A novel and simple colorimetric method for screening Giardia intestinalis and anti-giardial activity in vitro.
A new and simple colorimetric method has been developed for determining activity in vitro against Giardia intestinalis. The microtitre plate assay is based upon the nucleoside hydrolase activity released from G. intestinalis by lysis. Action of the nucleoside hydrolase on the substrate analogue, 4-nitrophenyl beta-D-ribofuranoside (NPR), gives rise to a coloured product which may be determined directly by the change in absorbance. A number of other such nucleoside analogues can be similarly used, but NPR is the preferred substrate, since it gives high enzymic activity at a relatively low substrate concentration. The IC50 values determined using this method for the known anti-giardials metronidazole, tinidazole and furazolidone were consistent with previously published values. The method is simple, does not involve radioisotopes or complex instrumentation, and thus provides a convenient method for screening potential anti-giardial agents.
School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, Australia.
E W
EW
Kang
K
K
Clinch
R H
RH
Furneaux
J E
JE
Harvey
P J
PJ
Schofield
A M
AM
Gero
D000818:Animals; D000994:Antitrichomonal Agents / Q000494:pharmacology / Q000627:therapeutic use; D002863:Chromogenic Compounds / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D005664:Furazolidone / Q000494:pharmacology / Q000627:therapeutic use; D016829:Giardia lamblia / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D005873:Giardiasis / Q000188:drug therapy*; D020128:Inhibitory Concentration 50; D008795:Metronidazole / Q000494:pharmacology / Q000627:therapeutic use; D009708:Nucleotidases / Q000737:chemistry*; D012263:Ribonucleosides / Q000737:chemistry; D012680:Sensitivity and Specificity; D014011:Tinidazole / Q000494:pharmacology / Q000627:therapeutic use
D000994:Antitrichomonal Agents; D002863:Chromogenic Compounds; D012263:Ribonucleosides; D014011:Tinidazole; D008795:Metronidazole; D005664:Furazolidone; D009708:Nucleotidases