Developing and Validating a Method for Separating Flavonoid Isomers in Common Buckwheat Sprouts Using HPLC-PDA

Abstract

Buckwheat sprouts that are synthesized during the germination process are rich in flavonoids, including orientin, vitexin, rutin, and their isomers (isoorientin, isovitexin, and quercetin-3-O-robinobioside, respectively). The purpose of this study was to optimize and validate an analytical method for separating flavonoid isomers in common buckwheat sprout extract (CSE). Factors, such as range, linearity, precision, accuracy, limit of detection, and limit of quantification, were evaluated for each standard using high-performance liquid chromatography (HPLC). On the basis of resolution and symmetry, a column temperature of 40 °C with 0.1% (v/v) acidic water and acetonitrile as mobile phases, at a flow rate of 1 mL min−1 were determined to be the optimal analytical conditions. Calibration curves for orientin, isoorientin, vitexin, isovitexin, and rutin exhibited good linearity with correlation coefficients of 0.9999 over the 6.25–100.00 μg mL−1 range. Recovery values of 96.67–103.60% confirmed that the method was accurate for all flavonoids. The relative standard deviations of intra-day repeatability and inter-day reproducibility confirmed method preciseness, with values of less than 5.21% and 5.40%, respectively. The developed method was used to analyze flavonoids in CSE, with isomers satisfactorily separated and simultaneously quantified. We demonstrated that the developed HPLC method can be used to monitor flavonoids in buckwheat sprouts.

Polyphenol profile of buckwheat honey, nectar and pollen

“…Aglycones are more potent antioxidants than corresponding glycosides, but the glucose portion can enhance the bioavailability of compounds [ 49 ]. Isomers of flavone 6- C- glycosides and flavone 8- C- glycosides were differentiated in buckwheat sprouts [ 50 ]. In our study, luteolin 6- C- hexoside and luteolin 8- C- hexoside were found in buckwheat honey from Poland.…”

A brief history and spectroscopic analysis of soy isoflavones

“…Despite this, acetonitrile has a higher elution strength, faster retention time, and lower viscosity than methanol for PR-LC. Therefore, acetonitrile allows a short analysis time and high performance (Jang et al, 2019;Welch et al, 2009).…”

“…In general, higher column oven temperatures improve separation and reduce analysis time but restrict the column lifetime and stability of analyzed compounds such as isoflavone glucosides (Mathias et al, 2006). Simultaneous analyses of the flavone and flavonol isomers showed good separation when the temperature of the column oven was 40°C rather than 20°C (Jang et al, 2019). Isoflavones, however, had the highest resolution at 25°C rather than 40°C (Baranowska and Magiera, 2011).…”

Determination of isovitexin from Lespedeza cuneata using a validated HPLC-UV method

“…Analytical studies regarding the quantification of isovitexin from other plant sources such as buckwheat sprouts have already been established [21]. This compound was also found and analyzed in plants such as Passiflora, pigeon pea, wheat leaves, mimosa, bamboo; it was also screened as a bioactive integrant [13,[22][23][24][25][26][27].…”