Supercritical CO2 enzyme hydrolysis as a pretreatment for the release of isorhamnetin conjugates from Opuntia ficus-indica (L.) Mill

Abstract

Isorhamnetin conjugates from Opuntia ficus-indica (L.) Mill (nopal) were obtained using enzymatic hydrolysis pretreatment under supercritical carbon dioxide (SC-CO2) conditions. Factorial designs and discriminate analysis were used to evaluate the influence of pressure, temperature, pH, time and aqueous ethanol solution on the total extraction yield and the isorhamnetin recovery using the enzymes Rapidase Maxi Fruit (RMF) and Viscozyme. Isorhamnetin triglycosides [isorhamnetin-3-O-glucosyl-rhamnosyl-rhamnoside (IG1) and isorhamnetin-3-O-glucosyl-rhamnosyl-pentoside (IG2)] and a diglycoside [isorhamnetin-3-O-glucosyl-rhmanoside (IG5)] were found in the extracts. The isorhamnetin profile pattern was dependent on the enzyme and process conditions used. The extract containing higher amounts of IG5 was the most potent inhibitor of nitric oxide reducing its production by 71.6±4.8%. Selective extraction of IG5 was achieved using RMF enzyme and optimal conditions determined by a response surface methodology. The use of enzyme under SC-CO2 conditions affected the release of isorhamnetin conjugate profiles which induced remarkable differences in the anti-inflammatory activity.