A
metal complex of a piperazineNONOate derivative of the formula: wherein a) R1 and R2 independently represent
hydrogen, linear or branched (C1-C4)
alkyl, optionally substituted by 1 or 2 groups selected from the group consisting of hydroxy, (C1-C4) alkoxy, (C1-C4) alkylthio, amino, (C1-C4) alkylamino, di-(C1-C4) alkylamino, carboxy, carbo(C1-C4) alkoxy,
aryl, aryloxy, arylthio; orb) R1 and R2 taken together, represent one of the following groups ═CR3-
aryl, where R3 represents
hydrogen, (C1-C4) linear or branched chain
alkyl, optionally substituted by 1 or 2 groups selected from the group consisting of hydroxy, carboxy,
aryl; n represents a whole number
ranging from 2 to 4; M+ represents a cation of a
transition metal or
zinc; x represents a whole number which varies from 1 to 3, and indicates the charge units of the cation of the
transition metal or of the
zinc in relation to its stable
oxidation state; A − represents an inorganic or
organic anion which forms stable salts with the NONOate
metal complex; y represents a whole number which varies from 1 to 3, and indicates the charge of the anion; m represents a whole number including zero, or a fractional, indicating the number of anions required to balance the cationic charge of the NONOate
metal complex and is related to the values of x, y, k and w by the relationship: m=(x+k)-(1+w)ywhere w is the number of possible further anionic charge units and k is the number of possible further cationic charge units present in the NONOate ligand substrate. The complex of the invention exhibits an endothelio-protective effect in the coronary
system and stimulates re-endothelialization and
angiogenesis proceses.