Table 1.

Mortality time of the leeches at different concentrations of methanol extract of N. biserrata.

No.	Group	Mortality time (min) Mean ± S. D	Mortality (%)
1	Normal control	720.00 ± 00	0
2	Positive control (formalin 0.25%) (v/v)	3.68 ± 0.46a	100
3	N. biserrata (25 mg/ml)	25.11 ± 3.26a,b	100
4	N. biserrata (50 mg/ml)	11.91 ± 0.99a,b,c	100
5	N. biserrata (100 mg/ml)	4.88 ± 0.50a,c,d	100

Each value represents the mean ± S.D of 6 parasitic leeches per group.

^aSignificance at p < 0.05 compared with the normal control group.

^bSignificance at p < 0.05 compared with the formalin treated group (0.25% v/v).

^cSignificance at p < 0.05 compared with N. biserrata (25 mg/ml).

^dSignificance at p < 0.05 compared with N. biserrata (50 mg/ml).