Influence of type 2 diabetes on the inflammatory response in rats

Ae1/Sbe1 maize-derived high amylose improves gut barrier function and ameliorates type II diabetes in high-fat diet-fed mice by increasing Akkermansia

Type II diabetes mellitus (T2DM) has its origins in chronic inflammation due to immune dysregulation. Improving chronic inflammation can significantly reduce the probability of T2DM and the rate of disease progression. Resistance to starch 2 (RSII) high-amylose maize starch (HAMS) has been widely implicated in the improvement and regulation of T2DM. However, its exact molecular mechanisms have not been fully discovered. Here, we used CRISPR/Cas9 technology to knock out two starch-branching enzyme genes, Ae1 and Sbe1, in maize to obtain mutants containing higher levels of HAMS. In experiments in which HAMS was fed to mice on a high-fat diet (HFD), we confirmed the function of HAMS in ameliorating hyperglycemia. Mechanistically, we found that HAMS improves the gut barrier function by increasing the Akkermansia abundance in the gut. This increase led to the alleviation of chronic inflammation in mice on a HFD, resulting in improved insulin sensitivity and a decrease in blood glucose.

Attenuation of nociceptive and paclitaxel-induced neuropathic pain by targeting inflammatory, CGRP and substance P signaling using 3-Hydroxyflavone

Paclitaxel is an anti-microtubule agent, most widely used chemotherapeutic agent for the treatment of malignant solid tumors. However, it is associated with some severe side effects including painful neurotoxicity with reporting of neuropathic pain and sensory abnormalities by patients during and after paclitaxel therapy. Peripheral neuropathy was induced by the administration of paclitaxel (4 mg/kg on days 1, 3, 5, and 7). In this study, the anti-nociceptive and anti-inflammatory propensity of 3-Hydroxyflavone (3HF) in mice and the preventive effect of 3HF against paclitaxel-induced peripheral neuropathy in Sprague Dawley (SD) rats were investigated. Moreover, tactile and cold allodynia, thermal and tail immersion hyperalgesia, and effects on motor-coordination were also evaluated. Furthermore, the expression of proinflammatory cytokines i.e. Calcitonin gene-related peptide (CGRP), and Substance P from the spinal cord was examined through RT-PCR. Additionally, a computational structural biology approach was applied to search the potential therapeutic targets and to predict the binding mechanism of 3HF. Treatment of 3HF alleviated the nociceptive pain, paw edema, development of tactile and cold allodynia, and hyperalgesia. Similarly, treatment with 3HF suppressed the paclitaxel-induced increase in mRNA expression of several inflammatory cytokines including tumor necrosis factor -α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), CGRP, and Substance P. However, the daily treatment of 3HF did not affect the motor behaviors of rats. The inhibitory mechanism of 3HF in neuropathic pain is predicted with extensive computational bioinformatics approach which indicates that the 3HF effectively interacts with the binding domains of Nuclear factor-kappa B (NF-κB), CGRP receptor and the receptor of Substance P to exert its inhibitory activities. However, the computationally predicted binding affinities revealed that the potential of binding of the compound with Substance P receptor (Neurokinin 1 receptor) is higher than the other receptors; there NK1R could be the most possible binding target of 3HF. These findings indicate that 3HF has anti-nociceptive, anti-inflammatory, and anti-neuropathic pain effects against paclitaxel-induced neuropathic pain.

Myrciaria dubia Juice (camu-camu) Exhibits Analgesic and Antiedematogenic Activities in Mice

The Myrciaria dubia (Myrtaceae) fruit is traditionally used to treat malnutrition due to its high levels of vitamin C and phenolic compounds. Because of its composition, this plant is very promising in the research of novel natural treatment for pain disorders. This study analyzed the phytochemical profile of M. dubia juice and assessed its antinociceptive and antiedematogenic potential. The phytochemical profile was determined through high-performance liquid chromatography (HPLC), the oral antinociceptive effect of M. dubia 50% juice (Md50) was evaluated by formalin, hot plate and Complete Freund's Adjuvant tests and the antiedematogenic activity by paw edema. HPLC revealed the presence of ascorbic acid, rutin, and ellagic acid as major compounds. Md50 showed an antinociceptive effect in the acute and chronic phases of the formalin test. In the hot plate test, Md50 also induced an antinociceptive effect of 0.5 up to 6 h, showing antinociceptive and antiedematogenic potential without changing the spontaneous locomotion of animals. All protocols were submitted and approved by the Ethics Committee for use of Animals of the Lutheran University of Brazil (protocol No. 2013-30P).

