Isolation, structure elucidation, total synthesis, and evaluation of new natural and synthetic ceramides on human SK-MEL-1 melanoma cells

Two new long-chain ceramides, trametenamides A (1) and B (2), were isolated from the methanolic extract of the fruiting body of the fungus Trametes menziesii. The structures were elucidated by spectroscopic analyses and chemical transformations, and the absolute stereochemistry of trametenamide B (2) was determined by stereoselective total synthesis of four possible diastereomers. The acetyl derivative of the natural ceramide (1a) and synthetic ceramides (24-27) showed cytotoxicity on the human melanoma cell line SK-MEL-1, which was caused by induction of apoptosis as determined by DNA fragmentation, poly-(ADP-ribose) polymerase cleavage, and procaspase-9 and -8 processing.