Minor cytotoxic and antibacterial compounds from the rhizomes of Amomum aculeatum

A new cytotoxic 1,7-dioxa-dispiro[5.1.5.2]pentadeca-9,2-dien-11-one derivat ive, aculeatin D, and a new alkenone, 5-hydroxy-hexacos-1-en-3-one, have be en isolated as minor compounds from the rhizomes of Amomum aculeatum. Their structures have been determined mainly by NMR spectroscopy and mass spectr ometry. Aculeatin D showed high cytotoxicity against the KB and the L-6 cel l line with IC50 of 0.38 mug/ml and 1 mug/ml, respectively. Additionally, i t revealed remarkable activity against two Plasmodium falciparum strains, a s well as against Trypanosoma brucei rhodesiense and Trypanosoma cruzi. 5-H ydroxy-hexacos-1-en-3-one exhibited neither cytotoxic nor antiprotozoal act ivity, whereas antibacterial testing against Bacillus cereus, Escherichia c oli and Staphylococcus epidermidis showed moderate to strong activity for b oth compounds. (C) 2001 Published by Elsevier Science Ltd. All rights reser ved.