Biological activity of 2α,3ß,23-trihydroxyolean-12-ene on glucose homeostasis.

We studied the effect and the mechanisms of action of 2α,3ß,23-trihydroxyolean-12-ene (THO), from Croton heterodoxus Baill. (Euphorbiaceae), in glucose uptake in hyperglycemic rats. The effect of in vivo pretreatment with THO in hyperglycemic rats was analyzed. The in vitro effects of THO were observed in adipocytes and in adipose tissue. THO reduced glycemia, in part by increasing serum insulin and augmenting the disposal of glucose as glycogen in hepatocytes but did not change the serum concentration of glucagon-like peptide-1. THO increased glucose uptake in adipocytes and in adipose tissue by a mechanism dependent on phosphatidylinositol 3-kinase vesicular traffic and on the process of vesicle fusion at the plasma membrane in regions containing cholesterol, indicating the involvement of glucose transporter-4 (GLUT4). This triterpene may act solely via the activation and translocation of GLUT4 (rather than via nuclear actions, such as upregulation of GLUT4 synthesis), since THO did not alter the amount of GLUT4 mRNA or the content of GLUT4. Consistent with these data, the stimulatory effect of this triterpene on the quantity of GLUT4 in the membrane fraction was dependent upon p38 phosphorylation. In this experimental model, orally administered 10 mg/kg THO did not modulate extracellular serum lactate dehydrogenase. In conclusion, THO decreases hyperglycemia by increasing serum insulin and hepatic glycogen content. The THO mechanism of action on adipose tissue for glucose uptake is suggested to be via GLUT4 translocation stimulation mediated by a p38-dependent mechanism. THO is a potential antihyperglycemic agent that acts in a target tissue for glucose homeostasis.

Mechanisms involved in the endothelium-dependent vasodilatory effect of an ethyl acetate fraction of Cyathea phalerata Mart. in isolated rats' aorta rings.

The species Cyathea phalerata Mart. is a tree fern, commonly known as "xaxim", which is found in tropical and subtropical areas of Brazil. The present study investigated the mechanisms related with the vasorelaxant effects of an Ethyl Acetate Fraction (EAF) obtained from C. phalerata in rats' thoracic aorta rings. In pre-contracted vessels, EAF (0.1-1000 µg/mL) caused a concentration-dependent relaxation. The endothelium denudation, the nitric oxide (NO) synthase and guanylyl cyclase inhibitor reduced the vasodilation, indicating the participation of NO/cGMP pathway in its effect. The relaxation of EAF was abolished in the absence of extracellular Ca2+ and was significantly decreased in the presence of Ca2+ entry blocker, suggesting that Ca2+ influx plays an important role in EAF effect and probably in eNOS activity. However, the PI3K/Akt pathway is not responsible for eNOS phosphorylation/activation. The vasodilator effect of EAF was partially inhibited by KCl 40 mM and almost totally abolished with L-NOARG + KCl 40 mM, indicating also the role of hyperpolarization in its effect. Calcium activated K+ channels are not involved in the EAF-induced hyperpolarization. The COX inhibitor, indomethacin, slightly reduced the vasodilation induced by EAF. In addition, EAF did not alter the relaxant effects of NO-donor, indicating that the relaxant activity cannot be attributed to free radical-scavenging properties. In conclusion, the present study showed that the EAF, causes an endothelium-dependent vasorelaxant effect in aorta that mainly involves the NO-cGMP pathway, hyperpolarization and prostanoids. The vasorelaxant activity of EAF can be attributed to the occurrence of polyphenol compounds.

Psychopharmacological effects and safety of styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction from Polygala sabulosa: absence of withdrawal syndrome and tolerance to anxiolytic-like and anticonvulsant effects.

