Antispasmodic effect of Piper nigrum fruit hot water extract on rat ileum

The aim of this study was to investigate the effect of black pepper fruit hot water extract (BPE) on rat ileum contractility and the mechanism(s) of its action. The extract was prepared by adding black pepper powder to boiling distilled water followed by evaporated the solvent. Ileum was dissected from male adult rat (Wistar) and in Tyrode solution the tissue contractions were recorded by an isotonic transducer under 1 g tension. The cumulative concentrations of the BPE (0.0625-1 mg mL(-1)) reduced the ileum contractions induced by KCl (60 mM) or carbachol (10 microM) concentration dependently (p<0.001). In Ca2+-free Tyrode solution with high potassium (60 mM), BPE, (0.0625-1 mg mL(-1)) attenuated the contractions induced by cumulative concentrations of CaCl2 (0.225-2.7 mM) concentration dependently (ANOVA, p<0.05). The incubation of the tissue preparation (20 or 30 min) with L-NAME (100 microM), naloxone (1 microM) or propranolol (1 microM) did not reduce the extract antispasmodic effect on KCl-induced ileum contraction. The extract spasmolytic effect was attenuated neither by glibenclamide (10 microM) nor by tetraethylammonium (1 mM). Present results suggest that the spasmolytic effect of the extract on rat ileum was possibly mediated via Ca2+ influx.     

Vasorelaxation, induced by Dictyota pulchella (Dictyotaceae), a brown alga, is mediated via inhibition of calcium influx in rats

This study aimed to investigate the cardiovascular effects elicited by Dictyota pulchella, a brown alga, using in vivo and in vitro approaches. In normotensive conscious rats, CH(2)Cl(2)/MeOH Extract (CME, 5, 10, 20 and 40 mg/kg) from Dictyota pulchella produced dose-dependent hypotension (-4 ± 1; -8 ± 2; -53 ± 8 and -63 ± 3 mmHg) and bradycardia (-8 ± 6; -17 ± 11; -257 ± 36 and -285 ± 27 b.p.m.). In addition, CME and Hexane/EtOAc Phase (HEP) (0.01-300 μg/mL) from Dictyota pulchella induced a concentration-dependent relaxation in phenylephrine (Phe, 1 μM)-pre-contracted mesenteric artery rings. The vasorelaxant effect was not modified by the removal of the vascular endothelium or pre-incubation with KCl (20 mM), tetraethylammonium (TEA, 3 mM) or tromboxane A(2) agonist U-46619 (100 nM). Furthermore, CME and HEP reversed CaCl(2)-induced vascular contractions. These results suggest that both CME and HEP act on the voltage-operated calcium channel in order to produce vasorelaxation. In addition, CME induced vasodilatation after the vessels have been pre-contracted with L-type Ca(2+) channel agonist (Bay K 8644, 200 nM). Taken together, our data show that CME induces hypotension and bradycardia in vivo and that both CME and HEP induce endothelium-independent vasodilatation in vitro that seems to involve the inhibition of the Ca(2+) influx through blockade of voltage-operated calcium channels.     

Ileal relaxation induced by Mentha longifolia (L.) leaf extract in rat

The effect of Mentha longifolia (L.) leaf hydroalcoholic extract (MLE) was examined on rat ileal smooth muscle contractions. Last portion of ileum from male adult Wistar rat was mounted in an organ bath containing Tyrode solution. The tissue was contracted by carbachol (CCh, 10 microM), KCl (60 mM) and BaC12 (4 mM) and then MLE (0.0625-1 mg mL(-1)) was added to the bath cumulatively. The effect of MLE on KCl-induced contraction was examined after tissue incubation with propranolol (1 microM), naloxone (1 microM) and N omega-nitro-L-arginine methyl ester (L-NAME, 100 microM). The effect of MLE on CaCl2-induced ileal contraction in Ca(2+)-free with high potassium Tyrode solution was also evaluated. The role of potassium channels was examined by ileum incubation (5 mim) with tetraethylammonium (TEA, 1 mM). The results showed that KCl-, CCh and BaCl2-induced ileal contractions were inhibited (p < 0.001) by cumulative concentrations of MLE with the same potency. In addition, MLE (0.25-1 mg mL(-1)) inhibited (p < 0.01) ileal contractions induced by CaCl2 (0.45-2.7 mM) in a concentration-related manner. The antispasmodic effect of MLE was affected neither by propranolol, L-NAME nor by naloxone. The MLE concentration-response curve was shifted to the right (p < 0.05) by tissue incubation with TEA. From results it may be suggested that Mentha longifolia hydroalcoholic leaf extract induces its spasmolytic activity mainly through disturbance in calcium mobilization and partly by potassium channels activation. Present results show that Mentha longifolia leaf extract exerts relaxant effects on intestinal smooth muscle, consistent with the traditional use of the plant to treat gastrointestinal disorders such as diarrhea and colic.     

