This study investigates the phytochemical composition and antidiabetic potential of various extracts from Cascabela Thevetia L. leaves. Phytochemical analysis revealed significant concentrations of phenols, flavonoids, alkaloids, tannins, saponins, and carbohydrates, with the ethanol extract showing particularly high levels of phenols (217.5±4.88 mg/g), flavonoids (76.49±4.10 mg/g), and alkaloids (18.61±3.64 mg/g). These compounds are known for their antioxidant, anti-inflammatory, and glucose lowering activities, which are crucial for managing diabetes. The study also evaluated the glucose adsorption capacity of the extracts, revealing that the ethanol extract effectively reduced the availability of free glucose for intestinal absorption, thus managing postprandial hyperglycemia. This capacity was proportional to the molar concentration of glucose, highlighting the extract’s efficacy at both low and high concentrations. The presence of soluble and insoluble fibers in the ethanol extract further enhances its glucose adsorption capability. The combined presence of phenolic compounds, flavonoids, alkaloids, and saponins in the ethanol extract suggests a multifaceted mechanism for its antidiabetic effects. These findings provide a strong foundation for future research, including animal and human trials, to validate the antidiabetic efficacy and safety of these extracts, and to explore the biochemical pathways involved. Overall, the study suggests that Cascabela Thevetia L. leaf extracts, particularly the ethanol extract, could be developed into effective natural treatments for diabetes, offering a complementary approach to conventional pharmacotherapy with potentially fewer side effects.