Quantitative Studies on Structure-DPPH• Scavenging Activity Relationships of Food Phenolic Acids

Abstract

Phenolic acids are potent antioxidants, yet the quantitative structure-activity relationships of phenolic acids remain unclear. The purpose of this study was to establish 3D-QSAR models able to predict phenolic acids with high DPPH• scavenging activity and understand their structure-activity relationships. The model has been established by using a training set of compounds with cross-validated q2 = 0.638/0.855, non-cross-validated r2 = 0.984/0.986, standard error of estimate = 0.236/0.216, and F = 139.126/208.320 for the best CoMFA/CoMSIA models. The predictive ability of the models was validated with the correlation coefficient r2pred = 0.971/0.996 (>0.6) for each model. Additionally, the contour map results suggested that structural characteristics of phenolics acids favorable for the high DPPH• scavenging activity might include: (1) bulky and/or electron-donating substituent groups on the phenol ring; (2) electron-donating groups at the meta-position and/or hydrophobic groups at the meta-/ortho-position; (3) hydrogen-bond donor/electron-donating groups at the ortho-position. The results have been confirmed based on structural analyses of phenolic acids and their DPPH• scavenging data from eight recent publications. The findings may provide deeper insight into the antioxidant mechanisms and provide useful information for selecting phenolic acids for free radical scavenging properties.

Potent 1,2,4‐Triazole‐3‐thione Radical Scavengers Derived from Phenolic Acids: Synthesis, Electrochemistry, and Theoretical Study

“…These two phenolic acids showed good antioxidant activities in DPPH assay (22.71 and 35.17 μM, respectively), but antioxidant activity of their corresponding triazoles was significantly higher ( p < 0.05). Literature data confirm high radical scavenging activities of 1 f and 1 h , while phenolic acids with one hydroxyl group, such as 1 a , 1 b and 1 c show negligible antioxidant capacities . Our results showed that phenolic acids with two hydroxyl groups, such as 1 g and 1 i are better antioxidants than monohydroxy acids, but their activity is also low.…”

Reactivity of phenolic compounds towards free radicals under in vitro conditions

“…The presence of electron donating or high electron density hydroxyl group at meta and para positions of gallic acid attributes to the high scavenging ability of gallic acid (Jing et al 2012 Fig. 1 Structure of the phenolic compounds assayed for free radical scavenging exhibited higher scavenging activity (38.9 %) than veratryl alcohol (0.38 %) due to para-hydroxy substitution.…”

Berry antioxidants: small fruits providing large benefits

“…As previously reported, hydroxylation in adjacent carbons (o-diphenyl structure) enhances antioxidant activity. 54 Jing and co-workers 55 also outlined that the presence of: (i) bulky and/or electrondonating substituents on the aromatic ring, (ii) electron-donating groups at the meta position and/or hydrophobic groups at the meta-ortho position, and (iii) hydrogen bond donor/electrondonating groups at the ortho position strengthen the antioxidant activity of phenolic acids. Hydroxylation and/or methoxylation on the C ring affects the antioxidant activity of anthocyanins.…”