Antiulcer activity of Muntingia calabura leaves involves the modulation of endogenous nitric oxide and nonprotein sulfhydryl compounds

Context: Muntingia calabura L. (Muntingiaceae) is a native plant species of the American continent and is widely cultivated in warm areas in Asia, including Malaysia. The plant is traditionally used to relieve pain from gastric ulcers.

Objective: This study was designed to determine the antiulcer activity of a methanol extract of M. calabura leaves (MEMC) and the possible mechanisms of action involved.

Materials and methods: An acute toxicity study was conducted using a single oral dose of 2000?mg/kg MEMC. The antiulcer activity of MEMC was evaluated in absolute ethanol- and indomethacin-induced gastric ulcer rat models. MEMC was administered orally (dose range 25–500?mg/kg) to rats fasted for 24?h. The animals were pretreated with N^G-nitro-l-arginine methyl esters (l-NAME) or N-ethylmaleimide (NEM) prior to MEMC treatment to assess the possible involvement of endogenous nitric oxide (NO) and nonprotein sulfhydryl (NP-SH) compounds in the gastroprotective effect of MEMC.

Results: As the administered dose did not cause toxicity in the rats, the oral median lethal dose (LD₅₀) of MEMC was >2000?mg/kg in rats. MEMC exerted significant (p?l-NAME and NEM pretreatment significantly (p?Discussion and conclusion: The results obtained indicate that MEMC has significant antiulcer activity that might involve the participation of endogenous NO and NP-SH compounds. These findings provide new pharmacological information regarding the potential use of M. calabura.     

Possible involvement of nitric oxide in antidepressant-like effect of silymarin in male mice

Abstract

Context: Silymarin (SM) is extracted from milk thistle Silybum marianum L. [Asteraceae (Compositae)] and known for antioxidative and anti-inflammatory effects.

Objective: The potential antidepressant-like effect of acute SM and possible involvement of nitric oxide (NO) were determined in male mice.

Material and methods: SM was administered orally (5, 10, 20, 50, 100, and 200?mg/kg; p.o.) 60?min before the tests. After assessment of locomotor activity, the immobility time was measured in forced swimming test (FST) and tail suspension test (TST). To assess the possible involvement of NO, a non-specific NO synthase inhibitor, l-NAME (10?mg/kg, i.p.), and a specific iNOS inhibitor, aminoguanidine (AG) (50?mg/kg, i.p.), were administered separately 30?min before SM (20 and 100?mg/kg).

Results: SM at its effective doses 10, 20, 50, and 100?mg/kg decreased the immobility time in a dose-dependent manner (p?<?0.01, p?<?0.05, p?<?0.05, and p?<?0.001, respectively) in FST. SM (10, 20, 50, and 100?mg/kg) also lowered the immobility measure dose dependently in TST (p?<?0.01, p?<?0.05, p?<?0.01, and p?<?0.001, respectively). In addition, 50% of maximum response (ED₅₀) of SM was around 10?mg/kg. The dose 100?mg/kg proved the most effective dose in both the tests. Further, this effect was not related to changes in locomotor activity. Moreover, l-NAME reversed the effect of SM (20 and 100?mg/kg) in FST and SM (100?mg/kg) in TST. However, AG did not influence this impact.

Conclusion: The antidepressant-like effect of SM is probably mediated at least in part through NO and SM may increase NO tune.     