Fermentation Products of Paenibacillus bovis sp. nov. BD3526 Alleviates the Symptoms of Type 2 Diabetes Mellitus in GK Rats

Gut microbiota is closely related to type 2 diabetes mellitus (T2DM). The gut microbiota of patients with T2DM is significantly different from that of healthy subjects in terms of bacterial composition and diversity. Here, we used the fermentation products of Paenibacillus bovis sp. nov. BD3526 to study the disease progression of T2DM in Goto-kakisaki (GK) rats. We found that the symptoms in GK rats fed the fermentation products of BD3526 were significantly improved. The 16S rRNA sequencing showed that the fermentation products of BD3526 had strong effects on the gut microbiota by increasing the content of Akkermansia. In addition, the interaction of the genus in the gut of the BD3526 group also significantly changed. Additional cytokine detection revealed that the fermentation products of BD3526 can reduce the inflammatory factors in the intestinal mucus of GK rats and thereby inhibit the inflammatory response and ameliorate the symptoms of T2DM.

Mild diabetes: long-term effects on gastric motility evaluated in rats

Moderate hyperglycaemic levels seem to be related to abnormal gastric motility in diabetes mellitus. However, experimental models designed to evaluate the relationship between motility and diabetes over time are not yet well established. Our objective was to investigate the long-term effects of mild diabetes on gastric motility in rats. Newborn male rats received streptozotocin (mild diabetes groups - MD) or vehicle (control groups - C), and both groups were evaluated after 3 (C3 and MD3) and 6 months (C6 and MD6) postinduction. Mild diabetic animals (MD3 and MD6) showed moderately elevated blood glucose and decreased insulin levels compared with control (C3 and C6). Insulin secretion was enhanced in MD6 compared with MD3, most likely due to partial β-cell regeneration indicated by HOMA-β. In HOMA-IR, it was noticed that MD6 animals had impaired insulin response compared with MD3. Gastric emptying was faster, amplitude of contraction was stronger in MD6 compared with MD3, and in both groups, the differences were significant when compared with control animals. A significant abnormal rhythmic index was calculated for the mild diabetic groups, despite unchanged mean frequency of contraction. In conclusion, despite increased insulin levels over time, constant levels of moderate hyperglycaemia are also related to abnormal gastric motility and impairment of gastric function.

Ficus hispida Bark Extract Prevents Nociception, Inflammation, and CNS Stimulation in Experimental Animal Model

Background. Ficus hispida is traditionally used in the ailment of pain, inflammation, and neurological disorders. The present study set out to evaluate the in vivo antinociceptive, anti-inflammatory, and sedative activity of the ethanol extract of Ficus hispida bark (EFHB). Methods. The antinociceptive activity of EFHB was evaluated by using acetic acid induced writhing, formalin, hot plate, and tail immersion methods in Swiss albino mice. Its anti-inflammatory activity was assessed by using carrageenan and histamine induced rat paw oedema test in Wister rats. The central stimulating activity was studied by using pentobarbital induced hypnosis, hole cross, and open field tests in Swiss albino mice. Results. EFHB demonstrated antinociceptive activity both centrally and peripherally. It showed 62.24% of writhing inhibition. It significantly inhibited licking responses in early (59.29%) and late phase (71.61%). It increased the reaction time to the thermal stimulus in both hot plate and tail immersion. It inhibited the inflammation to the extent of 59.49%. A substantial increase in duration of sleep up to 60.80 min and decrease of locomotion up to 21.70 at 400 mg/kg were also observed. Conclusion. We found significant dose dependent antinociceptive, anti-inflammatory, and sedative properties of EFHB in experimental animal models.

