inhibited the activity of α-glucosidase from Bacillus stearothermophilus (αGHBs) with an IC50 of 30.5µM, being less active than acarbose (IC50=0. 015µM); in this case, compound (2) (ki=20.0µM and α=2.9) and acarbose (ki=0.008µM and α=1.9) behaved as non-competitive inhibitors. Docking analysis predicted that all three thielavins and acarbose bind to homologated αGHBs and to αGHY (PDB: 3A4A) in a pocket close to the catalytic site for maltose and isomaltose, respectively. The α-glucosidase inhibitory properties of thielavin K (3) were corroborated in vivo since it induced a noted antihyperglycemic action during an oral sucrose tolerance test (3.1, 10.0 and 31.6mg/kg) in normal and nicotinamide-streptozotocin diabetic mice. In addition, at a dose of 10mg/kg, it provoked a moderate hypoglycemic activity in diabetic mice.