Scope: Amyloid-beta peptide is the main component of senile plaques in Alzheimer's disease. The inhibition of amyloid-beta peptide assembly, the destabilization of amyloid-beta peptide aggregates, and the decrease of its cytotoxicity for the prevention of neuronal death are considered neuroprotective effects. In this work, the protective effects against amyloid-beta peptide aggregation and cytotoxicity of eight indolic compounds are evaluated: tryptophan, tryptamine, serotonin, tryptophol, N-acetylserotonin, 3-indoleacetic acid, tryptophan ethyl ester, and melatonin. [br/] Methods and results: Thioflavin T spectroscopic assay, transmission electron microscopy, western blotting, circular dichroism, NMR, cell viability (thiazolyl blue tetrazolium bromide assay), quantitative PCR, and heme oxygenase activity are used. Serotonin is the most effective compound for inhibiting amyloid-beta peptide aggregation. Almost all the indolic compounds tested prevent amyloid-beta peptide-induced and increase cell viability, being between 9 and 25%. Melatonin and serotonin are the most active. Moreover, serotonin increased the expression of SIRT-1 and 2, heat shock protein 70, and heme oxygenase activity, this being a possible mechanism underlying the observed neuroprotective effect. [br/] Conclusion: Melatonin and other related indolic compounds, mainly serotonin, show an inhibitory and destabilizing effect on amyloid-beta peptide fibril formation and they possess neuroprotective properties related to the vitagenes system.Read less <