Backhousia citriodora F. Muell. (Myrtaceae), a superior source of citral

Leaf from the citral chemical variety of lemon myrtle, Backbousia citriodor a, was examined for volatile: constituents by (GC and GC/MS analysis of bot h steam volatile oils and solvent extracts. Identified constituents present at more than 0.1 per cent on average in the oil we-re found to be myrcene (0.1-0.7%,), 6-methyl-5-hepten-2-one (0.1-2.5%), linalool(0.3-1.0%)), citro nellal(0.1-0.9% ), iso-neral (0.6-2.7), iso-geranial.(1.0-4.2%), neral (32. 0-40.9%;) and geranial (/46.1-60.7%). I'hysPhsyical constants were found to fall within the ranges of 0.888-0.910 for relative density, 1.4853-1.4909 for refractive index, -1.5 degrees-+0.4 degrees for optical rotation and 0. 8-2.3 volumes for solubility in 70% ethanol. Comparison of chemical and phy sical data with those of other citral-rich commercial oils showed that B. c itriodora was richer in citral than both lemongrass (Cymbopogon flexuosus a nd C.citratus) and Litsea cubeba. Microextraction of fresh leaf with absolu te ethanol gave volatile extracts with higher proportions of citral and low er proportions of cogeners iso-neral and iso-geranial than steam distillati on suggesting partial double bond migration during the distillation process . No significant variation in citral content was observed between flush gro wth and mature leaf or between fresh and dried leaf.