Synthesis and Study of Antidiabetic Properties of the Neodymium Complexes with N⁵-[o-(un)Substituted Benzoyl]-N¹,N¹- dimethylbiguanide

N¹,N¹-Dimethylbiguanide hydrochloride (HDMBG·HCl) was introduced as an oral glucose-lowering agent to treat non-insulin dependent diabetes mellitus. In this paper, two solid complexes–trichlorotris(N⁵-benzoyl-N¹,N¹-dimethylbiguanidato)neodymium, [Nd(BDMBG)₃Cl₃), and chlorobis-[N⁵-(o-carboxybenzoyl)-N¹,N¹- dimethylbiguanidato]neodymium, [Nd(CDMBG)₂Cl], were synthesized and characterized by elemental analyses, fluorescence spectra, IR, UV, DG, DTA etc. Biological testings were conducted by diabetic rats and ESR The results showed that both the antidiabetic activity and the inhibition rates (Ih) to superoxide anion free radical O₂⁻ on lipid are in the order as follows: Nd(SDMBG)₃ [tris(N⁵-salicyloyl-N¹,N¹-dimethylbiguanidato)neodymium]>Nd(CDMBG)₂Cl≈HDMBG·HCl>Nd(BDMBG)₃Cl₃. It was concluded that different substituents at the o-position of the benzoyl group may affect these two kinds of behaviour to a great extent.