Anti-Inflammatory and Antioxidant Activity of Acalypha hispida Leaf and Analysis of its Major Bioactive Polyphenols by HPLC

PURPOSE

Inflammation and oxidative stress can lead to different chronic diseases including cancer and atherosclerosis. Many medicinal plants have the potential to show as anti-inflammatory activity. Present investigation was performed to investigate anti-inflammatory, antioxidant activity, and quantification of selected bioactive plant polyphenols of the ethanol (EAH) and aqueous (AAH) extracts of Acalypha hispida (Euphorbiaceae) leaves.

METHODS

Anti-inflammatory activity was evaluated by carragenan and histamine induced rat paw edema models while antioxidant capacity was evaluated by DPPH free radical scavenging, Fe+2 chelating ability, reducing power, NO scavenging, total phenolic and total flavonoid content assay. Identification and quantification of bioactive polyphenols was done by HPLC.

RESULTS

At the doses of 200 and 400 mg/kg, both EAH and AAH showed statistically significant inhibition of paw volume in the anti-inflammatory activity test. Both the extracts showed DPPH scavenging (IC50: 14 and 17 µg/ml, respectively), Fe+2 ion chelating (IC50: 40 and 46 µg/ml, respectively), NO scavenging activity (65.49 and 60.66% inhibition at 100 µg/ml), and concentration dependent reducing power ability. For EAH and AAH, flavonoid content was 126.30 and 149.72 mg QE/g dry extract, while phenolic content was 130.51 and 173.80 mg GAE/g dry extract, respectively. HPLC analysis of EAH and AAH indicated the presence of high content of ellagic acid along with other phenolic constituents.

CONCLUSION

High content of ellagic acid along with other phenolic constituents might have played an important role in the observed anti-inflammatory and antioxidant activity.

HPLC profiling, antioxidant and in vivo anti-inflammatory activity of the ethanol extract of Syzygium jambos available in Bangladesh

BACKGROUND

Syzygium jambos has been used as a traditional medicine for the treatment of inflammatory diseases in Bangladesh. The study investigates the high performance liquid chromatography (HPLC) profiling of phenolic compounds, and evaluates the antioxidant and anti-inflammatory activities of ethanol extract of S. jambos available in Bangladesh.

METHODS

The extract was subjected to HPLC for the identification and quantification of the major bioactive polyphenols present in S. jambos. Antioxidant activity was determined using 2, 2'-azino bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging, reducing power assay, total antioxidant capacity, total phenolic and flavonoid content. Furthermore, the anti-inflammatory effect of the extract in rats for two different test models: carrageenan and histamine-induced paw edema was inspected.

RESULTS

High levels of catechin hydrate and rutin hydrate (99.00 and 79.20 mg/100 g extract, respectively) and moderate amounts of ellagic acid and quercetin (59.40 and 69.30 mg/100 g extract, respectively) were quantified in HPLC. Catechin hydrate from this plant extract was determined for the first time through HPLC. For ABTS scavenging assay, the median inhibition concentration (IC50) value of S. jambos was 57.80 µg/ml, which was significant to that of ascorbic acid (12.01 µg/ml). The maximum absorbance for reducing power assay was found to be 0.4934. The total antioxidant capacity, phenolic and flavonoid contents were calculated to be 628.50 mg/g of ascorbic acid, 230.82 mg/g of gallic acid and 11.84 mg/g of quercetin equivalent, respectively. At a dose of 400 mg/kg, a significant acute anti-inflammatory activity (P < 0.01) was observed in rats for both the test models with a reduction in the paw volume of 58.04 and 53.95 %, in comparison to those of indomethacin (62.94 and 65.79 %), respectively.

CONCLUSIONS

The results suggest that the phenolic and flavonoid compounds are responsible for acute anti-inflammatory and antioxidant activities of S. jambos.

Hydroethanolic extract of Smallanthus sonchifolius leaves improves hyperglycemia of streptozotocin induced neonatal diabetic rats

OBJECTIVE

To evaluate the effect of hydroethanolic extract of yacon on the hyperglycemia induced by streptozotocin (STZ) in neonatal rats.

