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Chromatographic Science of Natural Products 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: closed (31 December 2021) | Viewed by 37235

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Special Issue Editors

Prof. Dr. Monika Waksmundzka-Hajnos

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Guest Editor

Department of Inorganic Chemistry, Medical University of Lublin, Lublin, Poland
Interests: liquid chromatography; phytochemistry; drug analysis
Special Issues, Collections and Topics in MDPI journals

Dr. Miroslaw Hawryl

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Guest Editor

Department of Inorganic Chemistry, Medical University of Lublin, Lublin, Poland
Interests: liquid chromatography; TLC; phytochemistry; chemometry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Phytochemistry is a crucial area that encompasses the confirmation of plant material identity as well as the qualitative and quantitative analysis of natural products and mixtures in the quality control of plant drugs and food and cosmetic products. The use of chromatographic analysis is able to fulfill most of the goals of phytochemistry and can be applied in various forms. TLC offers a quick and cheap method for the parallel separation of several samples on one plate, and it is the perfect method for comparison of extracts and/or standards in the same chromatographic run. Various detection methods and derivatizations allow for verification of the composition of complex samples and the determination of properties. Preliminary information connected with the pharmacological activity of plant material components can be obtained from the biodetection of different activities, including antioxidant and antibiotic activities as well as inhibitory activity against selected enzymes. Gas chromatography is a perfect tool for the determination of volatile active compounds of plant origin, such as essential oils or flavor compounds in food products such as wines, fruit products, and spices. High-performance liquid chromatography can be widely used for the identification of particular plant components, such as markers and other active compounds in plants and plant products. Various chromatographic methods, including countercurrent chromatography, can be applied in the isolation of compounds of interest from extracts. This Special Issue of Molecules aims to publish papers that will provide new and interesting information regarding the application of chromatographic methods in the area of plant chemistry. Due to the wide interest in the first edition of this Molecules Special Issue, “Chromatographic Science of Natural Products I”, we have decided to continue the consideration of this subject. We look forward to gathering and presenting further advances in this Special Issue entitled “Chromatographic Science of Natural Products II”.

Prof. Dr. Monika Waksmundzka-Hajnos
Dr. Miroslaw Hawryl
Guest Editors

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Keywords

TLC bioautography
HPLC, TLC, and GC in phytochemistry and food analysis
chemometrics
fingerprinting
examination of biological activity of plant components and food
isolation and identification of natural compounds

Published Papers (14 papers)

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Research

24 pages, 2793 KiB

Open AccessArticle

Characterization, Large-Scale HSCCC Separation and Neuroprotective Effects of Polyphenols from Moringa oleifera Leaves

by Qian Gao, Zongmin Wei, Yun Liu, Fang Wang, Shuting Zhang, Carmo Serrano, Lingxi Li and Baoshan Sun

Molecules 2022, 27(3), 678; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27030678 - 20 Jan 2022

Cited by 9 | Viewed by 2733

Abstract

Moringa oleifera leaves have been widely used for the treatment of inflammation, diabetes, high blood pressure, and other diseases, due to being rich in polyphenols. The main objective of this work was to largely separate the main polyphenols from Moringa oleifera leaves using the technique of high-speed counter-current chromatography (HSCCC). The phenolic composition in Moringa oleifera leaves was first analyzed qualitatively and quantitatively by UPLC-Q-Exactive Orbitrap/MS and UPLC-QqQ/MS, respectively, indicating that quercetin and kaempferol derivatives, phenolic acid and apigenin are the main polyphenols in Moringa oleifera leaves, with quercetin and kaempferol derivatives predominating. Furthermore, the conditions of HSCCC for large-scale separation of polyphenols from Moringa oleifera leaves were optimized, which included the selection of the solvent system, flow rate and the sample load. Only by one-step HSCCC separation (within 120 min) under the optimized conditions, six quercetin and kaempferol derivatives, a phenolic acid and an apigenin could be individually isolated at a large scale (yield from 10% to 98%), each of which possessed high purity. Finally, the isolated polyphenols and phenolic extract from Moringa oleifera leaves (MLPE) were verified to have strong neuroprotective activities against H₂O₂-induced oxidative stress in PC-12 cells, suggesting that these compounds would contribute to the main beneficial effects of Moringa oleifera leaves. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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11 pages, 732 KiB

