Identification of myo-inositol hexakisphosphate (IP6) as a β-secretase 1 (BACE1) inhibitory molecule in rice grain extract and digest

•Rice grain extract and digest inhibited BACE1 activity in vitro.•Rice digest inhibited amyloid-β peptide (Aβ) production in cultured neuroblastoma cells.•Rice extract and digest contained IP6 and IP4.•IP6 but not IP3, IP4 or IP5 inhibited BACE1 activity in vitro.•IP6 inhibited production of Aβ and β-CTF in cultured neuroblastoma cells.

Alzheimer’s disease (AD) is widely considered to be caused by amyloid-β peptide (Aβ) accumulation in the brain. Aβ is excised from amyloid-β precursor protein through sequential cleavage by β-secretase 1 (BACE1) and γ-secretase. Thus, BACE1 inhibition could prevent Aβ accumulation. Here, we identified myo-inositol hexakisphosphate (IP6) as a BACE1 inhibitory molecule in rice grain extract and digest. The rice digest and IP6 significantly inhibited Aβ production in neuroblastoma cells without cytotoxicity. These results suggested that rice components, including IP6, may be promising starting materials for the development of potent and safe drugs and/or food to prevent AD.