Termite trail-following substances in Houttuynia cordata
W Ohmura, K Yamamoto, M Saegusa, T Ohira, A Kato
Termite trail-following active compounds in the plant, Houttuynia cordata Thunb., were studied by a combination of chemical analyses and bioassay using Coptotermes formosanus Shiraki as a test termite. We have found that termites were attracted to methanol extracts from H. cordata. The n-hexane(Hex) extracts, that showed a trail-following activity, were fractionated by a silica-gel column chromatography with Hex/ethyl acetate(EtOAc) successively increasing the polarity. The obtained 5%, 10%, 15% EtOAc/Hex fractions were found to be active. GC-MS analysis of the 5% EtOAc/Hex fraction showed a peak corresponding to 2-undecanone, which revealed weak activity.