OBJECTIVES: To investigate whether mice develop tolerance to the anxiolytic-like and anticonvulsant effects of subchronic treatment with EA (the styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction of Polygala sabulosa), as well as any withdrawal symptoms after abrupt discontinuation; to compare the effects of EA with those of diazepam (DZP) on withdrawal-induced anxiety; and to evaluate the toxicity of EA according to OECD guidelines. METHODS: Male or female mice were acutely or subchronically treated with EA or DZP, and their tolerance to anxiolytic (evaluated in the elevated plus maze, EPM) and anticonvulsant effects (measured against pentylenetetrazole (PTZ)-induced convulsions) were investigated. Other groups received EA or DZP for 28 days followed by withdrawal, being the anxiety-like behaviour evaluated in the EPM. KEY FINDINGS: Both acute and subchronic treatments with EA induced an anxiolytic effect in the EPM. The anticonvulsant activity of DZP, but not EA, was reduced by protracted treatment. EA withdrawal retained the anxiolytic profile, while DZP withdrawal induced anxiogenesis. EA counteracted the anxiogenic-like actions of DZP withdrawal. EA has low toxicity as it did not cause any changes in the biochemical, haematological and histopathological markers. CONCLUSIONS: EA avoids the development of tolerance to its anxiolytic-like and anticonvulsant actions, and does not promote withdrawal syndrome. EA does not cause relevant toxic effects in rodents.

Fern-9(11)-ene-2α,3ß-diol Action on Insulin Secretion under Hyperglycemic Conditions.

The objective of this study was to investigate the effect and the mechanism of action of fernenediol as an insulin secretagogue. Wistar rats were treated with 0.1, 1, and 10 mg/kg fernenediol before inducing hyperglycemia by oral glucose. The glycaemia, insulin, LDH, calcium, and hepatic glycogen were analyzed. Considering the intestine and pancreas as targets for the triterpene action, the duodenum was used to verify the influence of fernenediol on intestinal glycosidases. Additionally, pancreatic islets were used for studies of 14C-deoxyglucose uptake and the influx of 45Ca2+ in hyperglycemic media with/without fernenediol in the presence/absence of an inhibitor/activator of KATP channels, glibenclamide, diazoxide, nifedipine, calcium chelator (BAPTA-AM), and H-89 and ST, the inhibitors of the PKA and PKC enzymes. Fernenediol significantly reduced glycaemia, potentiated glucose-induced insulin secretion, and stimulated liver glycogen deposition in hyperglycemic rats after an in vivo treatment without changing intestinal disaccharidases activities and showing no influence on intestinal glucose absorption. Also, it stimulated the glucose uptake and calcium influx in pancreatic islets. The involvement of voltage-dependent L-type calcium channels and ATP-dependent potassium channels and the release of calcium from intracellular stores are mandatory for the stimulatory effect of fernenediol on calcium influx. Fernenediol did not change PKA and PKC activities or modify calcium levels. This triterpene is a potent antihyperglycemic agent with a strong insulin secretagogue effect on glycogen accumulation as well. As a whole, this compound presents significant perspectives as a future new drug for the treatment of insulin resistance and/or diabetes.

Bis-Pyrano Prenyl Isoflavone Improves Glucose Homeostasis by Inhibiting Dipeptidyl Peptidase-4 in Hyperglycemic Rats.

Isoflavones widely distributed in plants prevent diabetes. This study investigated the in vivo and in vitro effect of 3',4'-dihydroxy-6″,6″,6″',6″'-tetramethylbis(pyrano[2″,3″:5,6::2″',3″':7,8]isoflavone (bis-pyrano prenyl isoflavone) on glucose homeostasis in hyperglycemic rats. The ethyl acetate fraction from aerial parts of Polygala molluginifolia that contain isoflavones was assayed on glucose tolerance, on in vitro maltase activity and on protein glycation. The isoflavone bis-pyrano prenyl isolated from this fraction was investigated on glucose homeostasis. The in vivo action of the isoflavone exhibits an anti-hyperglycemic effect by improving glucose tolerance, augmenting the liver glycogen, inhibiting maltase activity, and stimulating glucagon-like peptide-1 (GLP-1) and insulin secretion. The in vitro isoflavone inhibits dipeptidyl peptidase-4 (DPP-4) activity since the glucose tolerance was improved in the presence of the isoflavone as much as sitagliptin, an inhibitor of DPP-4. However, the co-incubation with isoflavone and sitagliptin exhibited an additive anti-hyperglycemic action. The isoflavone increased the GLP-1 faster than the positive hyperglycemic group, which shows that the intestine is a potential target. Thus, to clarify the main site of action in which isoflavone improves glucose balance, the in vitro mechanism of action of this compound was tested in intestine using calcium influx as a trigger for the signal pathways for GLP-1 secretion. The isoflavone stimulates calcium influx in intestine and its mechanism involves voltage-dependent calcium channels, phospholipase C, protein kinase C, and stored calcium contributing for GLP-1 secretion. In conclusion, the isoflavone regulates glycaemia by acting mainly in a serum target, the DPP-4 inhibitor. Furthermore, the long-term effect of isoflavone prevents protein glycation. J. Cell. Biochem. 118: 92-103, 2017. © 2016 Wiley Periodicals, Inc.