Effect of Anthocyanin-Rich Extract from Black Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L. <Emphasis Type="Italic">indica</Emphasis>) on Hyperlipidemia and Insulin Resistance in Fructose-Fed Rats

This study was designed to evaluate the effect of an anthocyanin-rich extract from black rice on hyperlipidemia and insulin resistance in fructose-fed rats. Rats fed fructose diet for 4 weeks exhibited significantly higher plasma insulin levels and lower insulin sensitivity than the control rats fed AIN-93G diet. Dietary supplementation with the anthocyanin-rich extract (5 g/kg of high-fructose diet) prevented the development of fructose-induced insulin resistance. After fructose-induced insulin resistance had been established, 4-week treatment with the anthocyanin-rich extract (5 g/kg of high-fructose diet) or pioglitazone (270 mg/kg of high-fructose diet) ameliorated the glucose intolerance and hyperlipidemia, but the extract failed to reverse the fructose-induced hyperinsulinemia as pioglitazone did. In addition, rats supplemented by the extract exhibited lower oxidative stress than the fructose-fed controls, as indicated by the lower concentrations of plasma thiobarbituric acid reactive substances and blood oxidized glutathione. Overall, these results suggest that the anthocyanin-rich extract from black rice improves certain metabolic abnormalities associated with diets high in fructose.     

Role of GABAB Receptor and L-Arg in GABA-Induced Vasorelaxation in Non-diabetic and Streptozotocin-Induced Diabetic Rat Vessels

Background:

Hypertension is considered an independent risk factor for cardiovascular mortality in diabetic patients. The present study was designed to determine the role of gamma amino butyric acid B (GABA_B) receptor and L-arginine (L-Arg) in GABA-induced vasorelaxation in normal and streptozotocin-induced diabetic rat vessels.

Methods:

Diabetes was induced by a single i.p. injection of streptozotocin (STZ, 60 mg/kg). Eight weeks later, superior mesenteric arteries of all groups were isolated and perfused according to the McGregor method.

Results:

Baseline perfusion pressure of STZ diabetic rats was significantly higher than non-diabetic rats in both intact and denuded endothelium. In the presence of faclofen, a selective GABA_B receptor blocker, GABA-induced relaxation in intact and denuded endothelium mesenteric beds of STZ diabetic rats was suppressed, but this response in non-diabetic rats was not suppressed. Our results showed that in the presence of L-Arg, a nitric oxide precursor, GABA induced vasorelaxation in both diabetic and non-diabetic vessels.

Conclusion:

From the results of this study, it may be concluded that the vasorelaxatory effect of GABA in diabetic vessel is mediated by the GABA_B receptor and nitric oxide, but it seems that in non-diabetic vessel GABA_B receptor does not play any role in GABA-induced vasorelaxation, but nitric oxide induced GABA relaxation in non-diabetic vessel. Key Words: Gamma amino butyric acid (GABA), Diabetes, GABA_B receptor     

