Phytotoxic activity of Calia secundiflora (Ortega) Yakovlev

Calia secundiflora (Ortega) Yakovlev [syn. Sophora secundiflora (Ortega) Lag. ex DC] (Fabaceae), is generally a bushy plant, growing at several sites in Mexico. It is considered a toxic species due to the presence of quinolizidine alkaloids. No documented studies have been found on the phytotoxic effects of C. secundiflora. The purpose of this study was to identify the alkaloids in the extract from seeds and evaluate the phytotoxic activity of alkaloid extract and quinolizidine alkaloids in the development of species Amaranthus hibridus and Lactuca sativa. Alkaloids were identified by Liquid Chromatography-Mass Spectrometry. Biotest was made to different concentrations of organic extract and cytisine. The evaluated characters (index of speed of germination, % of germination, length by root, length of the aerial portion and abnormal plants. Quinolizidine alkaloids were identified: cytisine, lupinine, anagyrine, sparteine, N-methylcytisine, 5,6-dehydrolupanine, and lupanine [1]. The major compound of the extract was cytisine, having the highest yield (0.6%). The alkaloid extract was the more toxic than the cytisine in the phytotoxicity bioassay done in dicotyledoneae seeds of A. hybridus and L. sativa seeds, provoking a large effect in the retardation and inhibition of seed germination, a large inhibition of root, and portion aerial, and a large percentage of abnormal plants. The results underscore the importance of C. secundiflora as an alternative source of natural products for the control of plants (herbicide effect).

References: 1. Harris D.J., Wilson P.E. (1988) Proceedings Fifth International Lupin Conference. Poznan, Polonia.