Triterpene derivative: A potential signaling pathway for the fern-9(11)-ene-2α,3ß-diol on insulin secretion in pancreatic islet.

AIM: Triterpenes and their derivatives influence on carbohydrate metabolism. In vivo and in vitro treatment investigated the effect of the natural triterpene fern-9(11)-ene-2α,3ß-diol (1), isolated from Croton heterodoxus, and a derivative triterpene (2) on glucose homeostasis. MAIN METHODS: The antidiabetic effect of the crude extract from C. heterodoxus leaves, the natural triterpene (1) as well as the derivative triterpene (2) were assayed on glucose tolerance. The effect and the mechanism of action on in vivo treatment with triterpene 2 on glycaemia and insulin secretion were studied. In addition, in vitro studies investigated the mechanism of triterpene 2 on glucose uptake and calcium influx on insulin secretion in pancreatic islets. KEY FINDINGS: The results show the extract slightly reduced the glycaemia when compared with hyperglycemic group. However, the presence of the substituent electron-withdrawing 4-nitrobenzoyl group in the A-ring of triterpene 2 powered the serum glucose lowering compared to triterpene 1. In addition, in vivo treatment with triterpene 2 significantly increased the insulin secretion induced by glucose and stimulated the glucose uptake and calcium influx in pancreatic islet. The effect of triterpene on calcium influx was completely inhibited by diazoxide, nifedipine and stearoylcarnitine treatment. SIGNIFICANCE: The stimulatory effect of triterpene 2 on glucose uptake, calcium influx, regulation of potassium (K(+)-ATP) and calcium (L-VDCCs) channels activity as well as the pathway of PKC highlights the mechanism of action of the compound in pancreatic islets on insulin secretion and glucose homeostasis. In addition, this compound did not induce toxicity in this experimental condition.

Modulatory effect of Senecio brasiliensis (Spreng) Less. in a murine model of inflammation induced by carrageenan into the pleural cavity.

