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Special Issue "Natural Product Isolation, Identification and Biological Activity"

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

Deadline for manuscript submissions: 31 March 2019

Special Issue Editor

Guest Editor
Prof. Dr. Francesco Epifano

Department of Pharmacy, University of G. d'Annunzio Chieti and Pescara, Chieti, Italy
Website | E-Mail
Phone: +3908713554654

Special Issue Information

Dear Colleagues,

In the last two decades, natural products have been re-discovered as valuable and effective pharmacological agents. In particular, they were shown to exert positive effects in the therapy of acute and chronic diseases, such as cancer, inflammation, neurological disorders, and microbial syndromes. To this concern, many examples of natural products were reported in recent and current literature. The aim of this Special Issue is to collect review and original research articles from several groups worldwide to gain further insights on the up-to-date knowledge in the field of isolation and structural characterization of novel pharmacologically-active agents obtained from the natural kingdom. Such an issue would be of great interest for several categories of scientists operating in different research fields, such as natural product chemistry, phytochemistry, pharmacology, molecular biology, pharmacognosy, medicinal chemistry, pharmaceutical technology, etc.

Prof. Dr. Francesco Epifano
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 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 products
  • Phytochemistry
  • Pharmacognosy
  • Pharmacology
  • Biological activity
  • Secondary Metabolites
  • Alkaloids
  • Terpenes
  • Phenylpropanoids
  • Polyketides
  • Glycosides
  • Analytical chemistry
  • NMR
  • Mass spectrometry
  • Liquid chromatography
  • Structure elucidation
  • Extraction

Published Papers (20 papers)

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Research

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Open AccessArticle Isolation of Chavibetol and Methyleugenol from Essential Oil of Pimenta pseudocaryophyllus by High Performance Liquid Chromatography
Molecules 2018, 23(11), 2909; https://doi.org/10.3390/molecules23112909
Received: 9 October 2018 / Revised: 1 November 2018 / Accepted: 4 November 2018 / Published: 8 November 2018
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Abstract
A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of P. pseudocaryophyllus leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID.
[...] Read more.
A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of P. pseudocaryophyllus leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID. Chavibetol was isolated with high purity (98.7%) and mass recovery (94.6%). The mass recovery (86.4%) and purity (85.3%) of methyleugenol were lower than those of chavibetol. Both compounds were identified on the basis of spectral analysis. The results suggest that the method can provide chavibetol with high purity, mass recovery, and productivity from crude essential, which will be used in bioassays against stored insect pests. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Isolation and Identification of Potent Antidiabetic Compounds from Antrodia cinnamomea—An Edible Taiwanese Mushroom
Molecules 2018, 23(11), 2864; https://doi.org/10.3390/molecules23112864
Received: 16 September 2018 / Revised: 31 October 2018 / Accepted: 1 November 2018 / Published: 2 November 2018
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Abstract
Antrodia cinnamomea (AC), an edible Taiwanese mushroom, has been recognized as a valuable natural resource with vast biological and medicinal benefits. Recently, the hypoglycemic and anti-diabetic effects of AC were mentioned in several studies. However, no studies have investigated α-glucosidase inhibitors from AC
[...] Read more.
Antrodia cinnamomea (AC), an edible Taiwanese mushroom, has been recognized as a valuable natural resource with vast biological and medicinal benefits. Recently, the hypoglycemic and anti-diabetic effects of AC were mentioned in several studies. However, no studies have investigated α-glucosidase inhibitors from AC fruiting bodies (ACFB) as they relate to type 2 diabetes (T2D) treatment. The purpose of this study was to gain evidence of potent α-glucosidase inhibitory effects, as well as isolate, identify and characterize the active compounds of ACFB. The MeOH extract of ACFB demonstrated potent α-glucosidase inhibitory activity, and possessed high pH stability (pH 2–11) and thermostable properties at 40–50 °C. Further purification led to the isolation of eight constituents from ACFB, identified as: 25S-antcin K (1), 25R-antcin K (2), dehydrosulphurenic acid (3), 25S-antcin I (4), 25S-antcin B (5), 25R-antcin B (6), dehydroeburicoic acid (7) and eburicoic acid (8). Notably, the ACFB extract and its identified compounds, except 1, 4, and 6 demonstrated a greater effect (EC50 = 0.025–0.21 mg/mL) than acarbose (EC50 = 0.278 mg/mL). As such, these active compounds were determined to be new potent mushroom α-glucosidase inhibitors. These active compounds were also identified on the HPLC fingerprints of ACFB. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Phytotoxic Compounds Isolated from Leaves of the Invasive Weed Xanthium spinosum
Molecules 2018, 23(11), 2840; https://doi.org/10.3390/molecules23112840
Received: 1 October 2018 / Revised: 26 October 2018 / Accepted: 28 October 2018 / Published: 1 November 2018
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Abstract
The aim of this study was to identify bioactive compounds from leaves of the invasive plant Xanthium spinosum and assess their phytotoxic activity. Activity-guided fractionation led to the isolation of 6 bioactive compounds: xanthatin (1), 1α,5α-epoxyxanthatin (2), 4-epiisoxanthanol (
[...] Read more.