METHODS

Wistar rats aged two days old received an intraperitoneal injection of STZ (160 mg/kg); after seven weeks, glycosuria was determined and animals with glucose levels above 250 mg/dL were included in the study. Groups of diabetic and non-diabetic rats were treated orally with yacon extract at a dose of 400 mg/kg/d for 14 d. Tests were made for phytochemical characterization, glucose tolerance and toxicity.

RESULTS

The results showed that treatment with the extract reduced the glucose levels of fed diabetic rats and did not change the glucose levels of fasting diabetic and normal rats. Additionally, also it was observed that treatment with the extract reduced blood glucose levels of diabetic rats during the oral and intravenous glucose tolerance tests. There was no change in body weight, liver enzymes or mortality with yacon extract treatment. The phytochemical screening revealed the presence of caffeic acid, chlorogenic acid, ferulic acid and gallic acid.

CONCLUSIONS

The data suggest that yacon extract reduces hyperglycemia, possibly by improving insulin sensibility through its phytochemicals constituents (phenolic compounds).

Evaluation of anti-inflammatory activity of the methanolic extract from Jungia rugosa leaves in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Jungia rugosa Less (Asteraceae), popularly known in Ecuador as "Carne humana" or "Fompo", is a vine present into the Andean region. It is traditionally used as medicine for the treatment of bruises, cuts and other external inflammatory processes. This study was designed to investigate the anti-inflammatory activity of J. rugosa leaves extract (JRLE) in rodents.

MATERIAL AND METHODS

The acute anti-inflammatory activity was evaluated by animal models, including croton oil-induced ear oedema in mice, carrageenan-induced paw oedema in rats and myeloperoxidase (MPO); the chronic anti-inflammatory activity was evaluated by cotton pellet-induced granuloma.

RESULTS

Intraperitoneal administration of JRLE (125, 250, 500mg/kg) significantly (p<0.01-0.001) inhibited the croton oil-induced ear oedema and MPO activity in mice; the carrageenan-induced paw oedema in rats was significantly (p<0.05) reduced by 500mg/kg. Repeated (6 days) administration of the extract to mice previously implanted with cotton pellets reduced the formed granuloma (125mg/kg: 11.7%; 250mg/kg: 17.9%; 500mg/kg: 32.4%) but only the inhibition by 500mg/kg reached statistical significance (p<0.01).

CONCLUSIONS

The results show that JRLE is effective as an anti-inflammatory agent in acute and chronic inflammation in mice, supporting its traditional use.

Cyane-carvone, a synthetic derivative of carvone, inhibits inflammatory response by reducing cytokine production and oxidative stress and shows antinociceptive effect in mice

Cyane-carvone (CC) was studied to elucidate its anti-inflammatory, antinociceptive, and antioxidant effects in Mus musculus. Anti-inflammatory (bradykinin, histamine, prostaglandin E2, serotonin, and carrageenan) and antinociceptive (acetic acid and formalin) models were utilized. Myeloperoxidase activity, interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), and glutathione (GSH) levels were evaluated. Analysis of variance followed by Student-Newman-Keuls' test was done. Results were compared with control groups (significantly when p < 0.05). In bradykinin, histamine, prostaglandin E2, and serotonin tests, 75 mg/kg CC decreased significantly paw edema (t = 30, 60, 90, and/or 120 min). In carrageenan test, 50 and 75 mg/kg CC (t = 3 h and t = 4 h) and 25 mg/kg CC (t = 4 h) decreased significantly paw edema. CC (75 mg/kg) inhibited significantly mieloperoxidase activity and decreased IL-1β and TNF-α, and all doses increased GSH levels. CC (75 mg/kg) decreased significantly the number of contortions of animals and time of licking (phase 2). CC showed anti-inflammatory, antinociceptive, and antioxidant effects in mice.

Anti-inflammatory and antinociceptive activities of the aqueous leaf extract of Phyllanthus amarus Schum (Euphorbiaceae) in some laboratory animals

BACKGROUND

Phyllanthus amarus has a history of use in Ayurvedic medicine for over 2000 years as well as a wide variety of traditional applications and has gained popularity in many continents as a herbal remedy; hence, it is being assessed for its safety potential and anti-inflammatory and analgesic properties in some laboratory animals.

