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Separation, Extraction and Purification of Natural Products

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A special issue of Separations (ISSN 2297-8739). This special issue belongs to the section "Analysis of Natural Products and Pharmaceuticals".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 19342

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Dr. Nguyen Van Quan

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Guest Editor

Transdisciplinary Science and Engineering Program, Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima 739-8529, Japan
Interests: natural products and applications in anticancer, anti-diabetes, anti-obesity, antioxidant, and anti-SARS-CoV-2

Prof. Dr. Tran Dang Xuan

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Guest Editor

Transdisciplinary Science and Engineering Program, Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima 739-8529, Japan
Interests: natural products; agricultural chemistry; weed science
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Special Issue Information

Dear Colleagues,

Natural products and their biological activities have been a hot topic in recent decades. Since side effects are more prevalent in synthetic medicines, the exploitation of natural products as alternative medicines has increasingly attracted interest owing to their safety in humans. Presently, natural products are also applied in various industries such as nanomaterials, garments, electricity, construction, etc.

Along with discovering more bioactive and novel compounds, the extraction and isolation techniques of natural products have achieved certain advancements. While conventional extraction and separation methods are time-consuming, laborious, and costly, advanced protocols are more efficient, convenient, and rapid. However, the current methods revolve around the small scale and do not satisfy applicability and sustainability at larger scales. Therefore, the discovery of novel methods and the development and improvement of the separation, extraction, and purification procedures of natural products are essential for future applications.

This Special Issue seeks to publish qualified studies focused on innovative methods, simplified processes, and highly applicable protocols in the separation, extraction, and purification procedures of natural products. We also welcome researchers and investigators to contribute their findings and reviews on the applicability and sustainability of natural compound extraction on the industrial scale. In particular, studies on the separation and isolation of anti-coronavirus and anti-SARS-CoV-2 compounds from natural sources are highly sought after in this issue.

Dr. Nguyen Van Quan
Dr. Tran Dang Xuan
Guest Editors

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Keywords

natural products
bioactive compounds
extraction of natural compounds
separation of natural compounds
isolation of natural compounds
purification of natural compounds
advanced techniques
novel extraction methods
sustainable extraction techniques
anti-SARS-CoV-2 compounds
anti-coronavirus

Published Papers (9 papers)

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Research

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18 pages, 2220 KiB

Open AccessArticle

Water-Based Microwave-Assisted Extraction of Pigments from Madder Optimized by a Box–Behnken Design

by Marine Chambaud, Cyril Colas and Emilie Destandau

Separations 2023, 10(8), 433; https://doi.org/10.3390/separations10080433 - 30 Jul 2023

Viewed by 1014

Abstract

Water is one of the greenest and most accessible solvents. To harness its potential, the water-based microwave-assisted extraction (MAE) of pigments from madder was optimized by the response surface methodology (RSM) using a Box–Behnken experimental design. The extract that presented both the highest extraction yield and the most intense color was obtained after a 30-s cycle at 1000 W using 100 mg of madder for 20 mL of water. This water-based MAE was more efficient than Soxhlet extraction and proved comparable to hydroalcoholic MAE. The optimized extract was further characterized using UHPLC-HRMS/MS to identify its main compounds. Glycosylated flavonoids and anthraquinones were putatively identified, as well as free anthraquinones, generally found in madder. The microwave-assisted extraction extended the range of polarity of the extracted compounds, making the water more versatile. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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23 pages, 3386 KiB

Open AccessEditor’s ChoiceArticle

Comparative Study of Conventional, Microwave-Assisted and Supercritical Fluid Extraction of Bioactive Compounds from Microalgae: The Case of Scenedesmus obliquus

by Ioulia Georgiopoulou, Vasiliki Louli and Kostis Magoulas

Separations 2023, 10(5), 290; https://doi.org/10.3390/separations10050290 - 04 May 2023

