Identification and determination of isoflavones in germinated black soybean sprouts by UHPLC−Q-TOF-MS mass spectrometry and HPLC-DAD

Abstract

Ultra-performance liquid chromatography coupled with electrospray ionization tandem quadrupole time-of-flight mass spectrometry (UHPLC−Q-TOF-MS) and HPLC-DAD with an ultrasonic extraction method was developed for qualitative and quantitative compositions and contents in black soybean sprouts. Operational conditions of ultrasonic extraction were optimized by single-factor experiment. Phytochemical compositions of black soybean sprouts were identified by UHPLC−Q-TOF-MS in positive ion mode. A total of 23 compounds were tentatively characterized and identified by means of accurate mass and characteristic fragment ions. Among of them, the six isoflavones in different germinated black soybean sprouts were further quantified by HPLC-DAD. The results indicated that the calibration curves showed good linearity (r 2 > 0.9994). The intra-day and inter-day precision variations were less than 1.65% and 1.73%, respectively. The recoveries were in the range of 94.95-106.45%. The results indicated that the maximum amounts of isoflavones were produced on the fourth to fifth day germinated black soybean sprouts.

Comprehensive profiling of bioactive compounds in germinated black soybeans via UHPLC-ESI-QTOF-MS/MS and their anti-Alzheimer’s activity

“…While a higher level of (+)-catechin was identified in BS1 (Se-Um) sprouts. These findings are in accordance with Ren et al [23], who observed an increment in the isoflavones after germination. However, cyanidin 3-glucoside was identified higher (2 folds) in the seeds than sprouts.…”

Untitled

“…Similarly, peak 47, [M-H]m/z 299, the main product ions were at m/z 284 (base peak), due to the loss of CH 3 from the methoxy group of the aglycone, and at m/z 255 that represents the loss of carbonyl moiety. This pattern is in consistent with diosmetin33 .Isoflavones were represented by four peaks, showed UV absorption at λ max 250-280 nm, which suggests that they might be isoflavones: peak 44, showed a molecular ion m/z 253 with a an ion fragment of m/z 209, assigned to the loss of 44 amu (CO 2 moiety), and was identified as Diadezein34 . Peak 43, with molecular ion m/z 268 correspondings to C 16 H 12 O 4 and MS 2 fragmentation ions at m/z 238 [M-H-OCH 3 ] -, this is in accordance with the mass spectrum of formonetin 34 .…”

A brief history and spectroscopic analysis of soy isoflavones

“…The calculated molecular weight of each soy isoflavone is shown in Table 1. The analysis of soy isoflavones using tandem MS has been reported in detail with fragment ions and fragmentation patterns under positive and negative ionization modes (Kang et al, 2007;Otieno et al, 2007;Raju et al, 2015;Ren et al, 2017).…”