Methoxylated fatty acids from the bark of Fraxinus sieboldiana.

Nine new fatty acid derivatives, including seven methoxylated (1, 2, and 4-8) and two hydroxylated (3 and 9) fatty acids, have been isolated from the ethanol extract of the stem bark of Fraxinus sieboldiana. Their structures were determined by spectroscopic methods including IR, MS, 1D, and 2D NMR experiments. The 3- or 9-methoxylated fatty acids are reported for the first time in nature.