Cited by 3 | Viewed by 2008

Abstract

The recovery of bioactive products with green processes is a critical topic for the research and industry fields. In this work, the application of solid–liquid (SLE), microwave-assisted extraction (MAE) with aq. ethanol 90% v/v and supercritical fluid extraction (SFE) with CO₂ for the recovery of biocomponents from Scenedesmus obliquus is studied. The effects examined were temperature (30–60 °C), time (6–24 h), and solvent-to-biomass ratio (20–90 mL_solv/g_biom) for SLE, temperature (40–60 °C), time (5–25 min), solvent-to-biomass ratio (20–90 mL_solv/g_biom), and microwave power (300–800 W) for MAE, and temperature (40–60 °C), pressure (110–250 bar), solvent flow rate (20–40 g_solv/min), and cosolvent presence (0, 10% w/w ethanol) for SFE in relation to the extract’s yield, phenolic, chlorophyll, carotenoid content, and antioxidant activity. The optimum extraction conditions determined were 30 °C, 24 h, and 90 mL_solv/g_biom for SLE, 60 °C, 5 min, 90 mL_solv/g_biom, and 300 W for MAE, and 60 °C, 250 bar, and 40 g_solv/min for SFE. Additionally, a kinetic SFE study was conducted and the obtained results were satisfactorily correlated using Sovová’s model. The comparison between the methods proved MAE’s efficiency in all terms compared to SLE. Moreover, SFE was accompanied with the lowest yield and chlorophyll content, yet led to an increased carotenoid content and improved antioxidant activity. Finally, the cosolvent addition significantly improved SFE’s yield and led to the most superior extract. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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15 pages, 934 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Cucumis metuliferus L. Fruits Extract with Antioxidant, Anti-Inflammatory, and Antidiabetic Properties as Source of Ursolic Acid

by Anna Cazanevscaia Busuioc, Giorgiana Valentina Costea, Andreea Veronica Dediu Botezatu, Bianca Furdui and Rodica Mihaela Dinica

Separations 2023, 10(5), 274; https://doi.org/10.3390/separations10050274 - 23 Apr 2023

Cited by 2 | Viewed by 1393

Abstract

To identify healthy, nutritious, and sustainable plant-based products rich in biologically active compounds, this present study was conducted, and the phytochemical composition and biological properties of the hydroethanolic ultrasound-assisted extract of the fruits of Cucumis metuliferus were investigated. Cucumis metuliferus is an unexplored fruit of a climbing plant in the Cucurbitaceae family, widely distributed in the tropical and subtropical regions of sub-Saharan Africa and whose nutritional and medicinal benefits are well known in African countries, especially. Therefore, its cultivation in other regions could influence chemical composition. The structural identification of the compounds from the hydroethanolic extract from Cucumis metuliferus fruits grown in Romania was carried out by chromatographic techniques (HPLC). The main compounds identified were catechin, oleanolic acid, ursolic acid, p-coumaric acid, and epicatechin. Subsequently, a method was proposed to isolate and characterize ursolic acid, one of the major compounds. The obtained results show that the hydroethanolic extract is rich in antioxidant compounds evaluated using the DPPH radical inhibition method (IC₅₀ = 32.74 ± 0.02 µg/mL) and ABTS cation radical inhibition method (IC₅₀ = 11.37 ± 0.07 µg/mL). It also demonstrate in vitro anti-inflammatory activities, such as anti-lipoxygenase (IC₅₀ = 32.90 ± 0.05 µg/mL) and anti-proteinase (IC₅₀ = 16.34 ± 0.07 µg/mL), and antidiabetic properties by inhibiting α-amylase (IC₅₀ = 429.541 ± 0.25 µg/mL) and β-glucosidase activity (IC₅₀ = 385.685 ± 0.76 µg/mL). Therefore, C. metuliferus fruits could be effectively used in the development of various health-promoting products, being not only appetizing, with spectacular appearance and with extended storage life, but also curative and healthy. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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12 pages, 1238 KiB

