Polyphenolic phytochemicals of Cola nitida, with their potential therapeutic ability can modulate metabolic and transcriptional expression of proteins and enzymatic activities that culminate to hyperglyceamic effects. This study investigated the hyperglyceamic effects of polyphenolic phytochemical extracts of Cola nitida in Wistar rat in-vivo and established a parallel inhibition of the enzymes (α-amylase and α-glucosidase) in their activities as the concentration increased. On administration of the extracts, the activity of α-amylase was inhibited from control, 32 ± 0.00 to 16 ± 0.02u/L as the concentration increased. Also, the activity of α- glucosidase was inhibited from 17 ± 0.01 to 10 ± 0.00u/L in relation to the concentration of the extracts. The inhibitory effect of Cola nitida on carbohydrate hydrolyzing enzymes delayed glucose utilization resulting to elevated glucose concentration from 6.07 ± 0.02 to 9.11 ± 0.01 mMol/L. The composition of the polyphenolic phytochemicals in the Cola nitida analyzed with gas chromatographic techniques was found to contain; apigenin, 6.0 ± 0.01; catechin, 7.1± 0.01; epicatechin, 4.8 ± 0.02; narigenin, 4.9 ± 0.10 mg/100mg and these are the active ingredients of the bioactive compounds that are responsible for the hyperglyceamic effects of Cola nitida.