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Extraction, Purification and Functional Substances of Natural Products and Plants

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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: 20 August 2026 | Viewed by 9127

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Special Issue Editor

Dr. Xiumei Li

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Institute of Feed Research of CAAS, Beijing 100081, China
Interests: technologies for the extraction and purification of plant natural products (e.g., supercritical fluid extraction, membrane separation); functional evaluation of bioactive compounds (polysaccharides, saponins, flavonoids); sustainable utilization of medicinal plants and agricultural by-products; quality control and standardization of natural substances; development of functional foods, pharmaceuticals, and cosmetics derived from plant-based materials
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Dear Colleagues,

The extraction, purification, and functional substances from natural products and plants is one of the most popular research fields in the literature. Determining the active ingredients in natural products or plants is essential for their application. The analysis of the composition of extracted compounds by chromatography, mass spectrometry and related techniques is a relevant step in determining the performance of the extraction process and the purity of the extracted compounds to be used for pharmaceutical applications.

Therefore, it is my pleasure to invite you to contribute your research article, communication, or review to this Special Issue dedicated to extraction, purification and functional Substances from natural products and plants.

Dr. Xiumei Li
Guest Editor

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Keywords

extraction
separation and purification
chromatography
membrane separation
solvent extraction method
macroporous resin adsorption method
functional substances
flavonoids
polyphenol
polysaccharide
identification
natural products

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Published Papers (9 papers)

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Research

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24 pages, 5974 KB

Open AccessArticle

Multidimensional Quality Evaluation of Drying Methods on the Bioactive Components and Antioxidant Activity of Astragalus membranaceus var. mongholicus Slices

by Feifan Leng, Jiale Wang, Lizhe Hu, Minmin Li, Yongwei Sun, Yonggang Wang, Jieyin Chen, Xiaofeng Dai, Bin Ma, Qing Lv and Zhiqiang Kong

Separations 2026, 13(5), 146; https://doi.org/10.3390/separations13050146 - 11 May 2026

Viewed by 348

Abstract

This study systematically evaluated the effects of five drying methods (sun drying, freeze drying, shade drying, and hot air drying at 40 °C and 60 °C) on the multidimensional quality of Astragalus membranaceus var. mongholicus slices using multiscale techniques and multivariate analysis. The results showed that the drying methods significantly influenced color, microstructure, volatile organic compound profiles, the content of 13 bioactive constituents, and antioxidant activity. Among all treatments, hot air drying at 40 °C achieved the highest composite score in the comprehensive evaluation. This treatment was associated with a marked increase in surface microroughness (Ra), higher levels of the pharmacopoeial markers astragaloside IV and calycosin-7-O-β-D-glucoside, and enhanced ABTS radical scavenging activity. However, other methods performed better in individual parameters: shade drying showed higher DPPH and FRAP values, while freeze drying gave the highest total phenolic content. Based on the observed strong correlations (e.g., roughness vs. astragaloside IV: r = 0.94; astragaloside IV vs. ABTS: r = 0.83), we propose a testable hypothesis that hot air drying at 40 °C may influence bioactivity partly through physical microstructural changes. The multidimensional evaluation framework established here provides a methodological reference for quality optimization of medicinal and edible herbs. Full article

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

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19 pages, 3188 KB

Open AccessArticle

Optimisation, Component Analysis, and Bioactivity Evaluation of Sunflower Calathide Flavonoids Obtained Using Ultra-High-Pressure Extraction

by Haoqian Yan, Guifeng Zhang and Li Ma

Separations 2026, 13(4), 114; https://doi.org/10.3390/separations13040114 - 9 Apr 2026

Viewed by 424

Abstract

This study aims to achieve the efficient preparation of sunflower calathide flavonoids (SCF) through optimized processes and to elucidate their composition and bioactivity. Total flavonoids were prepared by optimizing the ultra-high-pressure extraction (UHPE) process using a combination of single-factor experiments and response surface methodology, followed by purification and enrichment via macroporous resin. The components were identified with UPLC-QTOF-MS/MS technology, and their antioxidant activity and inhibitory capacity against xanthine oxidase (XOD) were systematically evaluated. The optimal extraction conditions were determined as follows: an extraction pressure of 290 MPa, a holding time of 8 min, an ethanol concentration of 67%, and a solid-to-liquid ratio of 1:14 g/mL. Under these conditions, the total flavonoid extraction yield reached 13.52 mg/g, which was further enriched to 16.74 mg/g after purification by macroporous resin. A total of 32 flavonoid compounds were identified, and the purified extract exhibited stronger free radical scavenging ability, total reducing power, ferric ion reducing activity, and XOD inhibitory effect compared to the unpurified extract. The combination of UHPE with macroporous resin separation technology effectively enriches SCF, and the resulting extract possesses both antioxidant and xanthine oxidase inhibitory activities, providing a theoretical basis and technical support for its industrial production and application. Full article

