UHPLC-UV analysis DDMS, thymol, 6-methylcoumarin, and NPOE were quantified using a Dionex UltiMate 3000 RS UHPLC system (Thermo Scientific, San Jose, CA, USA) comprising a pump, an auto-sampler, a temperature-controlled column compartment, and UV-detector. An Acquity UPLC® HSS T3 column (100 x 2.1 mm ID, 1.8 µm, Waters, Wexford, Ireland) maintained at 60°C was used. The mobile phase consisted of A) 95:5 v/v deionized water and acetonitrile with 5 mM phosphoric acid and B) 5:95 v/v deionized water and acetonitrile with 5 mM phosphoric acid, using a flow of 0.4 mL min -1 and gradient elution. The gradient was increased linearly from 20% to 100% B in 0.0-5.0 minutes, and held at 100% B from 5.0-6.0 minutes, before returning to 20% B in 0.1 minute for a final 4 minutes of re-equilibration. 1 µL was injected. DDMS and NPOE were detected at 210 nm, while thymol and 6-methylcoumarin were detected at 280 nm.