Spectroscopic, Thermal, Microbiological, and Antioxidant Study of Alkali Metal 2-Hydroxyphenylacetates.

Mariola Samsonowicz,Grzegorz Świderski,Monika Kalinowska,Joanna Zwolińska,Elżbieta Wołejko,Włodzimierz Lewandowski,Urszula Wydro,Ewelina Gołębiewska

doi:10.3390/ma14247824

Mariola Samsonowicz, Grzegorz Świderski + Show 6 more

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https://doi.org/10.3390/ma14247824

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Abstract

The structural, spectral, thermal, and biological properties of hydroxyphenylacetic acid and lithium, sodium, potassium, rubidium, and cesium 2-hydroxyphenylacetates were analyzed by means of infrared spectroscopy FT-IR, electronic absorption spectroscopy UV-VIS, nuclear magnetic resonance 1H and 13C NMR, thermogravimetric analysis (TG/DSC), and quantum-chemical calculations at B3LYP/6-311++G** level. Moreover, the antioxidant (ABTS, FRAP, and CUPRAC assays), antibacterial (against E. coli, K. aerogenes, P. fluorescens, and B. subtilis) and antifungal (against C. albicans) properties of studied compounds were measured. The effect of alkali metal ions on the structure, thermal, and biological properties of 2-hydroxyphenylacetates was discussed.

Highlights

Polyphenols are a wide group of natural bioactive substances found in many food sources, such as fruits, vegetables, cereals, legumes, spices, cocoa, and plant-derived beverages [1,2]
The results of our research showed that metal chelates can be characterized by higher antioxidant activity than their parent ligands [26,30,31,32], but not in every case [21,33]
The differences in the wavenumber of bands derived from the carboxylate group νas (COO− ), νs (COO− ), βas (COO− ), and βs (COO− ) did not change regularly with the increase in the atomic mass of the alkali metal ions

Summary

Introduction

Polyphenols are a wide group of natural bioactive substances found in many food sources, such as fruits, vegetables, cereals, legumes, spices, cocoa, and plant-derived beverages [1,2] They are secondary metabolites of plants, involved in plant protection system against biotic (pathogens) and abiotic (e.g., exposure to cold, high temperatures, UV lights, drought, excessive water, salinity, or heavy metals) stress factors [3,4]. Colon microflora degrades dietary phenolic compounds into small molecules, highly bioavailable metabolites such as hydroxyphenolic acids. Their biological activity (including antioxidant and microbiological) is often higher than the parent molecules.

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