Bioactive aromatic compounds from leaves and stems of Vanilla fragrans

Alcoholic extracts of leaves and stems of Vanilla fragrans were fractionate d with ethyl acetate and aqueous butanol. All three fractions of ethyl acet ate, butanol, and water were screened for toxic bioactivity against mosquit o larvae. The results of these experiments showed Im that the fractions fro m the ethyl acetate and butanol phases were both active in the bioassay. Bi oactivity of the ethyl acetate fraction was found to be much greater than t hat from the butanol fraction in mosquito larvae toxicity. The water phase appeared to contain no substances that impaired mosquito larval growth. Rep eated column chromatography of the ethyl acetate fraction on silica gel led to the isolation of 4-ethoxymethylphenol (1), 4-butoxymethylphenol (2), va nillin (3),4-hydroxy-2-methoxycinnamaldehyde (4), and 3,4-dihydroxyphenylac etic acid (5). Compounds 4 and 5 were isolated from Vanilla species for the first time and 2 has not been reported to have been found in a natural for m. 4-Ethoxymethylphenol (1) was the predominant compound, but 4-butoxymethy lphenol (2) showed the strongest toxicity to mosquito larvae. The structure s of the compounds were determined on the basis of their mass spectra and H -1 or C-13 NMR data.