Open AccessArticle

Antioxidant-Activity-Guided Purification and Separation of Octocrylene from Saussurea heteromalla

by Saboon, Yamin Bibi, Samha Al Ayoubi, Tayyiba Afzal, Sobia Gilani, Khafsa Malik, Abdul Qayyum, Mubashar Hussain and Sunjeet Kumar

Separations 2023, 10(2), 107; https://doi.org/10.3390/separations10020107 - 03 Feb 2023

Cited by 1 | Viewed by 1616

Abstract

Plants have been a source of medicine since ancient times, and such traditional medications are widely practiced nowadays. Saussurea heteromalla is widely used in traditional medicine in the Himalayan region for the treatment of different ailments. However, despite its traditional uses, it is not widely explored for its free radical scavenging abilities and other biological activities. Thus, the current study is aimed at exploring the free radical scavenging ability of S. heteromalla extracts, along with the isolation and evaluation of its compound through bioassay-guided purification. From different solvent fractions, an n-hexane extract of a whole plant is found to be most active; thus, it is processed for large-scale extraction and column chromatography. Further, the purification of an active fraction is performed using HPLC–DAD, which led to the isolation of an active peak, identified by GC/MS, as 2-ethylhexyl 2-cyano-3, 3-diphenylprop-2-enoate. This compound, commonly known as octocrylene, is widely recommended for UV-B filter, to be used in the cosmetic industry as photoprotection products. The presence of free radical scavenging activity enhances the sun protection factor of octocrylene. The present study presents the first report on the isolation of this compound from the family Asteraceae. The compound has good free radical scavenging activity and is widely used in the cosmetic industry as a sun protectant and is much less reported from botanical sources. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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26 pages, 1156 KiB

Open AccessArticle

Phytochemical and Biological Characterization of the Fractions of the Aqueous and Ethanolic Extracts of Parthenium hysterophorus

by Miguel A. Alfaro Jiménez, Alejandro Zugasti Cruz, Sonia Y. Silva Belmares, Juan A. Ascacio Valdés and Crystel A. Sierra Rivera

Separations 2022, 9(11), 359; https://doi.org/10.3390/separations9110359 - 09 Nov 2022

Cited by 1 | Viewed by 2029

Abstract

In this study, the fractions of the aqueous (AE) and ethanolic (EE) crude extracts of Parthenium hysterophorus were evaluated for their phytochemical composition, cytotoxic, and antioxidant activity. The two extracts were subjected to a fractionation by vacuum liquid chromatography, obtaining seven fractions for each extract. These fractions were evaluated for the presence of phenolic compounds by reverse phase high performance liquid chromatography coupled to mass spectrometer (RP-HPLC-MS) analysis. Their cytotoxic activity was tested with a hemolysis assay. The antioxidant activity was evaluated with the Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl radical (–OH) scavenging assays. In addition, the effect of the fractions on the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), from human erythrocytes, was evaluated. The phytochemical screening by RP-HPLC-MS mainly showed the presence of flavonoids and hydroxycinnamic acids. The hemolysis assay exhibited a low cytotoxic activity by the fractions of the AE, but the fractions of the EE exhibited a hemolytic effect. The fractions of the AE and EE showed significant antioxidant activity to inhibit radicals in the three radical scavenging assays. Moreover, only some fractions of the AE showed a significant increase in the activity of the SOD enzyme, while the activity of CAT exhibited a significant increase by the fractions of the two extracts. The fractions of the AE and EE of P. hysterophorus have phytochemicals with antioxidant activity to inhibit radicals and increase the activity of in vitro antioxidant enzymes. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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16 pages, 2294 KiB