Effect of Aframomum melegueta. Seed Extract on Castor Oil–Induced Diarrhea

ABSTRACT

The effect of the aqueous (aq) seed extract of Aframomum melegueta. K. Schum. (Zingiberaceae) on castor oil-induced diarrhea, intestinal fluid secretion, and gastrointestinal transit was investigated in the study. Castor oil (10 ml/kg, p.o.) induced copious diarrhea in all rats 3 h after treatment. Furthermore, it produced a significant increase in the volume of intestinal fluid secretion in rats and also enhanced intestinal transit in mice. The aq seed extract of A. melegueta. (100–500 mg/kg, p.o.) offered significant protection against diarrhea induced by the oil. At a dose range of 250–500 mg/kg, the extract reduced significantly the volume of fluid secretion in castor oil–treated rats. At these doses, it also demonstrated a significant antitransit activity in a dose-related manner. Acetylsalicylic acid (100 mg/kg, p.o.) delayed diarrhea and reduced the number of animals with diarrheal droppings to 20%. At the same dose level, acetylsalicylic acid reduced significantly the volume of intestinal fluid secretion but lacked antitransit property in castor oil–treated animals. N.-Nitro-L-arginine methyl ester (L-NAME) (2.5–10 mg/kg, i.p.) dose-dependently reduced the number of animals with diarrhea. At 50 mg/kg i.p., it offered 100% protection against diarrhea induced by the oil. Furthermore, L-NAME (10 mg/kg, i.p.) significantly inhibited both the intestinal fluid secretion and gastrointestinal transit induced by castor oil. However, L-NAME (10 mg/kg, i.p.) did not significantly modify the antidiarrheal effect of A. melegueta.. L-Arginine, a substrate of nitric oxide synthase or isosorbide dinitrate, a nitric oxide donor, did not alter the effect of A. melegueta. on diarrhea. Ascorbic acid (100 mg/kg, p.o.) and α.-tocopherol (20 mg/kg, p.o.) reduced the number of animals with diarrhea to 80% and 70%, respectively. However, they both lacked significant activities on intestinal fluid secretion and gastrointestinal transit induced by castor oil. The combination of ascorbic acid (100 mg/kg, p.o.) or α.-tocopherol (20 mg/kg, p.o.) with A. melegueta. (500 mg/kg) offered higher protection against diarrhea than the extract alone. Considering these results together, it may be inferred that Aframomum melegueta. seed extract may be a useful antidiarrheal agent.     

Hepatoprotective effect of Commiphora myrrha against d-GalN/LPS-induced hepatic injury in a rat model through attenuation of pro inflammatory cytokines and related genes

Abstract

Context: Commiphora myrrha (Burseraceae), a shrub resembling a small tree, has been used for several centuries for the treatment of various diseases.

Objective: This study investigates the hepatoprotective activity of C. myrrha ethanol extract against d-galactosamine/lipopolysaccharide (d-GalN/LPS)-induced acute hepatic injury in an animal model.

Materials and methods: Rats were pretreated with ethanolic extract C. myrrha (250 and 500?mg/kg; p.o.) for 7 d prior to the induction of an acute phase response by d-GalN/LPS. Animals were sacrificed 24?h after d-GalN/LPS (800?mg/kg and 50?µg/kg i.p.) administration for the biochemical and histological analyses.

Results: The administration of d-GalN/LPS increased plasma aminotransferases (174.47?±?4.5761 and 260.96?±?1.9839?µkat/l) and total bilirubin levels (1.012?±?0.0288?mg/dl), which were attenuated by C. myrrha treatment. Hepatic lipid peroxidation activity and nitric oxide content also increased, while the antioxidant activity measured by GSH (0.76 nmol/g protein), SOD (81.91?U/mg protein), and CAT (15.78?U/mg protein) was reduced. Commiphora myrrha provided significant restoration of GSH (0.815 nmol/gm protein), SOD (140.57?U/mg protein), and CAT (27.02?U/mg protein) levels. Furthermore, the acute phase response elicited by d-GalN/LPS administration enhanced mRNA expressions of TNF-α, IL-6, IL-10, iNOS-2, and HO-1, which were ameliorated by C. myrrha treatment.

Discussion and conclusion: These findings indicate that C. myrrha considerably reduces the oxidative stress of d-GalN/LPS-induced hepatic injury via multiple pathways including adown regulation of inflammatory mediators and cytokines. Such a property might be sufficient to combat cellular damage caused by various conditions that resemble fulminant hepatitis and could be of a potential clinical application.     

Chlorogenic acid protects d-galactose-induced liver and kidney injury via antioxidation and anti-inflammation effects in mice

Context Oxidative stress and inflammation are implicated in the aging process and its related hepatic and renal function decline. Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in the human diet. Recently, CGA has shown in vivo and in vitro antioxidant properties.

Objective The current study investigates the effects of protective effects of chlorogenic acid (CGA) on d-galactose-induced liver and kidney injury.

Materials and methods Hepatic and renal injuries were induced in a mouse model by subcutaneously injection of d-galactose (d-gal; 100?mg/kg) once a day for 8 consecutive weeks and orally administered simultaneously with CGA included in the food (200?mg/kg of diet). The liver and renal functions were examined. Histological analyses of liver and kidney were done by haematoxylin and eosin staining. The oxidative stress markers and pro-inflammatory cytokines in the liver and the kidney were measured.

