Secondary metabolites with antinematodal activity

Nematodes represent a serious threat to both plants and animals. New methods of control of these parasites are being sought since a number of soil-applied commercial nematocides are being phased out and resistance to anthelmintics is an increasing problem. Integrated pest management, transgenic plant resistance and biological control strategies are being investigated as methods of control. At the same time, the search for naturally occurring antinematodal compounds continues unabated. The discovery of the potent anthelmintic activity of the avermectins and milbemycins has stimulated interest in the identification of other natural products with high activity and selective mode of action towards nematodes. In this report, the wide range of metabolites shown to have antinematodal activity are reviewed. Aspects of their chemistry and activity are outlined and, wherever possible, the relationships between structure and bioactivity are emphasised.