Genistein, the Isoflavone in Soybean, Causes Amyloid Beta Peptide Accumulation in Human Neuroblastoma Cell Line: Implications in Alzheimer's Disease.

The isoflavone, genistein, present in soybean is being actively investigated for its potential beneficial effect against Alzheimer's disease. Our data, however, show that in SHSY5Y cells genistein causes increased expression (mRNA and protein) of amyloid precursor protein (APP), increased mRNA expression and activity of β-secretase and diminished level of insulin degrading enzyme (IDE) which also degrades amyloid beta peptide. These effects of genistein lead to enhanced accumulation of amyloid beta peptide (Aβ42) in SHSY5Y cells. The results do not support the view that genistein could be a putative drug against AD and instead strengthen the epidemiological study which implies that genistein content of soybean food product (Tofu) leads to cognitive impairment.