The aim of this study was to identify bioactive compounds from leaves of the invasive plant Xanthium spinosum and assess their phytotoxic activity. Activity-guided fractionation led to the isolation of 6 bioactive compounds: xanthatin (1), 1α,5α-epoxyxanthatin (2), 4-epiisoxanthanol (3), 4-epixanthanol (4), loliolide (5) and dehydrovomifoliol (6). Of them, compounds 26 were isolated from the X. spinosum for the first time. The structures of 16 were elucidated on the basis of extensive NMR studies and ESI-MS measurements as well as comparison with literature data. All of compounds were evaluated for their phytotoxic activity. Among them, compounds 14 exhibited stronger activity on 2 receiver plants compared with the other 2 compounds, with xanthatin (1) being the most potent compound, which suppressed root growth of the dicot plant Amaranthus retroflexus by 32.5%, 39.4%, 84.7% when treated xanthatin (1) at 5, 20, and 100 µg/mL, while for the monocot plant, root growth was inhibited by 14.7%, 28.0%, and 40.0%, respectively. Seedling growth was nearly completely inhibited when the concentration of xanthanolides increased to 500 µg/mL, whereas there was still some seedling growth when loliolide (5) and dehydrovomifoliol (6) were applied at the same concentration. Dehydrovomifoliol (6) did not negatively affect seedling growth of P. annua at all tested concentrations, and root length was still 42.0% of the control when the highest concentration 500 µg/mL was used. This is the first report of the phytotoxicity of 1α,5α-epoxyxanthatin (2), 4-epiisxanthanol (3) and 4-epixanthanol (4). These compounds have the potential to be utilized as natural herbicides, especially 4-epiisoxanthanol (3), which exhibited significant selective activity between the dicot and monocot plants. On the other hand, whether these bioactive substances serve as allelochemicals to facilitate the invasion success of X. spinosum needs to be further studied. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Comparative Gene Expression Analysis in WM164 Melanoma Cells Revealed That β-β-Dimethylacrylshikonin Leads to ROS Generation, Loss of Mitochondrial Membrane Potential, and Autophagy Induction
Molecules 2018, 23(11), 2823; https://doi.org/10.3390/molecules23112823
Received: 4 October 2018 / Revised: 19 October 2018 / Accepted: 22 October 2018 / Published: 30 October 2018
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Abstract
Skin cancer is currently diagnosed as one in every three cancers. Melanoma, the most aggressive form of skin cancer, is responsible for 79% of skin cancer deaths and the incidence is rising faster than in any other solid tumor type. Previously, we have
[...] Read more.
Skin cancer is currently diagnosed as one in every three cancers. Melanoma, the most aggressive form of skin cancer, is responsible for 79% of skin cancer deaths and the incidence is rising faster than in any other solid tumor type. Previously, we have demonstrated that dimethylacrylshikonin (DMAS), isolated from the roots of Onosma paniculata (Boraginaceae), exhibited the lowest IC50 values against different tumor types out of several isolated shikonin derivatives. DMAS was especially cytotoxic towards melanoma cells and led to apoptosis and cell cycle arrest. In this study, we performed a comprehensive gene expression study to investigate the mechanism of action in more detail. Gene expression signature was compared to vehicle-treated WM164 control cells after 24 h of DMAS treatment; where 1192 distinct mRNAs could be identified as expressed in all replicates and 89 were at least 2-fold differentially expressed. DMAS favored catabolic processes and led in particular to p62 increase which is involved in cell growth, survival, and autophagy. More in-depth experiments revealed that DMAS led to autophagy, ROS generation, and loss of mitochondrial membrane potential in different melanoma cells. It has been reported that the induction of an autophagic cell death represents a highly effective approach in melanoma therapy. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Isolation of Tricin as a Xanthine Oxidase Inhibitor from Sweet White Clover (Melilotus albus) and Its Distribution in Selected Gramineae Species
Molecules 2018, 23(10), 2719; https://doi.org/10.3390/molecules23102719
Received: 27 September 2018 / Revised: 16 October 2018 / Accepted: 18 October 2018 / Published: 22 October 2018
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Abstract
Xanthine oxidase, an enzyme present in significant levels in the intestine and liver, metabolizes hypoxanthine to xanthine and xanthine to uric acid in the purine catabolic pathway. An inhibitory compound acting against xanthine oxidase was isolated from sweet white clover (Melilotus albus
[...] Read more.
Xanthine oxidase, an enzyme present in significant levels in the intestine and liver, metabolizes hypoxanthine to xanthine and xanthine to uric acid in the purine catabolic pathway. An inhibitory compound acting against xanthine oxidase was isolated from sweet white clover (Melilotus albus) by bioassay and high-performance liquid chromatography guided separation. It was identified as tricin by spectroscopic analysis. Tricin possessed a potent xanthine oxidase inhibitory activity with an IC50 value of 4.13 μM. Further inhibition kinetics data indicated it to be a mixed-type inhibitor and Ki and KI values were determined to be 0.47 μM and 4.41 μM. To find a rich source of tricin, the distribution of tricin in seven different tissues from four Gramineae species was investigated by high-performance liquid chromatography analysis. The highest amount (1925.05 mg/kg dry materials) was found in the straw of wheat, which is considered as a potentially valuable source of natural tricin. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessFeature PaperArticle Characterization of Red Wine Proanthocyanidins Using a Putative Proanthocyanidin Database, Amide Hydrophilic Interaction Liquid Chromatography (HILIC), and Time-of-Flight Mass Spectrometry
Molecules 2018, 23(10), 2687; https://doi.org/10.3390/molecules23102687
Received: 19 September 2018 / Revised: 11 October 2018 / Accepted: 14 October 2018 / Published: 18 October 2018
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Abstract
Proanthocyanidins are complex polymers of flavan-3-ol monomers and play a key sensory and health role in foods and beverages. We describe here a novel method for characterizing wine proanthocyanidins using a theoretical database comprised of the chemical formula and exact mass of 996
[...] Read more.
Proanthocyanidins are complex polymers of flavan-3-ol monomers and play a key sensory and health role in foods and beverages. We describe here a novel method for characterizing wine proanthocyanidins using a theoretical database comprised of the chemical formula and exact mass of 996 compounds. The database was constructed using the four primary grape and wine proanthocyanidin monomers: (epi)catechin, (epi)catechin-3-O-gallate, (epi)gallocatechin, and (epi)gallocatechin-3-O-gallate, each combined in all possible combinations up to a polymerization of 10. The database was queried against spectra collected using ultrahigh performance liquid chromatography (UHLPC) with a hydrophilic interaction liquid chromatography (HILIC) column and coupled to a high-resolution accurate mass quadrupole time-of-flight mass spectrometer (Q-TOF MS). Two wine samples produced with different post fermentation maceration were analyzed using the presented method to demonstrate application for analysis of diverse proanthocyanidins. The first sample was pressed immediately at the end of fermentation when all sugar had been utilized and the second received eight weeks of post fermentation maceration. The HILIC column combined with high resolution tandem mass spectrometry and database matching provided tentative identification of 89 compounds with excellent resolution and without the need for two-dimensional separations. The identified compounds were visualized with Kendrick mass analysis, a simple technique allowing for rapid visualization of which compounds are present in a given sample. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Antioxidant Activity and Phytochemical Characterization of Senecio clivicolus Wedd.
Molecules 2018, 23(10), 2497; https://doi.org/10.3390/molecules23102497
Received: 7 September 2018 / Revised: 25 September 2018 / Accepted: 28 September 2018 / Published: 29 September 2018
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Abstract
Antioxidant phytochemicals play a key role in oxidative stress control and in the prevention of related disorders, such as premature aging, degenerative diseases, diabetes, and cancer. The aim of this study was to investigate the potential antioxidant activity and the phytochemical profile of
[...] Read more.
Antioxidant phytochemicals play a key role in oxidative stress control and in the prevention of related disorders, such as premature aging, degenerative diseases, diabetes, and cancer. The aim of this study was to investigate the potential antioxidant activity and the phytochemical profile of Senecio clivicolus Wedd., a perennial shrub, belonging to the Asteraceae family. Despite the wide interest of this family, this specie has not been investigated yet. S. clivicolus aerial parts were extracted with 96% ethanol. Then, the ethanol extract was fractionated by liquid/liquid extraction using an increasing solvents polarity. Total polyphenol and terpenoid contents were measured. Moreover, the antioxidant activity was evaluated by six different complementary in vitro assays. The Relative Antioxidant Capacity Index (RACI) was used to compare data obtained by different tests. The sample showing the highest RACI was subjected to characterization and quantitation of its phenolic composition using LC-MS/MS analysis. The ethyl acetate fraction, investigated by LC-MS/MS analysis, showed 30 compounds, most of them are chlorogenic acid and flavonoid derivatives. To the best of our knowledge, this is the first report about the evaluation of antioxidant activity and phytochemical profile of S. clivicolus, underlying the importance of this species as a source of health-promoting phytochemicals. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Azukisapogenol Triterpene Glycosides from Oxytropis chiliophylla Royle
Molecules 2018, 23(10), 2448; https://doi.org/10.3390/molecules23102448
Received: 6 September 2018 / Revised: 19 September 2018 / Accepted: 20 September 2018 / Published: 25 September 2018
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Abstract
Eight azukisapogenol triterpene glycosides, including five new compounds, oxychiliotriterpenosides A–E (15), two new methyl glucuronide derivatives that proved to be artifacts, oxychiliotriterpenoside E-glucuronic acid methyl ester (6) and myrioside B-glucuronic acid methyl ester (7), and
[...] Read more.
