LC-MS and GC-MS metabolite profiling of nickel(II) complexes in the latex of the nickel-hyperaccumulating tree Sebertia acuminata and identification of methylated aldaric acid as a new nickel(II) ligand

The latex from Sebertia acuminata contains the highest concentration of Ni found in any living organism. More than 120 compounds were detected in the latex by GC-MS and a methylated aldaric acid (2,4,5-trihydroxy-3-methoxy-1,6-hexan-dioic acid) was found co-ordinated to NiII. This is the first time this organic acid has been isolated from biological extracts. After citric acid, it appears to be one of the most abundant small organic molecules present in the latex studied.