Objective: To optimize extraction technology of rosmarinic acid in Melissa officinalis. Method: With the content of rosmarinic acid as index

based on single factor tests

effects of extraction time

extraction times and the amount of ethanol on extraction technology were investigated by orthogonal test.HPLC was employed to determine the content of rosmarinic acid and the chromatographic conditions were as follows:Hanbon Megres C18 column(4.6 mm×250 mm

5 μm)

mobile phase of formic acid-acetonitrile-water(0.5:20:80

A) and formic acid-methanol-acetonitrile(0.5:40:60

B) with gradient elution program(0-25 min

0%-45% B;25-30 min

45%-100% B)

detection wavelength 330 nm

injection volume 20 μL. Result: Optimal extraction technology was as following:extracted 3 times with 10 times the amount of 70% ethanol

1 h each time;Yield of rosmarinic acid was up to 25.27 mg· g-1. Conclusion: Optimized technology was stable and feasible to provide a reference for resource development of M. officinalis.