Eight azukisapogenol triterpene glycosides, including five new compounds, oxychiliotriterpenosides A–E (15), two new methyl glucuronide derivatives that proved to be artifacts, oxychiliotriterpenoside E-glucuronic acid methyl ester (6) and myrioside B-glucuronic acid methyl ester (7), and a known one, myrioside B (8), was isolated from the aerial part of Oxytropis chiliophylla Royle. Their structures were elucidated based on extensive spectroscopic analyses and chemical methods. Triterpene glycosides were first obtained from O. chiliophylla, and those containing a galactose unit (1, 2, 5 and 6) and diglucosidic or triglucosidic linkage at C-29 (14), were reported from Oxytropis species for the first time, which might be recognized as a chemotaxonomic feature of O. chiliophylla. All isolated compounds were evaluated for their anti-inflammatory activities against NO production using lipopolysaccharide (LPS)-induced RAW 264.7 cells, but no compounds showed potent inhibition on NO production. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Isolation, Characterization and Antitumor Effect on DU145 Cells of a Main Polysaccharide in Pollen of Chinese Wolfberry
Molecules 2018, 23(10), 2430; https://doi.org/10.3390/molecules23102430
Received: 16 August 2018 / Revised: 9 September 2018 / Accepted: 17 September 2018 / Published: 21 September 2018
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Abstract
Modern studies have shown that pollen has a certain role in the treatment of prostate-related diseases. In the present study, pollen polysaccharides from Chinese wolfberry (WPPs) were extracted by hot-water extraction and ethanol precipitation, further purified by chromatography on a DEAE-cellulose column and
[...] Read more.
Modern studies have shown that pollen has a certain role in the treatment of prostate-related diseases. In the present study, pollen polysaccharides from Chinese wolfberry (WPPs) were extracted by hot-water extraction and ethanol precipitation, further purified by chromatography on a DEAE-cellulose column and Sephadex G-100 column. Homogeneous polysaccharide CF1 of WPPS was obtained, the molecular weight of which was estimated to be 1540.10 ± 48.78 kDa by HPGPC-ELSD. HPLC with PMP derivatization analysis indicated that the monosaccharide compositions of CF1 were mannose, glucuronic acid, galacturonic acid, xylose, galactose, arabinose, and trehalose, in a molar ratio of 0.68:0.59:0.27:0.24:0.22:0.67:0.08. The antitumor effects of CF1 upon MTT, Tunel assay and flow cytometry assay were investigated in vitro. The results showed that CF1 exhibited a dose-dependent antiproliferative effect, with an IC50 value of 374.11 μg/mL against DU145 prostate cancer cells. Tunel assay and flow cytometry assay showed that the antitumor activity of CF1 was related to apoptosis in vitro. The present study suggested that the CF1 of WPPs might be a potential source of antitumor functional food or agent. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Influence of Eugenia uniflora Extract on Adhesion to Human Buccal Epithelial Cells, Biofilm Formation, and Cell Surface Hydrophobicity of Candida spp. from the Oral Cavity of Kidney Transplant Recipients
Molecules 2018, 23(10), 2418; https://doi.org/10.3390/molecules23102418
Received: 6 July 2018 / Revised: 31 July 2018 / Accepted: 2 August 2018 / Published: 20 September 2018
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Abstract
This study evaluated the influence of the extract of Eugenia uniflora in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of Candida spp. isolated from the oral cavity of kidney transplant patients. To evaluate virulence attributes in
[...] Read more.
