Low Doses of ß-Caryophyllene Reduced Clinical and Paraclinical Parameters of an Autoimmune Animal Model of Multiple Sclerosis: Investigating the Role of CB2 Receptors in Inflammation by Lymphocytes and Microglial.

Multiple Sclerosis (MS) is a prevalent inflammatory disease in which the immune system plays an essential role in the damage, inflammation, and demyelination of central nervous system neurons (CNS). The cannabinoid receptor type 2 (CB2) agonists possess anti-inflammatory effects against noxious stimuli and elevate the neuronal survival rate. We attempted to analyze the protective impact of low doses of ß-Caryophyllene (BCP) in experimental autoimmune encephalomyelitis (EAE) mice as a chronic MS model. Immunization of female C57BL/6 mice was achieved through two subcutaneous injections into different areas of the hind flank with an emulsion that consisted of myelin Myelin oligodendrocyte glycoprotein (MOG)35-55 (150 µg) and complete Freund's adjuvant (CFA) (400 µg) with an equal volume. Two intraperitoneal (i.p.) injections of pertussis toxin (300 ng) were performed on the animals on day zero (immunizations day) and 48 h (2nd day) after injection of MOG + CFA. The defensive effect of low doses of BCP (2.5 and 5 mg/kg/d) was investigated in the presence and absence of a CB2 receptor antagonist (1 mg/kg, AM630) in the EAE model. We also examined the pro/anti-inflammatory cytokine levels and the polarization of brain microglia and spleen lymphocytes in EAE animals. According to our findings, low doses of BCP offered protective impacts in the EAE mice treatment in a CB2 receptor-dependent way. In addition, according to results, BCP decreased the pathological and clinical defects in EAE mice via modulating adaptive (lymphocytes) and innate (microglia) immune systems from inflammatory phenotypes (M1/Th1/Th17) to anti-inflammatory (M2/Th2/Treg) phenotypes. Additionally, BCP elevated the anti-inflammatory cytokine IL-10 and reduced blood inflammatory cytokines. BCP almost targeted the systemic immune system more than the CNS immune system. Thus, a low dose of BCP can be suggested as a therapeutic effect on MS treatment with potent anti-inflammatory effects and possibly lower toxicity.

Combination of Imipramine, a sphingomyelinase inhibitor, and ß-caryophyllene improve their therapeutic effects on experimental autoimmune encephalomyelitis (EAE).

Multiple Sclerosis (MS) is one of the most common inflammatory diseases with the essential role of immune system in the demyelination, damage and inflammation of the central nervous system neurons (CNS). ß-Caryophyllene (BCP), a natural and selective CB2 agonist, possesses several protective effects. In the present study, we evaluated the protective effects of low dose of BCP (5 mg/kg), sphingomyelinase (SMase) inhibitor imipramine (IMP, 10 mg/kg), and the combination of BCP (2.5 and 5 mg/kg) with IMP in the treatment of experimental autoimmune encephalomyelitis (EAE) mice as a known model of chronic MS. These effects were assessed on the levels of pro- or anti-inflammatory cytokines as well as the polarization of spleen lymphocytes and microglia, in EAE mice. Our results indicated that low dose of BCP, IMP and BCP combined with a SMase inhibitor IMP exert protective effects in treatment of EAE mice. We also found that they reduced the clinical and pathological defects in EAE mice through modulation of both local (microglia) and systemic (lymphocytes and blood) immunity from inflammatory (Th1/Th17/M1) towards anti-inflammatory (Th2/Treg/M2) phenotypes. Therefore, it can be suggested that a low dose of BCP alone or combined with IMP as a known SMase inhibitor deserve a therapeutic position for treatment of MS.

Flavonoids for preserving pancreatic beta cell survival and function: A mechanistic review.