Results CGA significantly reduced the serum aminotransferase, serum creatinine (SCr) and blood urea nitrogen (BUN) levels in d-gal mice (p?<0.05). CGA also restored superoxide dismutase, catalase, and malondialdehyde levels and decreased glutathione content in the liver and kidney in d-gal mice (p?<0.05). Improvements in liver and kidney were also noted in histopathological studies. CGA reduced tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) protein levels in the liver and kidney in d-gal mice (p?<0.05).

Discussion and conclusion These findings suggest that CGA attenuates d-gal-induced chronic liver and kidney injury and that this protection may be due to its antioxidative and anti-inflammatory activities.     

Antidiabetic potential of triterpenoid saponin isolated from Primula denticulate

Context: Primula denticulate Sm. (Primulaceae), commonly known as drumstick primula, is traditionally used to treat diabetes and urinary disorders. In the present study, a new triterpenoid saponin was isolated. Triterpenoids generally show antidiabetic activity. Considering its traditional use and chemical nature of the molecule, the present study was designed to evaluate the antidiabetic activity.

Objective: Antidiabetic activity of triterpenoid saponin (TTS) isolated from P. denticulate.

Materials and methods: A new TTS was isolated from the leaf of P. denticulate by column chromatography on CHCl₃/MeOH (8.5:1.5) fraction. It was further characterized by using NMR, UV, and IR spectroscopic methods. Ethanol and aqueous extracts of the leaf were also prepared. Antidiabetic study for TTS, ethanol extract, and aqueous extract was carried out in streptozotocin (STZ)-induced diabetic rats at doses of 200, 1000, and 1000?mg/kg body weight, respectively. A toxicity study was also performed.

Results: Isolated new TTS molecule was characterized as 3-O[β-d-xylopyranosyl-(1?→?2)-β-d-glucopyranosyl-(1?→?4)-α-l-arabinopyranosyloxy]-16α-hydroxy-13β,28-epoxy-olean-30-al by NMR, UV, and IR spectroscopic methods. This new TTS was found to be effective in lowering blood-glucose level in the experimental rat model, thus establishing its antidiabetic property (168.8?±?4.58) when compared with disease control (258.8?±?0.60). Its LD₅₀ value was found at a dose of 2000?mg/kg. The level of insulin was restored by TTS and ethanol extract up to 31.49?µU/ml and 38.90?µU/ml, respectively, when compared with disease control (18.45?µU/ml).

Discussion and conclusion: In conclusion, 3-O[β-d-xylopyranosyl-(1?→?2)-β-d-glucopyranosyl-(1?→?4)-α-l-arabinopyranosyloxy]-16α-hydroxy-3β,28-epoxy-olean-30-al possesses potential glucose lowering properties, i.e., antidiabetic potential against STZ-induced diabetic rats.     

Hesperidin,a citrus flavonoid,protects against l-methionine-induced hyperhomocysteinemia by abrogation of oxidative stress,endothelial dysfunction and neurotoxicity in Wistar rats

Context: Hesperidin (HSP), a flavanoglycone found in citrus fruits, has antioxidant, anti-inflammatory and neuroprotective properties.

Objective: This study evaluates the protective effect of HSP on l-methionine-induced hyperhomocysteinemia (HHcy) in rats.

Materials and methods: Male Wistar rats were randomly divided into seven groups as DMSO, l-methionine, HSP (25, 50 and 100?mg/kg), HSP-per se (100?mg/kg) and donepezil (0.1?mg/kg). HHcy was induced by oral administration of l-methionine (1.7?g/kg) for 32 days. From the 14^th day of study HSP (25, 50 and 100?mg/kg) and donepezil was administered orally to l-methionine-treated rats. Cognitive impairment induced by HHcy was determined using the Morris water maze (MWM) and Y-maze on video tracking system (28^th–32^nd day). Different biomarkers of HHcy in serum and brain and vascular reactivity were evaluated and histopathology (thoracic aorta and brain) was done.

Results: HSP (100?mg/kg) treatment in l-methionine-treated rats exhibited significant (p?p?l-methionine on acetylcholine-induced endothelial-dependent relaxation and increased serum nitrite and vascular nitric oxide bioavailability along with the restoration of histological aberrations.