Open AccessArticle

Simultaneous Determination of Seven Lipophilic and Hydrophilic Components in Salvia miltiorrhiza Bunge by LC-MS/MS Method and Its Application to a Transport Study in a Blood-Brain-Barrier Cell Model

by Hui Wang, Mingyong Zhang, Jiahao Fang, Yuzhen He, Min Liu, Zhanying Hong and Yifeng Chai

Molecules 2022, 27(3), 657; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27030657 - 20 Jan 2022

Cited by 4 | Viewed by 1657

Abstract

Salvia miltiorrhiza Bunge (SM) has been extensively used in Alzheimer’s disease treatment, the permeability through the blood-brain barrier (BBB) determining its efficacy. However, the transport mechanism of SM components across the BBB remains to be clarified. A simple, precise, and sensitive method using LC-MS/MS was developed for simultaneous quantification of tanshinone I (TS I), dihydrotanshinone I (DTS I), tanshinone IIA (TS IIA), cryptotanshinone (CTS), protocatechuic aldehyde (PAL), protocatechuic acid (PCTA), and caffeic acid (CFA) in transport samples. The analytes were separated on a C18 column by gradient elution. Multiple reaction monitoring mode via electrospray ionization source was used to quantify the analytes in positive mode for TS I, DTS I, TS IIA, CTS, and negative mode for PAL, PCTA, and CFA. The linearity ranges were 0.1–8 ng/mL for TS I and DTS I, 0.2–8 ng/mL for TS IIA, 1–80 ng/mL for CTS, 20–800 ng/mL for PAL and CFA, and 10–4000 ng/mL for PCTA. The developed method was accurate and precise for the compounds. The relative matrix effect was less than 15%, and the analytes were stable for analysis. The established method was successfully applied for transport experiments on a BBB cell model to evaluate the apparent permeability of the seven components. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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12 pages, 1397 KiB

Open AccessArticle

LC-ESI-MS/MS Identification of Biologically Active Phenolics in Different Extracts of Alchemilla acutiloba Opiz

by Katarzyna Dos Santos Szewczyk, Wioleta Pietrzak, Katarzyna Klimek, Anna Grzywa-Celińska, Rafał Celiński and Marek Gogacz

Molecules 2022, 27(3), 621; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27030621 - 18 Jan 2022

Cited by 8 | Viewed by 1709

Abstract

Liquid chromatography electrospray ionization tandem mass spectrometric (LC-ESI-MS/MS) qualitative and quantitative analysis of different extracts from the aerial parts and roots of Alchemilla acutiloba led to the identification of phenolic acids and flavonoids. To the best of our knowledge, isorhamnetin 3-glucoside, kaempferol 3-rutinoside, narcissoside, naringenin 7-glucoside, 3-O-methylquercetin, naringenin, eriodictyol, rhamnetin, and isorhamnetin were described for the first time in Alchemilla genus. In addition, the antioxidant, anti-inflammatory and cytotoxic activity of all extracts were evaluated. The results clearly showed that among analyzed extracts, the butanol extract of the aerial parts exhibited the highest biological activity comparable with the positive controls used. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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11 pages, 2131 KiB

Open AccessArticle

Diversity of Volatile Compounds in Ten Varieties of Zingiberaceae

by Weiyao Peng, Ping Li, Ruimei Ling, Zhenzhen Wang, Xianhui Feng, Ju Liu, Quan Yang and Jian Yan

Molecules 2022, 27(2), 565; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27020565 - 17 Jan 2022

