Novel Alkaloids from Myrioneuron nutans

Two new alkaloids, dehydronitraramine (1) and N-formylmyrionine (2) were isolated from the leaves of Myrioneuron nutans, and their structures were determined from spectroscopic analysis, including mass spectrometry and 2D-NMR spectroscopy. The absolute configuration 8S, 9R, 10S of N-formylmyrionine (2) was established by N-formylation of the known (8S,9R,10S)-myrionine and then comparison of the optical rotation of the natural N-formylmyrionine (2) with that of the semi-synthetic (8S,9R,10S)-N-formylmyrionine. Dehydronitraramine (1) displayed a moderate antiplasmodial activity against Plasmodium falciparum with an IC50 value of 16 pm, whereas both I and 2 showed a weak cytotoxicity against KB cells. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)