Planta Med 2008; 74 - PB12
DOI: 10.1055/s-0028-1084359

Diterpene formamides from the tropical marine sponge Cymbastela hooperi, and their antimalarial activity

A Wright 1, N Lang-Unnasch 2
  • 1College of Pharmacy, University of Hawaii at Hilo, 96720 Hilo, Hawaii, USA
  • 2Division of Geographic Medicine, 485 South 19th Street, University of Alabama at Birmingham, Birmingham, AL 35294–2170, USA

Further investigations of the VLC fractions obtained from the dichloromethane solubles of the tropical marine sponge Cymbastela hooperi led to the isolation and characterisation of five new diterpene formamides; (1S, 3S, 4R, 7S, 8S, 11S, 12S, 13S, 15R, 20R)-7-formamido-20-isocyano-isocycloamphilectane (1), (1S, 3S, 4R, 7S, 8S, 11S, 12S, 13S, 15R, 20R)-7, 20-diformamido-isocycloamphilectane (2), (1S*, 3S*, 4R*, 7S*, 8S*, 12S*, 13S*)-7-formamido-cycloamphilect-11(20)-ene (3), (1R*, 3S*, 4R*, 7S*, 8S*, 12S*, 13S*)-7-formamido-amphilecta-11(20), 14-diene (4), (1S*, 3S*, 4R*, 7S*, 8S*, 12S*, 13S*)-7-formamido-amphilecta-11(20), 15-diene (5). Compound 1 is one of the very few examples of a natural product that contains both formamide and isonitrile functionality within the one molecule. In antiplasmodial bioassays 1 was found to have moderate activity (IC50 0.5µg/mL), 2 very weak activity (IC50 14.8µg/mL), and 3-5 to be inactive. The pattern of activity found for the metabolites investigated in the current study is consistent with previous findings for these classes of molecules.