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

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13 pages, 788 KB

Open AccessArticle

Four New Terpenoids from Fufang Yinhua Jiedu Granules and Their Anti-Influenza A Virus Activity

by Xiu Wang, Xiao-Juan Chen, Qing Sun, Juan Song, Hai-Zhen Liang and Bai-Ping Ma

Separations 2026, 13(4), 105; https://doi.org/10.3390/separations13040105 - 26 Mar 2026

Viewed by 503

Abstract

Fufang Yinhua Jiedu Granules (FFYHG) is usually applied to treat influenza and the common cold. However, there is no available report concerning the effects of chemical constituents in FFYHG on antiviral activity. In our study, four new terpenoid derivatives (1–4) and seventeen known compounds were isolated from FFYHG. Their structures and absolute configurations were determined by various techniques, including high-resolution mass spectrometry analysis, 1/2-dimensional (1D/2D) nuclear magnetic resonance (NMR) analysis, comparative electronic circular dichroism (ECD) studies (experiment vs. calculation), and acid hydrolysis. In addition, the inhibitory effects of twenty-one isolated compounds against influenza A viruses (H1N1) including A/California/07/2009 (CA07) and A/WSN/1933 (WSN) strains were evaluated in vitro, and compound 4 exhibited a moderate inhibitory effect on CA07 strain, with a half maximal inhibitory concentration (IC₅₀) value of 37.10 ± 1.35 μM. This study enhanced the understanding of the active ingredients in FFYHG against influenza virus, providing a foundation for further research on the material basis and quality control of FFYHG. Full article

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

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12 pages, 515 KB

Open AccessArticle

Schinus terebinthifolia Raddi: Compounds Isolated by Countercurrent Chromatography and Biological Activities

by Mara Junqueira Carneiro, Alexandre Augusto Borghi, Guilherme Perez Pinheiro, Ana Lucia Tasca Gois Ruiz, Daniela Mizobutti, Elaine Minatel, Lisieux Santana Juliao, Svetlana Ignatova, Peter Hewitson and Alexandra Christine Helena Frankland Sawaya

Separations 2026, 13(4), 103; https://doi.org/10.3390/separations13040103 - 25 Mar 2026

Viewed by 621

Abstract

The chemical composition of natural products is complex and the investigation of bioactivities of compounds of interest demands their isolation. S. terebinthifolia Raddi is a tree belonging to the Anacardiaceae family and is used in Brazilian folk medicine; its fruit (pink peppers) are used in cooking and its bark in phytomedicine. Extracts of other parts of this plant contain a plethora of components and merit further studies. Countercurrent chromatography (CCC) is frequently employed with natural products due to the high sample recovery rate. The objective of this work was to determine the best solvent system (SS) to fraction the ethanol extracts of leaves, flowers and fruit of Schinus terebinthifolia by CCC and isolate compounds of interest and elucidate their structures through nuclear magnetic resonance (NMR) and mass spectrometry (MS). In addition, antiproliferative, potential cell regeneration and antioxidant activities of the fractions of interest were evaluated. In the present work, three compounds were isolated; two were identified as anacardic acids [(6-(8′, 11′-heptadecadienyl)-salicylic acid and 6-(8′-heptadecenyl)-salicylic acid], as well as (Z)-masticadienoic acid. These compounds showed antiproliferative and potential cell regeneration activities as well as varying degrees of antioxidant capacity. Although these compounds present potential therapeutic activity, more studies are necessary to confirm their safety. Full article

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

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12 pages, 1910 KB

Open AccessArticle

Isolation and Identification of a Strain of Isaria cateniobliqua, Culture Condition Optimization and the Effect of Subculture on Its Active Compounds

by Jie Shang, Hui Zhao and Dun Wang

Separations 2026, 13(2), 52; https://doi.org/10.3390/separations13020052 - 2 Feb 2026

