F. Ugwu et al., A COMPARATIVE-STUDY ON THE PHOTOCYTOTOXICITY OF HYPERICIN ON A431 CELLS USING 3 DIFFERENT ASSAYS, Anticancer research, 18(2A), 1998, pp. 1181-1184
Background: Three assay models were adopted for assessing the photocyt
otoxicity of hypericin on A431 cells. The cells were incubated for 1 h
our of 24 hours with hypericin to evaluate the importance of the incub
ation period on the exerted photocytotoxicity. Materials and Methods:
A neutral red, an antiproliferative and a tetrazolium-reduction (MTT)
assay, were wed for the estimation of cytotoxicity. Results: IC50 valu
es were 296, 321 and > 500 nM after 1 hour; and to 70, 54 and 277 nM a
fter 24 hours, for the neutral red, antiproliferative and MTT assays,
respectively. Conclusions: Our results clearly show that it is imperat
ive to incubate cells for long periods to fully assess the hypericin p
hotocytotoxicity, and that the neutral red assay is as sensitive as th
e antiproliferative assay but superior to the MTT assay at detecting h
ypericin cell damage.