Abstract
Cyanamide (NH_2CN) has been synthesized for over a hundred years for agricultural and industrial uses. In 2001, this compound was isolated from Vicia villosa subsp. varia. A large proportion of the inhibitory activity in the crude extract was explained by the presence of cyanamide. This was the first isolation of cyanamide from natural sources. [^<15>N] Nitrate was administered to V. villosa subsp. varia seedlings, from which cyanamide was purified and subjected to GCMS analysis. The isotopic ratio of ^<15>N in the cyanamide was significantly higher than that of the cyanamide extracted from the seedlings grown in the presence of a natural N source. This ^<15>N-enrichment established the presence of natural cyanamide. Distribution of cyanamide in the plant kingdom was the subject investigated because knowledge of this could enable us to understand the physiological function of cyanamide in plants, obtain plant material suitable for biosynthetic study, and investigate the genetic code of cyanamide biosynthesis. We established a direct quantitative determination method to detect and measure cyanamide by stable isotope dilution gas chromatography-mass spectrometry. We investigated 553 species in total but have so far found only three species with the ability to accumulate cyanamide at detectable levels, V. villosa subsp. varia, V. cracca, and Robinia pseudo-acacia the distribution of the plants that accumulate natural cyanamide appears to be limited.
