**3.4 Antiplasmodial activity**

176 Toxicity and Drug Testing

obtained correspond with those with saline. However pethidine the reference agent

First phase (0-10 min) Second phase (15-60 min)

Time (min)

30 60

Time (min)

Fig. 3. Effect of aqueous extract of *V.amygdalina* leaves on thermal stimulus-induced tail-flick test in rats (NS, normal saline; Va, *V. Amygdalina*; PH, penthidine hydrochloride). All data are presented as means ± S.E.M., n=5. The asterisk (\*) denotes significance difference

\*

Fig. 2. Effect of aqueous extract of *V.amygdalina* leaves on formalin test in rats (NT, non treated animals; Va, *V. Amygdalina*; ASA acetyl salicilic acid). All data are presented as means ± S.E.M., n=5. The asterisk (\*) denotes significance (p<0.05) between treated group

> NS 10 ml/kg Va 50 mg/kg Va 100 mg/kg Va 200 mg/kg PH 50 mg/kg

> > \*

\* \*

\*

\*

\*

\*

markedly prolonged the tail-flick reaction time in rats (Fig 3)

 NT Va 50 mg/kg Va 100 mg/kg Va 200 mg/kg ASA 100 mg/kg

\* \*

0.0

0

1

2

3

4

Tail withdrawal time (s)

5

6

7

and NT control

(p<0.05).

0.5

1.0

1.5

Maximum pain score (Mean)

2.0

2.5

3.0

The extract caused a significant (P < 0.05) and dose-dependent reduction in mean parasitaemia in mice infected with Plasmodium berghei in comparison to CQ (5 mg/kg). The extract caused a parasitaemia reduction of 52% in 50 mg/kg, 64% and 73% in 100 and 200 mg/kg respectively (Table 2). One animal death was recorded in the 200 mg/kg extract groups throughout the 30 days observation period of the experiment while the remaining mice recovered fully. All mice in the saline group were lost within 15 days of the study.


Values are mean count S.E.M. (for n = 5)

\*Significantly (p<0.05) different from saline control group

N.S., Normal saline

Table 2. Curative activity of the aqueous extract of *V. amygdalina* and CQ against *Plasmodium berghei* in mice.
