LC-ESI-QTOF-MS profiling, protective effects on oxidative damage, and inhibitory activity of enzymes linked to type 2 diabetes and nitric oxide production of Vaccinium corymbosum L. (Ericaceae) extracts

Berries are worldwide recognized as “superfoods” due to the high content of bioactive compounds and the health benefits deriving from their consumption. OBJECTIVE:The present study was planned to assess and to compare the chemical profile and the in vitro antioxidant, hypoglycaemic, and anti-inflammatory activities of Vaccinium corymbosum L. berries and leaves extracts obtained by different extraction procedures. Ethanol was chosen as solvent because it is a GRAS (Generally Recognized As Safe) and widely used for the extraction of polar compounds. METHODS:Different extraction techniques such asmaceration, ultrasound-assisted extraction, Soxhlet extractor and decoction, have been applied by using food grade ethanol/water as solvent mixture, selected as environmentally friendly solvents. Extracts obtained from fruits and leaves were chemically investigated by liquid chromatography-electrospray ionization quadrupole-time of flight-mass spectrometry (LC-ESI-QTOF-MS) and for their potential in vitro antioxidant, hypoglycaemic, and anti-inflammatory effects. RESULTS:Some iridoids were detected for the first time in V. corymbosum. Dried leaves extracted by decoction and ethanol with Soxhlet apparatus showed the highest 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals scavenging activity with IC50 value of 0.77μg/mL, which is 2.2-time lower than that positive control ascorbic acid. A promising inhibition of the production of nitrate/nitrite, critical mediators of inflammation, was found. The decoction of berries showed the highest activity in counteracting nitric oxide (NO.) production. Furthermore, two leaves extracts (decoction of dried leaves and hydroalcoholic maceration of fresh leaves) were particularly active as α-amylase inhibitors with IC50 values of 16.16 and 20.55 μg/mL, respectively. CONCLUSIONS:This work could provide valuable basis for future research on V. corymbosum to improve recovery of specific active compounds such as flavonoids and iridoids