Abstract
            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.