Profile of Fatty Acids, Tocopherols, Phytosterols and Polyphenols in Mediterranean Oils (Argan Oils, Olive Oils, Milk Thistle Seed Oils and Nigella Seed Oil) and Evaluation of their Antioxidant and Cytoprotective Activities

Abstract

Background: The effects of vegetable oils on human health depend on their components. Therefore, their profiles of lipid nutrients and polyphenols were determined. Objective: To establish and compare the fatty acid, tocopherol, phytosterol and polyphenol profiles of Mediterranean oils: cosmetic and dietary argan oils (AO; Morocco: Agadir, Berkane); olive oils (OO; Morocco, Spain, Tunisia); milk thistle seed oils (MTSO; Tunisia: Bizerte, Sousse, Zaghouane); nigella seed oil (NSO). Methods: The biochemical profiles were determined by gas chromatography-flame ionization, high performance liquid chromatography and gas chromatography, coupled with mass spectrometry as required. The antioxidant and cytoprotective activities were evaluated with the KRL (Kit Radicaux Libres) and the fluorescein diacetate tests on nerve cells treated with 7-ketocholesterol (7KC). Results: The fatty acid profile revealed high linoleic acid (C18:2 n-6) content in AO, OO, MTSO and NSO. The highest levels of oleic acid (C18:1 n-9) were found in AO and OO. The tocopherol profile showed that Agadir AO contained the highest amount of α-tocopherol, also present at high level in MTSO and Tunisian OO; Berkane AO was rich in γ-tocopherol. The phytosterol profile indicated that β-sitosterol was predominant in the oils, except AO; spinasterol was only present in AO. Polyphenol profiles underlined that OO was the richest in polyphenols; hydroxytyrosol was only found in OO; few polyphenols were detected in AO. The oils studied have antioxidant activities, and all of them, except NSO, prevented 7KC-induced cell death. The antioxidant characteristics of AO were positively correlated with procatechic acid and compestanol levels. Conclusion: Based on their biochemical profiles, antioxidant and cytoprotective characteristics, AO, OO, and MTSO are potentially beneficial to human health.

Fatty Acid Profile and Bioactive Compound Extraction in Purple Viper's Bugloss Seed Oil Extracted with Green Solvents

“…β-sitosterol is usually more abundant than campesterol in seed oils (Fernández-Cuesta et al, 2012;Zarrouk et al, 2019), which is not in agreement with our results. However, a recent study reported higher amounts of campesterol than β-sitosterol in seed oils from some Boraginaceae species (Fabrikov et al, 2019).…”

Characteristics and Antioxidant Potential of Cold-Pressed Oils—Possible Strategies to Improve Oil Stability

“…Obtained high ALA content in studied rosehip and linseed oils agrees with previous studies [24,27], while amounts of ALA determined in camelina oil exceed previously reported values [29]. Quantities of PUFAs in pumpkin and milk thistle oil are in accordance with previously published data [27,30]. In the cited works, a higher n-6/n-3 ratio was found for these oils: Up to 440 for milk thistle and up to 117 for pumpkin oils, which resulted mainly from the lower level of ALA detected in the samples.…”

Evaluation of Chemical Properties of Commercial Extra Virgin Olive Oil in China

“…However, the content of these tocopherols was exceptionally low, less than 5 of the total tocopherol content. Zarrouk et al 25 reported the α-tocopherol content of olive oil from Morocco 30 mg/kg , which was much lower than that reported here. Although the average value of polyphenols in Mediterranean olive oil was quite similar, it was far lower than that reported for polyphenols in the EVOO of Portugal 344-1011 mg/kg 26 .…”

“…The total sterol content here was in accordance with that reported for oil from Portugal 26 . In addition, β-amyrin, Δ5avenasterol, cycloartenol, Δ7-avenasterol, 24 methylene cycloartenol, 24 methylene cycloarterol, campestanol, clerosterol, graminasterol, fucosterol, and citrostadienol were also specified in EVOO, which were reported by Zarrouk et al 25 .…”