Cited by 14 | Viewed by 2595

Abstract

Zingiberaceae plants are distributed in the tropical and subtropical regions of the world, being used in many famous medicinal materials. Meanwhile, some Zingiberaceae plants are important horticultural flowers because they are green all year round and have special aromas. To conduct an extensive investigation of the resources of Zingiberaceae plants, the volatile compounds of ten species of Zingiberaceae were extracted and analyzed by GC–MS, including Costus comosus var. bakeri (K.Schum.) Maas, Curcuma rubescens Roxb., Curcuma aeruginosa Roxb., Curcuma attenuata Wall., Hongfengshou, Hedychium coronarium Koeng, Zingiber zerumbet (L.) Smith, Hedychium brevicaule D. Fang, Alpinia oxyphylla Miq., and Alpinia pumila Hook.F. A total of 162 compounds were identified, and most of those identified were monoterpenes and sesquiterpenes. (E)-labda-8(17),12-diene-15,16-dial, n-hexadecanoic acid, 4-methoxy-6-phenethyl-2H-pyran-2-one, and L-β-pinene were found in high concentrations among the plants. These ten species of Zingiberaceae contained some of the same volatiles, but their contents were different. Pharmacological effects may be associated with the diversity of volatiles in these ten plants. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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13 pages, 2462 KiB

Open AccessArticle

HPTLC and ATR/FTIR Characterization of Antioxidants in Different Rosemary Extracts

by Snezana Agatonovic-Kustrin, Ksenia S. Balyklova, Vladimir Gegechkori and David W. Morton

Molecules 2021, 26(19), 6064; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26196064 - 07 Oct 2021

Cited by 15 | Viewed by 2783

Abstract

The effect of spontaneous fermentation by lactic acid bacteria on the extraction yield of bioactive compounds and antioxidant activity from rosemary leaf extracts was investigated using high-performance thin-layer chromatography (HPTLC). Brining and spontaneous fermentation with lactic acid bacteria more than doubled extraction of polyphenolics and antioxidants from the rosemary leaves. The results show that lactic acid fermentation enhances antioxidant activity in extracts by increasing the total phenolic content but does not increase extraction of phytosterols. Increased extraction of phenolic oxidants during fermentation assisted extraction, results from the in situ generated natural eutectic solvent from the plant sample. ATR-FTIR spectra from the bioactive bands suggests that this increased antioxidant activity is associated with increased extraction of rosmarinic acid, depolymerised lignin, abietane diterpenoids and 15-hydroxy-7-oxodehydroabietic acid. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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17 pages, 1855 KiB

Open AccessArticle

A Stability-Indicating Ultra Performance Liquid Chromato-Graphic (UPLC) Method for the Determination of a Mycophenolic Acid-Curcumin Conjugate and Its Applications to Chemical Kinetic Studies

by Yonelian Yuyun, Ponsiree Jithavech, Worathat Thitikornpong, Opa Vajragupta and Pornchai Rojsitthisak

Molecules 2021, 26(17), 5398; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26175398 - 05 Sep 2021

Cited by 1 | Viewed by 2234

Abstract

A simple, precise, and accurate reversed-phase ultra-performance liquid chromatographic (UPLC) method was developed and validated for the determination of a mycophenolic acid-curcumin (MPA-CUR) conjugate in buffer solutions. Chromatographic separation was performed on a C18 column (2.1 × 50 mm id, 1.7 µm) with a gradient elution system of water and acetonitrile, each containing 0.1% formic acid, at a flow rate of 0.6 mL/min. The column temperature was controlled at 33 °C. The compounds were detected simultaneously at the maximum wavelengths of mycophenolic acid (MPA), 254 nm, and curcumin (CUR), or MPA-CUR, at 420 nm. The developed method was validated according to the ICH Q2(R1) guidelines. The linear calibration curves of the assay ranged from 0.10 to 25 μg/mL (r² ≥ 0.995, 1/x² weighting factor), with a limit of detection and a limit of quantitation of 0.04 and 0.10 μg/mL, respectively. The accuracy and precision of the developed method were 98.4–101.6%, with %CV < 2.53%. The main impurities from the specificity test were found to be MPA and CUR. Other validation parameters, including robustness and solution stability, were acceptable under the validation criteria. Forced degradation studies were conducted under hydrolytic (acidic and alkaline), oxidative, thermal, and photolytic stress conditions. MPA-CUR was well separated from MPA, CUR, and other unknown degradation products. The validated method was successfully applied in chemical kinetic studies of MPA-CUR in different buffer solutions. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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14 pages, 37018 KiB

