Ultra-high-performance liquid chromatography profiling method for chemical screening of proanthocyanidins in Czech hops

• Published in: Talanta (Oxford) Vol. 116; pp. 919 - 926
• Main Authors: Olsovska, J, Kamenik, Z, Cejka, P, Jurkova, M, Mikyska, A
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-11-2013
• Subjects: acetone; Acetone - chemistry; bioactive properties; Biocompatibility; Catechin; Catechin - analogs & derivatives; Catechin - isolation & purification; Chromatography, High Pressure Liquid - methods; Cluster Analysis; Crops; Czech Republic; Diseases; epigallocatechin; Flavan-3-ol; free radical scavengers; High-Throughput Screening Assays; Hops; Humulus - chemistry; Liquid chromatography; mass spectrometry; monitoring; Oligomers; PCA; prediction; Principal Component Analysis; Proanthocyanidins; Proanthocyanidins - analysis; Proanthocyanidins - chemistry; Profiling; Reproducibility of Results; screening; Solvents - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; TOF MS; UHPLC; ultra-performance liquid chromatography; varieties; Cluster analysis; Catechin; Profiling; Hops; UHPLC; TOF MS; Flavan-3-ol; Proanthocyanidins; PCA
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2013.07.067

Hops represent an important natural source of bioactive polyphenols, particularly proanthocyanidins, which can contribute to prevention of several civilization diseases, owing to their antioxidant and radical scavenging activity. We have developed a high-throughput ultra-high-performance liquid chromatography time-of-flight mass spectrometry profiling method, which can be used for monitoring of bioactive proanthocyanidins in hops. The method was applied for analysis of hops of four Czech varieties (Saaz, Sladek, Preminat and Agnus) from the 2011 crop (9 localities, 11 samples) and the 2012 crop (24 localities, 40 samples). Hop samples were extracted by acetone and the analytes were separated on the Acquity UPLC BEH Shield RP18 column. Partial validation of the method revealed a satisfactory intra-day repeatability of the method for retention times (relative standard deviation within 1.39%) as well as areas under the peaks (within 9.89%). Experimental data were evaluated using principal component analysis and cluster analysis. Significant amounts of di-, tri- and tetramer proanthocyanidins consisting of (epi)catechin and (epi)gallocatechin were found in the hop samples. The dependence of the proantocyanidin composition on both the variety and the growing locality was observed. Specifically, the traditional Saaz variety contained more frequently oligomers formed by (epi)catechin units only, whereas the varieties Premiant and Agnus produced oligomers consisting of (epi)catechin as well as (epi)gallocatechin units. The relative abundance of proanthocyanidins in studied hop varieties from the two crops, 2011 and 2012, did correspond to each other. In the further perspective, the method may also be used for prediction of qualitative marks or authenticity verification of hops.
•High-throughput profiling method for screening of hops varieties was developed.•Method is based on analysis of proanthocyanidins using UHPLC-TOF MS.•Statistical evaluation by PCA and cluster analysis was applied.•Correlation between the content of proanthocyanidins and hops variety was observed.•Method may also be extended and applied for authenticity verification of hops.