I've been trying to evaluate the citoprotective potential of lyophilized ayahuasca against hydrogen peroxide induced damage in SH-SY5Y cells, but I can't find a positive control for the citoprotection assays. I've tested ayahuasca for citotoxicity with a 24h incubation protocol and chose a nontoxic concentration range for the citoprotection assays. I've also tested various concentrations of H2O2 in order to choose one taht yields 60% viability after 24h incubation. The first citoprotection assays showed no protection at all, but they had no positive control.

Now, I have been trying for months to find a positive control for the assays, but to no avail. After searching the literature I tried rutin, quercetin, melatonin and vitamin E. The protocol requires co-treatment for 24h. So far none of these compounds have worked and I haven't been able to replicate any of the results I've found. I'm starting to think that the problem is the treatment protocol. Should change it? Maybe try to pre-incubate the cells for a couple hours with the compounds before adding the H2O2 and also let the treatment last less than 24h?