VANADYL COMPLEX HAVING INSULIN-LIKE ACTION

PROBLEM TO BE SOLVED: To obtain a vanadyl (IV) complex having an insulin-like action by coordinating an N,N'-alkylenebisamino acid. SOLUTION: This vanadyl (IV) complex, e.g. an N,N'-ethylenebis-(S)valine vanadyl complex, is expressed by the formula: VIV=O(ligand) [the ligand is expressed by formula I X and X are each a 1-4C alkoxy, amino, mono-lower alkylamino, OH, etc.; R and R are each H, CH3 , CH(CH3 )2 , (CH2 )3 NHC(NH2 )= NH, benzyl, 4-imidazolyl, etc.; R and R are each H, a 1-4C alkyl, formula II (R and R are each H, a 1-4C alkyl, a 1-4C alkoxy, nitro, etc.); C* is asymmetric C; X is CH2 CH2 , CH3 CH(CH3 ), etc.}]. The complex is obtained by mixing the ligand of the formula I with a vanadium compound in an aqueous solution. The complex has high liposolubility and increased stability, and is useful as a therapeutic agent for diabetes, and further as a hypotensive agent.