Effects of Byrsocarpus coccineus (Connaraceae) extract on the central nervous system (CNS)

Abstract

In establishing the pharmacological profile of Byrsocarpus coccineus, we investigated the CNS effects of the aqueous leaf extract using the Y-maze, hexobarbitone sleeping time and hole board models in mice. In the Y-maze test, Byrsocarpus coccineus, BC (50–100mg/kg, p.o.) produced significant (P<0.05) increases in the time spent in the open arm at post-treatment times of 30–90min. Peak effect was elicited at 100mg/kg 30min post-treatment, with mice spending 2.63±0.21min in the open arm vs. 0.62±0.21min for control. This effect was significantly higher than that of diazepam, 1mg/kg p.o. (2.00±0.20min). At doses of 200 and 400mg/kg, the effect of BC in increasing the time spent in the open arm diminished with the effect at the higher dose (1.24±0.29min) being not significantly different from the control. In the hexobarbitone sleeping time test, BC (50–100mg/kg) increased the onset and decreased the duration of sleep, with effects only being significant at 100mg/kg (onset=7.00±1.18min and duration=10.00±1.84min vs. onset=3.43±0.81min and duration=20.71±2.34min for control). At doses of 200 and 400mg/kg, BC decreased onset and significantly increased sleeping time with the effect at the higher dose (onset=3.29±0.61min and duration=39.86±3.78min) being significantly lower than that of diazepam, 3mg/kg p.o., in respect of duration of sleep only (onset=3.14±0.26min and duration=87.29±9.87min). In the modified hole board experiment, BC (50–100mg/kg) caused an increase in both exploratory activity and locomotion, while at 200 and 400mg/kg the reverse was the case. These effects were not significant. Diazepam, 1mg/kg p.o., caused a non-significant increase in exploratory activity and a significant increase in locomotion (25.71±4.44 sectional crossings in 5min vs. 10.86±2.30 sectional crossings in 5min for control). Results obtained suggest that the aqueous leaf extract of Byrsocarpus coccineus possess a dose determined anxiolytic – sedative activity with no effect on exploratory activity and locomotion.