Pressurized Hot Water Extraction as a Viable Bioprospecting Tool: Isolation of Coumarin Natural Products from Previously Unexamined Correa (Rutaceae) Species

The potential of a recently developed pressurized hot water extraction (PHWE) method employing an unmodified household espresso machine to facilitate rapid bioprospecting was investigated. A survey of some 16 Australian native plant species identified three Correa (Rutaceae) species containing significant quantities of coumarin natural products. As part of this study, seselin, (+)-epoxysuberosin, alosin, (–)-meranzin and heraclenin were isolated and, subsequently, used to synthesize the related natural products (+)-trachypleuranin A and (–)-yuehgesin B. In addition, seselin, (+)-epoxysuberosin, alosin, and (–)-meranzin were found to inhibit NQO1 activity. Interestingly, (–)-meranzin showed inhibitory activity comparable to the known potent NQO1 inhibitor dicoumarol.