Isolation of anxiolytic principle from ethanolic root extract of Cardiospermum halicacabum

Cardiospermum halicacabum roots have been used traditionally for the treatment of epilepsy and anxiety disorders. The purpose of this study was to characterize the putative phytoconstituents present in the ethanolic root extract having anxiolytic activity using an elevated plus-maze (EPM) and light dark transition model. Control mice were orally treated with an equal volume of vehicle (4% gum acacia), and positive control mice were treated with diazepam (1 mg/kg). In the EPM test, out of pool of 19 master fractions (MF) only MF-14, 16 and 17 significantly (30 mg/kg, p < 0.05, p < 0.01 and p < 0.001) increased the number of entries in the open arm. MF-14, 16 and 17 (10, 20 and 30 mg/kg) had also increased the time spent by mice in illuminated part of the box significantly (p < 0.05, p < 0.01 and p < 0.001), as compared to control. However, significant changes (p < 0.05, p < 0.01 and p < 0.001) were recorded in other parameters, e.g., rearing, time spent in the closed arm and dark zone in both the models. These results suggested that C. halicacabum root is an effective anxiolytic agent. The phytoconstituent responsible for the observed central effects was isolated from MF-14 and identified as well-known compound, Cardiospermin, a cyanogenic glucoside.