Apply rough set theory in the function group analysis for phenolic amide compounds

Phenolic amide compounds are present in natural products. They are confirmed to possess very excellent antioxidant activities in previous literature. Therefore, the present study was focused on the synthesis of a series of phenolic amide compounds and the determination of their antioxidant activities. Each parameter between the functional group in the structure and the activity was investigated. Such research direction plays an important role in drug synthesis. The principle approach was based on the antioxidant activity (IC₅₀) values of various R₁-R₅ in the phenolic acid and phenethylamine backbones for the investigation of the impact of the functional group on the backbone. The weighting factor of each functional group was for the reference of the functional group replacement. Pursuant to the above, the present study took advantage of the features of the rough set attribute significances and incorporated Matlab toolbox to analyze the raw data obtained from the experiment to calculate the weighting factor of each functional group. Through the analysis and calculation by rough set mathematics, it was found that R₅ (C₅) was the functional group responsible for the most significant impact on the antioxidant activity. This finding indicated that the functional group at the para-position in the phenethylamine backbone was the most influential, followed by R₂ and R₄ (C₂ and C₄), inferring the critical role of the functional group at the meta-position. This result was consistent with the actual circumstance. Since the experimental data of the present study was derived from 15 compounds, the screening result would vary when the substituent in the structure was increased. In the future, the functional groups at different positions should be synthesized to increase the number of compounds followed by the integration of the mathematics model and computer toolbox to validate the accuracy and rationality.