Efficient Extraction and Isolation of Mangiferin from Mango Leaves by Ethyl Acetate Impurity Removal Method

[Objectives] To optimize the ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves, and provide raw materials and technical support for development and use of mangiferin related products. [Methods] Five steps (material crushing → ethyl acetate impurity removing → concentrated extract washing → extracting with methanol → crystallization and precipitation) were used. The single factor experiment and L9(34) orthogonal experiment was carried out to optimize the process parameters including extraction time, ultrasonic power, extraction times, and extraction temperature. [Results] The optimum process of ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves was as follows: the mango leaves were crushed and sieved; 3 mL/g of ethyl acetate was added, sealed and soaked for 4 h, ultrasonically shaken for 20 min (50℃, 350 W), filtered at room temperature, filtered with 100 mesh sieve, and extracted three times; added 100% methanol to the residue at 3 mL/g, extract by ultrasonic vibration for 20 min (350 W, 55℃) for four times, filtered with 100 mesh sieve when it was still hot; mixed the extract of each time, condensed by vacuum decompression to get the extract; added 100% methanol at 4 mL/g, mixed and washed for 5 min at room temperature, placed for 10 min, filtered with 100 mesh sieve, washed 3 times repeatedly, and dried the filter residue at 60℃ to obtain the crude mangiferin; added 100% methanol at 4 mL/g, mixed and washed at 50℃ for 5 min, placed at 6℃ for 8 h, dried the filter residue at 60℃, and repeatedly crystallized two times. According to the above process, crude and pure mangiferin products could be obtained, the purity of mangiferin of the crude product was higher than 64.00%, the total recovery rate was 83.90%, and the purity of mangiferin of the pure product was higher than 98.00%, and the total recovery rate was about 66.40%. [Conclusions] The optimized ethyl acetate impurity removal method is easy in operation, low in cost, and high in efficiency for extracting and isolating mangiferin, and can be applied for actual production of mangiferin.