METHODS

Standard phytochemical methods were used to test for the presence of phytoactive compounds in the plant. Acute toxicity testing was carried out in mice to determine safe doses for the extract. The anti-inflammatory activity of the leaf extract of this plant was assessed using carrageenan-induced and histamine-induced paw edema. The analgesic effect was determined using the acetic acid writhing method as well as formalin test.

RESULTS

The extract at 100 and 200 mg/kg body weight reduced significantly, the formation of edema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by reduction in the number of writhes when compared to the control. The extract caused dose-dependent decrease of licking time in rats injected with 2.5% formalin, signifying its analgesic effect. These results were also comparable to those of ibuprofen, the reference drug used in this study.

CONCLUSIONS

The plant extract reduced significantly the formation of edema induced by carrageenan and histamine as well as reducing the number of writhes in acetic acid-induced writhing models and dose-dependent decrease of licking time in rats injected with 2.5% formalin. The results have validated the basis for the traditional use of P. amarus as a medicinal plant.

Comparative Evaluation of Anti-Inflammatory Activity of Curcuminoids, Turmerones, and Aqueous Extract of Curcuma longa

Curcuma longa is widely known for its anti-inflammatory activity in traditional system of medicine for centuries and has been scientifically validated extensively. The present study was conducted to evaluate the anti-inflammatory activity of curcuminoids and oil-free aqueous extract (COFAE) of C. longa and compare it with that of curcuminoids and turmerones (volatile oil), the bioactive components of C. longa that are proven for the anti-inflammatory potential. The activity against inflammation was evaluated in xylene-induced ear edema, cotton pellet granuloma models in albino Swiss mice and albino Wistar rats, respectively. The results showed that COFAE of C. longa at three dose levels significantly (P ≤ 0.05) inhibited inflammation in both models, as evidenced by reduction in ear weight and decrease in wet as well as dry weights of cotton pellets, when compared to the vehicle control. The COFAE of C. longa showed considerable anti-inflammatory effects against acute and chronic inflammation and the effects were comparable to those of curcuminoids and turmerones.

Suppressions of serotonin-induced increased vascular permeability and leukocyte infiltration by Bixa orellana leaf extract

The aim of the present study was to evaluate the anti-inflammatory activities of aqueous extract of Bixa orellana (AEBO) leaves and its possible mechanisms in animal models. The anti-inflammatory activity of the extract was evaluated using serotonin-induced rat paw edema, increased peritoneal vascular permeability, and leukocyte infiltrations in an air-pouch model. Nitric oxide (NO), indicated by the sum of nitrites and nitrates, and vascular growth endothelial growth factor (VEGF) were measured in paw tissues of rats to determine their involvement in the regulation of increased permeability. Pretreatments with AEBO (50 and 150 mg kg⁻¹) prior to serotonin inductions resulted in maximum inhibitions of 56.2% of paw volume, 45.7% of Evans blue dye leakage in the peritoneal vascular permeability model, and 83.9% of leukocyte infiltration in the air-pouch model. 57.2% maximum inhibition of NO and 27% of VEGF formations in rats' paws were observed with AEBO at the dose of 150 mg kg⁻¹. Pharmacological screening of the extract showed significant (P < 0.05) anti-inflammatory activity, indicated by the suppressions of increased vascular permeability and leukocyte infiltration. The inhibitions of these inflammatory events are probably mediated via inhibition of NO and VEGF formation and release.

