Antioxidant, antidiabetic, and antihypertensive effects of peptides from some Quercus species

In the present study, the antihypertensive, antidiabetic, and antioxidant properties of oak peptides were determined in vitro. For this purpose, samples from most common oak species (Quercus coccifera, Quercus ilex, and Quercus cerris) were collected, the proteins were extracted and the bioactive properties of 48 different peptide fractions were monitored using a fast protein liquid chromatography. The results showed that acorn peptides had no remarkable antioxidant or antihypertensive effects. Comparing the bioactive peptides of all oak species, the peptides of Q. coccifera generally had higher DPP-IV inhibition activity than those of Q. cerris and Q. ilex. The highest DPP-IV inhibition activity was determined in Q. coccifera second peptide fraction (50.10%). To sum up, acorn peptides could positively contribute to the human health, and they could be evaluated as functional food ingredients for the prevention of type 2 diabetes.