Electrophilic Agonists Modulate the Transient Receptor Potential Ankyrin-1 Channels Mediated by Insulin and Glucagon-like Peptide-1 Secretion for Glucose Homeostasis.

This pre-clinical study investigated the transient receptor potential ankyrin-1 (TRPA1) channels on modulating targets for glucose homeostasis using agonists: the electrophilic agonists, cinnamaldehyde (CIN) and allyl isothiocyanate (AITC), and the non-electrophilic agonist, carvacrol (CRV). A glucose tolerance test was performed on rats. CIN and AITC (5, 10 and 20 mg/kg) or CRV (25, 100, 300, and 600 mg/kg) were administered intraperitoneally (i.p.), and glycemia was measured. In the intestine, Glucagon-like peptide-1 (GLP-1) and disaccharidase activity were evaluated (in vivo and in vitro, respectively). Furthermore, in vivo and in vitro insulin secretion was determined. Islets were used to measure insulin secretion and calcium influx. CIN and AITC improved glucose tolerance and increased insulin secretion in vivo and in vitro. CRV was unable to reduce glycemia. Electrophilic agonists, CIN and AITC, inhibited disaccharidases and acted as secretagogues in the intestine by inducing GLP-1 release in vivo and in vitro and contributed to insulin secretion and glycemia. The effect of CIN on calcium influx in pancreatic islets (insulin secretion) involves voltage-dependent calcium channels and calcium from stores. TRPA1 triggers calcium influx and potentiates intracellular calcium release to induce insulin secretion, suggesting that electrophilic agonists mediate this signaling transduction for the control of glycemia.

Signal transduction of the insulin secretion induced by the chalcone analogue, (E)-3-(phenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one, and its role in glucose and lipid metabolism.

A chalcone analogue, (E)-3-(phenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (DMU 101), was synthesized using classic base catalysis and Claisen-Schmidt condensation, and then screened for its antidiabetic properties. The compound's effects on glucose and lipid metabolism were assayed in rats that were treated acutely and for a short time to elucidate its mechanism of action, evaluating glucose tolerance and lactate dehydrogenase activity in response to chalcone analogue administration. The chalcone's in vitro and ex vivo effects on glycogen, glucose, lipid and lipolysis were also investigated, as well as the mechanism by which it induces 45Ca2+ influx-mediated insulin secretion. The analogue (10 mg/kg) diminished glycemia, without inducing acute cell damage, increased glycogen content in the skeletal muscle and reduced serum triacylglycerol and total cholesterol, but did not alter high-density lipoprotein or low-density lipoprotein. Chalcone (10 µM) stimulated glucose uptake in the soleus muscle and did not modulate in vitro or ex vivo lipolysis. This analogue also increased insulin secretion by triggering calcium influx and blocking ATP-sensitive K+ channels and voltage-dependent calcium channels. However, it also modulated stored calcium via sarco/endoplasmic reticulum calcium ATPase (SERCA) and ryanodine receptor (RYR) activity. These findings indicate that this chalcone may induce cellular repolarization via a mechanism mediated by calcium-dependent potassium channels.

What do we have that is new in antifungal peptides? A patent review.

Drugs used to fight fungal infections may cause toxic or adverse drug interactions. For this reason, there is an increase in the development of natural, semisynthetic and synthetic antifungal peptides. This study aimed to perform a patent review to identify the advances in peptides to treat fungal infections. In a preliminary assessment, 597 patents were identified from the database. Then, duplicated patents (62) and those with titles in disagreement with the scope of this review (196) were excluded. Then, six patents were not in English or Spanish. Following the screening, 288 patents were outside the focus of this review, according to their abstract and description. The final selection covered 45 patents.

Currently, medications used to treat fungal infections may interact negatively with other drugs or be hazardous to the host. Scientists have been looking for novel, safe and efficient antifungal drugs since the enhancement of fungal resistance. Antimicrobial peptides, as opposed to traditional antibiotics, offer a variety of antibacterial activity against bacteria, fungi, parasites, viruses and cancer cells. The production of isolated natural, semisynthetic and synthetic antifungal peptides has increased. As a result, patents are a reliable and up-to-date source of innovation. As a result, their content analysis provides crucial information for identifying trends in new medications and targeted treatment plans.