Although the currently available antidiabetic medications are effective in managing hyperglycemia, vascular complications are common in diabetic patients. Cohort studies have shown preserved beta cell function has a protective role against the development of diabetic complications. Accordingly, beta cell mass and function are important pharmacological targets in the field of diabetes. Growing number of evidence supports the efficacy of flavonoids (e.g., quercetin, kaempferol, luteolin, and epicatechin) for prevention and attenuation of diabetes consequences. The focus of this paper is to give an overview regarding the effects of flavonoids on pancreatic beta cells. Experiments on insulin-releasing cell lines, isolated pancreatic islets, and diabetic animal models have shown that flavonoids strengthen the survival processes and insulin secretory capacity of beta cells. The proposed mechanisms by which flavonoids preserve beta cells survival (against cytokines, glucotoxicity, and lipotoxicity) include inhibition of NF-κB signaling, activation of PI3K/Akt pathway, inhibition of nitric oxide generation, and decrease of reactive oxygen species levels. Improving mitochondrial bioenergetic function and stimulating pathways of insulin secretion (e.g., PLC/PKC and/or cAMP/PKA signaling) are mechanisms by which flavonoids improve the secretory capacity of beta cells. These beneficial effects of flavonoids are of great importance because may protect beta cells of diabetic patients before dramatic dysfunction and degeneration.

The protective effects of ß-caryophyllene on LPS-induced primary microglia M1/M2 imbalance: A mechanistic evaluation.

AIMS: Neuroinflammation is observed as a routine characterization of neurodegenerative disorders such as dementia, multiple sclerosis (MS) and Alzheimer's diseases (AD). Scientific evidence propounds both of the neuromodulatory and immunomodulatory effects of CB2 in the immune system. ß-Caryophyllene (BCP) is a dietary selective CB2 agonist, which deserves the anti-inflammatory and antioxidant effects at both low and high doses through activation of the CB2 receptor. METHODS: In this study, we investigated the protective effects of a broad range concentration of BCP against LPS-induced primary microglia cells inflammation and M1/M2 imbalance and identifying the portion of the involvement of related signaling pathways on BCP effects using pharmacological antagonists of CB2, PPAR-γ, and sphingomyelinase (SMase). KEY FINDINGS: The protective effects of BCP on LPS-induced microglia imbalance is provided by the M2 healing phenotype of microglia, releasing the anti-inflammatory (IL-10, Arg-1, and urea) and anti-oxidant (GSH) parameters and reducing the inflammatory (IL-1ß, TNF-α, PGE2, iNOS and NO) and oxidative (ROS) biomarkers. Moreover, we showed that BCP exerts its effects through CB2 receptors which overproduction of ceramides by SMase at middle to higher concentrations of BCP reduce the protective activity of BCP and results in the activation of the PPAR-γ pathway. SIGNIFICANCE: In conclusion, the low concentration of BCP has higher selective anti-inflammatory effects rather than high levels. On this occasion, BCP by modulating the microglia is able to have potential therapeutic effects in neuro-inflammation conditions and microglia cells such as MS and AD.

Promising neuroprotective effects of ß-caryophyllene against LPS-induced oligodendrocyte toxicity: A mechanistic study.

Myelin loss subsequent to oligodendrocyte death has been reported in a variety of myelin-associated disorders such as multiple sclerosis (MS). Lipopolysaccharide (LPS) has been shown to elicit cellular responses in the central nervous system (CNS) and trigger immune infiltrates and glial cells to release a variety of inflammatory cytokines and mediators. LPS-induced oligodendrocytes toxicity may be chosen as an efficient model to evaluate the role of oligodendrocytes in neuroprotective activities of compounds. ß-Caryophyllene (BCP) is a selective type 2 cannabinoid (CB2) receptor agonist. However, the mechanisms underlying the anti-inflammatory effects of BCP are not completely understood. On this basis, we aimed to investigate the protective effects of a wide range of BCP concentrations against LPS-induced toxicity in a proliferative oligodendrocyte cell line (OLN-93) and evaluate the possible correlation between BCP concentration and selective modulation of CB2, Nrf2, sphingomyelinase (SMase) and peroxisome proliferator-activated receptors (PPAR)-γ signaling pathways. We found that LPS significantly increases the levels of reactive oxygen species (ROS), nitric oxide (NO) metabolite and tumor necrosis factor (TNF)-α production while decreases the level of GSH. BCP could prevent LPS-induced cytotoxicity and excessive production of NO, ROS, and TNF-α. Also, we demonstrated that BCP's protective effects against LPS-induced oligodendrocytes toxicity were mediated via the CB2 receptor through different pathways including Nrf2/HO-1/anti-oxidant axis, and PPAR-γ, at low (0.2 and 1 µM), and high (10-50 µM) concentrations, respectively. Additionally, we observed that the addition of SMase inhibitors imipramine (IMP) and fluoxetine (FLX) synergistically increased the protective effects of BCP. Finally, BCP at low concentrations exerted promising protective effects that could be considered for the treatment of neurodegenerative disorders such as MS. However, more studies using other models of neurodegenerative diseases should be undertaken to assess different parameters such as the activity or expression of SMase.

