Two antinematodal phenolics from Knema hookeriana, a Sumatran rainforest plant.

The activity-guided chromatographic purification of the methanol extract of Knema hookeriana, using pine wood nematodes Bursaphelenchus xylophilus has successfully led to the isolation and characterization of two phenolic antinematodal compounds with minimum effective dose (MED) of 4.5 and 20 microg/cotton ball (microg/bl.) or 0.018 and 0.073 microM/cotton ball (microM/bl.), respectively. Based on their chemical and spectral properties, these compounds were determined to be 3-undecylphenol (1) and 3-(8Z-tridecenyl)-phenol (2). These compounds were isolated for the first time from this species, and 2 seems to be a novel compound.