Revealing the unique chemical composition of leatherwood honey

In this study, the chemical profile of leatherwood honey was analysed from a large sample size ( n = 133) to establish descriptors that could provide value as markers of botanical origin. Volatile and semi-volatiles were analysed by GC–MS and GC-FID revealing the major compounds 3,7-dimethylocta-1,5,7-trien-3-ol (2.4 ± 0.8 mg/kg), 2,6-dimethylocta-3,7-diene-2,6-diol (24.2 ± 5.4 mg/kg), 2,6-dimethylocta-2,7-diene-1,6-diol (3.9 ± 1.0 mg/kg), 3,4-dimethoxybenzaldehyde (2.4 ± 1.5 mg/kg), 1,4-dimethylindanyl acetate (5.0 ± 1.4 mg/kg), dehydrovomifoliol (18.2 ± 2.2 mg/kg) and 11 unknown compounds with concentrations above 2.7 mg/kg. Phenolic and non-polar compounds were analysed by HPLC-DAD/MS showing high quantities of 3-phenyllactic acid (15.8 ± 9.6 mg/kg), methyl syringate (7.5 ± 5.6 mg/kg), vanillic acid (4.8 ± 2.5 mg/kg) and 4-hydroxybenzoic acid (2.1 ± 0.5 mg/kg). A key finding of this study is the identification of the fluorescent compound lumiflavin in leatherwood honey, which could be used as a non-specific marker to authenticate leatherwood honey.