Inhibition of α-glucosidase activity by polyphenol compounds from C. occidentalis: Phytochemical screening and antidiabetic studies

Medicinal plants are recognized as a source of active molecules that can treat several diseases. Cassia occidentalis (C. occidentalis) is a medicinal plant traditionally used in rural areas of Burkina Faso for the treatment of diabetes. The objective of this work is to evaluate the antioxidant and antidiabetic properties of the fractions of this plant. The antidiabetic activity was investigated by following the inhibitory effect of the different fractions of plant extract on α-glucosidase. The antioxidant activities were performed using 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. TLC analysis revealed the presence of quercetin in the ethyl acetate fractions of stems and leaves of C. occidentalis. Ethyl acetate fractions of stems and leaves of C. occidentalis demonstrated significant antidiabetic properties with IC₅₀ values ca. 0.274 ± 0.003 and 0.538 ± 0.011 mg/mL respectively compared to the reference acarbose with IC₅₀ ca. 0.215 ± 0.004 mg/mL. The same fractions exhibited respectively the highest FRAP values close to 167.055 ± 0.008 and 128.490 ± 5.227 μg ET/mg and DPPH values of 114.062 ± 2.698 and 82.962 ± 3.189 μg ET/mg. Phytochemical screening revealed the presence of flavonoids, tannins and quinones. These results show that C. occidentalis possess molecules with interesting antidiabetic properties and demonstrate its use in the treatment of diabetes.