Novel cilostamide analogs, phosphodiesterase 3 inhibitors, produce positive inotropic but differential lusitropic and chronotropic effects on isolated rat atria.

OBJECTIVES: Recently, we showed that some new synthetic compounds structurally related to cilostamide (4-(1,2-dihydro-2-oxoquinolin-6-hydroxy)- N-cyclohexyl-N-methylbutanamide), a selective phosphodiesterase 3 (PDE3) inhibitor, produce inotropic effect comparable to that of IBMX (3-isobutyl-1-methylxanthine), a non-selective PDE inhibitor, but with differential chronotropic effect. In this investigation, we compared the pharmacological effects of these compounds as potential cardiotonic agents using the spontaneously beating atria model. MATERIALS AND METHODS: In each experiment, rats were treated with reserpine. The atrium was isolated and mounted in an organ bath. We assessed chronotropic and inotropic effects using cumulative log concentration-response curves of isoprenaline alone or in combination of each test-compound. RESULTS: Majority of test compounds augment atria contraction force (ACF) significantly but with different potencies on atrium contraction rate. Cilostamide, MCPIP ([4-(4-methyl piperazin-1-yl)-4-oxobutoxy)-4-methylquinolin-2(1H)-one]), methyl carbostyril compounds- (mc1), mc2 and mc5 increased the isoprenaline effect on ACF synergistically. But, mc6 failed to potentiate the effect of isoprenalin; mc3 and mc4 did not increase ACF, which may be because of their higher hydrophilic nature. It was interesting that mc2, alone or in combination with isoprenaline, produced the highest inotropic effect while it did not affect the basal contraction rate and almost blocked the isoprenaline chronotropic effect. CONCLUSION: Combination of mc2 with isoprenaline had synergistic effect on inotropic effect, but this combination reduced isoprenaline chronotropic effect; therefore, these effects cannot be related to reducing B-adrenergic receptors activity. These compounds showed different effects; probably all of them were not mediated via PDE3 inhibition and other mechanisms are involving.

A comprehensive review on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases.

Phosphodiesterases are a group of enzymes that hydrolyze cyclic nucleotides, which assume a key role in directing intracellular levels of the second messengers' cAMP and cGMP, and consequently cell function. The disclosure of 11 isoenzyme families and our expanded knowledge of their functions at the cell and molecular level stimulate the improvement of isoenzyme selective inhibitors for the treatment of various diseases, particularly cardiovascular diseases. Hence, future and new mechanistic investigations and carefully designed clinical trials could help reap additional benefits of natural/synthetic PDE inhibitors for cardiovascular disease in patients. This review has concentrated on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases.

Safety and efficacy of a polyherbal formulation for the management of dyslipidemia and hyperglycemia in patients with advanced-stage of type-2 diabetes.

The present clinical trial was designed to evaluate the safety and efficacy of a polyherbal formulation (PHF) consisted of Allium sativum, Aloe vera, Nigella sativa, Plantago psyllium, Silybum marianum and Trigonella foenum-graecum for controlling dyslipidemia and hyperglycemia in patients with advanced-stage of type-2 diabetes. An open-label phase I trial was carried out on 30 patients who had hyperlipidemia and hyperglycemia before the beginning of the trial in spite of receiving statins and oral hypoglycemic drugs. Patients were given one PHF sachet two times daily for 40 consecutive days. All subjects also continuously received their statins and oral hypoglycemic agents. Clinical assessments and laboratory findings were evaluated before starting treatment and at day 40. Treatment with PHF had no significant effects on serum biochemical parameters related to liver and kidney functions, on hematological parameters related to erythrocytes, leukocytes, and platelets, and on body weight and blood pressure. After consumption of PHF, 2 patients complained of mild nausea, and 2 patients reported diarrhea. PHF significantly decreased fasting blood glucose and HbA1c from 162±40mg/dL to 146±37mg/dL and from 8.4±1.5% to 7.7±1.1%, respectively. Also, it significantly decreased the level of LDL from 138±25mg/dL to 108±36mg/dL, and the level of triglycerides from 203±47mg/dL to 166±58mg/dL. In conclusion, the present results demonstrated that the PHF was safe and efficacious in lowering the levels of blood glucose and serum lipids in patients with advanced-stage of type-2 diabetes.

