Antinociceptive, anti-inflammatory and antipyretic effects of Solanum nigrum chloroform extract in animal models

AIM: The present study was carried out to evaluate the antinociceptive, anti-inflammatory and antipyretic effects of chloroform extract of Solanum nigrum leaves using various animal models. METHODS: The extract was prepared by soaking (1:20; w/v) the air-dried powdered leaves (20 g) in chloroform for 72 hrs followed by evaporation (40 degrees C) under reduced pressure to dryness (1.26 g) and then dissolved (1:50; w/v) in dimethylsulfoxide (DMSO). The supernatant, considered as the stock solution with dose of 200 mg/kg, was diluted using DMSO to 20 and 100 mg/kg, and all doses were administered (s.c.; 10 ml/kg) in mice/rats 30 min prior to tests. RESULTS: The extract exhibited significant (p<0.05) antinociceptive activity when assessed using the abdominal constriction, hot plate and formalin tests. The extract also produced significant (p<0.05) anti-inflammatory and antipyretic activities when assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests. Overall, the activities occurred in a dose-independent manner. CONCLUSION: The present study demonstrated that the lipid-soluble extract of S. nigrum leaves possessed antinociceptive, anti-inflammatory and anti-pyretic properties and confirmed the traditional claims.     

Antinociceptive,anti-inflammatory,and antipyretic properties of an aqueous extract of <Emphasis Type="Italic">Dicranopteris linearis</Emphasis> leaves in experimental animal models

This study was performed out to establish the antinociceptive, anti-inflammatory, and antipyretic properties of an aqueous extract of Dicranopteris linearis leaves in experimental animals. The antinociceptive activity was measured using the abdominal constriction, hot plate, and formalin tests. The anti-inflammatory and antipyretic activities were measured using the carrageenan-induced paw edema and brewer’s yeast-induced pyrexia tests, respectively. The extract, obtained after 72 h soaking of the air-dried leaves in distilled water and then prepared in the doses of 13.2, 66.0, 132.0, and 660.0 mg/kg, was administered subcutaneously 30 min before subjecting the animals to the assays mentioned above. Generally, the extract, at all doses used, was found to have significant (P < 0.05) concentration-independent antinociceptive, anti-inflammatory, and anti-pyretic activity. In conclusion, the aqueous extract of D. linearis has antinociceptive, anti-inflammatory, and antipyretic activity, supporting previous claims of its traditional use by the Malays to treat various ailments, particularly fever.     

Error monitoring and empathy: Explorations within a neurophysiological context

Past literature has proposed that empathy consists of two components: cognitive and affective empathy. Error monitoring mechanisms indexed by the error‐related negativity (ERN) have been associated with empathy. Studies have found that a larger ERN is associated with higher levels of empathy. We aimed to expand upon previous work by investigating how error monitoring relates to the independent theoretical domains of cognitive and affective empathy. Study 1 (N = 24) explored the relationship between error monitoring mechanisms and subcomponents of empathy using the Questionnaire of Cognitive and Affective Empathy and found no relationship. Study 2 (N = 38) explored the relationship between the error monitoring mechanisms and overall empathy. Contrary to past findings, there was no evidence to support a relationship between error monitoring mechanisms and scores on empathy measures. A subsequent meta‐analysis (Study 3, N = 125) summarizing the relationship across previously published studies together with the two studies reported in the current paper indicated that overall there was no significant association between ERN and empathy and that there was significant heterogeneity across studies. Future investigations exploring the potential variables that may moderate these relationships are discussed.     

Asiaticoside Inhibits TNF‐α‐Induced Endothelial Hyperpermeability of Human Aortic Endothelial Cells

The increase in endothelial permeability often promotes edema formation in various pathological conditions. Tumor necrosis factor‐alpha (TNF‐α), a pro‐atherogenic cytokine, impairs endothelial barrier function and causes endothelial dysfunction in early stage of atherosclerosis. Asiaticoside, one of the triterpenoids derived from Centella asiatica, is known to possess antiinflammatory activity. In order to examine the role of asiaticoside in preserving the endothelial barrier, we assessed its effects on endothelial hyperpermeability and disruption of actin filaments evoked by TNF‐α in human aortic endothelial cells (HAEC). TNF‐α caused an increase in endothelial permeability to fluorescein isothiocyanate (FITC)‐dextran. Asiaticoside pretreatment significantly suppressed TNF‐α‐induced increased permeability. Asiaticoside also prevented TNF‐α‐induced actin redistribution by suppressing stress fiber formation. However, the increased F to G actin ratio stimulated by TNF‐α was not changed by asiaticoside. Cytochalasin D, an actin depolymerizing agent, was used to correlate the anti‐hyperpermeability effect of asiaticoside with actin cytoskeleton. Surprisingly, asiaticoside failed to prevent cytochalasin D‐induced increased permeability. These results suggest that asiaticoside protects against the disruption of endothelial barrier and actin rearrangement triggered by TNF‐α without a significant change in total actin pool. However, asiaticoside seems to work by other mechanisms to maintain the integrity of endothelial barrier rather than stabilizing the F‐actin organization. Copyright © 2015 John Wiley & Sons, Ltd.     

