Phenolic profiles, antioxidant activity and inhibition of digestive enzymes of water caltrop pericarps.

Background: Water caltrop (Trapa natans L.) is widely cultivated as a popular vegetable or fruit in Asian countries. In China, water caltrop pericarp is also used as a functional food to treat metabolic syndrome. However, the profiling of bioactive substances and their pharmacological activities in different water caltrop varieties remains to be investigated. In the present study, three varieties of water caltrop pericarps collected from 13 origins in China were analyzed for their phenolic substances. To investigate the pharmacological activities, samples were tested for their free radical scavenging capacity and inhibitory potency against α-glucosidase and pancreatic lipase.

Results: In total, 46 phenolic compounds were identified in the ethanol extract of water caltrop pericarp using a liquid chromatography-quadrupole time of flight-tandem mass spectrometry method, most of which were hydrolyzable tannins. Two cultivated varieties samples exhibited a relatively higher phenolic content and stronger antioxidant and inhibitory activities against α-glucosidase and pancreatic lipase compared to those from the wild variety. Correlation analysis between phenolic contents and biological activities suggested that phenolic compounds exhibited potential free radical scavenging capacity, α-glucosidase and pancreatic lipase inhibitory activities.

Conclusion: It is concluded that the phenolic compounds of water caltrop pericarp are promising sources of natural antioxidants, α-glucosidase and pancreatic lipase inhibitors. © 2021 Society of Chemical Industry.