Phenolic compounds in common buckwheat sprouts: composition, isolation, analysis and bioactivities.

Phenolic compounds in common buckwheat sprouts (CBSs) have gained research interest because of their multiple health benefits. Phenolic acids, flavanones, flavonols, flavan-3-ols, and anthocyanins are important bioactive components of CBS that exhibit biological activities, including anti-inflammatory, antioxidant, anti-proliferative, and immunomodulatory effects. The isolation and quantitative and qualitative analyses of these phenolic compounds require effective and appropriate extraction and analytical methods. The most recent analytical method developed for determining the phenolic profile is HPLC coupled with a UV-visible detector and/or MS. This review highlights the extraction, purification, analysis, and bioactive properties of phenolic compounds from CBS described in the literature.

Optimizing the ultrasound-assisted deep eutectic solvent extraction of flavonoids in common buckwheat sprouts.

In this study, deep eutectic solvents (DESs) coupled with ultrasound-assisted extraction (UAE) were evaluated and optimized for the extraction of major flavonoids from common buckwheat sprouts. Initially, 18 different choline chloride (CC)-based DESs were evaluated as potential extraction solvents, and 80% CCTG (CC-based DES composed of triethylene glycol and 20 vol% water) extracted significantly higher (p < 0.05) amounts of flavonoids than other DESs studied. The extraction efficiency of 80% CCTG was even higher (p < 0.05) than that of methanol for the extraction of vitexin and quercetin-3-O-robinobioside. Procedure using 80% CCTG and UAE were optimized; an extraction temperature of 56 °C and extraction time of 40 min were considered optimal. The optimized extraction procedure was reliable and efficient for the extraction of major flavonoids from common buckwheat sprouts. In addition, flavonoids could be efficiently recovered from DES extracts with high recovery yields (>97%) by using a C18 solid-phase extraction.

Effects of light sources on major flavonoids and antioxidant activity in common buckwheat sprouts.

It is known that flavonoids in sprouts were accumulated more under light irradiation than under dark. Light source affecting flavonoid accumulation in sprouts is still investigating. We evaluated the effects of light sources, including red, blue and fluorescent lights, on the flavonoid accumulation and antioxidant activity in common buckwheat sprouts. Experimental results showed that blue light significantly enhanced the contents of C-glycosylflavones, including orientin, vitexin and their isomers, and rutin and a rutin isomer. Sprouts grown under blue light exhibit also the highest total phenolics and total flavonoids as well as the highest antioxidant activities. It was found that isoorientin is the highest antioxidant flavonoid whereas numerous former studies suggested that rutin is a typical antioxidant compound in common buckwheat. These results indicated that blue light could be applied for enhancing not only the content of flavonoids but also antioxidant activity in common buckwheat sprouts.