Analgesic and anti-inflammatory studies of cyclopeptide alkaloid fraction of leaves of Ziziyphus nummularia

Ziziyphus nummularia (family: Rhamnaceae) is a thorny small bush, grows in abundance in the grazing lands of the arid areas of Rajasthan, India. It is an important ethnomedicinal plant of the Thar Desert; local inhabitants use every part of the plant as medicine. Kernels are prescribed in pregnancy as soporific, antiemetic and for relieving abdominal pain. The insect gall is powered and given orally with water to cure bone fracture. Crushed root is applied on the paining shoulder of the bullock. The decoction of leaves is used for the treatment of cough and cold; leaves are also regarded as diaphoretic and prescribed in typhoid. Paste of leaves is used for healing of cuts, boils and cutaneous disease. It is widely used in pain and inflammatory conditions. Z. nummularia contains a unique group of alkaloids known as cyclopeptide alkaloids, in continuation of our work carried out on the leaves of Z. nummularia , present study was initiated to explore antiinflammatory and analgesic potential of cyclopeptide alkaloids isolated from the leaves of Z. nummularia (IFZN). Anti-inflammatory activity was tested against rat paw oedema, mouse peritonitis and cotton pellet granuloma. For screening of analgesic activity, acetic acid induced writhing, tail flick and hot plate test were performed. IFZN 30 mg/kg shows the anti-oedematogenic effect against paw oedema induced by carrageenan, dextran, serotonin and histamine; IFZN 20 and 30 mg/kg were found to have highly significant anti-nociceptive effects. Result of pharmacological studies indicated that IFZN is a potent and efficacious analgesic agent. The analgesic activity of IFZN is mediated by the peripheral as well as central pathways.

Anti-inflammatory and antioxidant activities of ethanolic extract of aerial parts of Vernonia patula (Dryand.) Merr

OBJECTIVE

To investigate the inflammatory and antioxidant activities of ethanolic extract of aerial part of Vernonia patula (Dryand.) Merr (EAV).

METHODS

The anti-inflammatory activity of EAV was studied using carrageenan and histamine-induced rat paw edema test at different doses (100, 200 and 400 mg/kg body weight). DPPH free radical scavenging, nitric oxide scavenging, reducing power and Fe(2+) ion chelating ability were used for determining antioxidant activities.

RESULTS

The EAV, at the dose of 400 mg/kg, showed a significant anti-inflammatory activity (P<0.01) both in the carrageenan and histamine-induced oedema test models in rats, showing 62.86% and 64.42% reduction in the paw volume comparable to that produced by the standard drug indomethacin (67.26% and 66.01%) at 5 h respectively. In DPPH free radical scavenging test, IC50 value for EAV was found fairly significant 36.59 μg/mL when compared to the IC50 value of the reference standards ascorbic acid 8.97 μg/mL. The IC50 values of the extract and ascorbic acid were 47.72 and 12.39 μg/mL, respectively in nitric oxide scavenging assay. The IC50 value of the EAV (33.59 μg/mL) as percentage of Fe(2+) ion chelating ability was also found significant compared to that of EDTA (9.16 μg/mL). The maximum absorbance for reducing power assay was found to be 1.928 at 100 μg/mL when compared to 2.449 for standard ascorbic acid. The total phenolic content was 198.81 mg/g of gallic acid equivalent. Acute toxicity test showed that the plant might be safe for pharmacological uses up to a dose level of 3 200 mg/kg of body weight in rats.

CONCLUSIONS

Therefore, the obtained results suggest the acute anti-inflammatory and antioxidant activities of the EAV and thus provide the scientific basis for the traditional uses of this plant part as a remedy for inflammations.

Anti-inflammatory, antinociceptive and antipyretic properties of the aqueous extract of Clematis brachiata leaf in male rats

Clematis brachiata Thunb. (Ranunculaceae) is used as a folk remedy for the treatment of pain, fever and inflammatory ailments. Aqueous extract of Clematis brachiata leaf was screened for its phytochemical constituents. The anti-inflammatory investigations were carried out using carrageenan and histamine-induced edema models; acetic acid writhing, formalin-induced pain and tail immersion models were used to evaluate antinociceptive activity while a Brewer's yeast-induced hyperthermia model was employed for the antipyretic experiment. Phytochemical screening of the extract revealed the presence of tannins, saponins, flavonoids and cardiac glycosides. The extract at 100, 200 and 400 mg/kg body weight significantly (P<0.05) reduced the edema paw volumes induced by carrageenan and histamine with the 400 mg/kg body weight extract being the most potent. On the antinociceptive front, while the extract reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose dependent manner, the increase in the reaction time by the extract in the tail immersion model was not dose-dependent. Again, there was significant (P<0.05) lowering of the Brewer's yeast-provoked elevated body temperature. The results suggest that the aqueous extract of Clematis brachiata leaves can be employed in the management of inflammation, pain and fever. These activities may be due in part to the flavonoid content of the extract.

