To pharmacologically investigate the methanol and petroleum ether extracts of the plant
leaves of Manilkara zapota
(MZME and MZPE, respectively), Abroma augusta
(AAME and AAPE,
respectively) and Vitex negundo
(VNME and VNPE, respectively).
Analgesic and anti-diarrheal activities were assessed by acetic acid-induced writhing and
castor oil-induced diarrhea in mice, respectively, while CNS depressant activity was evaluated using
hole-cross and open-field method by observing the decrease in exploratory behavior and spontaneous
motor activity in mice, respectively.
All the extracts exhibited good analgesic activity at a dose of 200 mg/kg with the following rank
order of activity: MZME > MZPE > VNME > VNPE > AAME > AAPE. Analgesic activity was insignificant
at 100 mg/kg dose except for VNPE (67.81 % inhibition). The extracts produced significant reduction in
diarrheal episodes in mice at a dose of 400 mg/kg MZPE (highest protection: 80.3 %, p < 0.05) and
VNME (lowest protection: 38.6 %, p < 0.001). The extracts demonstrated CNS depressant activity in a
dose-dependent manner (p < 0.05 compared to the standard except for AAME and AAPE which
showed insignificant activity).
The results indicate that the traditional use of the investigated plants appears to be
justified; however, further studies are required to unravel the underlying mechanisms of action.