Submit to Molecules Review for Molecules Propose a Special Issue

Journal Menu

Journal Browser

Exploitation of Natural Antioxidants: Isolation and Purification Techniques

Special Issue Editors
Special Issue Information
Keywords
Published Papers

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

Deadline for manuscript submissions: closed (30 September 2020) | Viewed by 20584

Share This Special Issue

Special Issue Editor

Prof. Dr. Vassiliki Oreopoulou

E-Mail Website
Guest Editor

National Technical University of Athens, Athens, Greece
Interests: antioxidants; polyphenols; extraction techniques; analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent decades, natural antioxidants have been broadly investigated and numerous articles have been published focusing on their isolation and identification from vegetables, cereals, seeds, aromatic herbs, and several agro-industrial by-products. Both the food and cosmetic industry are highly interested in the application of natural antioxidants in their products due to consumer preference for “natural” instead of “synthetic” additives. Moreover, terms like “polyphenols” and “bioflavonoids” are very appealing to consumers, as they have been related to health effects and anti-aging attributes. Although extensive data can be found in the literature about natural antioxidants encountered in vegetable and animal sources, few published works deal with extraction and purification methods. The development of appropriate isolation and purification techniques is indispensable for the industrial exploitation of natural antioxidants. Previously unpublished manuscripts that focus on isolation/extraction methods or examine purification techniques of the raw extracts, with the aim to prepare a ready-to-use additive of high antioxidant capacity are welcome for this Special Issue.

Prof. Vassiliki Oreopoulou
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Natural antioxidants
isolation
extraction
purification
exploitation

Published Papers (5 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

23 pages, 2577 KiB

Open AccessArticle

Extraction Kinetics of Phenolic Antioxidants from the Hydro Distillation Residues of Rosemary and Effect of Pretreatment and Extraction Parameters

by Irini Psarrou, Antigoni Oreopoulou, Dimitrios Tsimogiannis and Vassiliki Oreopoulou

Molecules 2020, 25(19), 4520; https://doi.org/10.3390/molecules25194520 - 02 Oct 2020

Cited by 23 | Viewed by 3145

Abstract

Rosemary residue, remaining after the distillation of essential oil, is currently unexploited, while it is a source of phenolic antioxidant components. This raw material was used for the extraction of phenolic compounds by aqueous ethanol or acetone in a continuously stirred reactor. The experimental results were fitted with a two-stage diffusion model. The highest extraction rates, total phenolic content (TPC) recovery, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity were obtained by acetone 60% and ethanol 60%. Grinding of the raw material enhanced the extraction rate and increased TPC yield and antioxidant capacity as the particle size decreased. Pre-treatment by maceration in water (4 h) dissolved a high amount of TPC and shortened the extraction time, while the combination with the pulsed electric field process did not provide further improvement. The use of ultrasound increased the efficiency of the extraction. Full article

(This article belongs to the Special Issue Exploitation of Natural Antioxidants: Isolation and Purification Techniques)

► Show Figures

Figure 1

14 pages, 2541 KiB

Open AccessArticle

Rana chensinensis Ovum Oil Based on CO₂ Supercritical Fluid Extraction: Response Surface Methodology Optimization and Unsaturated Fatty Acid Ingredient Analysis

by Yuanshuai Gan, Dongliang Xu, Jianqiu Zhang, Zhongyao Wang, Shihan Wang, Hongye Guo, Kexin Zhang, Yajing Li and Yongsheng Wang

Molecules 2020, 25(18), 4170; https://doi.org/10.3390/molecules25184170 - 11 Sep 2020

Cited by 13 | Viewed by 5159

Abstract

Rana chensinensis ovum oil (RCOO) is an emerging source of unsaturated fatty acids (UFAs), but it is lacking in green and efficient extraction methods. In this work, using the response surface strategy, we developed a green and efficient CO₂ supercritical fluid extraction (CO₂-SFE) technology for RCOO. The response surface methodology (RSM), based on the Box–Behnken Design (BBD), was used to investigate the influence of four independent factors (pressure, flow, temperature, and time) on the yield of RCOO in the CO₂-SFE process, and UPLC-ESI-Q-TOP-MS and HPLC were used to identify and analyze the principal UFA components of RCOO. According to the BBD response surface model, the optimal CO₂-SFE condition of RCOO was pressure 29 MPa, flow 82 L/h, temperature 50 °C, and time 132 min, and the corresponding predicted optimal yield was 13.61%. The actual optimal yield obtained from the model verification was 13.29 ± 0.37%, and the average error with the predicted value was 0.38 ± 0.27%. The six principal UFAs identified in RCOO included eicosapentaenoic acid (EPA), α-linolenic acid (ALA), docosahexaenoic acid (DHA), arachidonic acid (ARA), linoleic acid (LA), and oleic acid (OA), which were important biologically active ingredients in RCOO. Pearson correlation analysis showed that the yield of these UFAs was closely related to the yield of RCOO (the correlation coefficients were greater than 0.9). Therefore, under optimal conditions, the yield of RCOO and principal UFAs always reached the optimal value at the same time. Based on the above results, this work realized the optimization of CO₂-SFE green extraction process and the confirmation of principal bioactive ingredients of the extract, which laid a foundation for the green production of RCOO. Full article

(This article belongs to the Special Issue Exploitation of Natural Antioxidants: Isolation and Purification Techniques)

