HPLC-NMR and HPLC-MS Profiling and Bioassay-Guided Identification of Secondary Metabolites from the Australian Plant Haemodorum spicatum

Phytochemical dereplication was undertaken on the bioactive crude CH2Cl2 extract of the bulbs of the Australian plant Haemodorum spicatum employing HPLC-NMR and HPLC-MS methodologies. Subsequent bioassay-guided isolation resulted in the identification of two new phenylphenalenones [haemoxiphidone (8) and haemodoronol (17)] and two new chromenes [haemodordione (13) and haemodordiol (16)], together with seven previously described compounds. Antimicrobial testing showed that the compounds displayed selective antibacterial activity. Most noteworthy were the activities displayed by several of the compounds against multi-drug-resistant Pseudomonas aeruginosa.