A novel approach for lavender essential oil authentication and quality assessment

Authors: Wang, Mei; ZHAO, JIANPING - University Of Mississippi; ALI, ZULFIQAR - University Of Mississippi; AVONTO, CRISTINA - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi

Submitted to: Journal of Pharmaceutical and Biomedical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2021
Publication Date: 3/27/2021
Citation: Wang, M., Zhao, J., Ali, Z., Avonto, C., Khan, I. 2021. A novel approach for lavender essential oil authentication and quality assessment. Journal of Pharmaceutical and Biomedical Analysis. 199. Article e114050. https://doi.org/10.1016/j.jpba.2021.114050.
DOI: https://doi.org/10.1016/j.jpba.2021.114050

Interpretive Summary: Lavandula angustifolia Mill., commonly known as English lavender or true lavender, is an important agricultural plant which has been used to produce lavender oil. The oil has a multitude of applications such as a fragrance in cosmetics, personal care, and industrial products or as a flavoring ingredient in food and beverage products. The market for lavender oil was $36M in 2017, with the forecast for the global market indicating that it will reach $124.2 M by 2024. Despite its worldwide popularity and economic significance, lavender oil is one of the most frequently adulterated essential oils, primarily due to the plants lower oil production and its higher price when compared to other oils such as lavandin oil. As a result of the complexity of lavender oil’s composition, the current existing standards and analytical methods are not sufficient to detect lavender oil adulteration. Given this information, there is clearly a need to develop reliable and efficient methods for quality assessment of lavender oil. The present work describes a comprehensive study involving analysis of a large set of lavender essential oil (LEO) samples (n=72) by multiple techniques (GC/MS, GC/Q-ToF, NMR, and chemometric analysis). A new approach named Q-Index, was developed for lavender oil authentication and quality evaluation. The proposed Q-Index method was assessed by independent and complementary NMR methods, and was successfully applied to the quality evaluation of commercial LEO products. We expect that this novel approach might contribute to improvement of lavender oil quality assessment and adulteration detection.

Technical Abstract: Currently, the quality of lavender (Lavandula angustifolia Mill.) essential oil (LEO) is defined and regulated on the basis of the standards and methods established by various authoritative organizations. Due to the complexity of LEO, these existing standards and methods are not sufficient to protect LEO from adulteration. With increasing awareness of both adulteration and poor LEO quality, it has become necessary to develop reliable methods for LEO quality assessment and adulteration detection. After a comprehensive study, involving a large set of LEO samples (n=72) analyzed by multiple techniques (GC/MS, GC/Q-ToF, NMR, and chemometric analysis), a new approach named Q-Index, was proposed in this study. Fourteen marker compounds, along with transfurano- linalool oxide acetate (an indicator of synthetic compound adulteration in LEO), were identified. These marker compounds played significant roles in discriminating the adulterated samples from the authentic LEOs. Calculation of the Q-Index value using the identified marker compounds permitted the detection of the fraudulent samples. It was demonstrated that all of the authentic LEOs exhibited high Q-Index values (>100), whereas the adulterated samples displayed low Q-Index values (<100). The NMR-based chemometric analysis, which served as an independent and complementary approach to the GC/MS and Q-Index methods, was applied to all of the samples in order to assess the validity of the Q-Index method. Overall, the results obtained from different methods were in good agreement. Moreover, compared to the NMR method, the Q-Index approach showed greater sensitivity when detecting the LEO adulteration associated with the addition of synthetic compounds. Results of this study demonstrated that the QIndex method could be successfully used for LEO quality assessment and adulteration detection. This new approach is simple,robust, and efficient. If implemented, it may have significant potential to improve quality control for the LEO industry.