ETHNOPHARMACOLOGICAL RELEVANCE: Senecio brasiliensis (Spreng) Less (S. brasiliensis), known as "Flor-das-almas", "Margaridinha" or "Maria mole", is used in folk medicine as an anti-inflammatory and to treat gastric ulcers and stomach pain. While the Senecio genus has been widely studied for its pharmacological activities to support its use in traditional medicine, few studies focus on the anti-inflammatory activities of the species. AIM OF THE STUDY: To investigate the anti-inflammatory activities of S. brasiliensis, a specie native to Brazil, using a murine model of pleurisy induced by carrageenan. MATERIAL AND METHODS: The flowers of S. brasiliensis were air-dried for 3 days and subjected to ethanol (96%) extraction for 7 days to obtain the crude extract (CE). The CE was subjected to acid-base extraction to obtain the alkaloid fraction (AF). The hexane (HEX), dichloromethane (DCM) and ethyl acetate (EtOAc) fractions were obtained by extracting from CE with different solvents. The alkaloids senecionine (Sen), integerrimine (Int) and senecionine N-oxide were obtained from AF by chromatographic fractionation and a mixture of 1,4-, 3,4-, 3,5- and 4,5-dicaffeoylquinic acids (DCQs) were obtained from the EtOAc fraction. The isolated alkaloids were identified through spectroscopic analysis of IR, NMR and LC-MS coupled with electrospray ionization mass spectrometry (ESI-MS), and the dicaffeoylquinic acids through the hierarchical key method. Swiss mice were used in the in vivo experiments. We evaluated the effect of the CE, its derived fractions (AF, HEX, DCM and EtOAc), and the isolated compounds (Sen, Int, N-oxide senecionine, and DCQs) on: leukocyte migration, exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities, and tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß) and interleukin 17A levels in the fluid leakage from the pleural cavity using a mouse model of pleurisy induced by carrageenan. The effects of the isolated compounds, Sen, Int, N-oxide senecionine and DCQs, were also analyzed for their ability to inhibit p65 phosphorylation (p-p65) in the nuclear factor-kappa B (NF-κB) pathway in the lung tissue. MPO and ADA were analyzed by colorimetric assays, and the cytokines and protein p65 levels were determined using an enzyme immunoassay (EIA). RESULTS: The CE, its EtOAc and AF fractions, and its isolated compounds (Sen, Int and DCQs), significantly reduced leukocyte migration (P < 0.05), MPO and ADA activities (P < 0.01), and TNF-α (P < 0.05), and IL-17A levels (P < 0.01). The CE, the EtOAc and AF fractions, and the DCQs also decreased IL-1ß levels (P < 0.01). The isolated compounds, Sen, Int and the DCQs, inhibited p65 phosphorylation (NF-κB) (P < 0.05). CONCLUSION: This study demonstrated that S. brasiliensis has important anti-inflammatory properties that are capable of inhibiting activated leukocytes by decreasing neutrophil migration. This effect may be attributed to the inhibition of pro-inflammatory cytokines and the reduction of the NF-κB pathway. The compounds Sen, Int, and DCQs may be responsible for the anti-inflammatory actions of S. brasiliensis.

Acute effect of 3ß-hidroxihop-22(29)ene on insulin secretion is mediated by GLP-1, potassium and calcium channels for the glucose homeostasis.

The effect of 3ß-hidroxihop-22(29)ene (3-BHO) on insulin and glucagon-like peptide 1 (GLP-1) secretion as well as the mechanism of action of the compound in pancreatic islet on glucose homeostasis was investigated. The data from in vivo treatment show that 3-BHO significantly reduces the hyperglycemia by increasing the insulin and GLP-1 secretion, as well as by accumulating hepatic glycogen in hyperglycemic rats. In rat pancreatic ß-cell, 3-BHO stimulates the glucose uptake, insulin vesicles translocation to the plasma membrane and thus the insulin secretion through the involvement of potassium channels (ATP- and Ca(2+)-dependent K(+) channels) and calcium channels (L-type voltage-dependent calcium channels (L-VDCC)). Furthermore, this study also provides evidence for a crosstalk between intracellular high calcium concentration, PKA and PKC in the signal transduction of 3-BHO to stimulate insulin secretion. In conclusion, 3-BHO diminishes glycaemia, stimulates GLP-1 secretion and potentiates insulin secretion and increase hepatic glycogen content. Moreover, this triterpene modulates calcium influx characterizing ATP-K(+), Ca(2+)-K(+) and L-VDCC channels-dependent pathways as well as PKA and PKC activity in pancreatic islets underlying the signaling of 3-BHO for the secretory activity and contribution on glucose homeostasis.

The mechanism of action of ursolic acid as insulin secretagogue and insulinomimetic is mediated by cross-talk between calcium and kinases to regulate glucose balance.

