Varitatin A, a Highly Modified Fatty Acid Amide from Penicillium variabile Cultured with a DNA Methyltransferase Inhibitor

A new, highly modified fatty acid amide, varitatin A (1), was isolated from the fungus Penicillium variabile HXQ-H-1 cultivated with the DNA methyltransferase inhibitor 5-azacytidine. The structure including the absolute configuration of 1 was established by analysis of NMR and MS data, together with chemical degradation and Mosher's method based on MPA esters. Compound 1 showed cytotoxicity against HCT-116 cells with an IC50 value of 2.8 μM and also inhibited the effects of protein tyrosine kinases.