Open AccessArticle

Modification of Arabinogalactan Isolated from Larix sibirica Ledeb. into Sulfated Derivatives with the Controlled Molecular Weights

by Yuriy N. Malyar, Natalia Yu. Vasilyeva, Aleksandr S. Kazachenko, Valentina S. Borovkova, Andrei M. Skripnikov, Angelina V. Miroshnikova, Dmitriy V. Zimonin, Vladislav A. Ionin, Anna S. Kazachenko and Noureddine Issaoui

Molecules 2021, 26(17), 5364; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26175364 - 03 Sep 2021

Cited by 14 | Viewed by 2075

Abstract

The process of sulfation of arabinogalactan—a natural polysaccharide from Larix sibirica Ledeb.—with sulfamic acid in 1,4-dioxane using different activators has been studied for the first time. The dynamics of the molecular weight of sulfated arabinogalactan upon variation in the temperature and time of sulfation of arabinogalactan with sulfamic acid in 1,4-dioxane has been investigated. It has been found that, as the sulfation time increases from 10 to 90 min, the molecular weights of the reaction products grow due to the introduction of sulfate groups without significant destruction of the initial polymer and sulfation products. Sulfation at 95 °C for 20 min yields the products with a higher molecular weight than in the case of sulfation at 85 °C, which is related to an increase in the sulfation rate; however, during the further process occurring under these conditions, sulfation is accompanied by the destruction and the molecular weight of the sulfated polymer decreases. The numerical optimization of arabinogalactan sulfation process has been performed. It has been shown that the optimal parameters for obtaining a product with a high sulfur content are a sulfamic acid amount of 20 mmol per 1 g of arabinogalactan, a process temperature of 85 °C, and a process time of 2.5 h. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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13 pages, 973 KiB

Open AccessArticle

Optimization, Validation and Application of HPLC-PDA Methods for Quantification of Triterpenoids in Vaccinium vitis-idaea L.

by Gabriele Vilkickyte and Lina Raudone

Molecules 2021, 26(6), 1645; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26061645 - 16 Mar 2021

Cited by 20 | Viewed by 3172

Abstract

Triterpenoids have regained much attention as promising multi-targeting bioactive agents of natural origin in the treatment of numerous disorders. Due to the high potential for phytopharmaceutical development, accurate qualitative and quantitative analysis of triterpenoids for screening and quality control is required. Vaccinium vitis-idaea L. (lingonberry) raw materials have aroused interest as a rich source of triterpenoids. However, currently, no validated, rapid, and easy-to-perform quantification method is available for the routine control of these compounds in lingonberries. This research aimed at developing and validating HPLC-PDA methods for the determination and screening of triterpenoids in extracts of lingonberry leaves, fruits, and flowers. The developed methods were deemed satisfactory by validation, which revealed acceptable analytical specificity, linearity (r² > 0.9999), precision (RSD < 2%), trueness (94.70–105.81%), and sensitivity (LOD: 0.08–0.65 µg/mL). The real sample analysis demonstrated established methods applicability for quantification of 13 triterpenoids in lingonberries and emphasized differences between raw materials. Lingonberry fruits were distinguished by the richness of ursolic acid; lingonberry flowers by similar profile to fruits, but low content of neutral triterpenoids; whereas lingonberry leaves by the particularly high level of α-amyrin. Thus, the proposed methods proved to be reliable and applicable for quantification and routine analysis of triterpenoids in lingonberry samples. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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18 pages, 945 KiB

