Allelopathy of buckwheat: assessment of allelopathic potential of extract of aerial parts of buckwheat and identification of fagomine and other related alkaloids as allelochemicals.
The allelopathic potential of buckwheat (Fagopyrum esculentum) was investigated. Field study conducted showed that living buckwheat reduced weed biomass compared with plots without buckwheat. Laboratory study revealed that root exudates from buckwheat (collected from Aomori, Japan) suppressed root and shoot growth of weeds (Trifolium repens, Brassica juncea, Amaranthus palmeri, Echinochloa crus-galli, Digitaria ciliaris, and lettuce) and reduced weed dry weight. The sequential partitioning of the aqueous ethanolic extract of the aerial parts of buckwheat showed that the chloroform extract caused an 80% reduction in radicle elongation of lettuce seedlings at a concentration of less than 100 ppm. Fagomine, 4-piperidone, and 2-piperidinemethanol were isolated and identified by 1H and 13C nuclear magnetic resonance from the chloroform extract. These compounds caused a 50% inhibition of radicle elongation in lettuce seedlings at concentrations of less than 100 ppm. These results suggest that compounds 1, 2, and 3 might act as allelochemicals and affect the growth or germination of different plant species.