2.2. Pharmacological studies
2.2.1. Antitumor activity (cytotoxic activity)
A preliminary screening for cytotoxic activity towards Ehrlich ascities carcinoma using a set
of sterile test tubes; where 2.5 ×105 tumor cells /ml were suspended in phosphate buffer saline. 25, 50,
100 µg /ml of the extract were added to the suspension, kept at 37º C for 4 hrs. Trypan blue dye
exclusion test was carried out to calculate the percentage of non viable cells [11].
2.2.2. Determination of Median Lethal Dose (LD50)
LD50 of the alcoholic extract (70%) of Pteranthus dichotomus was determined [12]. Albino
mice (25-30 g) were divided into groups each of 5 animals. Preliminary experiments were done to
determine the minimal dose that kills all mice and the maximal dose that fails to kill any animal.
Animals were kept under observation for 24 h during which symptoms of toxicity and rate of
mortality were recorded.
2.2.3. Anti-inflammatory Activity
Anti-inflammatory effect of the alcoholic extract (70%) of Pteranthus dichotomus was studied
[13]. 20 rats were divided into 4 equal groups. The thickness of the left hind paw of each rat was
measured in mm. 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. The 3rd and 4th groups were orally administered the
tested extracts in doses of 50 and 100 mg/kg b.wt, respectively. After 30 min of extracts
administration, inflammation was induced by subcutaneous injection of 0.1 ml of 6% formalin in
normal saline into the left hind paw. The paw thickness was measured hourly for a period of 4 h. and
the magnitude of the paw swelling in the treated animals compared with that of the control.