The terpenoids acetyl sitosterol, lupeol, acetyl diosgenin and stigmasterol
were studied. Comparison of the thermogravimetric curves and the activatio
n energies of the terpenoids suggested the following sequence of thermal st
ability: acetyl sitosterol < acetyl diosgenin < lupeol < stigmasterol. The
DSC curves allowed determination of the melting points and the degrees of p
urity. Comparison of the TG and DSC curves revealed the presence of phase t
ransitions without mass loss that were attributed to rearrangements in the
terpenoid molecules.