Mechanism(s) of action involved in the gastroprotective activity of Muntingia calabura

Ethnopharmacological relevance

Muntingia calabura L. (Muntingiaceae) is locally known as kerukup siam. Its leaves, flowers, barks and roots have been used traditionally in East Asia and South America to treat various diseases including ulcer-related diseases. The present study aimed to investigate the mechanism(s) of gastroprotective effect of methanol extract of Muntingia calabura leaves (MEMC) using the pylorus ligation induced gastric ulceration in rats.

Materials and methods

Five groups of rats (n=6) were administered orally once daily for 7 days with 8% Tween 80 (negative control), 100 mg/kg ranitidine (positive control), or MEMC (100, 250 or 500 mg/kg), followed by the ulcer induction via ligation of the pyloric part of the rat’s stomach. This was followed by the macroscopic analysis of the stomach, evaluation of gastric content parameters, and quantification of mucus content. The antioxidant (measured using the superoxide anion and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging, oxygen radical absorbance capacity (ORAC) and total phenolic content (TPC) assays), anti-inflammatory (evaluated using the in vitro lipoxygenase and xanthine oxidase assays), phytoconstituents and HPLC analysis of MEMC were also carried out.

Results

The MEMC significantly (p<0.05) reduced gastric lesion in this model. Furthermore, the extract also significantly (p<0.01) reduced the volume of gastric content whereas the total acidity was significantly (p<0.05) reduced in the doses of 100 and 500 mg/kg MEMC. Moreover, the mucus content increased significantly (p<0.01) in MEMC-treated rats. The extract also showed high antioxidant and anti-inflammatory activities in all assays tested, and demonstrated the presence of high tannins and saponins followed by flavonoids.

Conclusion

The MEMC exerted gastroprotective effect via several mechanisms including the anti-secretory, antioxidant and anti-inflammatory activities. These activities could be attributed to the presence of tannins, saponins and flavonoids (e.g. rutin, quercitrin, fisetin and dihydroquercetin).     

Gastroprotective activity of chloroform extract of Muntingia calabura and Melastoma malabathricum leaves

Context: Muntingia calabura L. (family Muntingiaceae) and Melastoma malabathricum L. (family Melastomaceae) are traditionally used to treat gastric ulcer.

Objective: The present study determines the mechanisms of gastroprotective activity of the chloroform extract of leaves obtained from both the plants using several in vitro and in vivo assays.

Materials and methods: Phytochemical screening, HPLC analysis, and antioxidant activity of the respective extract were carried out. Gastroprotective activity was determined using ethanol-induced gastric ulcer assay while the mechanisms of gastroprotection were determined using the pyloric ligation assay. The test solutions [8% Tween-80 (vehicle), 20?mg/kg omeprazole, and different doses of extracts (50, 250, or 500?mg/kg] were administered orally once daily for 7 consecutive days before the animals were subjected to ethanol induced gastric ulcers.

Results: The chloroform-extracted M. calabura (CEMC) contains tannins, polyphenolics, triterpenes, and steroids while the chloroform-extracted M. malabathricum (CEMM) contains only triterpenes and steroids. CEMC, but not CEMM, exerted remarkably strong antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH)- (86% versus 16%) and superoxide- (73% versus 36%) radical scavenging assays. Both extracts demonstrated significant (p?<?0.05) gastroprotection with the EC₅₀ value recorded at 192.3 or 297.7?mg/kg, respectively. In the pylorus ligation assay, CEMC and CEMM significantly (p?<?0.05) reduced the total and free acidity and volume; while increased the pH of gastric juice as well as the gastric wall mucus content in comparison with the vehicle-treated group.

Discussion and conclusion: CEMC and CEMM exert gastroprotective effects in animals with ethanol-induced gastric ulcers via antioxidant and anti-secretory effects.     

Antinociceptive activity of methanolic extract of Acmella uliginosa (Sw.) Cass

Ethnopharmacological relevance

Acmella uliginosa (Sw.) Cass. is a medicinal herbaceous plant that is commonly used by the Malay community in Malaysia to relieve pain often associated with mouth ulcers, toothache, sore throat, and stomach ache.

Aim

The study was carried out to investigate the antinociceptive effect of the methanolic extract of A. uliginosa (Sw.) Cass. flowers (MEAU) using murine models of chemicals and thermal nociception.

Materials and methods

Chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-induced paw licking test) and thermal models (hot plate test) of nociception in mice were employed to evaluate the MEAU analgesic effect. The extract was given via oral administration at doses of 3, 10, 30 and 100 mg/kg.

Results

It was demonstrated that MEAU produced significant antinociceptive response in all the chemical- and thermal-induced nociception models, which indicates the presence of both centrally and peripherally mediated activities. Furthermore, the reversal of antinociception of MEAU by naloxone suggests the involvement of opioid system in its centrally mediated analgesic activity. Moreover, MEAU-treated mice did not show any significant motor performance alterations. No mortality and signs of toxicity were recorded following treatment of the MEAU.

Conclusion

The results from the present study appear to support the folkloric belief in the medicinal properties of A. uliginosa (Sw.) Cass. which against pain at both central and peripheral levels, in which the central antinociception is probably due to the participation of the opioid receptors.