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Kim, Backki,Woo, Sunmin,Kim, Mi-Jung,Kwon, Soon-Wook,Lee, Joohyun,Sung, Sang Hyun,Koh, Hee-Jong Elsevier 2018 Food chemistry Vol.241 No.-
<P><B>Abstract</B></P> <P>Flavonoids are naturally occurring phenolic compounds with potential health-promoting activities. Although anthocyanins and phenolic acids in coloured rice have been investigated, few studies have focused on flavonoids. Herein, we analysed flavonoids in a yellow grain rice mutant using UHPLC-DAD-ESI-Q-TOF-MS, and identified 19 flavonoids by comparing retention times and accurate mass measurements. Among them, six flavonoids, isoorientin, isoorientin 2″-<I>O</I>-glucoside, vitexin 2″-<I>O</I>-glucoside, isovitexin, isoscoparin 2″-<I>O</I>-glucoside and isoscoparin, were isolated and fully identified from the yellow grain rice mutant, and the levels were significantly higher than wild-type, with isoorientin particularly abundant in mutant embryo. Significant differences in total phenolic compounds and antioxidant activity were observed in mutant rice by DPPH, FRAP and TEAC assays. The results suggest that the representative six flavonoids may play an important role in colouration and antioxidant activity of embryo and endosperm tissue. The findings provide insight into flavonoid biosynthesis and the possibility of improving functionality in rice.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High level of flavonoids containing rice mutant is reported for the first time. </LI> <LI> 19 flavonoids were identified or tentatively identified in a yellow grain mutant by UHPLC-DAD-ESI-Q-TOF-MS. </LI> <LI> Isoorientin was particularly abundant in embryo tissue. </LI> <LI> Yellow grain mutant showed the high phenolic content and antioxidant activity. </LI> </UL> </P>
Kim, E.H.,Seo, H.S.,Ki, N.Y.,Park, N.H.,Lee, W.,Do, J.A.,Park, S.,Baek, S.Y.,Moon, B.,Oh, H.B.,Hong, J. Elsevier 2017 Journal of Chromatography A Vol.1491 No.-
<P>An analytical method for the reliable screening and confirmation of 156 illegal drugs (58 erectile dysfunction drugs, 49 synthetic steroids, 26 anabolic steroids, and 23 anti-histamine drugs) in supplementary diets using ultra-high-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UHPLC-QJTOF-MS) was developed. Various types of supplements (liquid, capsule, powder, pill and tablet) with complicated matrices were pretreated by simple liquid-liquid extraction. The wide scope of 156 target compounds was effectively determined within 15 min in the positive ion mode, detecting the compounds at a sub-ppb level. Their MS/MS spectra were preferentially investigated to find diagnostic common ions according to the structural similarity of diverse adulterants. For the rapid screening of multiple classes of the target adulterants, extracted common ion chromatograms (ECICs) based on specific fragments of similar molecular moieties were attempted. A database including the elemental compositions, retention times, and MS/MS spectra was built for the confirmation of adulterants. The established method was validated in terms of the linearity, limits of detection (LOD), precision, and accuracy. The linear correlation coefficient and limit of detection ranged from 0.9880 to 1 and from 0.02 to 16.04 ng/mL, respectively. The precision and accuracy of intra-and inter-day experiments for the spiked samples at the range of 0.2 and 16.0 ng/mL were from 0.16 to 13.50% and 0.19-11.48%, respectively, with relative standard deviation. Mean recoveries ranged from 81.6 to 124.7%, and relative standard deviation was less than 9.20%. The screening and confirmation method demonstrated the usefulness of UHPLCQJTOF-MS combined with ECICs as a promising approach for the analysis of multi-class adulterants. Finally, the established method was successfully applied for the monitoring of several types of dietary supplements in routine analysis. (C) 2017 Elsevier B.V. All rights reserved.</P>