Viewed by 584

Abstract

The genus Isaria is a group of abundant and widely distributed entomopathogenic fungi that plays an important role in the history of traditional Chinese medicine. Entomopathogenic fungi with medicinal value were collected from the field, and optimal temperature and growth media compositions were investigated to establish a theoretical foundation for the future development of these strains. A strain of Isaria cateniobliqua, designated ICF, was isolated from soil in the Hualongshan National Nature Reserve in southern Shaanxi. The optimal cultivation temperature and nutrient solution were screened, and the effects of subcultivation on mycelium production, metabolite production, and hydroxyl radical scavenging activity of strain ICF were investigated. The optimal growth temperature for strain ICF was determined to be 21 °C, with the ideal culture medium consisting of glucose and tussah silkworm pupa powder supplemented with KH₂PO₄ and MgSO₄. Mycelium production and cordycepin content peaked in the fourth generation (G4), whereas peak metabolite production and cordycepic acid production occurred in the fifth generation (G5). Polysaccharide content was highest in the first generation (G1), and hydroxyl radical scavenging activity was optimal in G4. Exploring the optimal culture conditions of the strain provides a theoretical basis for its development, utilization, and industrial production for medicinal applications. Full article

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

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20 pages, 1440 KB

Open AccessEditor’s ChoiceArticle

Phenolic Compounds in Plant-Based Milk Alternatives from the Greek Market

by Velisaria-Eleni Gerogianni, Christiana Mantzourani, Maria A. Theodoropoulou, Antonia Chiou and Maroula G. Kokotou

Separations 2025, 12(10), 282; https://doi.org/10.3390/separations12100282 - 11 Oct 2025

Cited by 1 | Viewed by 2223

Abstract

Plant-based milk alternatives (PBMAs) are plant-based fluid products that are marketed as substitutes for regular milk. The nutrient composition of PBMA products can vary widely, depending on the plant source, processing methods, potential additives, etc., and in recent years, considerable research effort has been devoted to the exploration of the nutritional content of PBMAs, which are increasingly consumed worldwide. In the present study, an established UHPLC–Orbitrap MS method was employed for the extensive characterization of phenolic compounds in PBMAs available in the Greek market. Twenty-eight PBMAs were studied, including a variety of almond-, soy-, coconut-, oat-, walnut-, and rice-based products. In almond-based milk products, low total concentrations and a broad distribution across compound classes were observed, with trans-chlorogenic acid and neochlorogenic acid being the most abundant constituents, whereas coconut-based milk samples were generally not rich in phenolic compounds. In soy-based milk samples, the presence of isoflavones including daidzein, genistein, and glycitein was uniquely detected, while oat-based products were the samples richer in phenolic content, in particular for hydroxycinnamic acids, such as trans-chlorogenic acid and neochlorogenic acid. In addition, a suspect screening approach, using Exactive Plus Orbitrap, enabled the exploration and semi-quantification of three avenanthramides (A, B, C) in the studied oat-based milk samples and six isoflavonoids, namely daidzein and genistein derivatives, in soy-based milk. Such compounds are known for their antioxidant and anti-inflammatory properties, and their occurrence in PBMAs highlights the potential health-promoting effects of these dairy alternatives. Full article

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

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23 pages, 6833 KB

Open AccessArticle

Ultrasound-Assisted Deep Eutectic Solvent Extraction of Flavonoids from Cercis chinensis Seeds: Optimization, Kinetics and Antioxidant Activity

by Penghua Shu, Shuxian Fan, Simin Liu, Yu Meng, Na Wang, Shoujie Guo, Hao Yin, Di Hu, Xinfeng Fan, Si Chen, Jiaqi He, Tingting Guo, Wenhao Zou, Lin Zhang, Xialan Wei and Jihong Huang

Separations 2025, 12(10), 269; https://doi.org/10.3390/separations12100269 - 2 Oct 2025

