High Voltage Electrical Discharges as an Alternative Extraction Process of Phenolic and Volatile Compounds from Wild Thyme (Thymus serpyllum L.): In Silico and Experimental Approaches for Solubility Assessment.

Marinela Nutrizio,Luisa Mazza,Giovanna Ferrari,Gianpiero Pataro,Daniele Carullo,Anet Režek Jambrak,Farid Chemat,Serena Carpentieri,Mara Banović

doi:10.3390/molecules25184131

Marinela Nutrizio, Luisa Mazza + Show 7 more

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https://doi.org/10.3390/molecules25184131

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Abstract

The objective of this study was to evaluate the potential of green solvents for extractions of bioactive compounds (BACs) and essential oils from wild thyme (Thymus serpyllum L.) using theoretical and experimental procedures. Theoretical prediction was assessed by Hansen solubility parameters (HSPs) and conductor-like screening model for realistic solvents (COSMO-RS), to predict the most suitable solvents for extraction of BACs. An experimental procedure was performed by nonthermal technology high voltage electrical discharge (HVED) and it was compared with modified conventional extraction (CE). Obtained extracts were analyzed for chemical and physical changes during the treatment. Theoretical results for solution of BACs in ethanol and water, as green solvents, were confirmed by experimental results, while more accurate data was given by COSMO-RS assessment than HSPs. Results confirmed high potential of HVED for extraction of BACs and volatile compounds from wild thyme, in average, 2.03 times higher yield of extraction in terms of total phenolic content was found compared to CE. The main phenolic compound found in wild thyme extracts was rosmarinic acid, while the predominant volatile compound was carvacrol. Obtained extracts are considered safe and high-quality source reach in BACs that could be further used in functional food production.

Highlights

Nowadays, there is growing interest among consumers in functional food production
Rosmarinic acid was found in higher concentrations in high voltage electrical discharge (HVED) extracts compared to conventional extraction (CE) and it was higher with higher concentrations of ethanol, up to 50% in extracts
The sum of all bioactive compounds (BACs) measured by UPLC-MS/MS was compared with results of Total Phenolic Content (TPC) and correlation of 0.384 (Table S1) was found between UPLC-MS/MS results and TPC, which is the highest correlation compared to DPPH

Summary

Introduction

Functional foods can be defined as natural dietary items that, besides providing nutrients and energy, have health-promoting, disease-preventing, or medicinal properties [1]. Thymus serpyllum L., known as a wild thyme, is a species belonging to the Lamiaceae family that grows autochthonously in the Mediterranean area. This plant is rich in polyphenolic compounds and essential oils and shows antiseptic, antioxidative, anthelmintic, diaphoretic, antispasmodic, expectorant, carminative, analgesic and diuretic properties [3,4,5]. In order to produce functional foods from wild thyme, it is important to extract its bioactive compounds (BACs) and essential oils and obtain high-quality natural products. Some thermally sensitive nutritional compounds, like phenols and antioxidants, may be lost during processing [6]

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