Conclusion: HSP exerts a protective effect on HHcy by abrogating oxidative stress, ED and neurotoxicity.     

Protective effect of Amaranthus spinosus against d-galactosamine/lipopolysaccharide-induced hepatic failure

The current study is an effort to identify the hepatoprotective activity of the 50% ethanol extract of the whole plant of Amaranthus spinosus Linn. (Amaranthaceae) against d-galactosamine/lipopolysaccharide (d-GalN/LPS)-induced liver injury in rats. d-GalN/LPS (300?mg/kg body weight/30 µg/kg body weight)-induced hepatic damage was manifested by a significant (p <0.05) increase in the activities of marker enzymes (aspartate transaminase, alanine transaminase, alkaline phosphatase, lactate dehydrogenase and gamma glutamyl transferase) and bilirubin level in serum while phospholipids significantly decreased. All other parameters, i.e. cholesterol, triglycerides and free fatty acids were increased significantly in both serum and liver compared to the control group. Pretreatment of rats with A. spinosus extract (400?mg/kg) significantly (p <0.05) reversed these altered parameters to normal compared to the intoxicated group. The biochemical observations were supplemented by histopathological examination of liver sections. There were no significant changes in the activities of marker enzymes, bilirubin level and lipids in the rats treated with A. spinosus extract alone. Results of this study revealed that A. spinosus extract could afford a significant protection against d-GalN/LPS-induced hepatocellular injury.     

Antimycobacterial activity of cyclic dipeptides isolated from Bacillus sp. N strain associated with entomopathogenic nematode

Context: Tuberculosis (TB) is one of the leading causes of morbidity and mortality with a global mortality rate of two million deaths per year; one-third of the world’s population is infected with Mycobacterium tuberculosis.

Objective: The aim of this study was to determine the antimycobacterial activity of six diketopiperazines (DKPs) purified from a Bacillus sp. N strain associated with entomopathogenic nematode Rhabditis (Oscheius) sp.

Materials and methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration of DKPs were determined using the broth dilution method on Middlebrook 7H11 against M. tuberculosis H₃₇Rv. Time-kill assay was used to determine the rate of killing of M. tuberculosis H₃₇Rv by DKPs. The cytotoxicity of the DKPs was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay against the VERO cell line.

Results: Out of six DKP-tested cyclo-(d-Pro-l-Leu), cyclo-(l-Pro-l-Met) and cyclo-(d-Pro-l-Phe) recorded antimycobacterial activity, the cyclo-(l-Pro-l-Met) showed the highest activity and MIC values of 4?μg/ml for M. tuberculosis H₃₇Rv. The MIC value for rifampicin was 0.06?μg/ml. Growth curve study by the MIC concentration of cyclic dipeptides recorded significant inhibition when compared with control. Time-kill curve showed maximum reduction of colony count was between 3 and 5 weeks. The DKPs are nontoxic to the VERO cell line up to 200?µg/ml. The antimycobacterial activity of cyclo-(d-Pro-l-Leu), cyclo-(l-Pro-l-Met) and cyclo-(d-Pro-l-Phe) is reported in this study for the first time.

Discussion and conclusion: In conclusion, the potency, low cytotoxicity and selectivity of these compounds make them valid lead compounds for treatment against TB.     

In vivo anti-inflammatory effect of a sulfated polysaccharide isolated from the marine brown algae Lobophora variegata

Context:?Lobophora variegata J.V. Lamouroux (Dictyotaceae) is a brown marine alga widely encountered in the Brazilian sea coast that presents high content of fucans. Anti-inflammatory effects of fucans are reported mostly in models in vitro, but little is known about its effects in vivo.

Objective:?To investigate vascular and cellular effects of a sulfated polysaccharide from the brown marine algae L. variegata (SP-Lv) in acute inflammatory models.

Materials and methods:?SP-Lv was isolated by DEAE-cellulose and analyzed by agarose gel electrophoresis and evaluated for its inhibitory effect on paw edema, vascular permeability, leukocyte migration and peritoneal nitrite content induced by zymosan in Wistar rats. Anticoagulant activities and possible systemic toxicity were also evaluated.

Results:?SP-Lv inhibited the paw edema (120 min: 1.42?±?0.11 vs. 0.95?±?0.05?mL), plasma exudation (21.53?±?0.62 vs. 11.96?±?0.68 μg/g), nitrite content (4.42?±?0.33 vs. 2.86?±?0.003 μM) and leukocyte migration (5.15?±?1.21 vs. 1.99?±?0.16 cells/10³ mL) induced by zymosan. SP-Lv and l-NAME reduced the paw edema (60–120?min) elicited by l-arginine. However, at 180?min SP-Lv effect was more accentuated and sustained until 240?min, while that of l-NAME was abolished. Similarly to indomethacin, SP-Lv inhibited the entire edema time-course induced by phospholipase A₂, except for the time of 60?min.

Discussion and conclusion:?The anti-edematogenic effect of SP-Lv seems to occur via inhibition of nitric oxide synthase and cyclooxygenase activities. These results suggest a potential applicability of polysaccharides from alga origin in acute inflammatory conditions.     

Sulfated polysaccharide isolated from Ulva lactuca attenuates d-galactosamine induced DNA fragmentation and necrosis during liver damage in rats

Context: Ulva lactuca Linnaeus (Chlorophyceae), a commonly distributed seaweed, is rich in polysaccharide but has not been studied extensively.

Objective: The present study investigated the effects of crude fraction of Ulva lactuca polysaccharide (ULP) on d-galactosamine (d-Gal)-induced DNA damage, hepatic oxidative stress, and necrosis in rats.

Materials and methods: The rats were treated with ULP (100?mg/kg, orally) for 4 weeks before a single intraperitoneal injection of d-Gal (500?mg/kg). In addition to liver cell necrosis and DNA damage, antioxidant parameters, such as lipid peroxide (LPO), superoxide dismutase, and catalase, and histopathology of liver tissue were evaluated.

Results: ULP pre-treatment significantly attenuated a d-Gal-induced decrease in DNA and RNA levels (3.67?±?0.38) and (5.42?±?0.46), respectively. Comet tail length and acridine staining confirmed the number of cells undergoing necrosis were relatively lower in ULP treated rats (30?µm and 8–10% of counted cells) compared to rats treated with d-Gal (60?µm and 16% of counted cells). Biochemical (LPO, SOD and CAT) and histological evaluation (p?d-Gal-induced elevation of LPO and infiltration of inflammatory cells into liver tissue.

Discussion and conclusion: Although our previous studies have reported on the protective role of ULP against liver toxicity, our present findings show that ULP improved the hepatic antioxidant defense system against d-Gal-induced DNA damage and necrosis in rats.     

Calendula officinalis ameliorates l-arginine-induced acute necrotizing pancreatitis in rats

Context: Calendula officinalis L. (Asteraceae) has been traditionally used in treating inflammation of internal organs, gastrointestinal tract ulcers and wound healing.

Objective: The present study investigates the effect of ethanol extract (95%) of Calendula officinalis flowers in l-arginine induced acute necrotizing pancreatitis in rats.

Materials and methods: Rats were divided into four groups: normal control, l-arginine control, Calendula officinalis extract (COE) treated and melatonin treated (positive control), which were further divided into subgroups (24?h, day 3 and 14) according to time points. Two injections of l-arginine 2?g/kg i.p. at 1?h intervals were administered in l-arginine control, COE and melatonin-treated groups to produce acute necrotizing pancreatitis. Biochemical parameters [serum amylase, lipase, pancreatic amylase, nucleic acid content, total proteins, transforming growth factor-β1 (TGF-β1), collagen content, lipid peroxidation, reduced glutathione and nitrite/nitrate] and histopathological studies were carried out.

Results: COE treatment (400?mg/kg p.o.) was found to be beneficial. This was evidenced by significantly lowered histopathological scores (2 at day 14). Nucleic acid content (DNA 21.1 and RNA 5.44?mg/g pancreas), total proteins (0.66?mg/mL pancreas) and pancreatic amylase (1031.3 100 SU/g pancreas) were significantly improved. Marked reduction in pancreatic oxidative and nitrosative stress; collagen (122 μmoles/100?mg pancreas) and TGF-β1 (118.56?pg/mL) levels were noted. Results obtained were comparable to those of positive control.

Discussion and conclusion: The beneficial effect of COE may be attributed to its antioxidant, antinitrosative and antifibrotic actions. Hence, the study concludes that COE promotes spontaneous repair and regeneration of the pancreas.     

