Identification and quantification of a major anti-oxidant and anti-inflammatory phenolic compound found in basil, lemon thyme, mint, oregano, rosemary, sage, and thyme

Abstract

Major phenolic compounds from basil, lemon thyme, mint, oregano, rosemary, sage, and thyme were investigated using a high-performance liquid chromatography (HPLC) profiling technique in combination with DPPH-radical scavenging, xanthine oxidase and cyclooxygenase assays. For the present study, 15 plant-derived phenolic compounds (gallic, protocatechuic, vanillic, syringic, chlorogenic, rosmarinic, caffeic, ferulic, and sinapic acids, protocatechualdehyde, vanillin, N-coumaroyltyramine, N-caffeoyltyramine, N-feruloyltyramine, and N-sinapoyltyramine) were selected and their DPPH-radical scavenging activities were first determined. Then, a standard HPLC profiling of these phenolics was constructed using an HPLC method to isolate anti-oxidant and anti-inflammatory phenolic compounds from MeOH extracts of the plants. Rosmarinic acid was identified as a major anti-oxidant compound (0.22–0.97%) in all seven herbs, confirmed by nuclear magnetic resonance. Rosmarinic acid from the plants quenched superoxide radicals from xanthine oxidase and inhibited cyclooxygenase I and II enzymes. In this study, the rosmarinic acid content of perilla was also determined and compared with those of the seven herbs.