Open AccessArticle

Quali–Quantitative Characterization of Volatile and Non-Volatile Compounds in Protium heptaphyllum (Aubl.) Marchand Resin by GC–MS Validated Method, GC–FID and HPLC–HRMS²

by Alberto Asteggiano, Andrea Occhipinti, Andrea Capuzzo, Enrica Mecarelli, Riccardo Aigotti and Claudio Medana

Molecules 2021, 26(5), 1447; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26051447 - 07 Mar 2021

Cited by 9 | Viewed by 3398

Abstract

Protium heptaphyllum (Aubl.) Marchand (PH) trees are endemic to the tropical region of South America, mostly Brazil. Antibacterial, antinociceptive, anti-inflammatory, anxiolytic, antidepressant and anti-hyperlipidemic/anti-hypercholesterolemic effects were reported for its resinous exudate Protiumheptaphyllum resin (PHR). This work aims to provide a qualitative and quantitative consistent chemical profiling of the major constituents of this resin and two extracts enriched in acid (acidic triterpene concentrated extract, ATCE) and neutral triterpenes (α and β-amyrin concentrated extract, AMCE). GC–MS/GC–FID was used for volatile terpene fraction, a validated GC–MS method was developed for quantification of neutral α and β-amyrin and HPLC–APCI HRMS² was used for acidic triterpenes analysis. The chemical investigation reported 29 molecules, including 14 volatile terpenes, 6 neutral triterpenes and 11 acid triterpenes. The most abundant compounds were α-amyrin (251.28 g kg⁻¹, 123.98 g kg⁻¹ and 556.82 g kg⁻¹ in PHR, ATCE and AMCE, respectively), β-amyrin (172.66 g kg⁻¹, 95.39 g kg⁻¹ and 385.58 g kg⁻¹ in PHR, ATCE and AMCE, respectively), 3-oxo-tirucalla-7,24-dien-21-oic acid (80.64 g kg⁻¹, 157.10 g kg⁻¹ and 15.31 g kg⁻¹ in PHR, ATCE and AMCE, respectively) and 3α-hydroxy-tirucalla-8,24-dien-21-oic acid (77.71 g kg⁻¹, 130.40 g kg⁻¹ and 11.64 g kg⁻¹ in PHR, ATCE and AMCE, respectively). Results showed specific enrichment of acidic and neutral triterpenoids in the two respective extracts. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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13 pages, 1438 KiB

Open AccessArticle

Exploitation of HPLC Analytical Method for Simultaneous Determination of Six Principal Unsaturated Fatty Acids in Oviductus Ranae Based on Quantitative Analysis of Multi-Components by Single-Marker (QAMS)

by Shihan Wang, Yuanshuai Gan, Hong Kan, Xinxin Mao and Yongsheng Wang

Molecules 2021, 26(2), 479; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26020479 - 18 Jan 2021

Cited by 10 | Viewed by 3226

Abstract

As one of the featured products in northeast China, Oviductus Ranae has been widely used as a nutritious food, which contains a variety of bioactive unsaturated fatty acids (UFAs). It is necessary to establish a scientific and reliable determination method of UFA contents in Oviductus Ranae. In this work, six principal UFAs in Oviductus Ranae, namely eicosapentaenoic acid (EPA), linolenic acid (ALA), docosahexaenoic acid (DHA), arachidonic acid (ARA), linoleic acid (LA) and oleic acid (OA), were identified using UPLC-MS/MS. The UFAs identified in Oviductus Ranae were further separated based on the optimized RP-HPLC conditions. Quantitative analysis of multi-components by single-marker (QAMS) method was implemented in content determination of EPA, ALA, DHA, ARA and OA, where LA was used as the internal standard. The experiments based on Taguchi design verified the robustness of the QAMS method on different HPLC instruments and chromatographic columns. The QAMS and external standard method (ESM) were used to calculate the UFA content of 15 batches of Oviductus Ranae samples from different regions. The relative error (r < 0.73%) and cosine coefficient showed that the two methods obtained similar contents, and the method validations met the requirements. The results showed that QAMS can comprehensively and effectively control the quality of UFAs in Oviductus Ranae which provides new ideas and solutions for studying the active components in Oviductus Ranae. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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14 pages, 4824 KiB

