Phytochemical Profiling by HPLC-ESI-MS/MS and In Vitro Investigation of the Antidiabetic Activity of Cassia bakeriana Bark Extract and Fractions

Type 2 diabetes mellitus is a global health problem, placing patients at a higher risk of developing cardiovascular diseases and cancer. This study investigates the antidiabetic potential of Cassia bakeriana bark extracts and fractions. We evaluate their ability to inhibit α-amylase and α-glucosidase enzymes and advanced glycation end-products (AGEs). The antioxidant potential was also examined. Extracts were prepared through maceration with hexane (HE) and ethanol (EE), and the fractions were obtained via liquid–liquid extraction from EE. Anti-enzymatic, anti-glycation, antioxidant, and cytotoxic assays were conducted in 96-well plates using different concentrations of samples to determine the half-maximal inhibitory concentration (IC₅₀). Active samples were further analyzed using HPLC-(−)-ESI-MS/MS. The ethyl acetate fraction (EAF) demonstrated a high percentage of α-amylase inhibition (94.0%) with a promising IC₅₀ value of 1.05 μg mL⁻¹. Additionally, EAF displayed 61.5% inhibition of α-glucosidase, with an IC₅₀ value of 537 μg mL⁻¹. The EE, EAF, and n-butanol fraction (BF) exhibited strong anti-glycation capacities. Furthermore, the EE, EAF, BF, and dichloromethane fractions showed promising antioxidant activity using the DPPH and ORAC methodologies. Cytotoxic activity was also evaluated with Vero cells, revealing no adverse effects on cell viability (CC₅₀ > 512.0 μg mL⁻¹). Active samples predominantly comprised proanthocyanidins, flavonoids, and anthraquinone, representing the main constituents of C. bakeriana bark. This study provides the first assessment of the antidiabetic potential of C. bakeriana bark and a comprehensive analysis of the chemical composition of its active extracts and fractions, offering hope for future treatments.