Several metal complexes and organic compounds and extracted herbs that might be involved in the bio-mechanism of the type 2 diabetes mellitus treatments. This research aims to synthesize a new platinum (II) complex and study its kinetics as an inhibitor for freshly purified amylase from type 2 human diabetics. The amylase enzyme was precipitated from diabetic patients. The complex cis-[Pt(Asc)(NH3)2] was synthesized and characterized experimentally and theoretically by DFT calculations to conclude the structure. Both calculations confirmed the square planar geometry for the prepared complex. The results showed that the complex is more stable and polar than the L-ascorbic acid derivative. Therefore, we suggested that the synthesized Pt(II) complex is appropriate to be examined as an inhibitor for the amylase enzyme. Several concentrations from the Pt(II) complex were prepared for kinetic purposes. Kinetic results have shown that the newly prepared complex has a remarkable inhibition effect on the amylase enzyme. Kinetic parameters were fitted using the Lineweaver–Burk plot. The inhibition reaction was confirmed as a non-competitive inhibitor. Also, an inorganic compound derived from vitamin C was prepared and diagnosed by several spectroscopic methods, and a comparison between the experimental and theoretical data was conducted. The DFT study of the prepared complex gave a useful explanation for the complex and its stability. Thus, an inhibitory effect on the activity of the amylase enzyme was clearly shown by the newly prepared Pt(II) complex. It can be concluded that Pt(II) complex could be used as an amylase inhibitor.