Bioassay-Guided Isolation of Antiproliferative Compounds from Limbarda crithmoides (L.) Dumort

Limbarda crithmoides (L.) Dumort (Asteraceae) n-hexane extract displayed high cell proliferation inhibitory activity against acute myeloid leukaemia cells (OCI-AML3) and was therefore subjected to a bioassay-guided multistep separation procedure. Two thymol derivatives, namely 10-acetoxy-8,9-epoxythymol tiglate (1) and 10-acetoxy-9-chloro-8,9-dehydrothymol (2), were isolated and identified by means of NMR spectroscopy. Both of them exhibited a significant dose-dependent inhibition of cell proliferation.