Quantitative estimation of pharmacologically relevant phenolic compounds in olive oils harvested in Jabal Al Akhdar in Oman

Abstract

Extra virgin olive oil (EVOO) is widely acknowledged for its health-promoting properties due to its rich composition. For example, certain phenolic compounds (PCs) present in EVOO, including hydroxytyrosol and tyrosol, oleacein, and oleocanthal (OHTs), are recognized for their superb pharmacological impacts. Herein, EVOO samples extracted from olives harvested in Jabal Al Akhdar (JA), Oman, were analyzed for their levels of OHTs. The study included six varieties of EVOO -Carotina, Kalamata, Picual, Dolce, Arbequina, and Karonaki- collected from Riyad Al Jabal Farm (RJ), administrated by the Royal Court. Identification of OHTs was carried out using liquid chromatography–tandem mass spectrometry (LC–MS/MS), and quantitative analysis was conducted using high-performance liquid chromatography (HPLC) coupled to a photodiode array detector (DAD). The method demonstrated strong linear relationships with a linear range between 0.2 and 40 mg kg⁻¹ for the four compounds. Results revealed that certain EVOO varieties such as Carotina (181.2 ± 0.1 mg kg⁻¹), Kalamata (137.16 ± 0.09 mg kg⁻¹), and Picual (107.7 ± 0.3 mg kg⁻¹) exhibited the highest concentration of OHTs, making them preferred choices for cultivation in JA. Furthermore, the Folin–Ciocalteu (FC) method was used to estimate the total phenolic content, revealing that Picual and Carotina exhibited the highest levels compared to the other varieties.