Natural products with biological nitrification inhibition (BNI) activity released from plant roots show potential for increasing the nitrogen-use efficiency and decreasing the extent of environmental pollution. We isolated two diterpenoids, coracanols A (1) and B (2), from finger millet grown under low-nitrogen conditions. Both compounds showed BNI activity against nitrifying bacterium Nitrosomonas europaea. The novel skeletons (1 and 2) featuring a tetracyclo10.2.2.01,10.02,7hexadecane core were elucidated by spectroscopic and X-ray crystal structure analyses utilizing the crystalline sponge method.
Otaka et al. (Mon,) studied this question.