Studies in New Zealand natural products (1994)
AuthorsNicholas, Gillian M.show all
Two terrestrial organisms were explored for biologically active and/or novel components. The genus Paeonia has long been know to contain numerous components that display a vast array of biological activities. The extract of P. lutea showed significant antiviral activity. Using bioassay-guided separation techniques three previously known compounds, paeonol (11), paeoniflorigenone (10) and methyl gallate (16), were identified using mass spectrometry and NMR techniques. These components showed varying biological activities and constituted the majority of the bioactivity in P. lutea. The chemistry of the New Zealand fungus Favolaschia calocera had not previously been investigated. A crude extract showed significant cytotoxicity against the P388 cell line and through bioassay-directed chromatography, 9-methoxystrobilurin L (33) was isolated as a novel cytotoxic compound. The structure was determined by MS and NMR techniques including HMBC, HMQC, COSY and nOe enhancements. Two closely related novel compounds were also characterised from the F. calocera extract. These were methyl-4,6-(E,E)-3-benzoyl-7-phenylheptadienoate (35) and the corresponding free carboxylic acid (36). Neither were found to have significant biological activity in the assays screened. A mixture of triglycerides (34) was also isolated and was analysed using NMR techniques followed by transesterification and GCMS analysis of the corresponding methyl esters.