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Extraction, Purification and Structure Elucidation of Active Natural Compounds

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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 (10 May 2023) | Viewed by 9805

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Special Issue Editors

Prof. Dr. Maged Saad Abdel-Kader Youssef

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Guest Editor

Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
Interests: natural products chemistry; drug discovery from nature; spectroscopy; quality control of herbal drugs; chromatography

Prof. Dr. Eman Shawky Anwar

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Guest Editor

Department of Pharmacognosy, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt
Interests: phytochemistry; plant metabolomics; structures elucidation; network pharmacology; plant analysis

Prof. Dr. Doaa Ahmad Ghareeb

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Guest Editor

Bio-Screening and Preclinical Trial Lab, Biochemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt
Interests: biochemistry; medical biotechnology; preclinical study; molecular biology; in vitro pharmacology

Special Issue Information

Dear Colleagues,

Following recent advances in the treatment and control of diseases, nature has provided, and still is providing, humanity with unique bioactive inities. For decades, natural products represent an important section in drug discovery and developments. Natural products and or their semisynthetic derivatives have great impact in our struggle to fight against the various health conditions which threaten human life. A considerable part of the discovery of natural products was achieved via comprehensive phytochemical and biological studies of traditionally used plants. This Special Issue seeks to publish high-quality manuscripts which describe the extraction and purification of bioactive compounds from natural sources. The new biological activity discovery for known compounds will be considered. The application of new chromatographic and spectroscopic techniques in the field of natural products will always be helpful for obtaining lead natural compounds for drug development.

Prof. Dr. Maged Saad Abdel-Kader Youssef
Prof. Dr. Eman Shawky Anwar
Prof. Dr. Doaa Ahmad Ghareeb
Guest Editors

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. Separations is an international peer-reviewed open access monthly 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 2600 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

structure elucidation
biological activity
biologically active natural compounds
chromatography
biologically guided purification
scientific evidences for traditional medicine

Published Papers (5 papers)

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Research

Jump to: Review

15 pages, 1120 KiB

Open AccessArticle

Flavonol-Glycoside and Rare Triterpenoid Derivatives Isolated from Leaves of Combretum glutinosum Perr. Ex Dc. with In Vitro Cytotoxic Activity

by Sherouk Hussein Sweilam, Maha B. O. Ebrahim, Mehnaz Kamal, El-Sayed Khafagy, Ashraf N. Abdalla, Mohamed E. Elzubier and Ehssan H. Moglad

Separations 2023, 10(3), 209; https://doi.org/10.3390/separations10030209 - 17 Mar 2023

Cited by 1 | Viewed by 1713

Abstract

Combretaceae plants are used traditionally by many cultures, especially in Sudanese patients for the treatment of diverse ailments such as anti-inflammatory, antimicrobial, antitumor, and antioxidant disorders. Of these plants, the genus Combretum are traditional medicinal plants. Thus, they are formed from the non-polar or polar extracts of many isolated phytochemicals. Of these necessities, the use of Combretum extracts for their medicinal properties can be found in the earliest of myths and traditions used to document the plants’ ability to treat diseases. Combretum glutinosum Perr. Ex Dc. is a common shrub native to the African continent, especially Sudan. Currently, there are no published data regarding its cytotoxic activity. Additionally, there are few chemical and biological reports of C. glutinosum. Therefore, the current study aimed to isolate the chemical bioactive compounds (1–6) from the ethyl acetate (EtOAc) extract of C. glutinosum. A new flavonoid compound, namely, glutosinumoside (4), was afforded, and five known compounds were obtained: three oleanane-glycosides (1–3) and two phenolic acids (5,6). The structures of the six compounds were determined by spectroscopic analysis, including one- and two-dimensional (1D and 2D) NMR, mass spectrometry, and chromatographic analysis. Moreover, an in vitro cytotoxic evaluation of the successive extracts and the bioactive EtOAc fractions of C. glutinosum against MCF7 (breast), HT29 (colon), HepG2 (liver), and MRC5 (normal lung) cell lines was performed. The isolated compounds showed comparable cytotoxic activities with the crude EtOH extract and doxorubicin against the tested cell lines. Compounds (1) and (6) exhibited the highest cytotoxicity against MCF7 (1.37 ± 0.21 and 1.48 ± 0.34 µg/mL, respectively) and HepG2 (3.30 ± 0.02 and 2.10 ± 0.22 µg/mL, respectively) in the MTT assay. In addition, compounds (1) and (3) demonstrated a significant upregulation of cancer’s two important hallmarks (caspase 3 and bax genes) by inducing apoptosis and perturbing the MCF7 cell cycle. Full article

