2.2.4. Antipyretic Activity
Antipyretic effect of the alcoholic extract (70%) of Pteranthus dichotomus and the new
compound was studied [14]. 20 rats of both sexes weighing 150-180 gm were divided into 5 equal
groups. Hyperthermia was induced by subcutaneous injection of Brewer's yeast in physiological saline
solution in a dose of 150 mg/g b.wt. After 17 h, the elevated body temperature of each rat was rectally
measured. The 1st group was used as a control, the 2nd one was subcutaneously injected with
paracetamol (100 mg/kg b.wt.), while the remaining groups were orally given the tested extract in
doses of 50 and 100 mg/kg b.wt and the isolated compound. Rectal temperature of each rat was then
recorded for 4 h at 1 h interval. The antipyretic effect was determined on the basis of the difference in
the mean temperature between the control and the tested extracts.
2.2.5. Analgesic Activity
Analgesic effect of the tested extract was evaluated using the writhing method [15]. 20 mice
of both sexes weighing 25-30 gm were divided into 4 equal groups. The 1st group was kept as a
control while the 2nd was subcutaneously injected with diclofenac sodium in a dose of 5 mg/kg b.wt.
Other groups were orally given the tested extract in doses of 50 and 100 mg/kg b.wt. After 30 min,
each mouse was intraperitonealy injected with 0.25 ml of p-benzoquinone aqueous solution (0.1 mg/
ml). Thereafter, mice in all groups were observed for writhing hourly for 4 h. animals devoid of
writhing in each group were counted and the analgesic potency of the tested extract was determined as
% protection against writhing.
No. of animals that didn't writhe
% Protection = -------------------------------------------*100
Original no. of animals