Open AccessArticle

HPLC and ToF‒SIMS Analyses of Toxicodendron vernicifluum Tree Sap Mixed with Other Natural Lacquers

by Hye Hyun Yu, Seung Wook Ham and Yeonhee Lee

Molecules 2021, 26(2), 434; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26020434 - 15 Jan 2021

Cited by 6 | Viewed by 2533

Abstract

Lacquer sap has been used by humans from antiquitywhen it was treated as a luxury item because of its desirable physical properties. In modern times, although access barriers are lower, lacquer is still considered to be rare and valuable. Thus, low quality, inexpensive Vietnamese and Myanmarese lacquers and cashew nutshell liquid are frequently added to the costly Toxicodendron vernicifluum lacquer sap from Korea, China, and Japan. However, these blended lacquers can diminish the quality of artisan works. The Toxicodendron vernicifluum lacquer saps mixed with other natural lacquers were characterized using time-of-flight secondary-ion mass spectrometry (ToF−SIMS) and high-performance liquid chromatography (HPLC). ToF-SIMS provided the chemical structure of the lacquer monomer, copolymerized dimers, trimers, etc. HPLC provided quantitative analysis of the components of a randomly mixed lacquer. These techniques can be used to control the quality of commercial lacquer sap for the Asian lacquer industry and the traditional conservation of ancient objects. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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11 pages, 1336 KiB

Open AccessArticle

Development and Validation of a Method for Determining the Quercetin-3-O-glucuronide and Ellagic Acid Content of Common Evening Primrose (Oenothera biennis) by HPLC-UVD

by Tae Heon Kim, Hyun Young Shin, Soon Yeong Park, Hoon Kim and Dae Kyun Chung

Molecules 2021, 26(2), 267; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26020267 - 07 Jan 2021

Cited by 8 | Viewed by 2955

Abstract

Toward the standardization of common evening primrose (Oenothera biennis) sprout extract (OBS-E), we aimed to obtain indicator compounds and use a validated method. HPLC-UVD allowed simultaneous quantification of the indicator compounds quercetin-3-O-glucuronide and ellagic acid. The method was validated in terms of specificity, linearity, precision, accuracy, and limit of detection/limit of quantification (LOD/LOQ). High specificity and linearity was demonstrated, with correlation coefficients of 1.0000 for quercetin-3-O-glucuronide and 0.9998 for ellagic acid. The LOD/LOQ values were 0.486/1.472 μg/mL for quercetin-3-O-glucuronide and 1.003/3.039 μg/mL for ellagic acid. Intra-day and inter-day variability tests produced relative standard deviation for each compound of <2%, a generally accepted precision criterion. High recovery rate were also obtained, indicating accuracy validation. The OBS-E prepared using various concentrations of ethanol were then analyzed. The 50% ethanol extract had highest content of quercetin-3-O-glucuronide, whereas the 70% ethanol extract possessed the lowest. However, the ellagic acid content was highest in the 70% ethanol extract and lowest in the 90% ethanol extract. Thus, quercetin-3-O-glucuronide and ellagic acid can be used industrially as indicator compounds for O. biennis sprout products, and our validated method can be used to establish indicator compounds for other natural products. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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11 pages, 10640 KiB

Open AccessArticle

An Integrated LC-ESI-MSⁿ and High Resolution LC-ESI-QTOF Approach for the Identification of Phloroglucinols from Nepalese Hypericum japonicum

by Gregorio Peron, Deepak Raj Pant, Shyam Sharan Shrestha, Sangeeta Rajbhandary and Stefano Dall’Acqua

