Isolation of ACE2 inhibitors from rice bran oil by-product

Abstract

This study aimed to isolate γ-oryzanol from the crude oil acid fraction (a by-product of rice bran oil refinery) and to evaluate their Angiotensin-Converting Enzyme 2 (ACE2) inhibitory activity. Chromatographic fractionation of the crude oil acid fraction gave 3 isolated fractions of γ-oryzanol containing cycloartenyl ferulate, campesteryl ferulate, sitosteryl ferulate, stigmasteryl ferulate, and cyclobranyl ferulate. The γ-oryzanol containing cycloartenyl ferulate and campesteryl ferulate as major component showed good ACE2 inhibitory activity with the IC50 value 10.57 μg/mL. Furthermore, the 19 structures of γ-oryzanol were also studied for its interaction against ACE2 through molecular docking. Based on the in-silico study, ADME investigation, and toxicity prediction of cycloartenyl ferulate and campesteryl ferulate were potential to be developed as novel inhibitors for ACE2. This result demonstrated that the isolated γ-oryzanol from the crude oil acid fraction had the potential to be ACE2 inhibitor and its significant ACE2 inhibitory activity could serve as leads for the development of novel therapeutics targeting COVID-19.