Menthacarin treatment attenuates nociception in models of visceral hypersensitivity.

BACKGROUND: Chronic visceral hypersensitivity is closely associated with irritable bowel syndrome (IBS), a very common disorder which significantly impairs quality of life, characterized by abdominal pain, and distension. Imaging studies have found that IBS patients show higher metabolic activities and functional differences from normal controls in the anterior cingulate cortex (ACC), in response to visceral pain stimulation. Non-clinical data and clinical data suggest that medicinal products containing essential oils such as peppermint or caraway oil exert beneficial effects on IBS symptoms. METHODS: We assessed acute and long-term treatment effects of a mixture of peppermint and caraway essential oils (Menthacarin) on brain electrophysiological markers of gut pain sensitivity in two rat models of visceral hypersensitivity. KEY RESULTS: Chronic administration of corticosteroids and acute repeated mechanical hyperstimulation under anesthesia induced hyperalgesia and hypersensitivity, characterized by an increase in electrophysiological excitatory responses of ACC neurons to colorectal distension (CRD) and an increase in the proportion of neurons responding to otherwise subthreshold stimulation, respectively. Long-term, but not acute, oral administration of Menthacarin (60 mg kg-1 day-1) significantly reduced the net excitatory response to CRD in normally responsive control animals and counteracted the development of visceral hyperalgesia and hypersensitivity induced by repeated corticosterone administration and acute mechanical stimulation. CONCLUSIONS & INFERENCES: The present study shows that, using the CRD method, chronic Menthacarin administration at a clinically relevant dose attenuates the neuronal discharge associated with visceral pain stimuli in the rat ACC, particularly in models of hypersensitivity, suggesting a potential for treating exaggerated visceral pain sensitivity.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents.

OBJECTIVES: Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study. METHODS: Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods. RESULTS: The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible. CONCLUSIONS: The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.

Datura stramonium abrogates depression- and anxiety-like disorders in mice: possible involvement of monoaminergic pathways in its antidepressant activity.

OBJECTIVES: Ethno-botanical surveys uncovered the use of Datura stramonium in the management of mental health abnormalities. Antidepressant- and anxiolytic-like activities of hydroethanol leaf extract of D. stramonium (HLDS) in mice and its possible mechanism of action were investigated in this study. METHODS: The hole-board test (HBT), open field test (OFT), elevated plus maze test (EPMT), and social interaction test (SIT) were used to investigate the anxiolytic-like activity while forced swim test (FST) and tail suspension test (TST) were employed for the antidepressant effect. Mice were pre-treated orally with purified water (10 mL/kg), bromazepam (1 mg/kg), fluoxetine (20 mg/kg) and D. stramonium (25, 50, 100 and 200 mg/kg). One hour post-treatment, mice were subjected to the various tests. RESULTS: In HBT, D. stramonium increased the head dips and sectional crossings turnover. D. stramonium increased the number of square crossed and rearings/assisted rearings in OFT. DS increased the time spent in open arms of EPM. In SIT, D. stramonium increased the frequency/duration of interactions. In FST and TST, D. stramonium decreased the duration of immobility which were reversed by doxazosin (α1 adrenoceptor antagonist) and ondasentron (5-HT3 receptor antagonist). CONCLUSIONS: HLDS has anxiolytic- and antidepressant-like activities through modulation of serotoninergic and adrenergic neurotransmissions.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents.

OBJECTIVES: Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study. METHODS: Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods. RESULTS: The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible. CONCLUSIONS: The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.