The work described herein shows the isolation and characterization of natural products present in the tomato roots (Solanum lycopersicum) with phytotoxic activity. Tomato was selected owing that almost all studies have focused on the fruit, but other parts have been less studied, ignoring in this way a possible source of new natural products with phytotoxic activity.

As result of that work, stigmasterol, bergapten and α-tomatine have been isolated.

The major compounds, stigmasterol and α-tomatine have been evaluated on wheat coleoptiles, being α-tomatine the most active. In the bibliography has been reported that α-tomatine protect the leaves of tomato against microorganisms, fungus and pathogens. However, phytotoxic activity has not been reported yet.

α-tomatine was identified in root exudates using LC-MS/MS. The results obtained confirm that α-tomatine is exudated by roots to environment. To confirm the allelopathic roll, α-tomatine was tested on the model seed Lactuca sativa and on two weeds of tomato crops (Lolium perenne and Echinochloa crus-galli). The stimulant activity of the parasitic plant germination of α-tomatine was also evaluated on the parasitic plant of tomato, Phelipanche ramose, and also on Orobanche crenata and Orobanche cumana.