Honikiol has shown activity that provides cognitive enhancement as well as protection.
Already in 2002 researchers demonstrated that Honokiol promotes neurite outgrowth and has neuroprotective effects in rat cortical neurons. Cortical neurons are the cells of the brain’s largest region, the two hemispheres of the cerebral cortex. Most of the complex activity of the brain enabling thought, perception, and voluntary movement is connected to the activity of these neurons. The study shows promotion of neurite growth in cortical neurons cultured in a serum-free medium (albeit supplemented with B27). In addition, the survival and growth of neurons were significantly enhanced by adding honokiol to the primary cultures in serum-free medium (this time supplemented with N2). Positively a similar outcome was found in this study of 2009 which showed neurite outgrowth effect of honokiol by induction of neurotrophic factors through ERK activation.
In 2014 this extensive paper was published, in it the researchers reviewed the various neuro-modulating effects of Honokiol and summarized what is known regarding the mechanisms involved. The researchers indicated that because of its ability to cross the blood brain barrier honokiol can exert its anti-tumorigenic effects in the central nervous system. It might be assumed that because of its accessibility to neuronal tissue, honokiol has direct beneficial effects on cellular health as opposed to neuroprotection via promotion of alternate pathways. Interestingly, honokiol appeared to exert its neuroprotective effects through a wide range of mechanisms as shown in the picture from the paper (above this article).
Finally in this study researchers investigated whether the ethanol extract of Magnolia officinalis prevents memory dysfunction and amyloidogenesis in an Alzheimer Disease mouse model by LPS injection. It was found that the extract indeed prevented LPS-induced memory deficiency as well as inhibited the LPS-induced elevation of inflammatory proteins and activation of astrocytes and microglia. In particular, the extract inhibited LPS-induced amyloidogenesis, which resulted in the inhibition of amyloid precursor proteins. This suggests the extract might be a useful intervention for neuroinflammation-associated diseases such as Alzheimer’s Disease.
In summary Honokiol appears to have several potential roles as a therapeutic for neurologists ranging from preserving and protecting healthy neurons, preventing deleterious results from neuroinflammation-associated diseases and possibly promote neurite outgrowth.