The ABC-AHP-NCNPR Botanical Adulterants Prevention Program (BAPP) has released a new Laboratory Guidance Document (LGD) on English lavender essential oil.
The essential oil of English lavender (Lavandula angustifolia), also known as common lavender or, simply, lavender, is made by steam distillation of the flowering tops of English lavender, a small shrub in the mint family (Lamiaceae) native to the Mediterranean area. The oil is widely used orally or via inhalation to help allay anxiety and to promote restful sleep. Lavender oil is also a popular ingredient in massage oils and personal care, home care and cosmetic products.
The wholesale price of bulk authentic English lavender essential oil ranges from $75-100 per liter. Due to its relatively high price, undisclosed substitution with essential oils from other, lower-cost species of Lavandula appears to be common. One of the reported adulterants of English lavender is the essential oil from lavandin (Lavandula × intermedia), although lavandin is regarded as an acceptable substitute by some authorities.
Other forms of adulteration of English lavender essential oil are the undeclared addition of other essential oils, or oil fractions (a part of the essential oil usually obtained by fractionated distillation, a process that separates the essential oil according to the volatility of the constituents) that are rich in the natural chemical compound linalool. Mixtures of undisclosed purified or synthetic chemicals, such as linalool and linalyl acetate, or non-volatile fatty oils like sunflower oil added as a diluent, have also been reported.
“English lavender is a name often misused by laymen due to its morphological and chemical similarities with other species of Lavandula and its commercial hybrid lavandin,” commented essential oil expert Kemal Hüsnü Can Başer, PhD, a professor in the Pharmacognosy Department of the Faculty of Pharmacy at Near East University in Nicosia (Lefkoşa, Northern Cyprus). Başer is the co-editor of Essential Oils: Science, Technology and Applications, 2nd edition (CRC Press, 2015), which received the ABC James A. Duke Excellence in Botanical Literature Award in 2017.
Başer noted that there are standards for lavender and lavandin oils by ISO (the International Organization for Standardization), and that the European Pharmacopoeia contains monographs of lavender and spike lavender (Lavandula latifolia) oils. “These standards can help authenticate the essential oils,” he continued.
“Some of the methods of lavender oil adulteration are easy to detect,” explained Stefan Gafner, PhD, chief science officer of the nonprofit American Botanical Council (ABC) and the director of BAPP. “For example, vegetable oils or compounds known as glycols leave a liquid residue when a drop of oil is placed on filter paper, while essential oils evaporate. On the other hand, some types of adulteration are difficult to determine because fraudsters have found ways to produce materials that resemble English lavender oil very closely. The new BAPP LGD provides an overview of the available laboratory analytical methods and their strengths and limitations, so quality control personnel in various industries can readily find the right approach for their needs.”
The new LGD was written by Oleksandr Shulha, PhD, an expert in natural products chemistry and analysis based in Cherkasy, Ukraine. It provides an evaluation of macroscopic and microscopic features for English lavender flowers, and 48 other analytical methods, including 17 gas chromatography and seven infrared spectroscopy methods, with respect to their suitability to properly determine the identity of lavender essential oil. The LGD was peer reviewed by 16 experts in quality control of medicinal plants from academia and the herb industry in the United States and internationally.
The lavender essential oil LGD is the 16th LGD and the 83rd peer-reviewed publication published by BAPP since its first publication in 2011. As with all BAPP publications, the English lavender essential oil LGD is freely available the BAPP website (registration required).