The influence of improved glycaemic control with chlorpropamide on microvascular reactivity and nitric oxide synthase activity in diabetic rats

Hyperglycaemia is a primary cause of vascular complications in diabetes. A hallmark of these vascular complications is endothelial cell dysfunction, which is partly due to reduced production of nitric oxide. The aim of this study was to verify the influence of improved glycaemic control with chlorpropamide on microvascular reactivity, endothelial nitric oxide synthase (e-NOS) expression, and NOS activity in neonatal streptozotocin-induced diabetic rats (n-STZ). Diabetes was induced by STZ injection into neonates Wistar rats. n-STZ diabetic rats were treated with chlorpropamide (200 mg kg−1, 15 days, by gavage). The changes in mesenteric arteriolar and venular diameters were determined in anaesthetized control and n-STZ diabetic rats, before and after topical application of acetylcholine, bradykinin and sodium nitroprusside (SNP). We also assessed e-NOS expression (using polymerase chain reaction after reverse transcription of mRNAs into cDNAs) and NOS activity (conversion of L-arginine to citrulline) in the mesenteric vascular bed of chlorpropamide-treated n-STZ, vehicle-treated n-STZ, and control rats. In n-STZ, chlorpropamide treatment reduced high glycaemic levels, improved glucose tolerance and homoeostatic model assessment (HOMA-beta), and restored NOS activity. Impaired vasodilator responses of arterioles and venules to acetylcholine, bradykinin and SNP were partially corrected by chlorpropamide treatment in n-STZ. We concluded that improved metabolic control and restored NOS activity might be collaborating with improved microvascular reactivity found in chlorpropamide-treated n-STZ.

Anti-inflammatory and analgesic activities of the aqueous extract of Acacia karroo stem bark in experimental animals

The aqueous extract of the stem bark of Acacia karroo Hayne was investigated for its anti-inflammatory and analgesic activities in animal models. The extract at 100 and 200 mg/kg reduced significantly the formation of oedema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by a significant reduction in the number of writhes with two doses (100 and 200 mg/kg) used when compared to the untreated control group. In the tail immersion test, the extract at the doses used (100 and 200 mg/kg) increased reaction time to pain after 30 min. of oral administration of the extract. Indomethacin at 10 mg/kg served as reference drug in all these tests. The results gave a scientific basis to the traditional uses of Acacia karroo mainly for wound poultices, eye treatments and cold remedies.

Antinociceptive and anti-inflammatory effects of Thespesia populnea bark extract

The ethanolic extract of Thespesia populnea bark (TPE) was investigated for anti-inflammatory and analgesic activity at the doses (p.o.) of 100, 200 and 400mg/kg body weight. For evaluation of inflammation carrageenan-, histamine- and serotonin-induced paw edema served as acute models and formaldehyde-induced arthritis served as a chronic model in rats. The acetic acid-induced writhing response and formalin-induced paw licking time in the early and late phases of mice were used to assess analgesic activity. The higher doses of TPE (200 and 400mg/kg, p.o.) were inhibiting carrageenan, histamine and serotonin-induced paw edema as well as formaldehyde-induced arthritis successfully. In addition, TPE (200 and 400mg/kg, p.o.) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and late phase of pain response induced by an subplantar injection of formalin in mice. Furthermore, our phytochemical studies indicated that the ethanolic extract of bark contains alkaloids, carbohydrates, protein, tannins, phenols, flavonoids, gums and mucilage, saponins and terpenes. From acute oral toxicity studies (OECD-423 guidelines), no mortality was observed even at highest dose of TPE (2000mg/kg, p.o.).

