Herboxidiene is a polyketide originally isolated from S. chromofuscus that has diverse biological activities.[1],[2,][3],[4],[5] It inhibits growth of HeLa S3, SK-MEL-2, PC3, A549, and EBC-1 cells with GI50 values ranging from 7.4 to 62 nM.3 Herboxidiene is cytostatic against human umbilical vein endothelial cells (HUVECs; (IC50 = 26 nM)) and inhibits VEGF-induced invasion and tube formation of serum-starved HUVECs in a concentration-dependent manner, indicating antiangiogenic activity.[4] Herboxidiene (0.05 μM) inhibits HIF-1α mRNA splicing and reduces HIF-1α protein levels in HepG2 cells grown under hypoxic conditions. It also inhibits splicing of p27Kip mRNA in HeLa cells in a concentration-dependent manner via interaction with the SAP155 subunit of the SF3b complex.[2] Herboxidiene (0.1 and 1 μM) increases LDL receptor promoter-driven transcription in a cell-based reporter assay.[5] It also exhibits herbicidal activity against wild buckwheat, morning glory, maize, hemp sesbania, and rapeseed when applied at 0.069 kg/hectare.[1]