DFT-based quantitative structure-activity relationship studies for antioxidant peptides

Peptides derived from food sources exhibit many different biological properties, including antioxidant activities. Some antioxidant activities are attributed to the scavenging of free radicals through electron transfer. In this study, the quantum chemical parameters associated with electron transfer were investigated. All calculations were performed using the Gaussian 03 W software package using DFT theory (B3LYP hybrid functions), together with the 6-311 + G (d, p) basis set that supported the experimental free radical (center dot OH and O-2 (-)center dot) scavenging activities. The results of the scavenging O-2 (-)center dot model (R (2) = 0.882, Q (2) = 0.824) demonstrated that O-2 (-)center dot model has a high statistical significance and remarkable predictive ability; however, center dot OH model was not prominent. We used the multiple linear regression to build the model and used the leave-one-out method to verify the regression's prediction. The results showed that E-HOMO and L, related to electron donating ability, are the most important parameters for understanding the free radical especially O-2 (-)center dot scavenging ability of antioxidant peptides. The information obtained from this study could provide clues for the guided synthesis of antioxidant peptides.