Feeding of potato, tomato and eggplant alkaloids affects food consumption and body and liver weights in mice

Abstract

Reduced liver weight was used to evaluate the potential toxicity in mice of four naturally occurring steroidal glycoalkaloids: α-chaconine and α- solanine, α-tomatine and solasonine. Increased liver weight was used to evaluate the three corresponding steroidal aglycones: solanidine, tomatidine, and solasodine and the non-alkaloid adrenal steroid dehydroepiandrosterone (DHEA). Adult female Swiss-Webster mice were fed diets containing test compound concentrations of 0 (control), 1.2, 2.4 or 4.8 mmol/kg diet for 7, 14 or 28 d. Absolute liver weights (LW) and relative liver weights (liver weight/body weight x 100, %LW/BW) were determined at autopsy. The %LW/BW was lower than that of the controls in mice fed the potato glycoalkaloid α- chaconine (-10%, P ≤ 0.05) for 7 d with the 2.4 mmol/kg diet dose. Under these same conditions, %LW/BW was greater than that of controls in mice fed two aglycones: solanidine (27%, P ≤ 0.001) and solasodine (8%, P ≤ 0.01). Relative liver weight increases induced by the aglycones were determined under time and dose conditions in which differences in body weight and food consumption were not significant (2.4 mmol/kg diet for 28 d). Under these conditions, the observed %LW/BW increases relative to the controls were as follows: solanidine (32%, P ≤ 0.001), solasodine (22%, P ≤ 0.001) and DHEA (16%, P ≤ 0.001). Solanidine, solasodine and DHEA were equally potent and were more potent than tomatidine. We also observed that the greater %LW/BW in mice fed 2.4 mmol/kg diet solasodine or solanidine for 14 d declined to near control values if they were fed control diets for another 14 d. The increase in relative liver weight induced by solanidine and solasodine is a reversible adaptive response. These findings and the apparent effects of structure on biological activity should serve as a guide for the removal of the most toxic compounds from plant foods. The implications of the results for food safety and health are discussed.