不同籼稻品种整株幼苗根系K+吸收和H+释放的关系：一种筛选高效K+吸收水稻品种的方法

 在0.2 mmol/L CaS04溶液中培养的不同籼稻品种低盐幼苗根系在1.0 mmol/L KCl和0.5 mmol/L K₂SO₄介质中的K+吸收和H+释放之间均呈非常显著的直线相关性。线性相关的斜率因测定方法而有所变化，但相关性意义不变。水稻在KCl介质的K^＋吸收速率比在K₂SO₄介质中的大， 但前者对应的H⁺释放速率却比后者的小，且K^＋吸收速率间没有对应的显著性相关意义。实验结果表明，虽然可以用直接测定吸收介质的酸化程度作为一种简捷的筛选高效K+吸收水稻品种的方法，但必须根据实际情况选用吸收介质。     

Pharmacological Studies of Tentacle Extract from the Jellyfish Cyanea capillata in Isolated Rat Aorta

Our previous studies demonstrated that tentacle extract (TE) from the jellyfish, Cyanea capillata, could cause a dose-dependent increase of systolic blood pressure, which seemed to be the result of direct constriction of vascular smooth muscle (VSM). The aim of this study is to investigate whether TE could induce vasoconstriction in vitro and to explore its potential mechanism. Using isolated aorta rings, a direct contractile response of TE was verified, which showed that TE could induce concentration-dependent contractile responses in both endothelium-intact and -denuded aortas. Interestingly, the amplitude of contraction in the endothelium-denuded aorta was much stronger than that in the endothelium-intact one, implying that TE might also bring a weak functional relaxation in addition to vasoconstriction. Further drug intervention experiments indicated that the functional vasodilation might be mediated by nitric oxide, and that TE-induced vasoconstriction could be attributed to calcium influx via voltage-operated calcium channels (VOCCs) from the extracellular space, as well as sarcoplasmic reticulum (SR) Ca²⁺ release via the inositol 1,4,5-trisphosphate receptor (IP₃R), leading to an increase in [Ca²⁺]_c, instead of activation of the PLC/DAG/PKC pathway or the sympathetic nerve system.     

Spasmolytic Effect of Caulerpine Involves Blockade of Ca2+ Influx on Guinea Pig Ileum

In this work, we investigated the spasmolytic effect of caulerpine, a bisindole alkaloid isolated from marine algae of the Caulerpa genus, on guinea pig ileum. Our findings indicated that caulerpine inhibited phasic contractions induced by carbachol (IC₅₀ = 7.0 ± 1.9 × 10⁻⁵ M), histamine (IC₅₀ = 1.3 ± 0.3 × 10⁻⁴ M) and serotonin (IC₅₀ = 8.0 ± 1.4 × 10⁻⁵ M) in a non-selective manner. Furthermore, caulerpine concentration-dependently inhibited serotonin-induced cumulative contractions (pD′₂ = 4.48 ± 0.08), shifting the curves to the right with E_max reduction and slope of 2.44 ± 0.21, suggesting a noncompetitive antagonism pseudo-irreversible. The alkaloid also relaxed the ileum pre-contracted by KCl (EC₅₀ = 9.0 ± 0.9 × 10⁻⁵ M) and carbachol (EC₅₀ = 4.6 ± 0.7 × 10⁻⁵ M) in a concentration-dependent manner. This effect was probably due to inhibition of Ca²⁺ influx through voltage-gated calcium channels (Ca_V), since caulerpine slightly inhibited the CaCl₂-induced contractions in depolarizing medium without Ca²⁺, shifting the curves to the right and with E_max reduction. According to these results, the spasmolytic effect of caulerpine on guinea pig ileum seems to involve inhibition of Ca²⁺ influx through Ca_V. However, other mechanisms are not discarded.     

Antinociceptive and anti-inflammatory activity of the ethanolic extract of Cymbidium aloifolium (L.)

The ethanol leaf extract of Cymbidium aloifolium (L.) was evaluated for its analgesic and antiinflammatory activities. The extract, at the dose of 200 and 400 mg kg(-1) body weight, exerted the analgesic activity by observing the number of abdominal contractions and anti-inflammatory activity against Carrageenin induced paw edema in mice by measuring the paw volume. The ethanolic extract of Cymbidium aloifolium (L.) showed statistically significant (p < 0.05) reduction of percentage of writhing of 33.57 and 61.31% at 200 and 400 mg kg(-1) oral dose, respectively, when compared to negative control. The Ethanolic plant extract also showed significant (p < 0.05) dose dependent reduction of mean increase of formation of paw edema. The results of the experiment and its statistical analysis showed that the ethanolic plant extract had shown significant (p < 0.05) dose dependent analgesic and anti-inflammatory activities when compared to the control.     

