Carbon-Carbon Double Bond and Resorcinol in Resveratrol and Its Analogues: What Is the Characteristic Structure in Quenching Singlet Oxygen?

Stilbenes, particularly resveratrol and resveratrol dimers, could effectively quench singlet oxygen (O). It was reported that both resorcinol and carbon-carbon double bond quenching O can participate in the mechanism. However, it is still not clear which structure plays a dominant role in quenching O. To investigate the characteristic structure in the mechanism of quenching O, the resveratrol, pterostilbene and piceatannol quenching O abilities were compared by UHPLC-QTOF-MS and UHPLC-QQQ-MS. Results showed that catechol, carbon-carbon double bond and resorcinol participated in the quenching of O. Catechol ring plays a leading role in the mechanism, and the contribution of the structures in quenching O activity are as follows: catechol ring > carbon-carbon double bond > resorcinol ring, which is supported by the calculation of energy. Our findings will contribute to the future screening of stilbenes with higher activity, and those stilbenes may have great therapeutic potential in O-mediated diseases.