(This article belongs to the Special Issue Extraction, Purification and Structure Elucidation of Active Natural Compounds)

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12 pages, 1552 KiB

Open AccessCommunication

Removal of Ni(II) from Aqueous Solution by Novel Lycopersicon esculentum Peel and Brassica botrytis Leaves Adsorbents

by Israf Ud Din, Qadeer Ullah Shah, Syed Tasleem, Abdul Naeem, Abdulrahman I. Alharthi and Mshari Ayad Alotaibi

Separations 2023, 10(2), 113; https://doi.org/10.3390/separations10020113 - 6 Feb 2023

Viewed by 1068

Abstract

The current work reports adsorption of Ni(II) using Brassica botrytis leaves (BBL), Brassica botrytis leaves-activated carbon (BBL-AC), Lycopersicon esculentum peel (LEP) and Lycopersicon esculentum peel-activated carbon (LEP-AC). The adsorption of Ni(II) was tested in batch experiments by varying different parameters such as pH, initial metal ion concentration, temperature, adsorbent dosage, and contact time. Thermodynamics and kinetics investigations were performed for Ni removal. The adsorption of Ni(II) was improved by incorporation of activated carbon to the parental Brassica botrytis leaves and Lycopersicon esculentum peel adsorbents. The studies revealed 40 min of equilibrium time for Ni(II) adsorption by different adsorbents. Adsorption of Ni was drastically declined by temperature with a minimum adsorption of 53% observed for BBL. Similarly, solution pH also played a vital role in Ni(II) adsorption by different adsorbents. A 95% adsorption of Ni was recorded in the case of LEP-AC at pH 7. The study concluded with the application of Lycopersicon esculentum peel and Brassica botrytis leaves as active adsorbents for Ni(II) adsorption from aqueous solution. Full article

(This article belongs to the Special Issue Extraction, Purification and Structure Elucidation of Active Natural Compounds)

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Graphical abstract

14 pages, 2163 KiB

Open AccessArticle

Galactolipids from Launaea capitata (Spreng.) Dandy with In Vitro Anti-Inflammatory and Neuroprotective Activities

by Fatma M. Abdel Bar, Asmaa E. Sherif and Mai H. ElNaggar

Separations 2023, 10(2), 83; https://doi.org/10.3390/separations10020083 - 25 Jan 2023

Cited by 1 | Viewed by 1556

Abstract

Plant secondary metabolites have a long history of potential use in managing human diseases by inhibiting enzymes that are highly expressed due to various pathogenic conditions. Prostaglandins (PGs) and leukotrienes (LTs) are proinflammatory mediators synthesized from arachidonic acid (AA) by the action of cyclooxygenases (COXs) and lipoxygenases (LOXs), respectively. Particularly, COX-2/5-LOX enzymes play a significant role in inflammatory processes and the pain associated with them. Butyrylcholinesterase (BchE) was recently suggested as a more reliable potential target for sustaining normal cholinergic function. In an attempt to identify new potential COX-2/5-LOX and BchE inhibitors, a phytochemical investigation of Launaea capitata (Spreng.) Dandy (Asteraceae) was executed. This investigation led to the isolation of a new digalactosyldiacylglycerol isomer, namely 1,2-dilinolenoyl-3-O-(α-galactopyranosyl-(1,6)-O-α-D-galactopyranosyl)-sn-glycerol (1) in addition to 1-myristoyl-2-palmitoyl-3-O-(α-galactopyranosyl-(1,6)-O-β-D-galactopyranosyl)-sn-glycerol (2), which was isolated herein for the first time from nature. The structures of the two isolates were elucidated by using 1D-, 2D-NMR, and ESI-MS spectroscopy. Compounds 1 and 2 exhibited good in vitro inhibitory activities against 5-LOX (59.01 and 21.67 μg/mL) and BchE (13.37 and 24.32 μg/mL), respectively. However, they exhibited weak inhibition of COX-2 (110.44 and 179.63 μg/mL, respectively). These inhibitory activities were explained in silico using a computational docking study. The docking results were consistent with the in vitro enzyme inhibitory activity. The lowest binding affinity for 1 and 2 was observed against COX-2 (−7.360 and −5.723 kcal/mol), whereas they exhibited greater binding affinity to 5-LOX (−8.124 and −8.634 kcal/mol), respectively, compared to its natural substrate, AA (−5.830 kcal/mol). Additionally, 1 and 2 exhibited remarkable binding affinity to BchE (−8.313 kcal/mol and −7.502 kcal/mol, respectively), which was comparable to the co-crystallized ligand, thioflavin T (−8.107 kcal/mol). This was related to the multiple and crucial hydrogen bonding interactions of these compounds with the amino acid residues in the active sites of the investigated enzymes. This study demonstrated the role of plant galactolipids as potential leads in the development of new drugs that alleviate the neuroinflammatory conditions associated with various diseases, such as Alzheimer’s disease and Type 2 diabetes mellitus. Full article