Open AccessArticle

Extraction, Separation and Purification of Bioactive Anticancer Components from Peganum harmala against Six Cancer Cell Lines Using Spectroscopic Techniques

by Huma Mehreen Sadaf, Yamin Bibi, Samha Al Ayoubi, Naila Safdar, Ahmad Sher, Darima Habib, Sobia Nisa, Khafsa Malik, Sunjeet Kumar, Waseem Ahmed and Abdul Qayyum

Separations 2022, 9(11), 355; https://doi.org/10.3390/separations9110355 - 07 Nov 2022

Cited by 2 | Viewed by 1847

Abstract

Conventional cancer treatments normally involve chemotherapy or a combination of radio- and chemotherapy. However, the adverse effects of synthetic medicines encouraged the exploration of novel therapeutic medications of a bio-friendly nature. In an effort to explore anticancer compounds from natural resources, crude extract of Peganum harmala (seeds) was fractionated on the basis of polarity, and the fractions were further tested for anticancer activity. Brine shrimp lethality assays and potato disc antitumor assays were used to test each fraction for cytotoxic and antitumor potential. The ethyl acetate fraction was found to be most potent, with LC₅₀ and IC₅₀ values of 34.25 µg/mL and 38.58 µg/mL, respectively. Further activity-guided fractionation led to the isolation of the bioactive compound PH-HM-10 which was identified and characterized by Mass Spectroscopy (MS), Infrared Spectroscopy (IR), Proton Nuclear Magnetic Resonance Spectroscopy (¹HNMR), Carbon Nuclear Magnetic Resonance Spectroscopy (¹³CNMR) and Heteronuclear Single Quantum Correlation (HSQC). Anticancer aspects in the isolated compound were determined against six human cancer cell lines with a maximum anticancer effect (IC₅₀ = 36.99 µg/mL) against the tested human myeloid leukemia (HL-60) cell line, followed by the human lung adenocarcinoma epithelial cell line (A549) and the breast cancer cell line (MCF-7) with an IC₅₀ of 63.5 µg/mL and 85.9 µg/mL, respectively). The findings of the current study suggest that the isolated compound (Pegaharmine E) is significantly active against the tested cancer cell lines and can be further investigated to develop future novel anticancer chemotherapeutic agents. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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14 pages, 2114 KiB

Open AccessArticle

Simple Isolation of Cordycepin from Cordyceps militaris by Dual-Normal Phase Column Chromatography and Its Potential for Making Kombucha Functional Products

by Nguyen Van Quan, Yu Iuchi, La Hoang Anh, Mehedi Hasan and Tran Dang Xuan

Separations 2022, 9(10), 290; https://doi.org/10.3390/separations9100290 - 06 Oct 2022

Cited by 4 | Viewed by 3891

Abstract

Cordycepin (3′-deoxyadenosine) is a potent bioactive metabolite of the medicinal fungus Cordyceps militaris, which has been increasingly exploited to treat various chronic diseases in humans. However, the current synthesis and purification procedures of cordycepin are principally laborious and complicated. This study provides a simple protocol approach to isolate and purify cordycepin from C. militaris by normal phase column chromatography at room temperature. Besides, this is the first to investigate the potential of cordycepin and cordycepin-included extracts from C. militaris for making Kombucha functional products. By a repeated column chromatography, an amount of 1.16 g of cordycepin is isolated from 2.8 kg of fruiting bodies of C. militaris, which obtained an efficiency of 83.26% compared to that estimated by high-performance liquid chromatography (HPLC). The purity of cordycepin is confirmed by thin-layer chromatography (TLC), HPLC, and proton nuclear magnetic resonance (¹H NMR). In addition, kombucha-fermented extracts from cordycepin and cordycepin-included fractions show potential biological activities in terms of antioxidant, anti-diabetes via α-glucosidase inhibitory assay, and cytotoxicity via MTT assay on Meg-01 and HL-60 cell lines. Further studies on optimization of extraction protocol and verification of health benefits of kombucha products from cordycepin should be conducted prior to the official mass production. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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28 pages, 2055 KiB