1α,25-(OH)2 vitamin D3 prevents insulin resistance and regulates coordinated exocytosis and insulin secretion.

Vitamin D3 is associated with improvements in insulin resistance and glycemia. In this study, we investigated the short-term effect of 1α,25(OH)2 Vitamin D3 (1,25-D3) and cholecalciferol (vitamin D3) on the glycemia and insulin sensitivity of control and dexamethasone-induced insulin-resistance rats. 45Ca2+ influx responses to 1,25-D3 and its role in insulin secretion were investigated in isolated pancreatic islets from control rats. In vivo, 5 d treatment with 1,25-D3 (i.p.) prevented insulin resistance in dexamethasone-treated rats. Treatment with 1,25-D3 improved the activities of hepatic enzymes, serum lipids and calcium concentrations in insulin-resistant rats. 25-D3 (o.g.) does not affect insulin resistance. In pancreatic islets, 1,25-D3 increased insulin secretion and stimulated rapid response 45Ca2+ influx. The stimulatory effect of 1,25-D3 on 45Ca2+ influx was decreased by diazoxide, apamine, thapsigargin, dantrolene, 2-APB, nifedipine, TEA, PKA, PKC, and cytoskeleton inhibitor, while it was increased by glibenclamide and N-ethylmaleimide. The stimulatory effect of 1,25-D3 on 45Ca2+ influx involves the activation of L-type VDCC, K+-ATP, K+-Ca2+, and Kv channels, which augment cytosolic calcium. These ionic changes mobilize calcium from stores and downstream activation of PKC, PKA tethering vesicle traffic and fusion at the plasma membrane for insulin secretion. This is the first study highlighting the unprecedented role of 1,25-D3 (short-term effect) in the regulation of glucose homeostasis and on prevention of insulin resistance. Furthermore, this study shows the intracellular ß-cell signal transduction of 1,25-D3 through the modulation of pivotal ionic channels and proteins exhibiting a coordinated exocytosis of vesicles for insulin secretion.

Flavonoids and saponins from Passiflora edulis f. edulis leaves (purple passion fruit) and its potential anti-inflammatory activity.

OBJECTIVES: The objective of this work was to evaluate the anti-inflammatory activity of the aqueous extract, fractions and major compounds, which are isolated and identified from Passiflora edulis f. edulis (purple passion fruit) leaves extract. METHODS: For the isolation of the major compounds, reversed-phase chromatography and normal phase countercurrent chromatography were used. The separation was followed by thin layer chromatography and HPLC-DAD-ELSD. One-dimensional and two-dimensional NMR and ESI-TOF-MS/MS were used for structural elucidation. The anti-inflammatory activity was evaluated on a TPA multiple dose model of skin chronic inflammation in mice. Additionally, myeloperoxidase (MPO) and nitric oxide synthase (NOS) activity assays were performed as possible mechanisms of action studies. KEY FINDINGS AND CONCLUSIONS: The study of the butanolic fraction mainly showed the presence of saponins and flavonoids. Three minor flavonoids were detected; and three known saponins, cyclopassiflosides IX, XI and III were isolated and identified. This is the first unequivocal report of the presence of these compounds in P. edulis f. edulis leaves. The most favourable results of anti-inflammatory activity were obtained for the flavonoid-rich fraction. All the fractions and isolated compounds evaluated, presented high percentages of inhibition of nitric oxide synthase activity.

Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study.

The leaves of Passiflora ligularis Juss (known as sweet granadilla for its edible fruits) are a crop byproduct that is discarded. With the aim of contributing to give value-added products from these crop by-side products to farmers of Colombian Andes, we carried out a 1H-NMR-metabolomics analysis of polar extracts from leaves collected in three locations and stored in two conditions in order to identify glucosyl-hydrolase inhibitors. Variations in the metabolic profile and the bioactivity among samples were analyzed by orthogonal partial least square discriminant analysis. Thus, 1H-NMR signals related to polyphenolic compounds, saponins, and amino acids were correlated with higher inhibitory activities. Moreover, a targeted NMR and HPLC-MS/MS analysis allowed the identification of 14 polyphenolic compounds and the structural characterization of a new triterpenoid saponin, ligularoside A. The measurements of IC50 values for α-amylase and α-glycosidase inhibitors allowed the identification of quercetin-3-O-ß-glucoside, kaempferol-3-O-ß-glucoside, and ligularoside A as the most active compounds. These results suggest that P. ligularis leaves are a source of glucosyl-hydrolase inhibitors and lay the foundation for exploring additional applications.

