Objective: To optimize extraction conditions of volatile oil from Olibanum and Myrrha in Tangshang ointments and analyze its compositions. Method: Taking 1

1

1

2-tetrafluoroethane(R134a) as extraction solvent

with yield of volatile oil as index

based on single factor tests

effects of materials granularity

extration temperature and time on extraction process were investigated by orthogonal test.Composition of volatile oil was analyzed by gas chromatography-mass spectrometry(GC-MS). Result: Optimum conditions was as following:materials granularity of 80 mash

subcirtical extraction temperature of 50 ℃

extraction once for 30 min.Under these conditions

yield of volatile oil from Olibanum and Myrrha was 5.19%.Thirty-nine components were identified by GC-MS

terpenes

aromatic hydrocarbons(hydrocarbons

alcohols

esters) were the major components among them

contents of 1-phenoxy-2-propanone and [1R-(1α

7β

8a. α)]-1

2

3

5

6

7

8

8a-octahydro-1

8a-dimethyl-7-(1-methylethenyl)-naphthalene were 37.04% and 8.16%

respectively. Conclusion: This extracting techniques is feasible and stable

this study can provide a scientific basis for quality control and further research of Tangshang ointments.