Background: Glutathione transferases (GSTs) catalyze the conjugation of glutathione
(GSH) to endogenous and xenobiotic electrophilic compounds and have been involved in the development
of resistance toward cancer chemotherapeutic drugs and in the etiology, pathology and progression
of several other diseases. In the present work, the human isoenzyme GSTA1-1 (hGSTA1-1)
was used to assemble a microplate-based platform for high-throughput screening of natural productbased
inhibitors from plant extracts.
Methods: The enzyme was immobilized using sol-gel chemistry and deposited as a layer at the bottom
surface of 96-well format ELISA microplate. The sensing signal was based on the inhibition of the
colorimetric reaction between 1-chloro-dinitrobenzene (CDNB) and GSH, catalyzed by the sol-gel entrapped
Results: As a proof of concept, the system was used for screening aqueous extracts from medicinal and
aromatic plants with excellent reproducibility (approximately 95%).
Conclusion: The operational simplicity and accuracy of this system, suggest that it can be explored as
a bioanalytical tool with potential use in drug design and development efforts for finding new sources
of GST inhibitors useful in chemomodulation of cancer drugs.