BACKGROUND: The effect of in vivo treatment with ursolic acid (UA) on glycemia in hyperglycemic rats and its mechanism of action on muscle were studied. METHODS: The UA effects on glycemia, glycogen, LDH, calcium and on insulin levels were evaluated after glucose tolerance curve. The ß-cells were evaluated through the transmission electron microscopy. UA mechanism of action was studied on muscles through the glucose uptake with/without specific insulin signaling inhibitors. The nuclear effect of UA and the GLUT4 expression on muscle were studied using thymidine, GLUT4 immunocontent, immunofluorescence and RT-PCR. RESULTS: UA presented a potent antihyperglycemic effect, increased insulin vesicle translocation, insulin secretion and augmented glycogen content. Also, UA stimulates the glucose uptake through the involvement of the classical insulin signaling related to the GLUT4 translocation to the plasma membrane as well as the GLUT4 synthesis. These were characterized by increasing the GLUT4 mRNA expression, the activation of DNA transcription, the expression of GLUT4 and its presence at plasma membrane. Also, the modulation of calcium, phospholipase C, protein kinase C and PKCaM II is mandatory for the full stimulatory effect of UA on glucose uptake. UA did not change the serum LDH and serum calcium balance. CONCLUSIONS: The antihyperglycemic role of UA is mediated through insulin secretion and insulinomimetic effect on glucose uptake, synthesis and translocation of GLUT4 by a mechanism of cross-talk between calcium and protein kinases. GENERAL SIGNIFICANCE: UA is a potential anti-diabetic agent with pharmacological properties for insulin resistance and diabetes therapy.

Antifungal activity of 6-quinolinyl N-oxide chalcones against Paracoccidioides.

BACKGROUND: Chalcones are an important class of natural compounds that have been widely applied as synthons in synthetic organic chemistry and possess diverse and interesting biological properties. METHODS: We conducted tests with the synthetic substances 6-quinolinyl N-oxide chalcones 4c and 4e to determine their antifungal activity against several isolates of Paracoccidioides spp. and their activity in a murine model. We also determined whether the chalcones interacted with other drugs or interfered with the morphology of Paracoccidioides brasiliensis (Pb18) yeast cells. RESULTS: We verified that the substances were active against Paracoccidioides spp., but we did not show an interaction with the drugs tested when only the fractional inhibitory concentration index values were considered individually. We observed that the substances induced in vitro morphological changes. Compounds 4c and 4e showed activity similar to itraconazole in treated mice, as demonstrated by their ability to reduce the number of cfu recovered from the lungs. Histopathological analysis showed that animals treated with 4c presented fewer areas containing inflammatory infiltrate and larger areas of preserved lung tissue, whereas animals treated with itraconazole showed accumulation of inflammatory infiltrate and some granulomas. Mice treated with 4e exhibited inflammation that compromised the tissue. CONCLUSIONS: The results presented in this paper confirm the antifungal potential of the chalcones tested. The chalcone 4c was the more effective at controlling the disease in mice and this compound could be a candidate for future studies of the treatment of paracoccidioidomycosis.

Neuroprotective effect of the proanthocyanidin-rich fraction in experimental model of spinal cord injury.

OBJECTIVES: In this study, we evaluated the effect of the proanthocyanidins-rich fraction (PRF) obtained from Croton celtidifolius bark in an experimental animal model of spinal cord injury and cell death induced by glutamate. METHODS: Experiments were conducted using adult male Wistar rats (10 weeks old and weighing 270-300g). Experimental groups were randomly allocated into the following groups: spinal cord injury (SCI) + vehicle group: rats were subjected to SCI plus intraperitoneal administration of vehicle (saline 10 ml/kg); SCI + PRF: rats were subjected to SCI plus intraperitoneal administration of PRF (10 mg/kg) at 1 and 6 h after injury and sham operated. KEY FINDINGS: The treatment with the proanthocyanidin-rich fraction significantly improved not only motor recovery and grip force but also H2 O2 or glutamate-induced cell death and reactive oxygen species generation induced by glutamate in dorsal root ganglion cells. In this study we demonstrate that the neuroprotective effect triggered by the proanthocyanidins-rich fraction appears to be mediated in part by the inhibition of N-methyl-D-aspartate-type glutamate receptors. CONCLUSIONS: Taken together, our results demonstrate that PRF treatment ameliorates spinal cord injury and glutamatergic excitotoxicity and could have a potential therapeutic use.

Betulinic acid and 1,25(OH)2 vitamin D3 share intracellular signal transduction in glucose homeostasis in soleus muscle.