Mechanistic assessment of the analgesic,anti-inflammatory and antipyretic actions of Dalbergia saxatilis in animal models

Context: Aqueous root extract of Dalbergia saxatilis, Hook, f., (Leguminosae) (DS) is reported useful for toothache, pains, and fever, but not scientifically proven.

Objective: This study determined its effectiveness in pain, inflammation, and fever, applying scientific models.

Materials and methods: Swiss mice or Sprague–Dawley rats (n?=?5) were pretreated with distilled water, DS (100 or 200?mg/kg), or standard drug for 30?min. The analgesic activity was measured by acetic acid writhing, tail flick, tail immersion, tail clip, hot plate, and formalin pain tests; anti-inflammatory effects were determined via carrageenan and dextran rat paw oedema tests; antipyretic activity was measured by Escherichia coli lipopolysaccharide (ECL) and turpentine in rabbits, and d-amphetamine sulphate (d-AS) pyrexia test in rats.

Results: Writhing frequency inhibition was produced by 200?mg/kg DS (33.10%), aspirin (38.19%) and morphine (93.68%). Unlike morphine, DS did not produce significant prolongation of the reaction times in the hot-plate, tail immersion, tail flick, and tail clip tests. In the first and second phases of formalin test, respectively, % inhibition was: 200?mg/kg DS (25.70% and 0%), aspirin (4.76% and 67.33%), morphine (81.42% and 66.11%); for carrageenan and dextran tests, significant difference was recorded between 200?mg/kg DS and control up to 6?h. Significant reduction in ECL, turpentine and d-AS pyrexia was recorded at 100 and 200?mg/kg DS.

Conclusion: DS produces mild non-steroidal analgesic and anti-inflammatory, as well as significant antipyretic actions involving cyclooxygenase, α₂ adrenoceptor and interleukin-1 β1 due to any of glycosides, saponins or phenolic tannins.     

Toxic rather than neuropharmacological effect of Ternstroemia sylvatica fruits and identification of 28-O-[β-l-6-rhamnopyranosyl]-R1-barrigenol as a new compound with toxic effects in mice

Abstract

Context: Fruits of Ternstroemia sylvatica Schltdl. and Cham. (Theaceae) are used in Mexican traditional medicine to alleviate anxiety, sleep disorders and seizures; however, the active principles have not been identified.

Objective: To identify the neuroactive principles of T. sylvatica fruits using neuropharmacological tests on mice.

Materials and methods: The methanol and aqueous extracts of pericarp or seeds of T. sylvatica fruits were intraperitoneally administered (1–562?mg/kg, single doses) to mice. The exploratory cylinder, hole board, open field, Rota-rod and sodium pentobarbital-induced hypnosis tests were used to evaluate the CNS depressant effect after 30?min single administration of extracts. From aqueous seeds extract, triterpene glycoside 28-O-[β-l-6-rhamnopyranosyl]-R₁-barrigenol was isolated an active compound.

Results: Crude extracts of T. sylvatica fruits, separated from seed and pericarp, showed sedative effect in mice. The aqueous (ED₅₀?=?4.9?±?0.8?mg/kg) seed extracts is the most active among them. This extract also decrease locomotor activity and disrupt motor coordination of mice. This extract was also the most toxic extract (LD₅₀?=?5.0?±?1.4?mg/kg; i.p.). The triterpene glycoside 28-O-[β-l-6-rhamnopyranosyl]-R₁-barrigenol was identified in this extract as one of the active sedative compounds (ED₅₀?=?0.12?±?0.01?mg/kg) also with toxic effect (LD₅₀?=?1.11?±?0.23?mg/kg).

Conclusion: The results suggest that T. sylvatica fruits has toxic activity rather than CNS depressant activity in mice and that this effect might be related to the presence of 28-O-[β-l-6-rhamnopyranosyl]-R₁-barrigenol, one of the active principles of T. sylvatica fruits with sedative and toxic effect.     

Effects of l-arginine and creatine administration on spatial memory in rats subjected to a chronic variable stress model

Context: Chronic stress results from repeated exposure to one or more types of stressors over a period, ranging from days to months, and can be associated with physical, behavioral, and neuropsychiatric manifestations. Some physiological alterations resulting from chronic stress can potentially cause deficits on spatial learning and memory.

