LC–MS Determination of Sterols in Olive Oil

A Comprehensive Update on Phytochemistry, Analytical Aspects, Medicinal Attributes, Specifications and Stability of Stigmasterol

Phytosterols are bioactive substances naturally found in plant cell membranes, and their chemical structure is comparable to cholesterol found in mammalian cells. They are widely distributed in plant foods like olive oil, nuts, seeds, and legumes. Amongst the variety of phytosterols, stigmasterol is the vital compound found abundantly in plants. Numerous hormones, including estrogen, progesterone, corticoids and androgen, are synthesized by stigmasterol. Multiple in-vitro and in-vivo investigations have shown that stigmasterol has various biological effects, including antioxidant, anticancer, antidiabetic, respiratory diseases, and lipid-lowering effects. Experimental research on stigmasterol provides indisputable proof that this phytosterol has the potential to be employed in supplements used to treat the illnesses mentioned above. This substance has a high potential, making it a noteworthy medication in the future. Although several researchers have investigated this phytosterol to assess its prospective qualities, it has not yet attained therapeutic levels, necessitating additional clinical studies. This review offers a comprehensive update on stigmasterol, including chemical framework, biosynthesis, synthetic derivatives, extraction and isolation, analytical aspects, pharmacological profile, patent status, clinical trials, stability and specifications as per regulatory bodies.

Mass Spectrometric Approaches for the Analysis of Phytosterols in Biological Samples

Plant sterols (phytosterols) are important structural components of plant cellular membranes, and they play a major role during development and metabolism. They have health-associated benefits, especially in lowering blood cholesterol levels. Because of their many health claims, there is a growing interest in their analysis. Although various analytical strategies have been employed in analyzing phytosterols, chromatography linked to mass spectrometry (MS) is superior due to its sensitivity. Furthermore, specificity and selectivity are enhanced by utilizing tandem mass spectrometry (MS/MS). This article reviews the various mass spectrometric strategies used for the analysis of phytosterols. It highlights the applications and limitations associated with each MS strategy in various sample matrixes such as plant, human, animal, food, and dietary supplements. GC-MS was historically the method of choice for analysis; however, the derivatization step rendered it tedious and time-consuming. On the other hand, liquid chromatography coupled to MS (LC-MS) simplifies the analysis. Many ionization techniques have been used, namely, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI). APCI showed superiority in terms of ion intensity and consistency in ion formation, primarily forming [M + H - H₂O]⁺ ions rather than [M + H]⁺. In addition, matrix assisted laser desorption ionization (MALDI) as well as ambient mass spectrometry such as direct analysis in real time (DART) have also been evaluated.

A rapid method for the simultaneous quantification of the major tocopherols, carotenoids, free and esterified sterols in canola (Brassica napus) oil using normal phase liquid chromatography

A normal phase high performance liquid chromatography (HPLC) method was developed to simultaneously quantify several prominent bioactive compounds in canola oil vis. α-tocopherol, γ-tocopherol, δ-tocopherol, β-carotene, lutein, β-sitosterol, campesterol and brassicasterol. The use of sequential diode array detection (DAD) and tandem mass spectrometry (MS/MS) allowed direct injection of oils, diluted in hexane without derivatisation or saponification, greatly reducing sample preparation time, and permitting the quantification of both free sterols and intact sterol esters. Further advantages over existing methods included increased analytical selectivity, and a chromatographic run time substantially less than other reported normal phase methods. The HPLC-DAD-MS/MS method was applied to freshly extracted canola oil samples as well as commercially available canola, palm fruit, sunflower and olive oils.

Fast separation and determination of sterols in vegetable oils by ultraperformance liquid chromatography with atmospheric pressure chemical ionization mass spectrometry detection

A method for the determination of sterols in vegetable oils by ultraperformance liquid chromatography (UPLC) with atmospheric pressure chemical ionization mass spectrometry detection has been developed. The separation of sterols was optimized in terms of mobile phase composition, column temperature and flow rate. The optimal conditions were achieved using an Acquity UPLC BEH C18 column (50 x 2.1 mm, 1.7 microm) with a mobile phase consistent of acetonitrile/water (0.01% acetic acid) using a linear gradient, at a flow rate of 0.8 mL min(-1) and column temperature of 10 degrees C, giving a total analysis time below 5 min. The determination was performed in selective ion recording mode. The limits of detection were in all cases below 0.07 microg mL(-1), with relative standard deviation values of retention times and peak areas below 0.4 and 5%, respectively. The content of main sterols present in several vegetable oils with different botanical origins was also established.

Classification of extra virgin olive oils produced at La Comunitat Valenciana according to their genetic variety using sterol profiles established by high-performance liquid chromatography with mass spectrometry detection

A method to classify extra virgin olive oils (EVOOs) according to their genetic variety using sterol profiles obtained by high-performance liquid chromatography (HPLC) with mass spectrometry (MS) detection has been developed. Sterol extracts were chromatographed on a dC18 Atlantis column (100x3 mm, 3 microm) with a gradient of acetonitrile/water (0.01% acetic acid) at a flow rate of 1.0 mL min(-1) and positive-ion mode MS detection. Using linear discriminant analysis of the HPLC-MS data (extracted ion chromatograms), EVOO samples belonging to six genetic varieties cultivated at La Comunitat Valenciana, Spain (Arbequina, Borriolenca, Canetera, Farga, Picual, and Serrana), were correctly classified with an excellent resolution among all of the categories.

Classification of vegetable oils according to their botanical origin using sterol profiles established by direct infusion mass spectrometry

A simple and quick method to classify vegetable oils according to their botanical origin, based on direct infusion of sterol extracts into a mass spectrometer, was developed. Using mass spectrometry (MS) with either an electrospray ionization or an atmospheric pressure photoionization source, followed by linear discriminant analysis of the mass spectral data, oil samples corresponding to eight different botanical origins were perfectly classified with an excellent resolution among all the categories. An excellent correlation between the sterol profiles obtained by MS and by the official gas chromatography (with flame ionization detection) method was obtained. Thus, the proposed method is a promising alternative for sterol fingerprinting of vegetable oils, with the advantage that prior chromatographic separation is not required.