The effect of betulinic acid on glycemia and its mechanism of action compared with 1,25(OH)2 vitamin D3 in rat muscle were investigated. Betulinic acid improved glycemia, induced insulin secretion and increased the glycogen content and glucose uptake in muscle tissue. Additionally, the integrity of both PI3K and the cytoskeleton is necessary for the stimulatory action of betulinic acid in glucose uptake. The genomic effect was apparent, since cycloheximide and PD98059 nullified the stimulatory effect of betulinic acid on glucose uptake. Therefore, although this compound did not modify the DNA transcription, the protein translation was significantly improved. Also, betulinic acid increased the GLUT4 immunocontent and its translocation was corroborated by GLUT4 localization at the plasma membrane (after 180 min). On the other hand, the effect of 1,25(OH)2 vitamin D3 on glucose uptake is not mediated by PI3K and microtubule activity. In contrast, the nuclear activity of 1,25(OH)2 vitamin D3 is necessary to trigger glucose uptake. In addition, the increased DNA transcription and GLUT4 immunocontent provide evidence of a mechanism by which 1,25(OH)2 vitamin D3 contributes to glycemia. In conclusion, betulinic acid acts as an insulin secretagogue and insulinomimetic agent via PI3K, MAPK and mRNA translation and partially shares the genomic pathway with 1,25(OH)2 vitamin D3 to upregulate the GLUT4. In summary, betulinic acid regulates glycemia through classical insulin signaling by stimulating GLUT4 synthesis and translocation. In addition, it does not cause hypercalcemia, which is highly significant from the drug discovery perspective.

Croton antisyphiliticus Mart. attenuates the inflammatory response to carrageenan-induced pleurisy in mice.

The aim of this study was to investigate the anti-inflammatory effect of the crude hydroalcoholic extract (CHE) from the aerial parts of Croton antisyphiliticus, its fractions and isolated compounds derived from it on the mouse model of pleurisy induced by carrageenan. The aerial parts of C. antisyphiliticus were dried, macerated and extracted with ethanol to obtain the CHE, which was fractionated by liquid-liquid extraction using solvents with increasing polarity to obtain hexane (Hex), ethyl acetate (EA) and aqueous (Aq) fractions. Vitexin and quinic acid were isolated from Aq fraction. Capillary electrophoresis analysis, physical characteristics and spectral data produced by infrared (IR), nuclear magnetic resonance ((1)H and (13)C NMR) and mass spectrometry analyses were used to identify and elucidate the structure of the isolated compounds. The experimental model of pleurisy was induced in mice by a single intrapleural injection of carrageenan (1 %). Leukocytes, exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities and nitrate/nitrite (NOx), tumor necrosis factor-α (TNF-α) and interleukin-17 (IL-17) levels were determined in the pleural fluid leakage at 4 h after pleurisy induction. Animals pre-treated with CHE, Hex, EA, Aq, vitexin and quinic acid exhibited decreases in leukocytes, exudate concentrations, MPO and ADA activities and NOx levels (p < 0.05). Also CHE, Hex, EA and vitexin but not quinic acid inhibited TNF-α and IL-17 levels (p < 0.05). C. antisyphiliticus caused anti-inflammatory effect by inhibiting the activated leukocytes, exudate concentrations, NOx, TNF-α, and IL-17 levels. The compounds vitexin and quinic acid may be responsible for this anti-inflammatory action.

Systemic administration of Rosmarinus officinalis attenuates the inflammatory response induced by carrageenan in the mouse model of pleurisy.

