A study conducted by researchers at Bay Pines VA Healthcare System and the University of South Florida found that Cotinine, a compound derived from tobacco,

As part of the study, young mice were genetically altered to suffer memory problems akin to Alzheimer’s disease. Cotinine was administered regularly for five months.
During the end of the study period, findings revealed that mice which received cotinine performed better at tasks involving their working memory and thinking skills as compared to mice which did not receive cotinine.
Long-term cotinine treatment caused a 26% reduction in deposits of amyloid plaques, which is an indicator of Alzheimer’s disease. Cotinine also activated the signaling factor Akt, which helps neurons survive, thus improving memory.
Source-Medindia