Abstract: The raw materials are Viburnum rhytidophyllum,Viburnum propinquum and Viburnum sargentii. The single factor experiment was carried out by selecting ethanol concentration, extraction time, extraction temperature and ratio of material to liquid as factors, absorbance as index, and then orthogonal test analysis was carried out at appropriate factor level and HPLC was used to carry out the experiment. The yield of coumarin from three varieties of Viburnum was compared by the optimized extraction process. The results showed that coumarin was found in all three kinds of Viburnum, Viburnum rhytidophyllum was the highest,Viburnum propinquum was the second, and Viburnum sargentii was the least. The optimum conditions of Viburnum rhytidophyllum and Viburnum propinquum were as followsThe concentration of ethanol was 55%, the extraction time was 60 min, the extraction temperature was 80 ℃, and the ratio of material to liquid was 1∶25. The optimum conditions of Viburnum sargentii were as followsThe concentration of ethanol was 55%, the extraction time was 80 min, the extraction temperature was 70 ℃, and the ratio of material to liquid was 1∶25. The content of coumarin was different in the extraction process of different varieties of Viburnum.

Key words: Viburnum dilatatum, coumarin, extraction optimization, comparison of measurements