This study evaluated the influence of the extract of Eugenia uniflora in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of Candida spp. isolated from the oral cavity of kidney transplant patients. To evaluate virulence attributes in vitro, nine yeasts were grown in the presence and absence of 1000 μg/mL of the extract. Adhesion was quantified using the number of Candida cells adhered to 150 HBEC determined by optical microscope. Biofilm formation was evaluated using two methodologies: XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and crystal violet assay, and further analyzed by electronic scan microscopy. CSH was quantified with the microbial adhesion to hydrocarbons test. We could detect that the extract of E. uniflora was able to reduce adhesion to HBEC and CSH for both Candida albicans and non-Candida albicans Candida species. We also observed a statistically significant reduced ability to form biofilms in biofilm-producing strains using both methods of quantification. However, two highly biofilm-producing strains of Candida tropicalis had a very large reduction in biofilm formation. This study reinforces the idea that besides growth inhibition, E. uniflora may interfere with the expression of some virulence factors of Candida spp. and may be possibly applied in the future as a novel antifungal agent. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Characterization of α-Glucosidase Inhibitors from Clinacanthus nutans Lindau Leaves by Gas Chromatography-Mass Spectrometry-Based Metabolomics and Molecular Docking Simulation
Molecules 2018, 23(9), 2402; https://doi.org/10.3390/molecules23092402
Received: 24 August 2018 / Revised: 15 September 2018 / Accepted: 18 September 2018 / Published: 19 September 2018
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Abstract
Background: Clinacanthus nutans (C. nutans) is an Acanthaceae herbal shrub traditionally consumed to treat various diseases including diabetes in Malaysia. This study was designed to evaluate the α-glucosidase inhibitory activity of C. nutans leaves extracts, and to identify the metabolites responsible
[...] Read more.
Background: Clinacanthus nutans (C. nutans) is an Acanthaceae herbal shrub traditionally consumed to treat various diseases including diabetes in Malaysia. This study was designed to evaluate the α-glucosidase inhibitory activity of C. nutans leaves extracts, and to identify the metabolites responsible for the bioactivity. Methods: Crude extract obtained from the dried leaves using 80% methanolic solution was further partitioned using different polarity solvents. The resultant extracts were investigated for their α-glucosidase inhibitory potential followed by metabolites profiling using the gas chromatography tandem with mass spectrometry (GC-MS). Results: Multivariate data analysis was developed by correlating the bioactivity, and GC-MS data generated a suitable partial least square (PLS) model resulting in 11 bioactive compounds, namely, palmitic acid, phytol, hexadecanoic acid (methyl ester), 1-monopalmitin, stigmast-5-ene, pentadecanoic acid, heptadecanoic acid, 1-linolenoylglycerol, glycerol monostearate, alpha-tocospiro B, and stigmasterol. In-silico study via molecular docking was carried out using the crystal structure Saccharomyces cerevisiae isomaltase (PDB code: 3A4A). Interactions between the inhibitors and the protein were predicted involving residues, namely LYS156, THR310, PRO312, LEU313, GLU411, and ASN415 with hydrogen bond, while PHE314 and ARG315 with hydrophobic bonding. Conclusion: The study provides informative data on the potential α-glucosidase inhibitors identified in C. nutans leaves, indicating the plant’s therapeutic effect to manage hyperglycemia. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Expression of Bioactive Lunasin Peptide in Transgenic Rice Grains for the Application in Functional Food
Molecules 2018, 23(9), 2373; https://doi.org/10.3390/molecules23092373
Received: 7 August 2018 / Revised: 2 September 2018 / Accepted: 4 September 2018 / Published: 17 September 2018
PDF Full-text (2276 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Lunasin, a bioactive peptide initially isolated from soybean, has anticancer, anti-inflammatory, and antioxidant activity. Due its great application value, lunasin seems to be a candidate gene in improving the nutritional value of crops. In this study, lunasin was inserted into the rice genome
[...] Read more.
Lunasin, a bioactive peptide initially isolated from soybean, has anticancer, anti-inflammatory, and antioxidant activity. Due its great application value, lunasin seems to be a candidate gene in improving the nutritional value of crops. In this study, lunasin was inserted into the rice genome to evaluate whether it was feasible to express lunasin using the rice expression system and improve the bioactivity of protein in rice for our needs. We generatedlunasin-overexpressing rice lines, and chose three independent transgenic rice lines for further study. The lunasin content in trans-lunasin rice detected by UPLC-MS/MS was 1.01 × 10−3 g·kg−1 dry rice flour with grease removal in the lunasin extracts. The antioxidant efficacy of LET (lunasin-enriched fraction from trans-lunasin rice) and PEW (peptide-enriched fraction from wild type rice) was compared. Due to the presence of lunasin, LET showed higher (p < 0.05) antioxidant activity than PEW. LET exhibited high DPPH radical scavenging activity (IC50 value, 8 g·L−1), strong ABTS+ radical scavenging activity (IC50 value, 1.18 g·L−1), and great oxygen radical scavenging activity (170 μmol·L−1 Trolox equivalents when the concentration reached 4 g·L−1). Moreover, LET presented significantly higher (p < 0.05) anti-inflammatory activity on macrophage cells, and the NO production and the release of pro-inflammatory cytokines (IL-6, MCP1, and TNF-α) were significantly inhibited by LET. However, because of the low purity, LET showed weaker antioxidant and anti-inflammatory activity when compared to the Lunasin standard. These results suggested that it is feasible to use the rice expression system to express the exogenous lunasin in rice, and lunasin-overexpressing rice seems to be a candidate resource for application in functional food. Rice rich in lunasin is beneficial for human health, and could be used as a functional food in the diets of cancer and obese patients in the future. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Antioxidant Activity and Neuroprotective Activity of Stilbenoids in Rat Primary Cortex Neurons via the PI3K/Akt Signalling Pathway
Molecules 2018, 23(9), 2328; https://doi.org/10.3390/molecules23092328
Received: 8 August 2018 / Revised: 5 September 2018 / Accepted: 6 September 2018 / Published: 12 September 2018
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Abstract
Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All
[...] Read more.
Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All three stilbenoids were able to inhibit Aβ neurotoxicity by decreasing intracellular reactive oxygen species (ROS) via the PI3K/Akt signalling pathway. Specifically, stilbenoids significantly promoted Akt phosphorylation; suppressed Bcl-2/Bax expression; and inhibited caspase-9, caspase-3, and PARP cleavage. Molecular docking between stilbenoids with Akt indicated that stilbenoids could form hydrogen bond interactions with the COOH-terminal region of Akt. Additionally, the neuroprotective activity of stilbenoids correlated with the number and position of hydroxyl groups. The lack of meta-dihydroxyl groups on THS did not affect its neuroprotective activity in comparison with RES, whereas the ortho-dihydroxyl moiety on PIC significantly enhanced neuroprotective activity. These results provide new insights into the correlation between the biological activity and chemical structure of stilbenoids. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Depsidone Derivatives and a Cyclopeptide Produced by Marine Fungus Aspergillus unguis under Chemical Induction and by Its Plasma Induced Mutant
Molecules 2018, 23(9), 2245; https://doi.org/10.3390/molecules23092245
Received: 17 August 2018 / Revised: 29 August 2018 / Accepted: 30 August 2018 / Published: 3 September 2018
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Abstract
A new depsidone derivative (1), aspergillusidone G, was isolated from a marine fungus Aspergillus unguis, together with eight known depsidones (29) and a cyclic peptide (10): agonodepside A (2), nornidulin (3
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A new depsidone derivative (1), aspergillusidone G, was isolated from a marine fungus Aspergillus unguis, together with eight known depsidones (29) and a cyclic peptide (10): agonodepside A (2), nornidulin (3), nidulin (4), aspergillusidone F (5), unguinol (6), aspergillusidone C (7), 2-chlorounguinol (8), aspergillusidone A (9), and unguisin A (10). Compounds 14 and 79 were obtained from the plasma induced mutant of this fungus, while 5, 6, and 10 were isolated from the original strain under chemical induction. Their structures were identified using spectroscopic analysis, as well as by comparison with literature data. The HPLC fingerprint analysis indicates that chemical induction and plasma mutagenesis effectively influenced the secondary metabolism, which may be due to their regulation in the key steps in depsidone biosynthesis. In bioassays, compound 9 inhibited acetylcholinesterase (AChE) with IC50 in 56.75 μM. Compounds 1, 5, 7, 8, and 9 showed moderate to strong activity towards different microbes. Compounds 3, 4, and 5 exhibited potent larvicidality against brine shrimp. In docking studies, higher negative CDOCKER interaction energy and richer strong interactions between AChE and 9 explained the greater activity of 9 compared to 1. Chemical induction and plasma mutagenesis can be used as tools to expand the chemodiversity of fungi and obtain useful natural products. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle A Comparative Metabolomics Analysis Reveals the Tissue-Specific Phenolic Profiling in Two Acanthopanax Species
Molecules 2018, 23(8), 2078; https://doi.org/10.3390/molecules23082078
Received: 21 June 2018 / Revised: 24 July 2018 / Accepted: 24 July 2018 / Published: 20 August 2018
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Abstract
Acanthopanax senticosus (Rupr. Maxim.) Harms (ASH) and Acanthopanax sessiliflorus (Rupr. Maxim.) Seem (ASS), are members of the Araliaceae family, and both are used in Asian countries. These herbals have drawn much attention in recent years due to their strong biological activity, with innocuity
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Acanthopanax senticosus (Rupr. Maxim.) Harms (ASH) and Acanthopanax sessiliflorus (Rupr. Maxim.) Seem (ASS), are members of the Araliaceae family, and both are used in Asian countries. These herbals have drawn much attention in recent years due to their strong biological activity, with innocuity and little side effects. However, the common and distinct mode of compound profiles between ASH and ASS is still unclear. In this study, a high performance liquid chromatograph-mass spectrometry (HPLC-MS) method was developed to simultaneously quantify the seven major active compounds, including protocatechuate, eleutheroside B, eleutheroside E, isofraxidin, hyperoside, kaempferol and oleanolic acid. Then the targeted metabolomics were conducted to identify 19 phenolic compounds, with tight relation to the above mentioned active compounds, including nine C6C3C6-type, six C6C3-type and four C6C1-type in the two Acanthopanax species studied here. The results showed that the seven active compounds presented a similar trend of changes in different tissues, with more abundant accumulation in roots and stems for both plants. From the view of plant species, the ASH plants possess higher abundance of compounds, especially in the tissues of roots and stems. For phenolics, the 19 phenols detected here could be clearly grouped into five main clusters based on their tissue-specific accumulation patterns. Roots are the tissue for the most abundance of their accumulations. C6C3C6-type compounds are the most widely existing type in both plants. In conclusion, the tissue- and species-specificity in accumulation of seven active compounds and phenolics were revealed in two Acanthopanax species. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Effect of Volatile Organic Chemicals in Chrysanthemum indicum Linné on Blood Pressure and Electroencephalogram
