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The occurrence of the cardiotoxin taxine (comprising taxine B and several other basic taxoids) in leaves of Taxus baccata L. (European yew) is well known and has led to public concerns about the safety of eating or drinking from utensils crafted from the wood of this poisonous species. The occurrence of basic taxoids in the heartwood of T. baccata had not been examined in detail, although the bark is known to contain 2′β-deacetoxyaustrospicatine. Initial examination of heartwood extracts for 2′β-deacetoxyaustrospicatine by liquid chromatography–mass spectrometry (LC–MS) revealed the presence of this basic taxoid at about 0.0007% dry weight, using a standard isolated from bark. Analyses for taxine B, however, proved negative at the extract concentration analysed. Observing other basic taxoids within the heartwood extracts was facilitated by developing generic LC–MS methods that utilised a fragment arising from the N-containing acyl group of basic taxoids as a reporter ion. Of the various MS strategies available on a hybrid ion trap-orbitrap instrument that allowed observation of this reporter ion, combining all-ion collisions with high resolution ion filtering by the orbitrap was most effective, both in terms of the number of basic taxoids detected and sensitivity. Numerous basic taxoids, in addition to 2′β-deacetoxyaustrospicatine, were revealed by this method in heartwood extracts of T. baccata. Red wine readily extracted the basic taxoids from heartwood while coffee extracted them less efficiently. Contamination with basic taxoids could also be detected in soft cheese that had been spread onto wood. The generic LC–MS method for detecting basic taxoids complements specific methods for detecting taxine B when investigating yew poisoning cases in which the analysis of complex extracts may be required or taxine B has not been detected.

The foliar metabolome of Cladrastis kentukea (Leguminosae) contains a complex mixture of flavonoids including acylated derivatives of the 3-O-rhamnosyl(1 → 2)[rhamnosyl(1 → 6)]-galactosides of kaempferol and quercetin and their 7-O-rhamnosides, together with an array of non-acylated kaempferol and quercetin di-, tri- and tetraglycosides. Thirteen of the acylated flavonoids, 12 of which had not been reported previously, were characterised by spectroscopic and chemical methods. Eight of these were the four isomers of kaempferol 3-O-α- l -rhamnopyranosyl(1 → 2)[α- l -rhamnopyranosyl(1 → 6)]-(3/4-O-E/Z-p-coumaroyl-β- d -galactopyranoside) and their 7-O-α- l -rhamnopyranosides, and three were isomers of quercetin 3-O-α- l -rhamnopyranosyl(1 → 2)[α- l -rhamnopyranosyl(1 → 6)]-(3/4-O-E/Z-p-coumaroyl-β- d -galactopyranoside) – the remaining 4Z isomer was identified by LC–UV–MS analysis of a crude extract. The final two acylated flavonoids characterised by NMR were the 3E and 4E isomers of kaempferol 3-O-α- l -rhamnopyranosyl(1 → 2)[α- l -rhamnopyranosyl(1 → 6)]-(3/4-O-E-feruloyl-β- d -galactopyranoside)-7-O-α- l -rhamnopyranoside while the 3Z and 4Z isomers were again detected by LC–UV–MS. Using the observed fragmentation behaviour of the isolated compounds following a variety of MS experiments, a further 18 acylated flavonoids were given tentative structures by LC–MS analysis of a crude extract. Acylated flavonoids were absent from the flowers of C. kentukea, which contained an array of non-acylated kaempferol and quercetin glycosides. Immature fruits contained kaempferol 3-O-α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside and its 7-O-α-rhamnopyranoside as the major flavonoids with acylated flavonoids, different from those in the leaves, only present as minor constituents. The presence of acylated flavonoids distinguishes the foliar flavonoid metabolome of C. kentukea from that of a closely related legume, Styphnolobium japonicum, which contains a similar range of non-acylated flavonoids.