Metabolic effects of newly synthesized phosphodiesterase-3 inhibitor 6-[4-(4-methylpiperidin-1-yl)-4-oxobutoxy]-4-methylquinolin-2(1H)-one on rat adipocytes.

BACKGROUND: Clinical use of selective PDE3 inhibitors as cardiotonic agents is limited because of their chronotropic and lipolytic side effects. In our previous work, we synthesized a new PDE3 inhibitor named MC2 (6-[4-(4-methylpiperidin-1-yl)-4-oxobutoxy]-4-methylquinolin-2(1H)-one) which produced a high positive inotropic action with a negative chronotropic effect. This work was done to evaluate the effects of MC2 on adipocytes and compare its effects with those of amrinone and cilostamide. METHODS: Preadipocytes were isolated from rat adipose tissue and differentiated to adipocyte in the presence of cilostamide, amrinone or MC2. Lipolysis and adipogenesis was evaluated by measuring glycerol level and Oil Red O staining, respectively. Adipocyte proliferation and apoptosis were determined with MTT assay and Annexin V/PI staining, respectively. RESULTS: Differentiation to adipocyte was induced by amrinone but not by cilostamide or MC2. Basal and isoproterenol-stimulated lipolysis significantly increased by cilostamide (p<0.05). Similarly, amrinone enhanced the stimulated lipolysis (p<0.01). On the other hand, MC2 significantly decreased both adipogenesis (p<0.05) and stimulated lipolysis (p<0.001). Also, incubation of differentiated adipocytes with MC2 caused the loss of cell viability, which was associated with the elevation in apoptotic rate (p<0.05). CONCLUSION: Our data indicate that selective PDE3 inhibitors produce differential effects on adipogenesis and lipolysis. MC2 has proapoptotic and antilipolytic effects on adipocytes and does not stimulate adipogenesis. Therefore, in comparison with the clinically available selective PDE3 inhibitors, MC2 has lowest metabolic side effects and might be a good candidate for treatment of congestive heart failure.

Pathological consequences of C-peptide deficiency in insulin-dependent diabetes mellitus.

Diabetes is associated with several complications such as retinopathy, nephropathy, neuropathy and cardiovascular diseases. Currently, insulin is the main used medication for management of insulin-dependent diabetes mellitus (type-1 diabetes). In this metabolic syndrome, in addition to decrease of endogenous insulin, the plasma level of connecting peptide (C-peptide) is also reduced due to beta cell destruction. Studies in the past decade have shown that C-peptide is much more than a byproduct of insulin biosynthesis and possess different biological activities. Therefore, it may be possible that C-peptide deficiency be involved, at least in part, in the development of different complications of diabetes. It has been shown that a small level of remaining C-peptide is associated with significant metabolic benefit. The purpose of this review is to describe beneficial effects of C-peptide replacement on pathological features associated with insulin-dependent diabetes. Also, experimental and clinical findings on the effects of C-peptide on whole-body glucose utilization, adipose tissue metabolism and tissues blood flow are summarized and discussed. The hypoglycemic, antilipolytic and vasodilator effects of C-peptide suggest that it may contribute to fine-tuning of the tissues metabolism under different physiologic or pathologic conditions. Therefore, C-peptide replacement together with the classic insulin therapy may prevent, retard, or ameliorate diabetic complications in patients with type-1 diabetes.

