Location: Subtropical Horticulture ResearchTitle: HPTLC analysis and chemical composition of selected melaleuca essential oils
|VÁZQUEZ, AIMÉ - Oak Ridge Institute For Science And Education (ORISE)|
Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2023
Publication Date: 5/6/2023
Citation: Vázquez, A., Tabanca, N., Kendra, P.E. 2023. HPTLC analysis and chemical composition of selected melaleuca essential oils. Molecules. 28(9):3925. https://doi.org/10.3390/molecules28093925.
Interpretive Summary: The Mediterranean fruit fly or medfly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is a devastating pest of agricultural crops with an extensive range of host plants worldwide. It has been detected in Florida, USA, since the early 1900s but has not become permanently established due to implementation of integrated pest management (IPM) programs and strict quarantine/eradication protocols upon incursion. Trimedlure (TML), a synthetic parapheromone, is currently used as a male attractant for field monitoring and detection of medfly populations. However, TML is expensive and limited to a single supplier, making identification of alternative attractants a priority. In previous studies, it was discovered that tea tree oil (TTO, derived from Melaleuca alternifolia) is highly attractive to sterile male medflies at short range. In this study, scientists from the USDA-ARS (Miami, FL) conducted research using high-performance thin layer chromatography (HPTLC) as a fast, reliable, non-destructive screening tool to separate TTO and other Melaleuca oil samples for identification of potential new attractants. This research will lead to the separation, isolation and identification of novel, alternative attractants for male medfly, with potential applications for the improvement of detection and management programs for this major agricultural pest.
Technical Abstract: Tea tree oil (TTO) is a volatile essential oil obtained by distillation mainly from the Australian native plant Melaleuca alternifolia (Maiden & Betche) Cheel (Myrtaceae). In this study, a comparative analysis of the chemical constituents in seven tea tree oils (M. alternifolia), and four other Melaleuca spp. oils (M. cajuputi, (MCa) two chemotypes of M. quinquenervia, (MNe and MNi) and M. ericifolia (MRo)) was carried out using gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC). Among TTOs, terpinen-4-ol (37.66-44.28%), gamma-terpinene (16.42-20.75%), alpha-terpinene (3.47-12.62%), alpha-terpineol (3.11-4.66%), and terpinolene (2.75-4.19%) were the most abundant compounds in seven TTOs. On the other hand, the most abundant compounds of other Melaleuca oils varied, such as 1,8-cineole (64.63%) in MCa oil, (E)-nerolidol (48.40%) and linalool (33.30%) in MNe oil, 1,8-cineole (52.20%) in MNi oil, and linalool (38.19%) and 1,8-cineole (27.57%) in MRo oil. HPTLC fingerprinting of Melaleuca oils enabled the discrimination of TTO oils from other Melaleuca spp. oils. Variation was observed in the profile of Rf values among EOs. This present study shows that HPTLC is one of the best ways to identify and evaluate the quality control in authenticating TTOs, other Melaleuca EOs, or EOs from other species within the Myrtaceae.