Rapid and feasible TLC screening of tea tree oil commercial samples

Tea tree oil is an essential oil used for medical and health purposes consisting of a complex mixture of organic compounds present in high or trace amounts. Several factors (i.e. chemotype, environmental conditions, preparation procedures) can affect the composition and consequently the biological properties, therefore, quality assurance is a key requisite to guarantee reproducibility among batches. Compliance with ISO standards by gas-chromatography mass-spectrometry techniques are universally accepted in check of tea tree oil formulations, while adulterations might be overlooked. In this study we set a TLC protocol for the easy and cheap evaluation of tea tree oil batches purchased from the marketplace and, coupled to the European Pharmacopoeia assay of fatty oils, for the detection of adulterations. This protocol aims to be a procedure for the quality evaluation of tea tree oil in small laboratories not equipped with expensive analytical instruments and by health professionals dealing with herbal medicines.