Context: Shankhpushpi, a well-known drug in Ayurveda, is extensively used for different central nervous system (CNS) effects especially memory enhancement. Different plants are used under the name shankhpushpi in different regions of India, leading to an uncertainty regarding its true source. Plants commonly used under the name shankhpushpi are: Convolvulus pluricaulis Chois., Evolvulus alsinoides Linn., both from Convolvulaceae, and Clitoria ternatea Linn. (Leguminosae).
Objective: To find out the true source of shankhpushpi by evaluating and comparing memory-enhancing activity of the three above mentioned plants. Anxiolytic, antidepressant and CNS-depressant activities of these three plants were also compared and evaluated.
Materials and methods: The nootropic activity of the aqueous methanol extract of each plant was tested using elevated plus-maze (EPM) and step-down models. Anxiolytic, antidepressant and CNS-depressant studies were evaluated using EPM, Porsolt?s swim despair and actophotometer models, respectively.
Results: C. pluricaulis extract (CPE) at a dose of 100 mg/kg, p.o. showed maximum nootropic and anxiolytic activity (p < 0.001). E. alsinoides extract (EAE) and C. ternatea extract (CTE) showed maximum memory-enhancing and anxiolytic activity (p < 0.001) at 200 and 100?mg/kg, respectively. Amongst the three plants, EAE and CTE showed significant (p < 0.05), while CPE did not exhibit any antidepressant activity. All the three plants showed CNS-depressant action at higher dose levels.
Discussion and conclusions: The above results showed all the three plants possess nootropic, anxiolytic and CNS-depressant activity. The results of memory-enhancing activity suggest C. pluricaulis to be used as true source of shankhpushpi.