CNS Depressant and Antinociceptive Effects of Different Fractions of Pandanus Foetidus Roxb. Leaf Extract in Mice.

BACKGROUND Various parts of Pandanus foetidus Roxb. are used as traditional medicines. However, scientific reports concerning the effect of this plant on central nervous system (CNS) depression and analgesia are unavailable. This study investigated the CNS depressant and antinociceptive effects of Pandanus foetidus leaf extracts in a rodent model. METHODS The sedative and anxiolytic activities of Pandanus foetidus extract (500 g) were tested using behavioural models of Swiss albino mice, and the analgesic activity was assessed by formalin-induced pain and tail immersion tests at 200 mg/kg body weight of the mice. The data were analysed by a one-way ANOVA, a repeated measure of ANOVA and a non-parametric test (Kruskal-Wallis test) using the SPSS software. Acute toxicity was tested using an established method. RESULTS Compared with the aqueous fraction, the methanol, petroleum ether and chloroform fractions of the extract exhibited a more significant (P < 0.001) reduction of locomotor activity in the mice in the open field, hole-cross, and elevated plus maze (EPM). The methanol fraction maximized the duration of sleeping time caused by the thiopental sodium induction. The extract produced a significant step-down in pain, as shown by the paw licking time in the early and late phases of the formalin test. In the tail immersion test, the chloroform fraction maximally reduced the heat-induced analgesia. The extract was found to be non toxic. CONCLUSION The methanol, petroleum ether, and chloroform fractions of P. foetidus have strong CNS depressant and antinociceptive effects and thus merit further pharmaceutical studies.