Table 1.

Result of caspase-9 assay: Higher eukaryotic cell known to undergo caspase-dependent apoptosis has been taken as positive control. On the contrary, living Giardia cells have served as negative control. Giardia dead cells treated with oxidative stress-producing agents have also exhibited negative results

Sample	Spectrophotometric reading at 405 nm
Eukaryotic cells undergoing apoptosis (positive control)	0.516
Giardia lamblia living cells (negative control)	0.021
Giardia lamblia cells treated with H2O2	0.013
Giardia lamblia cells treated with metronidazole	0.018
Giardia lamblia cells treated with modified medium	0.023