The concentration of Tomatidine found ripe tomatoes is rather low but rather high in green or cherry tomatoes. And although not eaten as a rule the tomato stalks and leaves also contain a lot of tomatidine.

Ursolic acid has a short Wikipedia page with some elaboration about the compound…

Ursolic acid is a weak aromatase inhibitor (IC50 = 32 μM) and has been shown to increase the amount of muscle and brown fat and decrease white fat obesity and associated conditions when added to diets fed to mice. Under physiological concentrations, ursolic acid also induces eryptosis (the apoptosis-like suicidal cell death in defective red blood cells). It has been found to reduce muscle atrophy and to stimulate muscular growth in mice, also shows a potential cardioprotection.