Antimalarial naphthoquinones from Nepenthes thorelii.

Roots of Nepenthes thorelii yielded plumbagin, 2-methylnaphthazarin, octadecyl caffeate, isoshinanolone, and droserone. In addition, seven derivatives were prepared from plumbagin. Each of these natural and semisynthetic compounds was evaluated for in vitro antimalarial potential.