Phytochemical screening and evaluation of phytotoxic activity of Solanum lycocarpum (Solanaceae) ripe fruit

The species Solanum lycocarpum A. St. Hil. (wolf fruit), belonging to the Solanaceae family, is used in folk medicine for the treatment of obesity, diabetes, and cholesterol reduction. The aim of this study was to perform phytochemical screening of the ethanol extract from the ripe fruit of S. lycocarpum to verify the presence of the main groups of secondary metabolites and to evaluate the phytotoxic effect on Lactuca sativa (lettuce) and Allium cepa (onion) seeds exposed to different concentrations of extract (125, 250 and 500 mu g per plate). The fruits of S. lycocarpum were collected, crushed and percolated with anhydrous ethanol and the solvent was dried in a rotatory evaporator to obtain the ethanol extract. The ethanol extract was able to completely inhibit the growth of hypocotyl and radicle of L. sativa (lettuce) seeds in all concentrations tested. In A. cepa (onion) seeds, a concentration of 500 mu g per plate was able to inhibit the growth of the hypocotyl and radicle by 100%. The metabolites detected in the extract were alkaloids, coumarins, flavonoids, and condensed tannins. The phytotoxic activity can be correlated to the presence of these compounds.