Molecules 2018, 23(8), 2063; https://doi.org/10.3390/molecules23082063
Received: 8 August 2018 / Revised: 16 August 2018 / Accepted: 16 August 2018 / Published: 17 August 2018
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Abstract
This study identified the volatile organic compounds in the essential oils that are extracted from Chrysanthemum indicum Linné (C. indicum Linné) and investigated the effects of the inhalation of these compounds. We detected a total of 41 volatile organic compounds, including 32
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This study identified the volatile organic compounds in the essential oils that are extracted from Chrysanthemum indicum Linné (C. indicum Linné) and investigated the effects of the inhalation of these compounds. We detected a total of 41 volatile organic compounds, including 32 hydrocarbons, four acids, three alcohols, two ketones, and one aldehyde. In a sniffing test, seven types of volatile organic compounds were identified. Furthermore, the volatile organic compounds in C. indicum Linné that were identified were found to be derived from 1,8-cineole and camphor. After inhalation of the essential oils, the subjects’ systolic blood pressure and heart rate decreased. This indicates that inhalation of the essential oils extracted from C. indicum Linné provides mental and physical relaxation. We examined the changes in electroencephalogram findings that are observed after C. indicum Linné essential oil inhalation. An increase in theta and alpha waves, which usually appear during relaxation, as well as a decrease in beta and gamma waves, which appear during brain activity such as excessive attention, were noted. These results indicate that C. indicum Linné essential oil inhalation helps to reduce blood pressure and may provide mental and physical relaxation. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Isolation and Purification of Galloyl, Caffeoyl, and Hexahydroxydiphenoyl Esters of Glucoses from Balanophora simaoensis by High-Speed Countercurrent Chromatography and Their Antioxidant Activities In Vitro
Molecules 2018, 23(8), 2027; https://doi.org/10.3390/molecules23082027
Received: 23 July 2018 / Revised: 7 August 2018 / Accepted: 10 August 2018 / Published: 14 August 2018
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Abstract
High-speed counter-current chromatography was used to separate and purify galloyl, caffeoyl, and hexahydroxydiphenoyl esters of glucoses from the aerial parts of the parasitic plant Balanophora simaoensis for the first time using n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v) as the optimum solvent
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High-speed counter-current chromatography was used to separate and purify galloyl, caffeoyl, and hexahydroxydiphenoyl esters of glucoses from the aerial parts of the parasitic plant Balanophora simaoensis for the first time using n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v) as the optimum solvent system. Accordingly, 1-O-(E)-caffeoyl-3-O-galloyl-β-d-glucopyranose (I, 12.5 mg), 1-O-(E)-caffeoyl-3-O-galloyl-4,6-(S)-hexahydroxydiphenoyl-β-d-glucopyranose (II, 27.2 mg), and 1-O-(E)-caffeoyl-4,6-(S)-hexahydroxydiphenoyl-β-d-glucopyranose (III, 52.8 mg) with 98.0%, 98.5%, and 98.7% purities, respectively, were purified from 210 mg crude extract of B. simaoensis in a one-step separation. The structures of the glucose esters were identified by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance spectra (NMR). Their antioxidant activities were evaluated by measuring their inhibition activity on liver microsomal lipid peroxidation induced by the Fe2+-Cys system in vitro. Compounds IIII showed significant antioxidant activities with IC50 values ranging from 2.51 to 6.68 μm, respectively. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessCommunication DPP-IV Inhibitory Potentials of Flavonol Glycosides Isolated from the Seeds of Lens culinaris: In Vitro and Molecular Docking Analyses
Molecules 2018, 23(8), 1998; https://doi.org/10.3390/molecules23081998
Received: 23 July 2018 / Revised: 8 August 2018 / Accepted: 8 August 2018 / Published: 10 August 2018
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Abstract
Dipeptidyl peptidase IV (DPP-IV), a new target for the treatment of type 2 diabetes mellitus, degrades incretins such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide. DPP-IV inhibitors shorten the inactivation of GLP-1, permitting the incretin to stimulate insulin release, thereby combating
