Iridoids, Phenolic Compounds and Antioxidant Activity of Edible Honeysuckle Berries (Lonicera caerulea var. kamtschatica Sevast.).

Anna Sokół-Łętowska,Narcyz Piórecki,Alicja Kucharska,Jan Oszmiański,Izabela Fecka

doi:10.3390/molecules22030405

Abstract

Iridoid and polyphenol profiles of 30 different honeysuckle berry cultivars and genotypes were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ion modes and quantified by HPLC-PDA. The 50 identified compounds included 15 iridoids, 6 anthocyanins, 9 flavonols, 2 flavanonols (dihydroflavonols), 5 flavones, 6 flavan-3-ols, and 7 phenolic acids. 8-epi-Loganic acid, pentosyl-loganic acid, taxifolin 7-O-dihexoside, and taxifolin 7-O-hexoside were identified in honeysuckle berries for the first time. Iridoids and anthocyanins were the major groups of bioactive compounds of honeysuckle constituents. The total content of quantified iridoids and anthocyanins was between 128.42 mg/100 g fresh weight (fw) (‘Dlinnoplodnaya’) and 372 mg/100 g fw (‘Kuvshinovidnaya’) and between 150.04 mg/100 g fw (‘Karina’) and 653.95 mg/100 g fw (‘Amur’), respectively. Among iridoids, loganic acid was the dominant compound, and it represented between 22% and 73% of the total amount of quantified iridoids in honeysuckle berry. A very strong correlation was observed between the antioxidant potential and the quantity of anthocyanins. High content of iridoids in honeysuckle berries can complement antioxidant properties of phenolic compounds.

Highlights

Edible honeysuckle berries (Lonicera caerulea L. var. kamtschatica Sevast.; Caprifoliaceae family) are gaining popularity in many European countries such as Russia, Poland, the Czech Republic, and others
We showed that for 7-epi-LA, ion [M − 162 − H]− was less stable in negative electrospray ionisation (ESI) mode, when the –OH group in C-7 is below the molecule plane; the ion appears after loss of water
22.86 μmol Trolox equivalent (TE)/g fw for ferric reducing antioxidant power ability of plasma (FRAP)) and ‘Karina’ (8.94 μmol TE/g fw for DPPH and 22.41 μmol TE/g fw for FRAP). These results showed that DPPH and FRAP assays for 30 cultivars and genotypes revealed the same trend

Summary

Introduction

Edible honeysuckle berries (Lonicera caerulea L. var. kamtschatica Sevast.; Caprifoliaceae family) are gaining popularity in many European countries such as Russia, Poland, the Czech Republic, and others. Kamtschatica Sevast.; Caprifoliaceae family) are gaining popularity in many European countries such as Russia, Poland, the Czech Republic, and others The attractiveness of these fruits derives from a number of factors, including early time of ripening (in Poland before strawberries), resistance to spring frost, flavor, high contents of vitamin C and polyphenol compounds, and health-related properties. The health benefits of honeysuckle berries have been known and used for a long time in traditional medicine in Russia and China. In addition to the anthocyanins, phenolic acids, flavonols, flavones and flavan-3-ols are present [3,4,7,8] Their contents vary in fruits, and depend on many factors, including cultivar and genotypes [9,10,11,12,13,14,15]. Among the 13 iridoids we have identified epimeric pairs of loganic acid and loganin, sweroside, secologanin, secoxyloganin, and pentosides of loganic acid (two isomers), pentosides of loganin (three isomers), and pentosyl-sweroside [19]

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