Cellular target of isoquercetin from Passiflora ligularis Juss for glucose uptake in rat soleus muscle.

Quercetin 3-O-beta-d-glucopyranoside (isoquercetin) is one of the most frequent metabolites of the Passiflora ligularis Juss. The purpose of this study was to investigate the effect of the aqueous extract and ethanol fraction from P. ligularis Juss leaves on glycaemia and the mechanism of action of isoquercetin on glucose uptake. In the glucose tolerance test, the aqueous extract and ethanol fraction from P. ligularis Juss (125 mg/kg to 500 mg/kg o. g.) reduced glycaemia and increased the hepatic and muscular glycogen content. Phytochemical analysis evidenced the dominant presence of isoquercetin in the extract and fraction from leaves of P. ligularis Juss. Isoquercetin mediates the stimulatory effect on glucose uptake independent of insulin receptor activation but, involve PI3K, MAPK, MEK/ERK pathways and de novo protein synthesis to GLUT-4 translocation. Overall findings revealed that isoquercetin and aqueous extract and ethanol fraction of P. ligularis Juss leaves might be a promising functional food or medicine for the treatment or prevention of diabetes.

Astragalin augments basal calcium influx and insulin secretion in rat pancreatic islets.

Astragalin is a flavonol glycoside with several biological activities, including antidiabetic properties. The objective of this study was to investigate the effects of astragalin on glycaemia and insulin secretion, in vivo, and on calcium influx and insulin secretion in isolated rat pancreatic islets, ex vivo. Astragalin (1 and 10 mg / kg) was administered by oral gavage to fasted Wistar rats and serum glucose and plasma insulin were measured. Isolated pancreatic islets were used to measure basal insulin secretion and calcium influx. Astragalin (10 mg/ kg) decreased glycaemia and increased insulin secretion significantly at 15-180 min, respectively, in the glucose tolerance test. In isolated pancreatic cells, astragalin (100 µM) stimulated calcium influx through a mechanism involving ATP-dependent potassium channels, L-type voltage-dependent calcium channels, the sarcoendoplasmic reticulum calcium transport ATPase (SERCA), PKC and PKA. These findings highlight the dietary coadjuvant, astragalin, as a potential insulin secretagogue that may contribute to glucose homeostasis.

In vitro intestinal permeability studies, pharmacokinetics and tissue distribution of 6-methylcoumarin after oral and intraperitoneal administration in Wistar rats

ABSTRACT 6-Methylcoumarin (6MC) is a semisynthetic coumarin with important in vitro and in vivo anti-inflammatory activity. In order to continue the pre-clinical characterization of this molecule, in vitro intestinal permeability, plasma profile and tissue distribution after oral administration in rats were studied. The permeability of 6MC was evaluated by the Caco-2 cellular model in both the apical-basal (A-B) and basal-apical (B-A) directions. The pharmacokinetics and biodistribution were evaluated in rats after oral and intraperitoneal administration at doses of 200 mg/kg. Transport experiments with Caco-2 cells showed that 6MC presented high permeability at all concentrations evaluated. This finding suggested that 6MC could be transported across the gut wall by passive diffusion. The plasma concentration-time curve showed that the maximum concentration (Cmax) was 17.13 ± 2.90 µg/mL at maximum time (Tmax) of 30 min for the oral route and Cmax 26.18 ± 2.47 µg/mL at 6.0 min for the intraperitoneal administration, with elimination constant of (Ke ) 0.0070 min-1 and a short life half time of (T1/2 ) lower that 120 min. The distribution study showed that 6MC has high accumulation in the liver, and widespread distribution in all the organs evaluated.

Anti-inflammatory R-prostaglandins from Caribbean Colombian soft coral Plexaura homomalla.

