Extraction and Analysis Methods for Ursolic Acid from Loquat Leaf

Through the comparison of extraction solvent, solvent dosage, extraction period, extraction times, it can be concluded that the optimal extraction process of ultrasonic extraction of ursolic acid from the loquat leaf is as follows: methanol is selected as the solvent, the required amount of solvent is 30 times the weight of the raw material, the extraction time is 40min, and the extraction times are 2 times.

The content of ursolic acid in loquat leaf was determined by high performance liquid chromatography (HPLC). The optimum chromatographic condition was Lichrospher Cl8 (250mmx4.6mm,5um) column. Methanol-water-phosphoric acid (90:10:0.05) is the mobile phase. Flow rate: 0.8mL/min; Column temperature: room temperature; Detection wavelength: 215nm. Under these conditions, the extraction rate of ursolic acid was the highest and the content of ursolic acid in loquat leaf was 0.79%. This experimental method has simple operation process, low time cost, good reproducibility and high extraction rate, which provides certain data support for making full use of loquat leaf plant resources, and can effectively control the quality of loquat leaf medicinal materials.

With mobile phase of Methanol-water-phosphoric acid (90∶10∶0.05), the retention time of ursolic acid was about 18min, the baseline of the graph was stable, and there was no peak shape trailing. In the mobile phase, the additive we choose phosphoric acid, which is used to create a weakly acidic environment, which is conducive to the separation of ursolic acid and the effect of improving the peak shape.

Preparation of standard solution: weigh 2mg ursolic acid, put the weighed ursolic acid in the volumetric flask, the volumetric flask was selected as 10mL, add methanol to the volumetric flask, and dilute the solution to the lowest concave surface of the solution line, shake evenly, ursolic acid concentration of 0.2 mg/mL solution prepared, filter and ready for use.

Sample content calculation method:

A precision instrument was used to take 20mL from the standard solution and 20mL from the sample solution and put them into the sample bottle. The ursolic acid peak areas of the two were measured respectively and recorded. The recorded data were substituted into the following formula to calculate the ursolic acid content.

Ursolic acid content %= (AX/AR*CR*S*0.000001)/w*100%

Formula:

AX is the peak area of the sample;

CR is the concentration of the reference solution;

AR was the peak area of the control substance.

S is the sample volume;

W is the weighing sample.