Molecules 2020, 25(24), 5937; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25245937 - 15 Dec 2020

Cited by 4 | Viewed by 2332

Abstract

Phloroglucinols are characteristic constituents of Hypericumjaponicum that are claimed to exert several bioactivities, such as anti-inflammatory, anti-depressant and anti-viral ones. Phloroglucinols are unstable compounds and their synthesis is challenging; thus, isolation from natural sources is still one of the main strategies for obtaining these constituents in purified form. Assessing the presence of phloroglucinols in plant materials can be of interest for compound isolation, and LC-MS approaches afford sensitivity and specificity in this regard. In this work, we combined data from quadrupole-time of flight (QTOF) and ion trap (IT) mass spectrometers in order to assess the presence of the phloroglucinols characteristic of H. japonicum and to elucidate their MS fragmentation pathways. The identified compounds present similar structures bearing the 1,3,5-trihydroxybenzene core with different substitutions, which, in constituents at higher MW, is linked to 3′,3′-dimethyl-6′-oxo-phlorisobutyrophenone by a methylene bridge. Differences in MS² spectra of the considered phloroglucinols are useful for compound identification and differentiation, and to perform dereplication studies. Overall, the proposed approach could be useful for the analysis of phloroglucinols in H. japonicum and other plant species. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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20 pages, 14011 KiB

Open AccessArticle

Chromatographic Separation of Breynia retusa (Dennst.) Alston Bark, Fruit and Leaf Constituents from Bioactive Extracts

by Stefano Dall’Acqua, Kouadio Ibrahime Sinan, Irene Ferrarese, Stefania Sut, Kouadio Bene, Mohamad Fawzi Mahomoodally, Nabeelah Bibi Sadeer, Gunes Ak and Gokhan Zengin

Molecules 2020, 25(23), 5537; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25235537 - 25 Nov 2020

Cited by 8 | Viewed by 2323

Abstract

Breynia retusa (Dennst.) Alston (also known as Cup Saucer plant) is a food plant with wide applications in traditional medicine, particularly in Ayurveda. Extracts obtained with four solvents (dichloromethane, methanol, ethyl acetate and water), from three plant parts, (fruit, leaf and bark) were obtained. Extracts were tested for total phenolic, flavonoid content and antioxidant activities using a battery of assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), total antioxidant capacity (TAC) (phosphomolybdenum) and metal chelating. Enzyme inhibitory effects were investigated using acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase as target enzymes. Results showed that the methanolic bark extract exhibited significant radical scavenging activity (DPPH: 202.09 ± 0.15; ABTS: 490.12 ± 0.18 mg Trolox equivalent (TE)/g), reducing potential (FRAP: 325.86 ± 4.36: CUPRAC: 661.82 ± 0.40 mg TE/g) and possessed the highest TAC (3.33 ± 0.13 mmol TE/g). The methanolic extracts were subjected to LC-DAD-MSⁿ and NMR analysis. A two-column LC method was developed to separate constituents, allowing to identify and quantify forty-four and fifteen constituents in bark and fruits, respectively. Main compound in bark was epicatechin-3-O-sulphate and isolation of compound was performed to confirm its identity. Bark extract contained catechins, procyanidins, gallic acid derivatives and the sulfur containing spiroketal named breynins. Aerial parts mostly contained flavonoid glycosides. Considering the bioassays, the methanolic bark extract resulted a potent tyrosinase (152.79 ± 0.27 mg kojic acid equivalent/g), α-amylase (0.99 ± 0.01 mmol acarbose equivalent ACAE/g) and α-glucosidase (2.16 ± 0.01 mmol ACAE/g) inhibitor. In conclusion, methanol is able to extract the efficiently the phytoconstituents of B. retusa and the bark is the most valuable source of compounds. Full article

(This article belongs to the Special Issue Chromatographic Science of Natural Products II)

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