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Chemical and Functional Properties of Amazonian Fruits
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Elaine Pessoa, Josilene Lima Serra, Hervé Rogez, Sylvain Darnet
The unsaturated lipid fraction of the Brazil nut is also rich in β-tocopherol. However, lower levels of α-tocopherol (11.3%) and γ-tocopherols (0.4%) are observed. The high β-tocopherol content, corresponding to 88% of the total tocopherols, is a peculiar characteristic of this oil and could be used as a marker of discrimination from other oils, such as soy oil and olive oil. The steroidal content is similar to olive oil, and β-sitosterol and squalene are the primary steroids found in the nut (Chunhieng et al., 2008; Cicero et al., 2018).
Vitamin E, α-Tocopherol
Published in Ruth G. Alscher, John L. Hess, Antioxidants in Higher Plants, 2017
Vitamin Ε belongs to a family of antioxidants that includes four methylated tocols, substituted with a phytyl chain, and the analogous tocotrienols, substituted with a geranylgeranyl chain (Figure l).2,14 Of the tocopherols, vitamin E, is the major constituent and contains the fully substituted benzoquinone ring, and is identified as 5,7,8-trimethyl tocol. The β-tocopherol (5,8-dimethyl tocol) and γ-tocopherol (7,8-dimethyl tocol) may exist as intermediates in the synthesis of vitamin Ε from the common precursor, δ-tocopherol (8-methyl tocol) (Figure 3). Although one might interconnect the pathways for the biosynthesis of these two classes of antioxidants,20 it is likely that there are similar but distinct methylation and cyclization steps for the synthesis of the tocols and the tocotrienols. Their synthesis may depend on both the site of synthesis and the availability of either phytyl pyrophosphate or geranylgeranyl pyrophosphate. The committed step for tocopherol biosynthesis is catalyzed by homogentisate decarboxylase phytyltrans-ferase.21 It is this cyclization step that forms the physiologically active d-isomer of the tocochromanols.
Annexes
Published in Claude Leray, Dietary Lipids for Healthy Brain Function, 2017
The amounts of vitamin E are expressed in milligram equivalents of α-tocopherol; the other vitamers are usually estimated by applying a specific coefficient (0.56 for β-tocopherol, 0.16 γ-tocopherol, 0.5 for δ-tocopherol, and 0.16 for α-tocotrienol).
Retinoic acid (all-trans) presents antioxidant properties within human ovary and reduces progesterone production by human granulosa cells
Published in Systems Biology in Reproductive Medicine, 2023
Bruno M. Fonseca, Rebeca Cruz, Beatriz Pinto, Lia Costa, Eduarda Felgueira, Pedro Oliveira, Susana Casal, Irene Rebelo
Fat extraction was performed on the basis of the Smedes method, with minor adjustments (Cruz and Casal 2018), using 2.5 mL portions of FF. The lipidic extract was analyzed by normal-phase HPLC (Jasco, Japan) equipped with DAD (Jasco MD – 4010, Japan), and a dual-channel fluorescence detector (FLD, Jasco FP – 4025, Japan) as described previously (Cruz and Casal 2018). Separation was achieved on a Luna silica column (100 mm × 3 mm; 3 µm, Phenomenex, USA), with a gradient of hexane and 1,4-dioxane. The standards α-tocopherol, β-tocopherol, γ-tocopherol, beta-carotene, lutein, retinyl palmitate and tocol (internal standard) were purchased from diverse suppliers. Quantification was based on fluorescence (tocopherols and retinols) and DAD (carotenes and lutein) signals.
Inflammation, oxidative stress and altered heat shock response in type 2 diabetes: the basis for new pharmacological and non-pharmacological interventions
Published in Archives of Physiology and Biochemistry, 2022
Gabriela Elisa Hirsch, Thiago Gomes Heck
Antioxidants act on the mitochondrial respiratory chain to protect the mitochondria and the whole cell (Kowaltowski and Vercesi 1999) against oxidative stress. There are studies in several models showing that oxidative stress in mitochondria is reduced by antioxidants as N-acetylcysteine, ubiquinol and β-tocopherol (Victor et al.2003, Victor et al.2004, Victor et al.2005, Dimitrovska 2018). However, since this antioxidants do not act specifically in this organelle, its efficacy is limited (Kagan 1994).