Metformin treatment restores the altered microvascular reactivity in neonatal streptozotocin-induced diabetic rats increasing NOS activity, but not NOS expression

Abnormalities in vascular function are well recognized in diabetes. Hyperglycemia may be central to the pathogenesis of vascular dysfunction but is not certain whether improvements in glycaemic control will improve vascular function. The effects of metformin, an antidiabetic agent that improves insulin sensitivity and glycaemic control, on the microvascular reactivity have not been reported in neonatal streptozotocin-induced (n-STZ) diabetes. Diabetes was induced by STZ injection (160 mg/kg, ip) in neonates (2-day-old) Wistar rats. n-STZ diabetic rats were treated with metformin (300 mg/kg, 15 d, by gavage). Using intravital microscopy the changes in mesenteric arteriolar and venular diameters were determined in anesthetized control and n-STZ diabetic rats, before and after topical application of endothelium-dependent vasodilator agents, mediators or not of the inflammatory response, and endothelium-independent vasodilator agent. We also determined the total nitric oxide synthase (NOS) activity (conversion of L-arginine to citrulline) and endothelial(e), inducible(i), and neuronal(n) NOS expression (using polymerase chain reaction after reverse transcription of the mRNAs into cDNAs) in the mesentery of metformin-treated n-STZ diabetic and vehicle-treated n-STZ diabetic and control rats. Although metformin treatment did not correct the high glycaemic levels and the impaired glucose tolerance, the reduced vasodilator responses and total NOS activity in n-STZ diabetic rats were corrected by the treatment. Neither diabetes nor metformin treatment altered the expression of the three NOS isoforms. We concluded that metformin restores the reduced response to vasodilator agents, independently of the correction of the metabolic alterations. Improvement of total NOS activity might be in part responsible for the correction.

Anti-inflammatory, analgesic and antipyretic effects of methanol extract from Bauhinia racemosa stem bark in animal models

In this study, the anti-inflammatory, analgesic, and antipyretic effects of 50, 100 and 200 mg/kg body weight of methanol extract obtained from Bauhinia racemosa stem bark, the so-called MEBR, were investigated. The effects of MEBR on the acute and chronic phases of inflammation were studied in carrageenan, dextran and mediators (histamine and serotonin)-induced paw oedema and cotton pellet-induced granuloma, respectively. Analgesic effect of MEBR was evaluated in acetic acid-induced writhing and hotplate tests. Antipyretic activity of MEBR was evaluated by yeast-induced hyperpyrexia in rats. The anti-oedema effect of MEBR was compared with 10 mg/kg of indomethacin orally. In acute phase of inflammation, a maximum inhibition of 44.9, 43.2, 44.8 and 45.9% (P<0.001) was noted at the dose of 200 mg/kg b.w. after 3h of treatment with MEBR in carrageenan, dextran, histamine and serotonin-induced paw oedema, respectively. Administration of MEBR (200 mg/kg b.w.) and indomethacin (10 mg/kg b.w.) significantly (P<0.05) decreased the formation of granuloma tissue induced by cotton pellet method at a rate of 50.4 and 56.2%, respectively. The extract also inhibited peritoneal leukocyte migration in mice. The MEBR also produced significant (P<0.01) analgesic activity in both models. Further, the MEBR potentiated the morphine- and aspirin-induced analgesic in mice. Treatment with MEBR showed a significant (P<0.01) dose-dependent reduction in pyrexia in rats. The results suggest that MEBR possess potent anti-inflammatory, analgesic and antipyretic activity.

Anti-inflammatory and antinociceptive properties of dantrolene sodium in rats and mice

Our study aimed at examining the possible anti-inflammatory and antinociceptive effects of dantrolene sodium in rats and mice. The anti-inflammatory effect of dantrolene sodium (2.5, 5 and 10 mg kg (-1)) was investigated and compared with diclofenac sodium (5 mg kg (-1)) using the formalin-, histamine-, and carrageenan-induced paw oedema and cotton pellet granuloma tests. Analgesic effects of dantrolene sodium were evaluated and compared with metamizol (200 mg kg (-1)) in acetic acid-induced writhing and formalin-induced paw licking tests. It was found that dantrolene sodium significantly diminished the nociceptive response in mice, showing at the same time considerable anti-inflammatory properties in rats.