Pancreatic beta cell protection/regeneration with phytotherapy

Although currently available drugs are useful in controlling early onset complications of diabetes, serious late onset complications appear in a large number of patients. Considering the physiopathology of diabetes, preventing beta cell degeneration and stimulating the endogenous regeneration of islets will be essential approaches for the treatment of insulin-dependent diabetes mellitus. The current review focused on phytochemicals, the antidiabetic effect of which has been proved by pancreatic beta cell protection/regeneration. Among the hundreds of plants that have been investigated for diabetes, a small fraction has shown the regenerative property and was described in this paper. Processes of pancreatic beta cell degeneration and regeneration were described. Also, the proposed mechanisms for the protective/regenerative effects of such phytochemicals and their potential side effects were discussed.

Embora medicamentos disponíveis atualmente sejam úteis no controle de complicações da Diabetes, complicações aparecem em grande número de pacientes. Considerando-se a fisiopatologia do Diabetes, a prevenção da degeneração de células beta e o estímulo da regeneração endógena de ilhotas será abordagem essencial para o tratamento de diabetes mellitus insulino-dependente. A presente revisão aborda compostos fitoquímicos, cujo efeito é provado na proteção/regeneração de células beta de pâncreas. Entre centenas de plantas que têm sido investigadas para o diabetes, pequena fração tem mostrado propriedade regenerativa, que será descrita neste trabalho. Os processos de degeneração e de regeneração das células beta do pâncrease são descritos. Além disso, mecanismos propostos para efeitos de proteção e regeneração desses compostos fitoquímicos e seus possíveis efeitos colaterais também serão discutidos neste trabalho.

Different effects of adenylyl cyclase activators and phosphodiesterases inhibitors on cervical cancer (HeLa) and breast cancer (MCF-7) cells proliferation.

Breast and cervical cancers are the most common cancers in Iran and worldwide. Hormonal stimulation of cyclic adenosine mono phosphate (cAMP) and the cAMP-dependent protein kinase PKA regulates cell growth by different mechanism. cAMP can stimulate cell growth in many cell types while inhibiting cell growth in others. In some cell lines have been shown that the proliferation of tumor cells is reduced by increasing cAMP in cells. In this study, we evaluate growth arrest of selective PDE3 and non-selective PDE inhibitors, which lead to increase level of cAMP in cervical (HeLa) and breast cancer (MCF7) cell lines have been studied. Cells were incubated with different concentrations of selective, non-selective PDE inhibitors, beta adrenergic receptor agonist and direct stimulator of adenylyl cyclase. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). Result showed that selective PDE inhibitors decreased cell viability in HeLa and MCF-7 cells as a time-dependent manner. Non-selective inhibitor and beta-adrenergic receptor agonist also decrease cell viability but they are less powerful than selective PDE3 inhibitors. Forskolin had no effect in viability of cells. Analysis of DNA fragmentation by flow cytometry showed apoptosis involved in selective PDE3 inhibitors induced toxicity in HeLa cell. Thus, the growth inhibitory effects of selective PDE3 inhibitors are more effective than non-selective inhibitor. Further studies are needed to investigate the mechanism of action is on the field.

Combination of Nigella sativa with Glycyrrhiza glabra and Zingiber officinale augments their protective effects on doxorubicin-induced toxicity in h9c2 cells.

OBJECTIVES: The use of doxorubicin (DOX) is limited by its dose-dependent cardio toxicity in which reactive Oxygen Species (ROS) play an important role in the pathological process. The aim of this study was to evaluate the protective effect of three medicinal plants, Nigella sativa (N), Glycyrrhiza glabra (G) and Zingiber officinale (Z), and their combination (NGZ), against DOX-induced apoptosis and death in H9c2 cells. MATERIALS AND METHODS: The cells were incubated with different concentrations of each extract or NGZ for 4 hr which continued in the presence or absence of 5µM doxorubicin for 24 hr. Cell viability and the apoptotic rate were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) and propidium iodide (PI) staining assays, respectively. The level of ROS and lipid peroxidation were measured by fluorimetric methods. RESULTS: Treatment with doxorubicin increased ROS generation, enhanced malondialdehyde (MDA) formation, and induced apoptosis. Co-treatment of the cells with each herb extract increased viability of cells dose-dependently with a maximum protection effect of about 30%, and their potencies were N>G>Z. The combination of the threshold dose of each extract (NGZ) produced a similar effect, which was increased dose-dependently to a maximum protection of 70%. These effects were correlated with the effects of NGZ on ROS and MDA. CONCLUSION: All of the extracts have some protective effects against DOX-induced toxicity in cardiomyocytes with similar efficacies, but with different potencies. However, NGZ produced much higher protective effect via reducing oxidative stress and inhibiting of apoptotic induction processes. Further investigations are needed to determine the effects of NGZ on DOX chemotherapy.