Objective: This study investigated the effects of chronic variable stress (CVS) and administration of l-arginine and creatine on spatial memory in rats. Furthermore, body, heart, adrenal weight, and plasma glucose and corticosterone levels were analyzed.

Material and methods: Male Wistar rats were subjected to a CVS model for 40 days and evaluated for spatial memory after the stress period. Chronically stressed animals were treated daily by gavage with: 0.5% carboxymethylcellulose (Group Cs), 500?mg/kg l-arginine (Group Cs/La), 300?mg/kg creatine (Group Cs/Cr); and 500?mg/kg l-arginine and 300?mg/kg creatine (Group Cs/La + Cr) during the entire experimental period.

Results: Our results showed that animals in the Cs/Cr and Cs/La + Cr groups presented significantly decreased corticosterone levels compared to group Cs (p?p?0.01); and animals in group Cs/La + Cr significantly improved in reference memory retention compared to controls (p?0.05).

Discussion and conclusion: Overall, these results demonstrated that a single administration of creatine improves working memory efficiency, and, when co-administrated with l-arginine, improves reference memory retention, a phenomenon that is possibly associated with increased creatine/phosphocreatine levels and l-arginine-derived NO synthesis.     

Intracerebroventricular administration of the (1→6)-β-d-glucan (lasiodiplodan) in male rats prevents d-penicillamine-induced behavioral alterations and lipoperoxidation in the cortex

Context: Lasiodiplodan, an exocellular (1→6)-β-d-glucan of molecular weight >1.4?×?10⁶?Da produced by MMPI strain of Lasiodiplodia theobromae (Pat.) Griffon &; Maubl. (Brotyosphaeriaceae) is known to exhibit anti-proliferative activity on breast cancer cells (MCF-7), anticoagulant activity when sulfonylated, and reduction in transaminase activity when administered in rats.

Objective: The effect of intracerebroventricular (I.C.V) injection of lasiodiplodan on neurotoxicity and behavioural changes induced by d-penicillamine was investigated.

Materials and methods: Twenty-four male Wistar rats were initially separated in groups of six and treated with 0.15?μmol/μL of NaCl (Groups Ct and d-Pen) and 0.01?μg/μL of lasiodiplodan (Groups Las and Las?+?d-Pen). After 15?min, they received 6?μmol/μL of NaCl (Groups Ct and Las) and 2?μmol/μL of d-penicillamine (Groups d-Pen and Las?+?d-Pen). The animal behavior was observed in an open-field test for 60?min. Twenty-four h later, the animals were sacrificed and histopathological analysis and Thiobarbituric acid reactive substances (TBARS) production measurements were performed.

Results: Lasiodiplodan prevented neurotoxicity induced by d-penicillamine significantly reducing the production of TBARS (308%; p?Discussion and conclusion: The reduction of TBARS production and convulsive episodes suggests that the protector effect provided by lasiodiplodan passes thought an antioxidant path, possibly interfering in a cascade of neurochemical events, triggering cell death and convulsive episodes. These results demonstrated that lasiodiplodan can be effective in treating neurotoxicity, and reducing damage triggered by convulsions in neuropathies related to GABAergic system.     

Effects of oleuropein in rats with simultaneous type 2 diabetes and renal hypertension: a study of antihypertensive mechanisms

The mechanism of oleuropein's antihypertensive effects was examined in rat model of simultaneous type 2 diabetes and renal hypertension (diabetic hypertensive). Five groups of male Sprague-Dawley rats including a control, a diabetic-hypertensive group receiving vehicle, and three diabetic-hypertensive groups receiving oleuropein at 20, 40, or 60 mg/kg/day were used. The duration of diabetes was 10 weeks; during the last 4 weeks of which, animals were hypertensive and received vehicle or oleuropein. Systolic blood pressure, glucose and malondialdehyde, heart rate, and maximal response to phenylephrine (PE) in the absence of nitro-l-arginine methyl ester (l-NAME) of oleuropein-treated groups were significantly lower than those of vehicle-treated group. Erythrocyte superoxide dismutase, maximal response to PE in the presence of l-NAME, and maximal response to acetylcholine (Ach) of oleuropein-treated groups were significantly higher than those of vehicle-treated group. The findings indicate that antihypertensive effects of oleuropein might be partly mediated by improving the release of nitric oxide, and antioxidant and sympathoplegic activities.     

