Chemical Fingerprinting, Total Phenolics and Antioxidant Activity of Some Iris Taxa

Ivan Duka,Željan Maleš,Mirza Bojić,Dario Hruševar,Božena Mitić

doi:10.5562/cca3673

Abstract

Some Iris taxa covered in this study were used or are still being used as remedies in European folk medicine. The most common indication for the decoction of Iris rhizomes is sore throat and productive cough, especially in case of the taxon I. domestica (L.) Goldblatt & Mabb., the well-known remedy in traditional Chinese medicine. The aim of this study is to chemically characterize rhizomes of seven wild and medicinal Iris taxa and to assess the antioxidant activity of the rhizome extracts. The HPTLC chromatograms and densitometric spectrum scan of the spots were used for untargeted metabolic profiling and tentative metabolite class identification of Iris taxa. Total number of found spots is 41, three major spots are found in all taxa, and 22 spots are found to be taxon specific. Two xanthones, three isoflavonoid glycosides, 18 isoflavonoid aglycons (isoflavonoids), and five acetophenones/benzophenones are tentatively identified. The taxon I. pallida Lam. contains largest amount of phenolic substances (28.5 ± 2.0 mg GAE / g dry plant material) and was the most effective ABTS scavenger (27.5 ± 2.4 mg TROLOXE / g dry plant material). The taxon I. illyrica Tomm. ex Vis. was the most effective in both DPPH and FRAP assays, 10.1 ± 1.5 and 17.3 ± 0.1 mg TROLOXE / g dry plant material, respectively. The most effective taxa in the metal chelating assay were I. croatica Horvat & M.D.Horvat (6.1 ± 0.1 mg EDTAE / g dry plant material) and I. germanica var. florentina (L.) Dykes (5.8 ± 0.1 mg EDTAE / g dry plant material). European Iris taxa have a relatively similar and partly shared chemical profile with Asian taxon I. domestica, which might be a sign of equivalence in the medicinal value. This work is licensed under a Creative Commons Attribution 4.0 International License .

Highlights

R HIZOMES of taxa of the genus Iris L. have been used in Croatian traditional medicine, as well as throughout Northern hemisphere where other taxa of the very numerous genus Iris are well known medicinal herbs in their respective habitat.[1]
Xanthones were tentatively identified based on characteristic absorption bands at 230–245 nm, 250–265 nm, 305–330 nm and 340–400 nm;[8] isoflavonoids are characterized by absorption maxima at 260–272 nm and shoulder peak at 310–340 nm;[12,18] and acetophenones/benzophenones by characteristic shape of the UV spectra and their absorption maxima on the shorter wavelengths comparing to the other two classes of compounds.[11]
Analysis performed in this study found that I. pallida is clustered primarily with I. adriatica, showing greater similarity in the chemical composition than is the case with supposed subspecies I. pseudopallida and I. illyrica

Summary

Introduction

R HIZOMES of taxa of the genus Iris L. have been used in Croatian traditional medicine, as well as throughout Northern hemisphere where other taxa of the very numerous genus Iris are well known medicinal herbs in their respective habitat.[1]. Florentina (L.) Dykes, which is considered as the valid plant material for Rhizoma Iridis[4], are included in this study. German commission E monograph on orris root (Rhizoma Iridis) features taxon I. pallida Lam. as the dalmatian sweet iris[4], the taxa from the series Pallidae native to Dalmatia are I. pseudopallida Trinajstić and I. illyrica Tomm. Another endemic tall bearded iris, I. croatica Horvat & M. Short-stemmed bearded I. adriatica Trinajstić ex Mitić, are tested due to the phylogenetic proximity to the medicinal taxa, which can affect their chemical composition

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Results

Conclusion