Optimizing Conditions for Enzymatic Extraction of Flavonoids from Lotus Leaves

This study aimed at determining the optimum hydrolysis conditions for the extraction of flavonoids from lotus leaves.Cellulase and pectinase were used in combination for one-step hydrolysis of lotus leaves and the solvent used was 70%.The effects of five extraction conditions including solid-to-solvent ratio,pH,enzyme dosage,temperature and hydrolysis time on extraction efficiency were investigated by one-factor-at-a-time method.The optimum solid-to-solvent ratio was found to be 1:20 g/mL.pH,enzyme dosage,temperature and hydrolysis time were optimized using a 16-run orthogonal array design to be 3.5,3.0 h,35 ℃,2800 U/g cellulase + 2000 U/g pectinase,respectively.Under the optimized conditions,the extraction yield of flavonoids was 3.74% compared with 1.59% for aqueous extraction technique as optimized also using a 16-run orthogonal array design(P0.01).Hence,we concluded that enzymatic hydrolysis provides a high-yield method for the extraction of flavonoids from lotus leaves.