Induction of Phase II Enzymes Glutathione-S-Transferase and NADPH: Quinone Oxydoreductase 1 with Novel Sulforaphane Derivatives in Human Keratinocytes: Evaluation of the Intracellular GSH Level

Phase II enzymes including NADPH: Quinone Oxydoreductase 1 (NQO1) and Glutathione-S-Transferase (GST) represents a major and natural cellular protection system against deleterious environmental factors which cause skin damages. Sulforaphane is one of the most popular isothiocyanates found in cruciferous vegetables and known for its cytoprotective effects by inducing Phase II enzymes. Five novel sulforaphane derivatives were synthetized and tested for their activity on NQO1 and GST induction as well as for their effect on total GSH intracellular level using colorimetric assays on human keratinocytes cell line (HaCat). As sulforaphane and the synthetized components showed variable toxicity after their evaluation by means of in vitro cytotoxicity (MTT test), cells were treated at a concentration of 5 μM during 48 hours. The results showed that the addition products of sulforaphane decreased cytotoxity but none of those derivatives had a better effect than referenced sulforaphane on Phase II enzymes. It seems that the isothiacyanate function remains important for the sulforaphane activity.