Buckwheat bioactive compounds, their derived phenolic metabolites and their health benefits.

SCOPE: Buckwheat (BW) consumption has been associated with a broad range of health benefits: antioxidant, anti-inflammatory and anticancer. These beneficial effects have been partially related to the presence of flavonoids. However, some of these compounds (i.e., rutin and quercetin) are metabolized in the gastrointestinal tract generating derived phenolic metabolites. In this study, we investigated the biological activity of rutin (Ru), quercetin (Q) an their derived phenolic metabolites 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), 3-hydroxyphenylacetic acid (3-HPAA), and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid, HVA).

METHODS AND RESULTS: Q showed the highest antioxidant and reducing activity, and Ru the maximum chelating activity (85.33%). Antioxidant activity of 3,4-DHPAA was 5-fold higher than that of HVA, whereas their reducing activity was similar. The formation of methylglyoxal (MGO)-BSA and glucose-BSA (advanced glycation end products) was inhibited by Ru (98.5 and 92.7%), Q (95.6 and 89.1%) and 3,4-DHPPA (84.4.6 and 77.5%). Furthermore, Q (10-50 μM) and Ru (1-50 μM) downregulated the release of PGE2 , IL-8 and MCP-1, molecules involved in the inflammatory response, in IL1β-inflamed myofibroblasts of colon CCD-18Co.

CONCLUSION: This study suggests that BW phytochemicals and their phenolic metabolites may be responsible for the beneficial effects against chronic diseases attributed to BW consumption.