Antihyperlipidemic effect of a polyherbal mixture in streptozotocin-induced diabetic rats.

The effects of a polyherbal mixture containing Allium sativum, Cinnamomum zeylanicum, Citrullus colocynthis, Juglans regia, Nigella sativa, Olea europaea, Punica granatum, Salvia officinalis, Teucrium polium, Trigonella foenum, Urtica dioica, and Vaccinium arctostaphylos were tested on biochemical parameters in diabetic rats. The animals were randomized into three groups: (1) normal control, (2) diabetic control, and (3) diabetic rats which received diet containing 15% (w/w) of this mixture for 4 weeks. Diabetes was induced by intraperitoneal injection of streptozotocin (55 mg/kg). At the end of experiment, the mixture had no significant effect on serum hepatic enzymes, aspartate aminotransferase, and alanine aminotransferase activities. However, the level of fasting blood glucose, water intake, and urine output in treated group was lower than that in diabetic control rats (P < 0.01). Also, the levels of triglyceride and total cholesterol in polyherbal mixture treated rats were significantly lower than those in diabetic control group (P < 0.05). Our results demonstrated that this polyherbal mixture has beneficial effects on blood glucose and lipid profile and it has the potential to be used as a dietary supplement for the management of diabetes.

Differential metabolic effects of novel cilostamide analogs, methyl carbostiryl derivatives, on mouse and hyperglycemic rat.

OBJECTIVE(S): PDE3 has a functional role in insulin secretion and action. We investigated the metabolic effects of new synthetic PDE3 inhibitors (mc1, mc2, mc5 and mc6), on mice and hyperglycemic rat. MATERIALS AND METHODS: The test compound or solvent was injected subcutaneously to mice, for 7 days. On day 8, blood and liver samples were obtained. In hyperglycemic rat, 0.5 g/kg glucose with or without test compounds was injected, and followed with infusion of 1.5 g/kg/hr glucose. Blood samples were collected in mentioned intervals and liver was dissected. RESULTS: In hyperglycemic rat, all test compounds decreased blood glucose and the effect of milrinone was potentiated by glybenclamide. Milrinone or IBMX did not change plasma insulin levels, but it was augmented by combination of milrinone and glybenclamide. In both species, liver glycogen storage was decreased by IBMX, mc5, mc6 or MCPIP, increased by mc2 (liver glycogen, rat, control=56±2, mc2=70±3 P< 0.01, mice, control=33±0.7, mc2=42±2.3 P< 0.01) and was not changed in the presence of mc1. Milrinone did not change the glycogen storage in rats though increased it in mice (control= 33±0.7, milrinone= 40±1 P< 0.05). CONCLUSION: Increasing plasma insulin levels by combination of milrinone and glybenclamide confirmed that in hyperglycemic rat, the hypoglycemic effect was correlated with increasing insulin secretion. Variations of plasma insulin were obscured by the pulsative characteristic of pancreatic insulin release. Decreasing glycogen storage reflected inhibition of liver PDE activity. The reasons for ineffectiveness of mc1, anabolic effect of mc2, and differential effects of milrinone were not clear.

Chronic administration of a combination of six herbs inhibits the progression of hyperglycemia and decreases serum lipids and aspartate amino transferase activity in diabetic rats.

