Table 2.

Fish disinfestation time of leeches at different concentrations of methanol extract of N. biserrata.

No.	Group	Disinfestation time (min) Mean ± S.D	Disinfestation (%)
1	Normal control	–	–
2	Negative control	720.00 ± 0.00	0
3	Positive control (formalin 0.1%) (v/v)	26.33 ± 1.52a	100
4	N. biserrata (2.5 mg/ml)	108.33 ± 12.65a,b	100
5	N. biserrata (5 mg/ml)	65.83 ± 9.70a,b,c	100
6	N. biserrata (10 mg/ml)	29.16 ± 5.85a,c,d	100

Each value represents mean ± S.D of 6 fishes per group.

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

^bSignificance at p < 0.05 compared with the formalin treated group (0.1%) (v/v).

^cSignificance at p < 0.05 compared with N. biserrata (2.5 mg/ml).

^dSignificance at p < 0.05 compared with N. biserrata (5.0 mg/ml).