Determination of Flavonoids in Magnolia officinalis Leaves Based on Response Surface Optimization of Infrared Assisted Extraction Followed by High-Performance Liquid Chromatography (HPLC)

Abstract

A simple and economical method for the rapid extraction and measurement of rutin, isoquercitrin, and quercitrin in Magnolia officinalis leaves was developed using response surface methodology with determination by high performance liquid chromatography (HPLC). By the use of Box-Behnken response surface optimization of infrared-assisted extraction (IRAE), the optimized conditions of flavonoids were as follows: extraction time of 11 min, ethanol concentration of 53% (v/v), liquid–solid ratio of 40:1, and extraction power of 60 W. The yields of flavonoids by the IRAE protocol were higher by 7.12 and 10.59% than using heating reflux extraction (HRE) and ultrasound-assisted extraction (UAE), respectively. In addition, the extraction period of flavonoids by the IRAE method was approximately 1/3 and 1/9 of the time intervals required employing HRE and UAE, respectively. IRAE method was verified by HPLC and successfully applied for analysis of ten samples collected from different geographical areas. The relative standard deviation values of the precision and accuracy were favorable for analytical applications, with values from 0.21 to 2.33% and 0.50 to 1.96%, respectively. The recovery results were achieved at a 95% confidence level. The study shows that the IRAE method coupled with HPLC is a simple, cost-effective and reliable tool for the routine determination of flavonoids in M. officinalis leaves for quality control applications.