(This article belongs to the Special Issue Extraction, Purification and Structure Elucidation of Active Natural Compounds)

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Graphical abstract

11 pages, 956 KiB

Open AccessArticle

Bronchodilator Secondary Metabolites from Rhazya stricta Decne Aerial Parts

by Maged S. Abdel-Kader, Najeeb U. Rehman, Abdullah F. Aldosari, Fahad S. Almutib, Ali I. Al Muwinea and Abdulaziz S. Saeedan

Separations 2022, 9(12), 412; https://doi.org/10.3390/separations9120412 - 6 Dec 2022

Cited by 1 | Viewed by 1993

Abstract

The plant kingdom comprises medicinally useful plants that have provided many new drugs used to treat various diseases. In our search for bronchodilator secondary metabolites from plants growing in Saudi Arabia, the total extract of Rhazya stricta showed activity against carbamylcholine- (CCh) induced bronchoconstriction in guinea pig tracheal muscles used as an ex vivo model. The fractions obtained from liquid–liquid extraction process were tested for bronchodilator effects. The most active ethyl acetate fraction (RS-E) and aqueous fraction (RS-H) were subjected to biologically guided phytochemical study using different stationary phases and chromatographic techniques to isolate the pure secondary metabolites. Five known compounds were isolated from the active fractions. Three alkaloids namely; (-)-quebrachamine (1), (+)-eburenine (2), (+)-stemmadenine (3) as well as the two iridoid glycosides loganic acid (4) and loganine (5) were identified by various spectroscopic methods. Among the isolated compounds 1 and 5 were the only active as bronchodilators in the plant. It is worth to mention that iridoid glycosides are isolated for the first time from R. stricta. Full article

(This article belongs to the Special Issue Extraction, Purification and Structure Elucidation of Active Natural Compounds)

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Review

Jump to: Research

24 pages, 3233 KiB

Open AccessReview

Strategies for Natural Product Discovery by Unlocking Cryptic Biosynthetic Gene Clusters in Fungi

by Ji Yun Hur, Eunju Jeong, Young Chan Kim and Seoung Rak Lee

Separations 2023, 10(6), 333; https://doi.org/10.3390/separations10060333 - 26 May 2023

Cited by 4 | Viewed by 2858

Abstract

Recent advancements in genome sequencing and bioinformatic analysis of fungal genomes have revealed that fungi possess cryptic or silent biosynthetic gene clusters (BGCs). This discovery suggests that our understanding of the universe of fungal secondary metabolomes is limited. In this review, we summarize recent strategies for activating cryptic BGCs in fungi, identify fungal secondary metabolites, and highlight their biological activities. We also briefly discuss the isolation and purification methods for these compounds. Our focus is on genetics-dependent and genetics-independent approaches for activating cryptic BGCs in fungi. Using the strategies discussed here, cryptic fungal natural products hold significant potential as a source for the discovery of new drug candidates. Full article

(This article belongs to the Special Issue Extraction, Purification and Structure Elucidation of Active Natural Compounds)

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