► Show Figures

Graphical abstract

16 pages, 1650 KiB

Open AccessArticle

Mangiferin Rich Products from Aphloia theiformis (Vahl) Benn Leaves: Extraction, Fractionation, Phytochemical Characterization, and Antioxidant Properties

by Dovilė Grauzdytė, Audrius Pukalskas, Chaker El Kalamouni and Petras Rimantas Venskutonis

Molecules 2020, 25(9), 2081; https://doi.org/10.3390/molecules25092081 - 29 Apr 2020

Cited by 4 | Viewed by 2857

Abstract

Aphloia theiformis is traditionally used in Mauritius, Madagascar, and Reunion Island for treating several diseases. In this study, various extraction solvents and schemes were applied for the recovery of antioxidant rich fractions from the leaves of A. theiformis. The products were evaluated for their antioxidant capacity using well known in vitro assays. Major compounds were characterized by UPLC–QTOF–MS. Hydrophilic extracts of A. theiformis demonstrated strong antioxidant properties, which are comparable with the synthetic antioxidant Trolox. UPLC analysis confirmed mangiferin as the main secondary metabolite of A. theiformis. Tormentic and hydroxytormentic acids as well as their isomers were also abundant in A. theiformis extracts and fractions, while their amounts were determined for the first time. The most potential extract was further separated into the fractions by liquid-liquid extraction and by precipitation at low temperature. Antioxidant capacity and composition of secondary metabolites of derived fractions were determined. Some of the fractions possessed remarkable antioxidant capacity, comparable to pure mangiferin. The results obtained reveal high potential of A. theiformis for recovery of natural antioxidants and other bioactive phytochemicals, particularly mangiferin. Full article

(This article belongs to the Special Issue Exploitation of Natural Antioxidants: Isolation and Purification Techniques)

► Show Figures

Figure 1

12 pages, 704 KiB

Open AccessArticle

Phenolic Profile of Croton urucurana Baill. Leaves, Stems and Bark: Pairwise Influence of Drying Temperature and Extraction Solvent

by Jáliston Júlio Lopes Alves, Maria Inês Dias, João C. M. Barreira, Lillian Barros, Osvaldo Resende, Ana Carolina Ribeiro Aguiar and Isabel C. F. R. Ferreira

Molecules 2020, 25(9), 2032; https://doi.org/10.3390/molecules25092032 - 27 Apr 2020

Cited by 5 | Viewed by 2288

Abstract

Cerrado biome represents an area with great biodiversity. Some of its plants have significant ethnopharmacological uses, with specific purposes. Croton urucurana Baill., for instance, was previously acknowledged for its anti-hemorrhagic, anti-inflammatory, antiseptic, healing, and potentially antifungal and entomopathogenic actions. Nevertheless, the compounds supporting these empirical applications are still unknown. Accordingly, this work was designed to achieve a complete characterization of the phenolic profile of different botanical tissues obtained from C. urucurana, and also to verify how different operational conditions (different drying temperatures and extraction conditions) affect that profile. All samples were further characterized by HPLC–DAD–ESI/MSn, and results were compared by advanced chemometric tools. In general, the drying temperatures that maximize the extraction yield of specific individual phenolic compounds were established. Likewise, it was possible to verify that samples extracted with the hydroethanolic solution allowed higher phenolic yields, either in individual compounds (except (epi)catechin-di-O-gallate) or total phenolics. The identification of the best operational conditions and phenolic profiles associated with each C. urucurana botanical part contributes to enabling their use in food or pharmaceutical-related applications. Full article

(This article belongs to the Special Issue Exploitation of Natural Antioxidants: Isolation and Purification Techniques)

► Show Figures

Figure 1

Review

Jump to: Research

29 pages, 2394 KiB

Open AccessReview

Green and Sustainable Valorization of Bioactive Phenolic Compounds from Pinus By-Products

by Pedro Ferreira-Santos, Elisa Zanuso, Zlatina Genisheva, Cristina M. R. Rocha and José A. Teixeira

Molecules 2020, 25(12), 2931; https://doi.org/10.3390/molecules25122931 - 25 Jun 2020

Cited by 84 | Viewed by 6618

Abstract

In Europe, pine forests are one of the most extended forests formations, making pine residues and by-products an important source of compounds with high industrial interest as well as for bioenergy production. Moreover, the valorization of lumber industry residues is desirable from a circular economy perspective. Different extraction methods and solvents have been used, resulting in extracts with different constituents and consequently with different bioactivities. Recently, emerging and green technologies as ultrasounds, microwaves, supercritical fluids, pressurized liquids, and electric fields have appeared as promising tools for bioactive compounds extraction in alignment with the Green Chemistry principles. Pine extracts have attracted the researchers’ attention because of the positive bioproperties, such as anti-inflammatory, antimicrobial, anti-neurodegenerative, antitumoral, cardioprotective, etc., and potential industrial applications as functional foods, food additives as preservatives, nutraceuticals, pharmaceuticals, and cosmetics. Phenolic compounds are responsible for many of these bioactivities. However, there is not much information in the literature about the individual phenolic compounds of extracts from the pine species. The present review is about the reutilization of residues and by-products from the pine species, using ecofriendly technologies to obtain added-value bioactive compounds for industrial applications. Full article

(This article belongs to the Special Issue Exploitation of Natural Antioxidants: Isolation and Purification Techniques)

► Show Figures

Journal Menu

Journal Browser

Exploitation of Natural Antioxidants: Isolation and Purification Techniques

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (5 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI