Flavan-3-ols and Proanthocyanidins in Japanese, Bohemian and Giant Knotweed.

Maja Bensa,Vesna Glavnik,Irena Vovk

doi:10.3390/plants10020402

Maja Bensa, Vesna Glavnik + Show 1 more

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https://doi.org/10.3390/plants10020402

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Abstract

Flavan-3-ols and proanthocyanidins of invasive alien plants Japanese knotweed (Fallopia japonica Houtt.), giant knotweed (Fallopia sachalinensis F. Schmidt) and Bohemian knotweed (Fal lo pia × bohemica (Chrtek & Chrtkova) J.P. Bailey) were investigated using high performance thin-layer chromatography (HPTLC) coupled to densitometry, image analysis and mass spectrometry (HPTLC–MS/MS). (+)-Catechin, (−)-epicatechin, (−)-epicatechin gallate and procyanidin B2 were found in rhizomes of these three species, and for the first time in Bohemian knotweed. (−)-Epicatechin gallate, procyanidin B1, procyanidin B2 and procyanidin C1 were found in giant knotweed rhizomes for the first time. Rhizomes of Bohemian and giant knotweed have the same chemical profiles of proanthocyanidins with respect to the degree of polymerization and with respect to gallates. Japanese and Bohemian knotweed have equal chromatographic fingerprint profiles with the additional peak not present in giant knotweed. Within the individual species giant knotweed rhizomes and leaves have the most similar fingerprints, while the fingerprints of Japanese and Bohemian knotweed rhizomes have additional peaks not found in leaves. Rhizomes of all three species proved to be a rich source of proanthocyanidins, with the highest content in Japanese and the lowest in Bohemian knotweed (based on the total peak areas). The contents of monomers in Japanese, Bohemian and giant knotweed rhizomes were 2.99 kg/t of dry mass (DM), 1.52 kg/t DM, 2.36 kg/t DM, respectively, while the contents of dimers were 2.81 kg/t DM, 1.09 kg/t DM, 2.17 kg/t DM, respectively. All B-type proanthocyanidins from monomers to decamers (monomers—flavan-3-ols, dimers, trimers, tetramers, pentamers, hexamers, heptamers, octamers, nonamers and decamers) and some of their gallates (monomer gallates, dimer gallates, dimer digallates, trimer gallates, tetramer gallates, pentamer gallates and hexamer gallates) were identified in rhizomes of Bohemian knotweed and giant knotweed. Pentamer gallates, hexamers, hexamer gallates, nonamers and decamers were identified for the first time in this study in Bohemian and giant knotweed rhizomes.

Highlights

The aim of our work was to: (1) obtain chromatographic fingerprints for rhizomes of Japanese, Bohemian and giant knotweed; (2) compare chromatographic fingerprints for rhizomes and leaves of the same knotweed species; (3) compare the total contents of flavan-3-ol and dimers in all three knotweeds; (4) evaluate the contents of proanthocyanidins in all three knotweeds based on the total peak area; (5) identify proanthocyanidins in rhizomes of Bohemian and giant knotweeds using high performance thin-layer chromatography coupled to mass spectrometry (HPTLC–MS)
Qualitative analyses of flavan-3-ols and proanthocyanidins in the sample test solutions (STSs) prepared from rhizomes of Japanese, Bohemian and giant knotweed were performed using the high performance thin-layer chromatography (HPTLC) method on the HPTLC silica gel plates developed with toluene–acetone–formic acid (3:6:1, v/v) [9,16]
After the completion of the HPTLC–MS/MS analyses, the plate was documented with the DigiStore 2 system at white light illumination in order to connect the MS, MS2, and MS3 spectra with RF s on the plate. This is the first report about: (1) comparison of HPTLC chromatographic fingerprints of rhizomes of Japanese, Bohemian and giant knotweed; (2) comparisons of chromatographic fingerprints for rhizomes and leaves of the same knotweed species; (3) quantifications of the total content of monomers and procyanidin dimers in rhi zomes of all three knotweed species; (4) evaluations of rhizomes of the three knotweed species based on comparisons of B-type proanthocyanidins total peak areas; (5) evaluations of the contents of proanthocyanidins in rhizomes of all three knotweeds based on the total peak area; (6) analyses and identification of all B-type proanthocyanidins from monomers to decamers and some of their gallates in Bohemian and giant knotweed using HPTLC–MS

Summary

Introduction

This study examines three perennial herbaceous plants that belong to the genus Fallopia and the family Polygonaceae and are globally very problematic invasive alien plant species. The studied plants were: (1) Japanese knotweed Schmidt); and (3) Bohemian knotweed (Fallopia × bohemica (Chrtek & Chrtkova) J.P. Bailey; synonyms: Reynoutria × bohemica

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