Abstract:Five new mexicanolide-type limonoids, heytrijunolides A-E (1-5) were isolated from the branches and leaves of Heynea trijuga. The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis. Compound 3 showed weak cytotoxicity against HL-60, SMMC-7721 and A-549 human tumor cell lines with the IC 50 values of 21.88, 20.66 and 12.70 μM, respectively.