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Dipeptidyl peptidase IV (DPP-IV), a new target for the treatment of type 2 diabetes mellitus, degrades incretins such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide. DPP-IV inhibitors shorten the inactivation of GLP-1, permitting the incretin to stimulate insulin release, thereby combating hyperglycemia. In our ongoing search for new DPP-IV inhibitors from medicinal plants and foods, three flavonol glycosides (13) were isolated from the seeds of Lens culinaris Medikus (Fabaceae) and tested for their DPP-IV–inhibitory activity. We demonstrated for the first time, that compounds 13 inhibited DPP-IV activity in a concentration-dependent manner in our in vitro bioassay system. In addition, molecular docking experiments of compounds 13 within the binding pocket of DPP-IV were conducted. All investigated compounds readily fit within the active sites of DPP-IV, in low-energy conformations characterized by the flavone core structure having optimal electrostatic attractive interactions with the catalytic triad residues of DPP-IV. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessArticle Toxin-Pathogen Synergy Reshaping Detoxification and Antioxidant Defense Mechanism of Oligonychus afrasiaticus (McGregor)
Molecules 2018, 23(8), 1978; https://doi.org/10.3390/molecules23081978
Received: 27 June 2018 / Revised: 5 August 2018 / Accepted: 6 August 2018 / Published: 8 August 2018
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Abstract
Current study reveals the likelihood to use pathogen and toxin mutually as an effective and eco-friendly strategy for Oligonychus afrasiaticus (McGregor) management, which could reduce toxicant dose and host killing time. Therefore, phytol and Beauveria bassiana in different proportions were evaluated to determine
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Current study reveals the likelihood to use pathogen and toxin mutually as an effective and eco-friendly strategy for Oligonychus afrasiaticus (McGregor) management, which could reduce toxicant dose and host killing time. Therefore, phytol and Beauveria bassiana in different proportions were evaluated to determine their effectiveness. Prior to ascertaining host mortality and defense mechanisms, we have recorded in vitro action of phytol using different concentrations (0.70, 1.40, 2.10, 2.80, and 3.50 mg/mL) against B. bassiana suspension. In vitro compatibility assays revealed that growth parameters (vegetative growth, sporulation, and viability) of B. bassiana were least affected by the action of phytol at all tested concentrations. Biological Index of B. bassiana exhibited compatibility with phytol allowed us to conduct Joint toxicity bioassays in which phytol and spores mixed in different proportions in order to attain maximum treatment effect in terms of high mortality at low concentration under short time. Results revealed that joint-application exhibited both synergistic (treatments with higher proportions of phytol), and antagonistic interaction (treatments with higher proportions of spores) interactions. Biochemical mechanisms involved in host antioxidant and detoxification response were explored by quantifying their respective enzymatic activities. Lethality of different treatments induced different patterns of detoxification enzymes including glutathione S-transferase (GST) and acetylcholinesterase (AchE). Overall, the least potent treatments (20% phytol:80% spores, and 40% phytol:60% spores) established in the current study induced relatively higher GST and AchE activities. On the other hand, the most potent treatment (80% phytol:20% spores) at its maximum concentration exhibited negligible relative GST and AchE activities. Antioxidant enzyme activities of CAT and SOD measured in the current study showed moderate to complex interaction might because of toxin-pathogen remarkable synergy. This study suggested that joint application of phytol with B. bassiana spores have shown tremendous acaricidal potential and found to be promising new strategy for controlling old world date mites. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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Open AccessReview Linear Triquinane Sesquiterpenoids: Their Isolation, Structures, Biological Activities, and Chemical Synthesis
Molecules 2018, 23(9), 2095; https://doi.org/10.3390/molecules23092095
Received: 22 July 2018 / Revised: 17 August 2018 / Accepted: 19 August 2018 / Published: 21 August 2018
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Abstract
Linear triquinane sesquiterpenoids represent an important class of natural products. Most of these compounds were isolated from fungi, sponges, and soft corals, and many of them displayed a wide range of biological activities. On account of their structural diversity and complexity, linear triquinane
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Linear triquinane sesquiterpenoids represent an important class of natural products. Most of these compounds were isolated from fungi, sponges, and soft corals, and many of them displayed a wide range of biological activities. On account of their structural diversity and complexity, linear triquinane sesquiterpenoids present new challenges for chemical structure identification and total synthesis. 118 linear triquinane sesquiterpenoids were classified into 8 types, named types I–VIII, based on the carbon skeleton and the position of carbon substituents. Their isolation, structure elucidations, biological activities, and chemical synthesis were reviewed. This paper cited 102 articles from 1947 to 2018. Full article
(This article belongs to the Special Issue Natural Product Isolation, Identification and Biological Activity)
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