Introduction
Dipeptidyl peptidase-4 inhibitors (gliptins) can be used as a second line of treatment to improve blood glucose levels in patients with type 2 diabetes by blocking the action of dipeptidyl peptidase-4 enzyme, however, these medications possess side effects, which include flu-like illness and acute pancreatitis, besides, they are expensive and need medical prescription. Hence, alternative natural supplements may be a good option.
Objectives
This study aims to illustrate the dipeptidyl peptidase-4 inhibitor activity of selected citrus bioflavonoid nutraceuticals to be used as alternative natural dipeptidyl peptidase-4 inhibitors to gliptins.
Methods
In this study, we selected three commercially available nutraceutical supplements containing citrus bioflavonoids (Thompson’s Super Bioflavonoid Complex®; Ethical Nutrients Bioflavonoid®; and Country Life Citrus Bioflavonoid and Rutin®). Bioinformatics analysis was performed using 2ONC crystal structure of DPP-4 and docking with the active compounds present in inhibiting DPP-4.
Dipeptidyl peptidase-4 inhibitory assay was also performed to measure the inhibition level of these nutraceuticals with a starting concentration of 100mg/ml and sonicating it for 45 minutes and then preparing 8 concentrations in half log dilution. The reference nutraceutical supplements activity was analysed with the reference to sitagliptin.
HPLC was done using agilent 1200 with 2% acetic acid and Acetonitrile phase.
Results
Bioinformatics analysis showed that various individual citrus compounds have DPP-4 inhibitory activity.
With a starting concentration of 100mg/ml, Thompson’s Super Bioflavonoid Complex® had 99% dipeptidyl peptidase-4 inhibition, Ethical Nutrients Bioflavonoid® had 97% inhibition, and Country Life Citrus Bioflavonoid and Rutin® had 98% inhibition
HPLC showed that all the three selected nutraceuticals have various citrus bioflavonoid peaks.
Conclusion
Our results above indicate that citrus bioflavonoids possess dipeptidyl peptidase-4 inhibitor activity and they can be used as alternative to gliptins. However, further studies are required to measure their bioavailability and its effects in-vivo.