Biotransformation of Flavonoid Conjugates with Fatty Acids and Evaluations of Their Functionalities

Abstract

Enzymatic conjugation with fatty acids including omega-3 polyunsaturated fatty acids (ω-3 PUFAs) derived from fish oil to three citrus fruit-derived flavonoids: grapefruit extract, naringin, and neohesperidin dihydrochalcone were investigated. The conversions were achieved over 85% under the catalysis of lipase Novozyme 435 in acetone at 45°C at semi-preparative scale. The conjugates were purified via solvent partition and silica gel chromatography and achieved 90–98% in purity. The NMR analysis of the conjugates confirmed that the fatty acid carbon chain was linked onto the primary –OH group on the glucose moiety of the flavonoids. The purified flavonoid conjugates alongside their original flavonoids were analyzed for antioxidant activities via 2,2-diphenyl-1-picrylhydrazyl scavenging assay, and anti-peroxidation test via peroxide values measured during a 1-week fish oil storage trial. Vascular endothelial growth factor (VEGF) assay was conducted with 1, 10, and 100 μM of naringin and grapefruits and their conjugates, respectively, and total VEGF levels were measured at 24 and 48 h, respectively, using ELISA and dot blot analysis. The results from these functionality experiments demonstrated that flavonoid FA conjugates have at least comparable (if not higher) antioxidant activity, anti-peroxidation activity, and anti-angiogenic activity.

Application of accelerated solvent extraction coupled with online two‐dimensional countercurrent chromatography for continuous extraction and separation of bioactive compounds from Citrus limon peel

“…The MS and NMR data are presented in the Supporting Information. The 1 H and 13 C NMR data of the compounds acquired herein are consistent with the data in the literature [23][24][25][26][27][28].…”

“…β-Amyloid protein (Aβ) is widely considered to play a central role in the pathogenesis of AD [21]. In this study, the AChE inhibition assay and Aβ (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) -induced PC12 cell damage were used as in vitro means to evaluate the anti-AD activity of chemical compounds from the C. limon peel extract, and the metabolism of the main active ingredients of C. limon peel in rat liver microsomes (RLMs) were evaluated by in vitro metabolism of the microsomes [22]. The main metabolites were then studied via high-resolution MS where the risk of metabolic-based drug interactions can be predicted early in the drug discovery process using in vitro methods.…”

Contribution of Dietary PUFAs and Micronutrients in the Protection against Food Allergy Development

“…PUFAs alone are highly susceptible to lipid oxidation. Several studies report the protective antioxidative effect of different flavonoids on PUFAs [126][127][128][129]. Some vitamins have been described to exhibit a similar effect [130][131][132].…”

Biotransformation of hesperidin from lime peel (Citrus limettaRisso) in solid fermentation byAspergillus saitoi

“…The characteristic flavonoids in Citrus are flavanones and polymethoxylated flavones, which are relatively rare in other plants and are mostly localized in the peel (Manthey & Grohmann, 1996;Xi, Fang, Zhao, Jiao, & Zhou, 2014). Flavanones are usually glycosylated and, depending on the Citrus species, this glycosylation may be the rutinoside type, such as hesperidin in the orange (Citrus sinensis) and sweet lime (Citrus limetta), or neohesperidoside type, as in naringin in the grapefruit (Citrus paradise), or neohesperidin in the bitter orange (Citrus aurantium) (Tripoli, La Guardia, Giammanco, Di Majo, & Giammanco, 2007). Due to their structure, these flavonoids are highlighted due to their antioxidant activity, i.e., Free Radicals (FR) scavenging activity.…”

“…In addition to low bioavailability, glycosylated flavonoids exhibit low solubility and stability in commercial preparations, which restricts their use in many applications. The biotransformation of flavonoids includes these problems by altering the structure of the flavonoid while maintaining or improving its original bioactivity when is introduced a hydroxyl group (Sun, Johnson, Wong, & Foo, 2017). Additional benefits include an increase in antioxidant activity or metal chelating activity (Mellou et al, 2005), the formation of new compounds (Dymarska et al, 2017) and they may possess amphiphilic properties for expanding their commercial application.…”