Objective: To study the main chemical components and anti-tumor activities of essential oil from the leaves of Polyalthia consanguinea

and provide experimental basis for further research and development of P. consanguinea. Method: The essential oil from the leaves of P. consanguinea was extracted by steam distillation method to calculate its yield; then gas chromatography-mass spectrometry (GC-MS) was used to analyze its chemical components. MTT assay was used to investigate the inhibitory effect of essential oil on the proliferation of leukemia cells (K-562)

liver cancer cells (BEL-7402)

lung cancer cells (SPC-A-1) and gastric cancer cells (SGC-7901). Result: The extraction yield of P. consanguinea oil was 0.83%; 65 chromatographic peaks were detected and 44 compounds were identified

accounting for 84.382%of the total essential oil. The major components were monoethylhexyl phthalate (16.824%)

diphenylamine (10.321%)

diisobutyl phthalate (8.904%) and spathulenol (4.920%). Conclusion: The results of anti-tumor activity showed that the essential oil had moderate inhibitory activity against the four tumor cell lines. The inhibition ratio was above 80%for K-562

BEL-7402 and GSC-7901 cells proliferation in the high concentration sample group. The assay exhibited good inhibitory effect against K-562 and BEL-7402 cell lines with IC50 value of 3.78

8.14 g · L-1 respectively

which was better than positive control mitomycin C. Meanwhile

the essential oil showed moderate inhibitory effect against SGC-7901 cell line with IC50 of 22.94 g · L-1.This experiment has provided scientific foundation for further utilization of P. consanguinea.