HPLC and GC-MS identification of the major organic constituents in New Zealand propolis

The major organic constituents of New Zealand sourced propolis have been identified and quantified in tincture solutions by a combination of HPLC and GC-mass spectrometry (MS). HPLC was the preferred method for the analysis of flavonoids because of their very low response factors in CC-MS. Flavonoid levels ranged from 30-40 mg ml(-1). A distinctive characteristic of the flavonoids in New Zealand propolis is the unusually high proportion (ca 70%) of dihydroflavonoids, e.g. pinocembrin, pinobanksin and pinobanksin 3-acetate. Nonflavonoid components analysed by CC-MS comprised a range of aromatic compounds (3-7.5 mg ml(-1)), together with low levels (0.25-0.78 mg ml(-1)) of fatty acids. The former comprised mainly cinnamic acids and their esters, but also included the rare 5-phenyl-trans-trans-2,4-pentadienoic acid and the new natural product, 5-phenyl-trans-3-pentenoic acid. Both were synthesized to confirm their identity.