Rosmarinus officinalis, also named rosemary, is a native plant from the Mediterranean region that is useful for the treatment of inflammatory diseases. Studies using experimental models and/or in vitro tests have shown the important biological effects of rosemary. In this context, the mechanism of the anti-inflammatory activity of rosemary must be investigated to support the discovery of new substances with anti-inflammatory effects. The aim of the present study was to investigate the anti-inflammatory effects of crude extract oil free obtained from the leaves of rosemary in an animal model of inflammation, thus evaluating its medicinal use for the treatment of inflammatory conditions. Also its ethanol, hexane, and ethyl acetate fractions, as well as its isolated compounds carnosol and rosmarinic acid were analyzed. Swiss mice were used for the in vivo experiments. The effect of this herb on the inhibition of the leukocytes, exudation, myeloperoxidase, and adenosine-deaminase activities, nitrite/nitrate, interleukin 17A, and interleukin 10 levels and mRNA expression was determined. The crude extract and its derived fractions, in addition to its isolated compounds, inhibited leukocytes and decreased exudation and myeloperoxidase and adenosine-deaminase activities, as well as nitrite/nitrate and interleukin 17A levels and mRNA expression, besides increasing interleukin 10 levels and mRNA expression. Rosemary showed important anti-inflammatory activity by inhibiting leukocytes and decreasing exudation. These effects were associated with a decrease in the proinflammatory parameters (myeloperoxidase, adenosine-deaminase, nitrite/nitrate, and interleukin 17A) and an increase in the anti-inflammatory cytokine (interleukin 10). This study confirms the anti-inflammatory properties of rosemary and validates its use in folk medicine to treat inflammatory diseases such as rheumatism and asthma.

Insulin signaling: a potential signaling pathway for the stimulatory effect of kaempferitrin on glucose uptake in skeletal muscle.

The aim of the study was to investigate the in vitro effect and the mechanism of action of kaempferitrin on glucose uptake in an insulin target (soleus muscle). A stimulatory effect of kaempferitrin on glucose uptake was observed when rat soleus muscle was incubated with 10, 100 and 1000 ηM of this flavonoid glycoside. The presence of specific insulin signaling inhibitors, such as wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), RO318220, an inhibitor of protein kinase C (PKC), PD98059, an inhibitor of mitogen-activated protein kinase (MEK), HNMPA(AM)3, an insulin receptor tyrosine kinase activity inhibitor, colchicine, a microtubule-depolymerizing agent, SB239063, an inhibitor of P38 MAPK and cycloheximide, an inhibitor of protein synthesis showed that kaempferitrin triggers different metabolic and nuclear pathways in skeletal muscle. Besides the influence on glycogen storage, the metabolic action involves the insulin receptor, PI3K, atypical PKC activity and the translocation of GLUT4. Additionally, the nuclear pathways (via MAPK and MEK) provide evidence of the stimulation of the expression of glucose transporters or other signaling proteins, reinforcing proposals that skeletal muscle represents a primary site at which kaempferitrin exerts its effect promoting glucose homeostasis. Also, these similarities with the signaling pathways of insulin constitute strong evidence for the insulin-mimetic role of kaempferitrin in glucose homeostasis.

Increasing the instrumental throughput of gas chromatography method using multiple injections in a single experimental run: application in determination of friedelan-3-ol and friedelin in Maytenus ilicifolia.

The aim of this study was to develop a separation method using multiple injections in a single experimental run (MISER) employing gas chromatography with flame ionization detection (GC-FID) for the first time, without instrument modification, to increase the instrumental throughput. The method was applied to the determination of the triterpenes friedelan-3-ol and friedelin in a plant extract obtained from Maytenus ilicifolia leaves. The column used in the chromatography system was a ZB-50 (30 m × 0.25 mm × 0.15 µm) with 50% phenyl-50% methyl-polysiloxane. The samples (1.0 µL) were injected using the split mode (1:90), with the injector at 280 °C and FID detector at 320 °C. The column temperature was programmed to isothermal mode at 300°C. Helium was used as the carrier gas with a constant flow of 1.5 mL min(-1). It was possible to perform three injections in the same run using the MISER method. An increase in the instrumental throughput by a factor of around 2.6 was observed when the use of multiple injections was compared with the single injection method. This method showed good linearity for both analytes with R(2)>0.99 and the values for the limit of detection were 0.24 mg L(-1) and 0.44 mg L(-1), for friedelan-3-ol and friedelin, respectively. Furthermore, the values for the limits of quantification were 0.79 mg L(-1) for friedelan-3-ol and 1.16 mg L(-1) for friedelin. The proposed method has potential for other GC applications, allowing an increase in the instrumental throughput of the methods by applying this separation technique.

