Central Nervous System Activity of Rhazya Stricta (Decne) in Mice

Abstract

1. The effects of orally administered aqueous lyophilized extract of the leaves of Rhazya stricta (2, 4 & 8 g/kg) on aspects of nervous system function were investigated in mice. 2. In three antinociceptive tests (hot plate, abdominal constriction, and warm water tail flick tests), the extract exhibited dose-dependent and significant antinociceptive activity. Naloxone was ineffective in antagonizing the analgesic effect of Rhazya stricta on tail-flick and abdominal constriction tests, possibly indicating that this effect occurs via non-opiate pathways. 3.Pretreatment of mice with the xenobiotic metabolizing enzymes inhibitor cimetidine (50 mg/kg) did not significantly alter the antinociceptive action of the extract, indicating that the effect is probably due to the parent compound(s) present in the extract and not to metabolites thereof. 4. Rhazya stricta produce dose-dependent sedation, decreased motor activity, and impaired motor control. Time spent on a rotarod treadmill was significantly decreased after treatment with the extract. 5. Rhazya stricta extract (8 g/kg) produced a degree of sedation comparable to that produced by diazepam (5-10 mg/kg), and also significantly increased the reaction time of the tail-flick test, an action which was not produced by diazepam. 6. Administration of R. stricta extract potentiated pentobarbitone sleeping time in a dose dependent manner. The extract did not significantly antagonize picrotoxin induced convulsions. The extract (4 and 8 g/kg) significantly decreased the rectal temperature of normothermic and hyperthermic mice. 7. Pretreatment with R. stricta extract (8 g/kg) completely prevented the occurrence of aggressive behaviour in male mice. 8. It is concluded that the crude extract of R. stricta has central nervous system depressant properties.

Phytochemical, pharmacological and ethnobotanical studies of Rhazya stricta Decne.

“…stricta has exhibited the following properties in rodents: antidepressant (Ali et al, 1995), sedative , no significant effect on inhibitory and stimulatory amino acids in brain regions (Ali et al, 2000b), reduction in concentration of adrenaline , reduction in blood pressure (Tanira et al, 2000), immunomodulating (Tanira et al, 1998), antispasmodic (Tanira et al, 1996b), ameliorating gentamicin nephrotoxicity (Ali, 2002), increased hepatic and cerebral activity of monoamine oxidase (Ali et al, 2000b) and hepatoprotective actions (Ali et al, 2001). The coadministration of the extract with oral hypoglycemic drugs adversely interferes with glycemic control in diabetes (Ali et al, 2000a).…”

“…The active ingredients in the extract responsible for this interaction are not yet known (Ali et al, 2000a). Oral doses of various concentrations of R. stricta leaf extracts expressed antidepressant and sedative properties in mice (Ali et al, 1995 and. This may be due to the presence of two different components in the leaves of R. stricta that affect tribulin activity in opposite directions (Ali et al, 2000a).…”

Nootropic, anxiolytic and CNS-depressant studies on different plant sources ofshankhpushpi

“…The remaining activities were evaluated by using single dose of the vehicle, standard drugs and different test extracts administered orally, 45 min before the test. Diazepam, at doses of 2 and 10 mg/ kg (Ali et al, 1995;Shri et al, 2010), was used as standard anxiolytic and CNS-depressant, respectively. Imipramine (12.5 mg/kg, p.o.)…”

Evaluation of sedative and anticonvulsant activities of Unmadnashak Ghrita

“…The analgesic activity showed by UG in tail flick test may be attributed to increase in the central inhibitory neurotransmitter GABA, since GABA is known to induce antinociception. (Ali et al, 1995). It seems probable that the UG did not act through peripheral neuromuscular blockage, but rather it evoked its action through centrally located mechanism centrally and thus acts as a CNS-depressant (Capasso et al, 1996).…”