Study on the mechanisms of the bronchodilator effects of Folium Eriobotryae and the selected active ingredient on isolated guinea pig tracheal strips

Context: Folium Eriobotryae (FE), the dry leaf of Eriobotrya japonica (Thunb.) Lindl. (Rosaceae), has been widely used to treat respiratory disorders.

Objective: To examine the bronchodilatory activity of FE and the potential mechanisms involved.

Materials and methods: The effects of ethyl acetate fraction of FE (EFE) (0.05–0.3?mg/mL) on the isolated tracheal strips, and ursolic acid (UA) (5–30?μg/mL) that was the main constituent of EFE, were tested in vitro. Meanwhile, acetylcholine (Ach) and histamine (His)-induced bronchospasm were conducted in vivo in guinea pig. Furthermore, mechanisms of relaxant effects of EFE and UA were evaluated in the absence and presence of specific inhibitors.

Results: With in vitro studies, the contractile response evoked by Ach or His (EC_50?=_?0.21 and 0.16?mg/mL) was decreased by EFE, and UA caused a concentration-dependent relaxation precontracted by His (EC_50?=_?23.2?μg/mL). With in vivo studies, EFE strongly prolonged preconvulsive time similar to isoprenalin. The bronchodilator effects of EFE could be blocked by propranolol (1?μM), N^G-nitro-l-arginine methyl ester (l-NAME) (100?μM) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ) (1?μM). EFE also inhibited the contraction in Ca²⁺-free medium and produced rightward parallel displacement of CaCl₂ curves. In addition, the relaxant effects of UA could only be blocked by l-NAME and ODQ.

Discussion and conclusion: These results suggest that bronchodilator activities of EFE were related to activation of β-adrenoceptor and NO/cGMP pathway. Blockage of Ca^2+?channels and inhibition of IP₃R-mediated internal Ca^2+?release were also involved. Additionally, UA produced relaxant effects by the NO/cGMP pathway.     

Treated effect of silymarin on vascular function of aged rats: Dependant on nitric oxide pathway

Context: Aging leads to endothelial dysfunction and vascular stiffness which are the main causes of many cardiovascular diseases. Previous reports have shown that the cell protective effect of silymarin (SM) is dependent on its antioxidant properties.

Objectives: We investigated the effect of SM on vascular functions of aged rats and the involvement of nitric oxide or cyclooxygenase (COX) activity in this effect.

Materials and methods: Isolated rat aortas were obtained from 22-month old rats. Each ring was incubated with SM (50?mg/L), SM/l-nitro-arginine methyl ester (100?μM, l-NAME) or SM/indomethacin (10?μM, INDO) in tissue bath. Three- to four-month-old rats were used as young controls. Endothelium-intact rings were precontracted with α-receptor agonist phenylephrine (0.001–30?µM) or voltage-dependent high potassium (40?mM), endothelium dependent/independent relaxant responses were obtained using acetylcholine (0.001–30?µM) and sodium nitroprusside (0.0001–3?µM), respectively.

Results: Aging increased phenylephrine sensitivity (6.45?±?0.08; 6.88?±?0.09) and decreased KCl contraction (882?±?118.4; 499?±?80.4). SM treatment decreased the E_max of both agents (548?±?109; 223?±?48.9). Aging deteriorated acetylcholine relaxation (93.9?±?2.09; 72.0?±?2.56) and SM improved the response (86.3?±?1.90). l-NAME prevented the SM effect whereas INDO was ineffective.

Discussion and Conclusion: Immediate SM treatment partially restored endothelial dysfunction and vascular tone in aging. The possible mechanism might not be mediated by prostacyclin or the COX pathway in acute administration; the nitric oxide pathway and calcium antagonistic features of SM relate to its action on the vessel.     

Two new phenolic glycosides from the rhizome of Gastrodia elata

Two new phenolic glycosides, named parishins F–G (1–2), together with known parishin E, were isolated from the rhizome of Gastrodia elata. The new structures were established as 1,3-di-[4-O-(β-d-glucopyranosyl) benzyl]-2-{4-O-[β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl] benzyl} citrate (1) and 2-[4-O-(β-d-glucopyranosyl)benzyl] citrate (2), by means of MS, 1D, and 2D NMR spectral analyses, as well as chemical methods.