New compounds of the following general formula: ##STR1## wherein R.sub.1 is acyl, alkyl, cycloalkyl, carboxyalkyl or ester thereof, heterocyclic group, saccharide residue or hydrogen atom, R.sub.2 stands for hydrogen atom or a lower alkyl and R.sub.3 represents hydrogen atom or a nitrogen-containing group,are provided, among these, some of the compounds to be isolated and purified from a plant belonging to Genus Rubia, other compounds being prepared by chemically modifying the isolated compounds with various kind of substituents and these new compounds having therapeutic effect, in particular such as antineoplastic, emetic, anorexigenic, psychotropic, vasoconstrictive, papaverinic, antiperkinsonian and/or antidiuretic effect.