Free and Esterified Tocopherols, Tocotrienols and Other Extractable and Non-Extractable Tocochromanol-Related Molecules: Compendium of Knowledge, Future Perspectives and Recommendations for Chromatographic Techniques, Tools, and Approaches Used for Tocochromanol Determination

Abstract

Free and esterified (bound) tocopherols, tocotrienols and other tocochromanol-related compounds, often referred to “tocols”, are lipophilic antioxidants of great importance for health. For instance, α-tocopherol is the only tocochromanol with vitamin E activity, while tocotrienols have a positive impact on health and are proposed in the prevention and therapy of so-called modern diseases. Tocopherols, tocotrienols and plastochromanol-8 are the most well-known tocochromanols; in turn, knowledge about tocodienols, tocomonoenols, and other rare tocochromanol-related compounds is limited due to several challenges in analytical chemistry and/or low concentration in plant material. The presence of free, esterified, and non-extractable tocochromanols in plant material as well as their biological function, which may be of great scientific, agricultural and medicinal importance, is also poorly studied. Due to the lack of modern protocols as well as equipment and tools, for instance, techniques suitable for the efficient and simultaneous chromatographical separation of major and minor tocochromanols, the topic requires attention and new solutions, and/or standardization, and proper terminology. This review discusses the advantages and disadvantages of different chromatographic techniques, tools and approaches used for the separation and detection of different tocochromanols in plant material and foodstuffs. Sources of tocochromanols and procedures for obtaining different tocochromanol analytical standards are also described. Finally, future challenges are discussed and perspective green techniques for tocochromanol determination are proposed along with best practice recommendations. The present manuscript aims to present key aspects and protocols related to tocochromanol determination, correct identification, and the interpretation of obtained results.

Oilseed Radish: Nitrogen and Sulfur Management Strategies for Seed Yield and Quality—A Case Study in Poland

“…Tocopherols are naturally occurring antioxidants that contribute to the oxidative stability of vegetable oils [84,85]. Oilseed crops of the family Brassicaceae are a rich source of Ts [17,[84][85][86].…”

“…Tocopherols are naturally occurring antioxidants that contribute to the oxidative stability of vegetable oils [84,85]. Oilseed crops of the family Brassicaceae are a rich source of Ts [17,[84][85][86]. Oilseed rape seeds contain 9.0-46.0 mg 100 g −1 of Ts [17,87], with a predominance of γ-T (57-78%) and α-T (22-43%) [17,87].…”

“…Oilseed radish seeds are equally abundant in γ-T (11-12 mg 100 g −1 ), but they contain far less δ-T (~1.0-1.4 mg 100 g −1 ) and are practically devoid of α-T [17]. Cereal grain [85,[88][89][90], olive (Olea europaea L.), and sunflower (Helianthus annuus L.) seeds are rich sources of α-T [85,91,92]. In turn, δ-T is the dominant isomer in pumpkin (Cucurbita maxima Duchesne) seed oil [93] and seed oil from plants of the family Boraginaceae in the genus Borago, such as the starflower (Borago officinalis L.) [85,86].…”

“…Cereal grain [85,[88][89][90], olive (Olea europaea L.), and sunflower (Helianthus annuus L.) seeds are rich sources of α-T [85,91,92]. In turn, δ-T is the dominant isomer in pumpkin (Cucurbita maxima Duchesne) seed oil [93] and seed oil from plants of the family Boraginaceae in the genus Borago, such as the starflower (Borago officinalis L.) [85,86]. In the present study, the total content of Ts in the seeds of OSR cv.…”

Bleaching techniques impact on some quality parameters in two different cold‐pressed oils obtained at farm scale

“…Tocopherols, tocotrienols (the lasts absent in flax and hemp oils), and other tocochromanol‐related compounds are lipophilic antioxidants of great importance for health (Siger & Gornas, 2023). Among homologues tocopherols, α‐tocopherol is the only tocochromanol with vitamin E activity that meets the criteria of preventing vitamin E ataxia, a disease caused by a vitamin E deficiency in humans (Azzi, 2019; Górnas et al, 2022). Hempseed oil is known to be a good source of vitamin E with high antioxidant activity due to its high levels of tocopherols, which could play an important role in the protection of edible oils against lipid oxidation (Faugno et al, 2019; Ghazani & Marangoni, 2013).…”