Cited by 4 | Viewed by 1404

Abstract

This study establishes an efficient and eco-friendly ultrasound-assisted extraction (UAE) method for total flavonoids present in Cercis chinensis seeds using natural deep eutectic solvents (NADES). Among nine NADES formulations screened, choline chloride–levulinic acid (ChCl–Lev, 1:2) demonstrated optimal performance, yielding 112.1 mg/g total flavonoids. Through Response Surface Methodology (RSM), the ultrasound-assisted extraction (UAE) parameters were explored. Under the optimized conditions (water content of 30%, time of 28 min, temperature of 60 °C, and solvent-to-solid ratio of 1:25 g/mL), the total flavonoid yield reached 128.5 mg/g, representing a 195% improvement compared to conventional ethanol extraction. The recyclability of NADES was successfully achieved via AB-8 macroporous resin, retaining 80.89% efficiency after three cycles. Extraction kinetics, modeled using Fick’s second law, confirmed that the rate constant (k) increased with temperature, highlighting temperature-dependent diffusivity as a key driver of efficiency. The extracted flavonoids exhibited potent antioxidant activity, with IC₅₀ values of 0.86 mg/mL (ABTS•⁺) and 0.69 mg/mL (PTIO•). This work presents a sustainable NADES-UAE platform for flavonoid recovery and offers comprehensive mechanistic and practical insights for green extraction of plant bioactives. Full article

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

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Review

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18 pages, 1062 KB

Open AccessReview

Hesperidin from Citrus Processing By-Products: Integrated Strategies from Extraction to Downstream Separation

by Li Shang, Yiyang Zhang and Miao Long

Separations 2026, 13(3), 90; https://doi.org/10.3390/separations13030090 - 8 Mar 2026

Viewed by 907

Abstract

The extraction of functional organic compounds from natural products has become an important focus of current research. Citrus fruits are among the most widely produced fruits worldwide and have attracted increasing attention because of their pleasant flavor and rich content of bioactive compounds. Hesperidin, the focus of this review, is a representative flavonoid glycoside that is abundant in citrus fruits and their processing by-products. Owing to its unique molecular structure and physicochemical properties, hesperidin frequently coexists with structurally similar flavonoids. This similarity makes its separation and purification particularly challenging. Although many studies have reported different methods for the extraction and purification of hesperidin, most of them concentrate on individual techniques. Systematic analyses of how upstream extraction strategies affect downstream separation efficiency are still limited. In this review, separation strategies for hesperidin are systematically discussed, covering the entire process from extraction to downstream purification. The focus shifts from isolated separation methods to a strategy-oriented design. Special attention is given to how different extraction approaches influence matrix complexity, and, consequently, the difficulty of subsequent separation steps. Downstream separation technologies, including adsorption, liquid–liquid partitioning, crystallization, and chromatography, are compared from the perspectives of separation mechanisms and process integration. Based on a comparative analysis of crystallization, phase partitioning, membrane processing, adsorption, and chromatographic techniques, this review discusses the typical process roles of different separation strategies. Solubility-driven crystallization and membrane-based clarification are identified as more suitable for large-scale processing, whereas adsorption and chromatography are more appropriate as enrichment and polishing steps, respectively. In addition, key control points for green extraction–separation integration are identified, including solvent recyclability, matrix complexity control, and early-stage load reduction. This work aims to provide a practical reference for the sustainable and scalable separation of flavonoid glycosides from citrus by-products. Full article

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

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18 pages, 1969 KB

Open AccessEditor’s ChoiceReview

Artemisia frigida Willd.: Advances in Traditional Uses, Phytochemical Constituents, Extraction and Separation Methods, and Pharmacological Activities

by Wei Tian, Mengjie Zhang, Tongcun Zhang, Xianglong Li, Haiying Zhang and Xiumei Li

Separations 2025, 12(10), 280; https://doi.org/10.3390/separations12100280 - 11 Oct 2025

Cited by 1 | Viewed by 1184

Abstract

Artemisia frigida Willd. (A. frigida), a traditional medicinal herb widely distributed in northern China, Mongolia, and Siberia, has garnered increasing scientific interest due to its diverse phytochemical profile and extensive pharmacological potential. Modern studies have identified a wide range of bioactive compounds in A. frigida, including flavonoids, sesquiterpene lactones and phenolic acids. These compounds exhibit various biological activities, such as antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. This review systematically summarizes the research progress on the chemical constituents of A. frigida and their extraction and separation methods, including solvent extraction, ultrasonic-assisted extraction, macroporous resin adsorption, and chromatography-based techniques. By integrating traditional knowledge with modern pharmacological evidence, this review provides a scientific foundation for the further development and utilization of A. frigida in functional food, pharmaceuticals, and ethnomedicine. Full article

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

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