The effects of a polyherbal compound, containing six plants (Allium sativum, Cinnamomum zeylanicum, Nigella sativa, Punica granatum, Salvia officinalis and Teucrium polium) were tested on biochemical parameters in streptozotocin-induced diabetic rats. Streptozotocin caused an approximately 3-fold increase in fasting blood sugar level after 2 days. The diabetic control rats showed further increase in blood glucose after 30 days (384 ± 25 mg/dl in day 30 versus 280 ± 12 mg/dl in day 2, P < 0.001). Administration of the compound blocked the increase of blood glucose (272 ± 7 and 269 ± 48 mg/dl at day 2 and day 30, respectively). Also, there was significant difference in the level of triglyceride (60 ± 9 versus 158 ± 37 mg/dl, P < 0.01), total cholesterol (55 ± 2 versus 97 ± 11 mg/dl, P < 0.01) and aspartate amino transferase activity (75 ± 12 versus 129 ± 18 U/L, P < 0.05) between treated rats and diabetic control group. In conclusion, the MSEC inhibited the progression of hyperglycemia and decreased serum lipids and hepatic enzyme activity in diabetic rats. Therefore, it has the potential to be used as a natural product for the management of diabetes.

Effect of Ganoderma lucidum hydroalcoholic extract on insulin release in rat-isolated pancreatic islets.

OBJECTIVE: Ganoderma Lucidum (G. Lucidum) has been suggested to increase serum insulin level. This study was undertaken to investigate its direct effect on the islets of Langerhans. MATERIAL AND METHODS: Male albino Wistar rats were anesthetized and the islets were isolated after digestion of the pancreas with collagenase. The islets were incubated for 60 min in Krebs bicarbonate buffer containing 3 or 10 mM glucose in the presence of hydroalcoholic extract of G. Lucidum (1 mg/ml), 3-isobutyl-1-methylxanthine (IBMX, 100 µM) or vehicle. RESULTS: Exposure of islets to the extract increased insulin secretion at basal (3 mM) glucose concentration. Increase of glucose concentration to 10 mM resulted in a significant increase in the rate of insulin secretion. While the IBMX could augment insulin release evoked by 10 mM glucose, the extract failed to modify it. CONCLUSION: Our results demonstrate that G. lucidum acts directly on the Langerhans islets to increase basal insulin release.

Inotropic and chronotropic effects of 6-hydroxy-4-methylquinolin-2(1H)-one derivatives in isolated rat atria.

BACKGROUND: Selective phosphodiesterase (PDE3) inhibitors improve cardiac contractility and may use in congestive heart failure. However, their proarrhythmic potential is the most important side effect. METHODS: In this research, we evaluated the potential cardiotonic activity of six new synthesized selective PDE3 inhibitors (6-hydroxy-4-methylquinolin-2(1H)-one derivatives) using the spontaneously beating atria model. In each experiment, atrium of reserpine-treated rat was isolated and the contractile and chronotropic effects of a synthesized compound were assessed. The 3-isobutyl-1-methylxanthine, a non-selective PDE inhibitor, was used for comparison. RESULTS: The results showed that, among new compounds, the best pharmacological profile was obtained with the compound 6-[4-(4-methylpiperazine-1-yl)-4-oxobutoxy]-4-methylquinolin-2(1H)-one, C6, which displayed selectivity for increasing the force of contraction (168 +/- 5% change over the control) rather than the frequency rate (138 +/- 5% change over the control) at 300 microM. However, C6 at concentrations of 10 and 100 microM produced left and upward shift in the positive inotropic concentration-response curve of isoprenaline. The -log EC50 of isoprenaline was 8.843 +/- 0.171 in the absence, 9.448 +/- 0.138 and 9.456 +/- 0.107 in the presence of 10, 100 microM of C6, respectively (P<0.001, n = 6). Also, amrinone, a selective PDE3 inhibitor, shifted the isoprenaline concentration-response curve to the left and upward. The concentration of 10 and 100 microM amrinone decreased -log EC50 of isoprenaline to 9.527 +/- 0.287 and 9.423 +/- 0.243, respectively (P<0.001, n = 6). Moreover, the positive chronotropic effect of isoprenaline was not affected by amrinone or C6. CONCLUSION: This study provides functional evidence for the positive inotropic effect of C6. Considering the augmentation of isoprenaline positive inotropic concentration-response with C6 and amrinone, we conclude that C6 produces its effect via potentiation of cAMP-dependent signaling system and possibly by inhibition of PDE3 activity.