Antioxidant Profiling, In Silico Toxicity, and Virtual Bioactivity Assessment of Selected Plant-Derived Phenolics

Background and Aim: Oxidative stress is a major contributing factor in the pathogenesis of many diseases. However, approaches to reduce oxidative stress, such as the use of antioxidants, are thought to be potentially protective. Towards this goal, the antioxidant potential of 38 plant phenolics from various chemical classes was screened through in vitro methods in the current work.

Methods: The phenolic compounds were tested for their metal chelation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity along with copper-reducing antioxidant capacity (CUPRAC) and ferric-reducing antioxidant power (FRAP) assays at 10 mM. In silico toxicity and adverse effect estimations, as well as the potential bioactivity probabilities of the compounds, were assessed through PASS and Swiss prediction programs.

Results: All the tested compounds displayed metal chelation activity below 50%, while the highest chelating capacity was exhibited by vitexin (44.12 ± 0.09%). Twenty-two of the compounds displayed a scavenging effect of over 50%, where the highest scavenging effect was caused by oleuropein (87.05 ± 0.05%). In the CUPRAC and FRAP assays, all compounds exhibited remarkable levels of antioxidant activity. The most active ones in the CUPRAC assay were lined up according to their absorbance values as compared to quercetin (3.99 ± 0.01, the reference) as isoquercitrin (3.99 ± 0.01), luteolin (3.96 ± 0.05), myricetin (3.78 ± 0.11), kaempferol (3.60 ± 0.28), morin (3.48 ± 0.26), catechin (3.33 ± 0.28), and hyperoside (3.11 ± 0.50). All compounds possessed FRAP values close to or better than the reference (i.e., quercetin). Our data reveals that the tested phenolics match well with the in silico estimations considering their antioxidant effects, which is the in silico first data on them in this regard.

Conclusion: Our extensive screening indicated oleuropein, gallic acid, taxifolin, rosmarinic acid, catechin, quercetin, kaempferol, luteolin, myricetin, hyperoside, morin, isoquercitrin, fisetin, epigallocatechin gallate, and vitexin as the most promising phenolic antioxidants in the current work.