Some pharmacological studies on Hyphaene thebaica Mart. fruit

Hyphaene thebaica Mart. (Palmae) fruit, when investigated chemically, proved to contain alkaloid (S), reducing sugars and glucosides. The aqueous extract stimulated the contractions of frog's heart and rat intestine but inhibited uterine contractions in rats. On the arterial blood pressure, the extract proved to be capable of lowering the blood pressure both in normotensive and hypertensive anaesthetised dogs. The mechanism of its hypotensive action proved to be through ganglionic blockage. The extract had no diuretic effect in rabbits and was devoid of oestrogenic and androgenic properties when tested on uterine and seminal vesicle weights of ovariectomized and castrated rats.     

Possible involvement of fructose 1,6-bisphosphatase in cold-induced sweetening of potato tubers

Summary In measuring fructose 1,6-bisphosphatase (EC 3.1.3.11; FBPase) in potato tubers, we used anti PFP antibodies to ensure that the assay was specific for FBPase and that PPi:fructose 6-phosphate 1-phosphotransferase (EC 2.7.1.90: PFP) did not contribute to the production of fructose 6-phosphate (Fru-6-P). The involvement of cytosolic FBPase in cold sweetening was determined by monitoring enzyme activity during storage ofSolanum tuberosum cv. Erntestolz tubers at 2 or 8°C. In contrast to the rapid increase in sucrose and reducing sugars, the specific activity of FBPase showed no change and PFP rose slightly during storage at 2°C. Sugar concentrations and enzyme activities remained virtually unchanged during storage at 8°C. These data allow the interconversion of fructose 1.6-bisphosphate (Fru-1,6-P₂) to Fru-6-P and vice versa by FBPase and PFP, respectively, in potato tubers, but do not support a causal relationship between coarse metabolic control of FBPase and cold-induced sweetening.     

Effect of Quercus infectoria and Rosa damascena on lipid profile and atherosclerotic plaque formation in rabbit model of hyperlipidemia

Hyperlipidemia is the cause of many complications in the human societies. In this study, the effect of methanol extracts of Quercus infectoria (QI) galls and Rosa damascena (RD) Mill flower were studied on lipid profile and atherosclerotic plaques formation in hyperlipidemic rabbits. Thirty-six New Zeland white rabbits randomly divided into 6 groups as control (I), hyperlipidemic (II), hyperlipidemic+QI (III), hyperlipidemic+RD (IV), +Atorvastolin (V) and hyperlipidemic+Orlistat (VI) and were fed with high fat diet (0.5% cholesterol and 16% hydrogenated vegetable oil) for 45 days. At the end of the study period, lipid profile and plaque formation were assessed. Total Cholesterol (TC), Low Density Lipoprotein (LDL) and Triglyceride (TG) levels were significantly increased in hyperlipidemic group compared with control group (p < 0.001). Methanol extract consumption of Quercus infectoria significantly decreased plasma levels of TC, TG and LDL (p < 0.001). It also decreased plaques formation in semi lunar valve and thoracic aorta. Rosa damascena mill flower methanol extract moderately decreased the levels of TC, TG, LDL and plaques formation but it was not significant. HDL levels and weight of animals did not show significant difference among groups. Based on the doses used in this study, our finding indicated that QI but no RD methanol extract has anti atherogenic and hypolipidemic activities.     

Some observations on the toxic effects of the seed extract ofSphenostylis stenocarpa (Hochst ex A. Rich) Harms. on intestinal muscle

The effects of the water extract ofSphenostylis stenocarpa were observed on the guinea pig ileum and rabbit jejunum. The extract produced dose dependent — contractions of the guinea pig ileum with an ED₅₀ of 3.664×10^–5 g/ml and a calculated dose ratio of 1.25. The extract specifically stimulated muscarine receptors. Atropine (8×10^–7 g/ml) caused a parallel shift to the right of the log dose — response curve in the guinea pig ileum suggesting a competitive antagonism. Boiling for about 12 h did not affect the contractile action of the extract on tissue preparations. However, boiling for 12–14 h completely abolished its contractile effect. Incubation of the extract with cholinestrerase at 37°C for 1 h did not abolish its contractile action on the intestine.     