Open AccessEditor’s ChoiceReview

Identification and Isolation Techniques for Plant Growth Inhibitors in Rice

by Nguyen Thi Hai Anh, La Hoang Anh, Nguyen Phuong Mai, Nguyen Van Quan and Tran Dang Xuan

Separations 2023, 10(2), 105; https://doi.org/10.3390/separations10020105 - 03 Feb 2023

Cited by 2 | Viewed by 3175

Abstract

Plant growth inhibitors (PGIs) in rice (Oryza sativa), or rice allelochemicals, are secondary metabolites that are either exudated by rice plants to cope with natural competitors or produced during the decomposition of rice by-products in the paddy fields. Of these, the major groups of rice PGIs include phenolics, flavonoids, terpenoids, alkaloids, steroids, and fatty acids, which also exhibit potential medicinal and pharmaceutical properties. Recently, the exploitation of rice PGIs has attracted considerable attention from scientists worldwide. The biosynthesis, exudation, and release of PGIs are dependent on environmental conditions, relevant gene expression, and biodiversity among rice varieties. Along with the mechanism clarification, numerous analytical methods have been improved to effectively support the identification and isolation of rice PGIs during the last few decades. This paper provides an overview of rice PGIs and techniques used for determining and extracting those compounds from rice. In particular, the features, advantages, and limitations of conventional and upgraded extraction methods are comprehensively reported and discussed. The conventional extraction methods have been gradually replaced by advanced techniques consisting of pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), and solid-phase extraction (SPE). Meanwhile, thin-layer chromatography (TLC), liquid chromatography (LC), gas chromatography (GC), mass spectrometry (MS), nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HR-MS), infrared spectroscopy (IR), near-infrared spectroscopy (NIRS), and X-ray crystallography are major tools for rice PGI identification and confirmation. With smart agriculture becoming more prevalent, the statistics of rice PGIs and extraction methods will help to provide useful datasets for building an autonomous model for safer weed control. Conceivably, the efficient exploitation of rice PGIs will not only help to increase the yield and economic value of rice but may also pave the way for research directions on the development of smart and sustainable rice farming methods. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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11 pages, 1178 KiB

Open AccessBrief Report

The Self-Disproportionation of Enantiomers (SDE) of α-Pinene via Evaporation off Silica Gel and Foam Fractionation—Validation of the Plausibility of SDE via Gas Chromatography (GC) for α-Pinene

by Alicja Wzorek, Vadim A. Soloshonok and Karel D. Klika

Separations 2023, 10(7), 382; https://doi.org/10.3390/separations10070382 - 29 Jun 2023

Cited by 1 | Viewed by 838

Abstract

α-Pinene is an intriguing monoterpene as it has been reported to undergo the self-disproportionation of enantiomers (SDE) phenomenon via gas chromatography (GC), the only compound to decisively demonstrate this. Examples of the SDE involving the gaseous phase—sublimation aside—are extremely rare. Attempts to replicate the GC results were unsuccessful, though the authors argued convincingly for the difficulty of observing the phenomenon. However, we could effect for α-pinene SDE via evaporation off silica gel and by foam fractionation—albeit the SDE magnitude for both was only very slight—to confirm that α-pinene can undergo the SDE for processes involving a gaseous phase and thus validate the plausibility of the GC report. The indications are that the molecular associations responsible for the various SDE observations of α-pinene occur not in the gaseous phase or the bulk phase but rather in two-dimensional (2D) adsorbed monolayers and are not based on conventional functional group-based intermolecular interactions and instead are, most likely, as a result of homo- and heterochiral packing differences in the 2D monolayers—a well-known 2D chiral-based association packing effect. These are also the first reports of the occurrence of the SDE using an adsorptive bubble separation process (foam fractionation) and involving a gaseous phase other than sublimation, GC, and distillation. Full article

(This article belongs to the Special Issue Separation, Extraction and Purification of Natural Products)

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