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Antioxidants from Natural Sources: Separation and Characterization Ⅱ

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: 30 April 2024 | Viewed by 8468

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Prof. Dr. Petras Rimantas Venskutonis

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Department of Food Science and Technology, Kaunas University of Technology, Kaunas, Lithuania
Interests: isolation; fractionation, and characterization of natural antioxidants and other substances from various natural sources which are valuable for human consumption; particularly plant-origin materials and their processing byproducts; preferably using methods meeting green chemistry principles
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Dr. Michail Syrpas

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Guest Editor

Department of Food Science and Technology, Bioprocess Research Centre, Kaunas University of Technology, Kaunas, Lithuania
Interests: algal biotechnology; natural product chemistry; chromatography; bioactivity; extraction; antioxidants; food waste valorization

Special Issue Information

Dear Colleagues,

Through long periods of evolution, living organisms have developed various self-protection mechanisms and have learned to biosynthesize a vast diversity of molecules that are important for survival, antioxidant properties possessing microconstituents being among them. The interest in the discovery of the natural antioxidant structures, their isolation, purification, and, finally, application in foods, nutraceuticals, cosmeceuticals, and pharmaceuticals has demonstrated a remarkable increase in the last few decades. Consumer preferences towards natural additives and ingredients in foods and other products for human consumption have also fostered the search for and the characterization of natural antioxidants. To date, thousands of antioxidants belonging to various chemical classes have been isolated and characterized. For instance, a large number of polyphenolics antioxidants such as flavonoids, phenolic acids and their derivatives, carotenoids, terpenoids, vitamins, among others, have been identified and quantified in various plants, while many antioxidant peptides have been reported in materials of animal and marine origin. However, regardless of the various considerable scientific achievements, their industrial production and commercialization still remains a challenge that requires technological upscaling solutions and the development of economically feasible processes. Natural antioxidants are usually incorporated in a very complex biomatrix, and their content may be rather small; therefore, the development of effective separation methods for natural antioxidants remains a topical research issue. Depending on the expected application, the process may include several steps, including isolation, fractionation, and purification. From this point of view, nutraceutical, cosmeceutical, and pharmaceutical applications require standardized ingredients with the specified purity and concentration of active constituents. Last but not least, green chemistry principles and the use of biorefining concepts for developing zero-waste technological schemes have also become very important issues in modern society. The results of original studies as well as review manuscripts covering the above-defined topics are invited for submission to this Special Issue of Molecules.

Prof. Dr. Petras Rimantas Venskutonis
Dr. Michail Syrpas
Guest Editors

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Keywords

extraction of natural antioxidants
fractionation of natural antioxidants
purification of natural antioxidants
biorefining of natural sources for antioxidants
characterization of natural antioxidants
radical scavenging capacity
chromatographic analysis of antioxidants
spectroscopic analysis of antioxidants
bio-guided assays of antioxidants

Published Papers (6 papers)

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Research

15 pages, 2896 KiB

Open AccessArticle

Post-Chromatographic Derivatization Coupled with Mass Spectrometry as a Method of Profiling and Identification of Antioxidants; Ligustrum vulgare Phytocomplex as an Example

by Szymon Litewski, Marika Mróz, Agnieszka Bartoszek and Barbara Kusznierewicz

Molecules 2023, 28(24), 8000; https://doi.org/10.3390/molecules28248000 - 07 Dec 2023

Cited by 1 | Viewed by 790

Abstract

High-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) coupled with radical scavenging assays, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) can be both used for the detection of the antioxidants in plant extracts. In this study, the ethanolic (70% v/v) extracts from different morphological parts of Ligustrum vulgare collected at different stages of maturity were used as the source of antioxidants. The final identification of antioxidants was performed using high-resolution mass spectroscopy (HRMS). As a result, 19 compounds with antioxidant properties detected with HPLC-ABTS assay and 10 compounds detected with HPTLC-DPPH/ABTS assay were identified, mostly from the group of iridoids, phenylethanoids, and flavonoids. When comparing different L. vulgare samples, it was found that the extracts obtained from leaves contained the greatest number of antioxidants. The results of this study suggest that HPTLC-DPPH/ABTS as well as HPLC-ABTS derivatization coupled with the HRMS can be successfully used for profiling and identification of antioxidants from natural sources. Planar chromatography is more suitable for screening multiple samples because of its simplicity, whereas more challenging liquid chromatography provides more detailed information and is therefore better for a selected set of samples. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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12 pages, 649 KiB

Open AccessArticle

Antioxidant and Hypolipidemic Activities of Cinnamic Acid Derivatives

by Christina Nouni, Panagiotis Theodosis-Nobelos and Eleni A. Rekka

Molecules 2023, 28(18), 6732; https://doi.org/10.3390/molecules28186732 - 21 Sep 2023

Cited by 2 | Viewed by 916

Abstract

Oxidative stress and hyperlipidemia are important factors for the initiation and progression of various cell degenerative pathological conditions, including cardiovascular and neurological diseases. A series of cinnamic acid-derived acids, such as ferulic acid, sinapic acid, 3,4-dimethoxycinnamic acid, p-coumaric acid, and (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid, were esterified or amidated with various moieties, bearing different biological activities, and evaluated. The antioxidant and radical scavenging abilities of the compounds via inhibition of rat hepatic microsomal membrane lipid peroxidation, as well as their interaction with the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), were assessed. Further, their hypolipidemic activity in vivo was tested. The majority of the obtained compounds demonstrated considerable radical scavenging and antioxidant action, with a parallel decrease in Triton-induced hyperlipidemia in rats. The (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid derivative with morpholine and 4-methylpiperidine (compounds 4 and 13, respectively) significantly decreased triglycerides and total cholesterol in the plasma of hyperlipidemic rats, with an antioxidant capacity similar to that of the antioxidant Trolox. The compounds were designed to exhibit antioxidant and hypolipidemic pharmacological actions, and this succeeded for the majority of them. Thus, such agents may be of interest in conditions and diseases implicating oxidative stress and dyslipidemia. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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19 pages, 2619 KiB

Open AccessArticle

Sustainable Recovery of Phenolic Compounds from Distilled Rosemary By-Product Using Green Extraction Methods: Optimization, Comparison, and Antioxidant Activity

by Maria Irakli, Adriana Skendi, Elisavet Bouloumpasi, Stamatia Christaki, Costas G. Biliaderis and Paschalina Chatzopoulou

Molecules 2023, 28(18), 6669; https://doi.org/10.3390/molecules28186669 - 17 Sep 2023

Cited by 4 | Viewed by 1657

Abstract

Rosemary solid distillation waste (SWR), a by-product of the essential oil industry, represents an important source of phenolic antioxidants. Green technologies such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and accelerated solvent extraction (ASE) of phenolic compounds from SWR were optimized as valorization routes to maximize yield, rosmarinic acid (RMA), carnosol (CARO) and carnosic acid (CARA) contents. Response surface methodology was used in this context, with ethanol concentration (X₁), extraction temperature (X₂), and time (X₃) being the independent variables. A second-order polynomial model was fitted to the data, and multiple regression analysis and analysis of variance were used to determine model fitness and optimal conditions. Ethanol concentration was the most influential extraction parameter, affecting phenolic compounds, while the influence of other parameters was moderate. The optimized conditions were as follows: X₁: 67.4, 80.0, and 59.0%, X₂: 70, 51, and 125 °C, and X₃: 15, 10, and 7 min for MAE, UAE, and ASE, respectively. A comparison of optimized MAE, UAE, and ASE with conventional Soxhlet extraction techniques indicated that ASE provided a higher extraction yield and content of phenolic compounds. However, UAE represented the best process from an environmental point of view, allowing an improved extraction of phenolics from SWR with high energy efficiency and low energy costs. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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12 pages, 850 KiB

Open AccessArticle

Optimization of the Acid Cleavage of Proanthocyanidins and Other Polyphenols Extracted from Plant Matrices

by Jesus N. S. Souza, Tatiana Tolosa, Bruno Teixeira, Fábio Moura, Evaldo Silva and Hervé Rogez

Molecules 2023, 28(1), 66; https://doi.org/10.3390/molecules28010066 - 21 Dec 2022

Cited by 1 | Viewed by 990

Abstract

The chemical mechanism of the acid cleavage of proanthocyanidins (PAs) has been known for decades but has yet to be optimized. Therefore, we optimized this process in Byrsonima crassifolia, Euterpe oleracea and Inga edulis extracts using the response surface methodology and assessed the effect of hydrochloric acid concentration (0.3–3.7 N), time (39–291 min), and temperature (56–98 °C) on the following response variables: PAs reduction, astringency reduction, antioxidant capacity/total polyphenols (TEAC/TP) ratio, and cyanidin content. The response variables were maximized when cleavage was performed with 3 N HCl at 88 °C for 165 min. Under these conditions, the mean PAs value and astringency in the three extracts decreased by 91% and 75%, respectively, the TEAC/TP ratio remained unchanged after treatment (p > 0.05), and the increase in cyanidin confirmed the occurrence of cleavage. Thus, the results suggest that acid cleavage efficiently minimizes undesirable technological PAs characteristics, expanding the industrial applications. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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10 pages, 3485 KiB

Open AccessArticle

Extraction with Acidified Methanol—An Easy and Effective Method of Methyl Chlorogenate Formation, as Studied by ESI-MS

by Karolina Szymborska, Rafał Frański and Monika Beszterda-Buszczak

Molecules 2022, 27(21), 7543; https://doi.org/10.3390/molecules27217543 - 03 Nov 2022

Cited by 2 | Viewed by 1875

Abstract

Among the different Hawthorn species, Crataegus monogyna seems to be one of the most often used in herbal medicine, and is commercially available. The methanolic extract and the acidified methanol extract of an herbal medicinal product based on Crataegus monogyna inflorescences were analyzed by using high-pressure liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS). On the basis of m/z of [M-H]⁻ ions and characteristic fragmentation patterns, a number of polyphenolic compounds, namely flavonoids and chlorogenic acids, were identified. It was found that the contents of the acid extract were enriched with methyl chlorogenates showing attractive biochemical properties. Analogous results were obtained for other plant materials, e.g., nectarine kernels. Apart from that, acid extraction had a minor influence on the polyphenolic compounds present in the plants, and thus it did not affect the natural antioxidant values of the plant extracts. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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14 pages, 2694 KiB

Open AccessArticle

Optimization of 5-CQA Extraction Conditions from Green Coffee By-Product (Coffea arabica) Using a Response-Surface Design and the Study of Its Extraction Kinetics

by Miriam Granados-Vallejo, Enrique Arriola-Guevara, Rosa Isela Corona-González, David Antonio Flores-Méndez, José Daniel Padilla-de la Rosa, Hugo Esquivel-Solis, Carlos Pelayo-Ortiz and Guadalupe María Guatemala-Morales

Molecules 2022, 27(17), 5704; https://doi.org/10.3390/molecules27175704 - 04 Sep 2022

Cited by 2 | Viewed by 1557

Abstract

To take advantage of the residues generated in the production of products from green coffee and due to the special interest in the compounds contained in the bean, a by-product obtained after the extraction of the oil was studied. The physical characterization of the green-coffee-bean by-product was carried out. Subsequently, the extraction of compound 5-CQA was carried out via leaching using central composition design 2⁴ and evaluating factors such as temperature, time, solid/solvent ratio, and ethanol percentage, and its yield was quantified using HPLC. In addition, the response-surface methodology was used to maximize the efficiency of 5-CQA extraction and to perform the kinetic study. Yields of 59 ± 2 mg of 5-CQA/g from the by-product were obtained, and by selecting the best leaching conditions, the kinetic study was performed at 45, 60, and 75 °C, increasing the yield to a total of 61.8 ± 3 mg of 5-CQA/g. By applying the kinetic model of mass transfer, a fit of R² > 0.97 was obtained, with

K_{L} a

values between 0.266 and 0.320 min⁻¹. This study showed an approach to optimize the 5-CQA extraction conditions, resulting in a simple, fast, reproducible, accurate, and low-cost method. Full article

(This article belongs to the Special Issue Antioxidants from Natural Sources: Separation and Characterization Ⅱ)

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