Assessment of the anti-diabetic potential of the Cratoxylum formosum subsp. formosum extracts via carbohydrate hydrolyzing enzymes inhibitory activities

Introduction: This research aims to evaluate the anti-diabetic activity of the extracts from different parts of Cratoxylum formosum subsp. formosum. Methods: The in vitro inhibitory activities of the hexane (HEX), dichloromethane (DCM) and ethyl acetate (EtOAc) extracts from the flowers, leaves, roots and stems on pancreatic α-amylase (pAA), Saccharomyces α-glucosidase (SAG), rat intestinal maltase (rIM), and sucrase (rIS) were investigated. Results: The DCM and EtOAc extracts from the flowers (IC50 5.4 ± 1.5 and 10.5 ± 0.6 μg/mL) displayed the similar inhibitory activities as acarbose (IC50 7.2 ± 0.4 μg/mL) in the pAA assay. The inhibitory activities of the DCM and EtOAc extracts from the flowers (IC50 56.7 ± 8.9 and 20.4 ± 0.4 μg/mL), EtOAc extract from leaves (IC50 45.0 ± 3.5 μg/mL), DCM and EtOAc extracts from roots (IC50 35.0 ± 6.7 and 16.7± 3.6 μg/mL), and EtOAc extract from stems (IC50 31.1 ± 7.3 μg/mL) were more potent than acarbose (IC50 431.4 ± 16.7 μg/mL) on SAG inhibitory assay (P 0.05). In the rIM assay, DCM and EtOAc extracts from the flowers (IC50 8.5 ± 0.2 and 12.4 ± 0.3 μg/mL) exhibited stronger inhibitory activity than acarbose (IC50 38.5 ± 7.2 μg/mL) (P 0.05). Moreover, the inhibitory activity of DCM extract from the flowers (IC50 16.9 ± 1.5 μg/mL) was comparable to the acarbose (IC50 15.5 ± 1.2 μg/mL) on rIS assay. Conclusion: The DCM and EtOAc extracts from the flowers were more active than the leaves, roots and stems in the inhibition of our defined target enzymes.