Structural Analysis and Anti-Inflammatory Effect of a Digalactosyldiacylglycerol-Monoestolide, a Characteristic Glycolipid in Oats

• Published in: Nutrients 2022-10, Vol.14 (19), p.4153
• Main Authors: Yamada, Hiroki, Ito, Junya, Shimizu, Naoki, Takahashi, Takumi, Kato, Chikara, Parida, Isabella Supardi, Jutanom, Mirinthorn, Ishihara, Katsuyuki, Nakagawa, Kiyotaka
• Format: Article
• Language: English
• Subjects: Amino acids; Analysis; Anti-inflammatory drugs; anti-inflammatory effect; Avena sativa; Chemical properties; Chromatography; DGDG; DGDG-estolides; Diet therapy; FAHFA; Fatty acids; Functional foods; Functional foods & nutraceuticals; Glycolipids; Health aspects; Inflammation; Interleukin 10; Interleukin 6; Laboratories; Linoleic acid; Lipids; Lipopolysaccharides; Metabolites; Molecular structure; Nitric oxide; NMR; Nuclear magnetic resonance; Oats; Physiological aspects; Physiological effects; Physiology; Reagents; Spectrum analysis; Structural analysis; Tumor necrosis factor-α; Unsaturated fatty acids
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu14194153

Digalactosyldiacylglycerol- (DGDG-) monoestolide is a characteristic glycolipid in oats. DGDG-monoestolides possess a unique structure whereby a fatty acid of DGDG is replaced by a fatty acid ester of hydroxy fatty acid (FAHFA). While the physiological effects of DGDG and FAHFA have been reported previously, the effects of DGDG-monoestolides are unknown. Hence, we isolated a major DGDG-monoestolide molecular species from oats, analyzed its structure, and evaluated its anti-inflammatory effect. Based on GC-MS, MS/MS, and NMR analyses, the isolated compound was identified as a DGDG-monoestolide that contains the linoleic acid ester of 15-hydroxy linoleic acid (LAHLA) and linoleic acid (i.e., DGDG-LAHLA). The isolated DGDG-LAHLA was evaluated for its anti-inflammatory effect on LPS-stimulated RAW264 cells. The production of nitric oxide and cytokines (IL-6, TNF-α, and IL-10) were significantly decreased by DGDG-LAHLA, suggesting the anti-inflammatory effect of DGDG-LAHLA for the first time. In addition, our data showed a pronounced uptake of DGDG-LAHLA by cells. Some compounds corresponding to the predicted DGDG-LAHLA metabolites were also detected, suggesting that both intact DGDG-LAHLA and its metabolites may contribute to the above anti-inflammatory activities. These results are expected to expand the availability of oats as a functional food.