Purpose: To assess the central nervous system (CNS) depressant, analgesic and antidiarrheal
activities of the dried seed crude extracts of
Dimocarpus longan
Lour in rodents.
Methods: Selected pharmacological effects of the ethanol (ENLS), petroleum ether (PELS), chloroform
(CHLS) and ethyl acetate (EALS) extracts of D. longan fruit seeds were investigated. CNS depressant
activity was evaluated by open field and hole cross tests; analgesic activity by acetic acid-induced
writhing test and formalin-induced licking test; and anti-diarrheal activity was assessed in castor oil and
magnesium-induced diarrhea rat model. The extracts were given orally in a rat model at doses of 200
and 300 mg/kg body weight. Normal saline served as control in all experiment. In CNS depressant test,
diazepam (1 mg/kg) was used as reference drug while indomethacin (10 mg/kg) and loperamide(2
mg/kg) were used as standard drugs in analgesic and antidiarrheal tests, respectively.
Results: In hole cross method, EALS showed the most effective depressant effect, viz, 1.17±0.17 for
200 mg/kg dose and 0.83±0.31 number of movements for 300 mg/kg dose after 120 min (p < 0.01),
whereas in the open field test, all the extracts exhibited significant (p < 0.01) depressant effect in
relation to positive control, diazepam. In acetic acid-induced pain test, PELS gave the lowest number of
writhing (2.83±0.307) and the highest inhibition (88.45 %, 300 mg/kg dose) which was statistically
significant. All the extracts also significantly (p < 0.01) suppressed licking activity in both phases of the
formalin-induced licking test, in contrast to indomethacin. In the antidiarrheal tests, diarrheal
suppression was highest at 300 mg/kg dose for all the extracts, compared with loperamide in both
castor oil and magnesium sulphate induced diarrhea model.
Conclusion: The extracts of
Dimocarpus longan tested demonstrated significant CNS depressant,
analgesic and antidiarrheal activities in a rodent model.