Effects of Two Energy-Restricted Diets Containing Different Fruit Amounts on Body Weight Loss and Macronutrient Oxidation

The consumption of specific foods in energy-restricted diets may affect the weight loss process. The purpose of this research was to evaluate whether obese women following two hypocaloric diets with distinct fruit content differ in weight loss and metabolic responses. Fifteen obese women were included, who were randomly assigned to follow a low or a high-fruit energy-restricted diet for 8 weeks. The main outcome variables were weight and fat losses. Metabolic measurements concerning macronutrient oxidation were also assessed by using ¹³C labelled fructose and indirect calorimetry. The induced weight loss was similar for both diets (6.9 ± 2% vs. 6.6 ± 2%, p = 0.785). Both experimental diets similarly improved the lipid plasma profile in the participants, but the cholesterol fall was higher in obese subjects receiving the diet containing more fruit. No statistical differences in lipids carbohydrates and ¹³C labelled fructose utilisation were observed, but protein oxidation was differently affected by the experimental diets. The compensatory effects of the associated fibre/fructose intake may explain the lack of a specific effect of the fruit amount on hypocaloric diets designed to weight loss, although the increased fibre content from enriched fruit diets may be involved in the favourable effects on cholesterol plasma levels.     

Heated Leaf Extract of Coriandrum sativum L. Protects Nigral Dopaminergic Degeneration in Rats

Coriandrum sativum L. (coriander), which is an annual herb of the Apiaceae family, has been traditionally used as a remedy. Here we tested whether heated extract of coriander leaf protects nigral dopaminergic neurodegeneration after exposure to 6-hydroxydopamine (6-OHDA). After injection of 6-OHDA into the rat substantia nigra pars compacta (SNpc), dopaminergic degeneration, which was determined by tyrosine hydroxylase immunostaining, was rescued by co-injection of CaEDTA, an extracellular Zn²⁺ chelator, suggesting that extracellular Zn²⁺ influx is involved in neurodegeneration. Both intracellular Zn²⁺ dysregulation determined by ZnAF-2 fluorescence and dopaminergic degeneration in the SNpc induced by 6-OHDA were rescued by co-injection of 0.25% coriander extract, which also reduced reactive oxygen species (ROS) production in the SNpc determined by aminophenyl fluorescein fluorescence. The present study suggests that coriander leaf extract protects nigral dopaminergic neurodegeneration induced by intracellular Zn²⁺ dysregulation. It is likely that the nutraceutical property of coriander leaf extract contributes to the protection via reducing ROS production.

     

Tissue-specific enhancement of xenobiotic detoxification enzymes in mice by dietary rosemary extract

Plant foods contain nutritive and minor, nonnutritive components capable of inhibiting experimental carcinogenesis. Many of these cancer-protective extracts act by enhancing the activities of enzymes that can detoxify reactive substances. In the present study an extract of the spice plant rosemary was fed at concentrations of 0.3% and 0.6% (by weight) for 4 weeks to female A/J mice prior to determination of the activities of the detoxification enzymes glutathione-S-transferase (GST) and NAD(P)H: quinone reductase (QR) in lung, liver and stomach. Liver activities of GST and QR, and stomach GST activity were significantly increased in animals fed diets containing rosemary extract. However, diets supplemented with rosemary extract did not affect lung GST and QR activities. These results indicate that components of rosemary extract have the potential to protect mouse liver and stomach from carcinogenic or toxic agents.     