Antiulcer effect of bark extract of Tabebuia avellanedae: activation of cell proliferation in gastric mucosa during the healing process.

Tabebuia avellanedae (syn. Handroanthus impetiginosus) is popularly known as 'ipê-roxo' and has been used in folk medicine as anti-inflammatory and in the treatment of ulcers, bacterial and fungal infections. This study evaluated the gastric ulcer healing property of the ethanolic extract (EET) of barks from Tabebuia avellanedae and investigated the mechanisms that may underlie this effect. Rats were treated with EET (twice a day for 7 days) after induction of chronic gastric ulcers by 80% acetic acid. Following treatment, histological and immunohistochemical analysis were performed in gastric ulcer tissues. Oral administration of EET (100 and 300 mg/kg) significantly reduced the gastric lesion induced by acetic acid in 44 and 36%, respectively. Histopathological evaluation demonstrated a contraction of gastric ulcer size, increase of mucus layer (periodic acid-Schiff stained mucin-like glycoproteins) and cell proliferation (proliferating cell nuclear antigen immunohistochemistry) in animals treated with EET (100 and 300 mg/kg). The results demonstrate that EET significantly accelerates healing of acetic acid induced gastric ulcer in rats through increase of mucus content and cell proliferation, indicating a potential usefulness for treatment of peptic ulcer diseases.

Acute effect of ß-sitosterol on calcium uptake mediates anti-inflammatory effect in murine activated neutrophils.

OBJECTIVES: To evaluate the effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, and interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) levels, in carrageenan-induced inflammation in the mouse air pouch model. METHODS: Dried Esenbeckia leiocarpa bark was macerated and extracted resulting in a crude hydroalcoholic extract (CHE) that was partitioned to obtain an alkaloid fraction. The alkaloid was then partitioned in polar and nonpolar subfractions. ß-Sitosterol was isolated from the nonpolar subfraction and identified by comparison with the literature. The effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, IL-1ß and TNF-α levels in carrageenan-induced inflammation in mice were evaluated. KEY FINDINGS: ß-Sitosterol promoted a time- and dose-dependent increase of the calcium uptake in activated neutrophils that was promptly reversed by nifedipine, BAPTA-AM, LY294002, and colchicine. ß-Sitosterol inhibited myeloperoxidase and adenosine deaminase activity, and IL-1ß and TNF-α levels. CONCLUSIONS: ß-Sitosterol inhibited either myeloperoxidase and adenosine deaminase activity or IL-1ß and TNF-α levels. This effect seemed to be mediated by the calcium uptake in activated neutrophils in a time- and concentration-dependent manner through L-type voltage dependent calcium channels, intracellular calcium, phosphoinositide kinase-3, and microtubule modulation.

Cardioprotective effects of a proanthocyanidin-rich fraction from Croton celtidifolius Baill: focus on atherosclerosis.

Proanthocyanidins are the most abundant polyphenols in human diets. Epidemiological studies have pointed to proanthocyanidins as promising molecules that could prevent the development of several coronary syndromes by inhibiting the atherogenic process. The present study was designed to investigate the antiatherogenic effects of a proanthocyanidin-rich fraction (PRF) obtained from Croton celtidifolius Baill (Euphorbiaceae) barks. In isolated human LDL, PRF caused a concentration-dependent inhibition of Cu2+-induced oxidative modifications, evidenced by the increasing of the lag phase of lipid peroxidation and decreasing in the oxidation rate (Vmax), moreover, the protein moieties from LDL were protected against Cu2+-induced oxidation. In human umbilical vein endothelial cells (HUVECs), PRF reduced the ROS production stimulated by oxidized LDL. Herein, we demonstrate that oral treatment with PRF improved endothelium-dependent vasorelaxation in hypercholesterolemic LDL receptor knockout mice (LDLr-/-), however, the fraction did not modify plasma lipids and atherosclerotic lesion size in this experimental model. Finally, our results showed for the first time that PRF prevent isolated LDL oxidation, decrease oxidative stress in endothelial cells and improve endothelial function in mice.