OBJECTIVES: This study aims to evaluate the effect of prostaglandins isolated from soft coral Plexaura homomalla, collected in Colombian Caribbean Sea, on in vivo and in vitro inflammation models. METHODS: Extracts from P. homomalla were fractionated and sequentially chromatographed to obtain the prostaglandins: (15R)-PGA2 (1), (15R)-PGA2 -Me (2), (15R)-O-Ac-PGA2 (3), (15R)-O-Ac-PGA2 -Me (4) and (15R)-PGE2 (5) in addition to three semi-synthetic prostaglandins obtained by transformations of the natural products. The anti-inflammatory properties of natural and semi-synthetic compounds were determined in vivo using 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear oedema model and in vitro leucocyte degranulation, myeloperoxidase (MPO) and elastase enzymatic activities from human polymorphonuclear cells (PMNs). The cell viability was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. KEY FINDINGS: In the in vivo assay, (15R)-PGE2 (1) and (15R)-O-Ac-PGA2 (3) showed anti-inflammatory activity, as well as in vitro inhibition of elastase release from PMNs. In the PMNs degranulation assay, (15R)-PGE2 (5), was the most active compound in the inhibition of MPO release. Finally, all the tested prostaglandins showed moderate inhibition for elastase enzyme activity, whereas none of the prostaglandins exhibit significative inhibition on MPO activity. CONCLUSION: (15R)-PGE2 (1) and (15R)-O-Ac-PGA2 (3) present significant inhibition on three important events related to the topical inflammatory response induced by TPA: the oedema formation, the PMNs degranulation, events that modulate MPO and elastase levels at inflammation site, and the inhibition of the enzyme activity.

Fuscoside E: a strong anti-inflammatory diterpene from Caribbean octocoral Eunicea fusca.

The screen of 10 soft coral extracts collected from the Colombian Caribbean Sea in the TPA-induced ear edema model allowed us to identify Eunicea fusca extract among others as an interesting source of active compounds. The new diterpene, fuscoside E (1), along with the known fuscoside B (2), fuscol (3), (+)-germacrene D (4) and a mixture of six sterols (5-10), were isolated from this soft coral. Their structures were elucidated by 1D and 2D NMR spectroscopy techniques. Fuscoside E (1) absolute stereochemistry was determined by chiroptical methods. Fuscoside E (1) and B (2) showed strong anti-inflammatory in the above mentioned bioassay. Additionally, fuscoside E (1) and the sterol mixture (5-10) presented antifouling activity against bacterial strains involved in surface colonization.

Mecanismos generales de cesión de principios activos a partir de matrices monolíticas hidrofílicas preparadas con éteres de celulosa / Overall mechanisms that rule the active pharmaceutical ingredient’s delivery process from hydrophilic matrices elaborated with ether cellulose

Las matrices hidrofílicas son uno de los sistemas de liberación controlados más empleados a escala mundial. El reconocido éxito global de este tipo de sistemas está ligado a su manufactura por medio de tecnología convencional para la obtención de comprimidos, además de su bajo costo. Estos sistemas han sido objeto de investigación desde hace ya algunas décadas, mediante el uso de técnicas como la creación de imágenes a partir de resonancia magnética, calorimetría de barrido diferencial y la espectroscopia dieléctrica de baja frecuencia, entre otras. Varios autores han estudiado los diferentes estados del agua dentro de una matriz, así como el estado y los cambios en los estados de los materiales en el tiempo, con el fin de estudiar los mecanismos de cesión de los activos a partir de las matrices, así como para buscar modelos matemáticos que describan la evolución de la concentración en el tiempo. En la actualidad se cuenta con modelos matemáticos de gran utilidad que permiten identificar dichos mecanismos a partir de un análisis de los parámetros de los modelos y que conducen finalmente a predecir la velocidad de liberación a partir de estos sistemas.

The hydrophilic matrices are one of the most used controlled delivery systems in the world, due to the simple technology and low cost. A number of publications, over the last decades, have reported investigations in regard with the mechanisms of drug release from hydrophilic matrices. Nevertheless, the mechanisms of drug release from these systems continue to be a matter of debate. Differential scanning calorimetry, low frequency dielectric spectroscopy and nuclear magnetic resonance have been used to examine the distribution of water within ether cellulose matrices, as well as to describe the state of the materials inside the device. The objective is to study the release and hydration rate of hydrophilic matrices in order to contribute to the rationalization of the design of these controlled release systems through mathematical modeling and to obtain a better knowledge of the processes that occur during the release of the drug.