Seaweed Supplements Normalise Metabolic,Cardiovascular and Liver Responses in High-Carbohydrate,High-Fat Fed Rats

Increased seaweed consumption may be linked to the lower incidence of metabolic syndrome in eastern Asia. This study investigated the responses to two tropical green seaweeds, Ulva ohnoi (UO) and Derbesia tenuissima (DT), in a rat model of human metabolic syndrome. Male Wistar rats (330–340 g) were fed either a corn starch-rich diet or a high-carbohydrate, high-fat diet with 25% fructose in drinking water, for 16 weeks. High-carbohydrate, high-fat diet-fed rats showed the signs of metabolic syndrome leading to abdominal obesity, cardiovascular remodelling and non-alcoholic fatty liver disease. Food was supplemented with 5% dried UO or DT for the final 8 weeks only. UO lowered total final body fat mass by 24%, systolic blood pressure by 29 mmHg, and improved glucose utilisation and insulin sensitivity. In contrast, DT did not change total body fat mass but decreased plasma triglycerides by 38% and total cholesterol by 17%. UO contained 18.1% soluble fibre as part of 40.9% total fibre, and increased magnesium, while DT contained 23.4% total fibre, essentially as insoluble fibre. UO was more effective in reducing metabolic syndrome than DT, possibly due to the increased intake of soluble fibre and magnesium.     

Mineral balances in humans as affected by fructose,high fructose corn syrup and sucrose

The utilization of selected minerals when sugars were supplemented to basal diets was investigated in two separate, laboratory-controlled human feeding studies. Fructose-fed subjects had higher fecal excretions of iron and magnesium than did subjects fed sucrose. Apparent iron, magnesium, calcium, and zinc balances tended to be less positive during the fructose feeding period as compared to balances during the sucrose feeding period. Conversely, high fructose corn syrup (HFCS) did not affect the mineral balances when compared to sucrose feeding. Subjects fed fructose experienced diarrhea which possibly decreased absorption of minerals and thus increased fecal mineral losses. No such adverse effects were noticed when HFCS was fed.     

Antinociceptive Activity of Stephanolepis hispidus Skin Aqueous Extract Depends Partly on Opioid System Activation

Stephanolepis hispidus is one of the most common filefish species in Brazil. Its skin is traditionally used as a complementary treatment for inflammatory disorders. However, there are very few studies on chemical and pharmacological properties using the skin of this fish. This study was undertaken in order to investigate the effect of aqueous crude extract of S. hispidus skin (SAE) in different nociception models. Here, we report that intraperitoneal administration of SAE inhibited the abdominal constrictions induced by acetic acid in mice. In addition to the effect seen in the abdominal constriction model, SAE was also able to inhibit the hyperalgesia induced by carrageenan and prostaglandin E2 (PGE2) in mice. This potent antinociceptive effect was observed in the hot plate model too, but not in tail-flick test. Naloxone, an opioid receptor antagonist, was able to block the antinociceptive effect of SAE in the abdominal constriction and hot plate models. In addition, SAE did not present cytotoxic or genotoxic effect in human peripheral blood cells. Our results suggest that aqueous crude extract from S. hispidus skin has antinociceptive activity in close relationship with the partial activation of opioid receptors in the nervous system. Moreover, aqueous crude extract from S. hispidus skin does not present toxicity and is therefore endowed with the potential for pharmacological control of pain.     

灌浆结实期高温对水稻籽粒蔗糖及降解酶活性的影响

选用水稻品种越光和笹锦为材料,在开花后设置自然温度和高温两种处理,研究了不同温度处理下籽粒蔗糖、果糖和葡萄糖含量的动态变化以及蔗糖合酶、液泡型转化酶和细胞壁结合型转化酶活性的差异。高温处理下,蔗糖合酶活性值大于转化酶活性值,且与淀粉积累速率呈显著正相关,表明蔗糖合酶在蔗糖的分解和淀粉的合成过程中起着重要作用;高温下两品种籽粒的蔗糖含量明显增加,但分解的葡萄糖和果糖含量并未相应增加,表明高温有利于籽粒中蔗糖的积累,而不利于籽粒中蔗糖的分解。高温下蔗糖合酶、液泡型转化酶和细胞壁结合型转化酶活性明显下降,表明蔗糖分解速率的下降与蔗糖合酶和转化酶活性下降有关。