This is a critical study and points the way forward to the effective treatment of Alzheimer's disease.

Memory and learning and neurodegenration both pivot on one receptor: NMDA.  In the absence of oxidative stress, NMDA receptor activation leads to neuronal plasticity and the regeneration of neurons via the phosphatidylinositol 3-kinase/Akt pathway, but in the presence of oxidative stress, NMDA receptor activation leads to peroxynitrites which in turn leads to the double DNA strand breakage, the activation of PARP (to try to repair that damage), the cleavage of PARP by caspases, the depletion of energy from neurons, and the death of neurons.

Peroxynitrite scavengers are the key to inhibiting this cascade.  Several of these scavengers--eugenol in rosemary essential oil and geraniol in lemon essential oil via aromatherapy and ferulic acid, syrinigic acid, p-coumaric acid, vanillin, and maltol in panax ginseng have already partially reversed Alzheimer's disease in human clinical trials.

onlinelibrary.wiley.com/.../abstract

www.ncbi.nlm.nih.gov/pmc/articles/PMC3659550/