Bioassay-Guided Isolation of Marine Natural Products for Drug Discovery

A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (31 August 2019) | Viewed by 64196

Special Issue Editor

School of Chemical and Physical Sciences, and Center for Biodiscovery, Victoria University of Wellington, Wellington 6140, New Zealand
Interests: marine invertebrate natural products; bioactive natural products; structure determination of new metabolites; isolation and purification; chemical analysis; analytical chemistry of natural compounds and xenochemicals
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Special Issue Information

Dear Colleagues,

From the potential human harm caused by the exquisitely potent dinoflagellate cytotoxins, maitotoxin and brevetoxin, through the knowledge gained regarding cellular function and metabolism from the use of latrunculin and laulimalide, right through to new blockbuster anticancer drugs like Eribulin mesylate and Trabectedin, the bioassay-guided isolation of new marine natural products has informed science and helped save many lives over the past half century. The new and exciting molecules sourced from the marine environment are varied in structure and, most importantly, the wide ranging and diverse potent bioactivities they possess. With a significantly greater number of phyla represented in our marine environments than that found on land, the sheer biodiversity found in the oceans, coupled with difficulties, and hence opportunities for obtaining marine organisms, continue to make investigations of marine natural products a lucrative area for medicinal and biochemical research.

Given the great value still waiting to be discovered from the life within our planet’s oceans, as the Guest Editor of this Special Issue of Marine Drugs, I personally invite you to contribute your latest research describing bioassay-guided isolation and identification of novel, bioactive marine natural products, from any marine-based organisms.

Dr. Rob Keyzers
Guest Editor

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Keywords

  • Biological activity
  • Phenotypic assay
  • Enzyme inhibition assay
  • Mode of action
  • Isolation
  • Structural elucidation
  • Bioassay guided fractionation

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Published Papers (10 papers)

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Research

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10 pages, 1381 KiB  
Article
Asperienes A–D, Bioactive Sesquiterpenes from the Marine-Derived Fungus Aspergillus flavus
by Yun-Feng Liu, Yu-Fei Yue, Li-Xi Feng, Hua-Jie Zhu and Fei Cao
Mar. Drugs 2019, 17(10), 550; https://doi.org/10.3390/md17100550 - 26 Sep 2019
Cited by 28 | Viewed by 3849
Abstract
Marine-derived fungi of the genera Aspergillus could produce novel compounds with significant bioactivities. Among these fungi, the strain Aspergillus flavus is notorious for its mutagenic mycotoxins production. However, some minor components with certain toxicities from A. flavus have not been specifically surveyed and [...] Read more.
Marine-derived fungi of the genera Aspergillus could produce novel compounds with significant bioactivities. Among these fungi, the strain Aspergillus flavus is notorious for its mutagenic mycotoxins production. However, some minor components with certain toxicities from A. flavus have not been specifically surveyed and might have potent biological activities. Our investigation of the marine-derived fungus Aspergillus flavus CF13-11 cultured in solid medium led to the isolation of four C-6′/C-7′ epimeric drimane sesquiterpene esters, asperienes A–D (14). Their absolute configurations were assigned by electronic circular dichroism (ECD) and Snatzke’s methods. This is the first time that two pairs of C-6′/C-7′ epimeric drimane sesquiterpene esters have successfully been separated. Aperienes A–D (14) displayed potent bioactivities towards four cell lines with the IC50 values ranging from 1.4 to 8.3 μM. Interestingly, compounds 1 and 4 exhibited lower toxicities than 2 and 3 toward normal GES-1 cells, indicating more potential for development as an antitumor agent in the future. Full article
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27 pages, 18221 KiB  
Article
Cytotoxic and Antiproliferative Effects of Preussin, a Hydroxypyrrolidine Derivative from the Marine Sponge-Associated Fungus Aspergillus candidus KUFA 0062, in a Panel of Breast Cancer Cell Lines and Using 2D and 3D Cultures
by Fernanda Malhão, Alice A. Ramos, Suradet Buttachon, Tida Dethoup, Anake Kijjoa and Eduardo Rocha
Mar. Drugs 2019, 17(8), 448; https://doi.org/10.3390/md17080448 - 30 Jul 2019
Cited by 24 | Viewed by 6167
Abstract
Preussin, a hydroxyl pyrrolidine derivative isolated from the marine sponge-associated fungus Aspergillus candidus KUFA 0062, displayed anticancer effects in some cancer cell lines, including MCF7. Preussin was investigated for its cytotoxic and antiproliferative effects in breast cancer cell lines (MCF7, SKBR3, and MDA-MB-231), [...] Read more.
Preussin, a hydroxyl pyrrolidine derivative isolated from the marine sponge-associated fungus Aspergillus candidus KUFA 0062, displayed anticancer effects in some cancer cell lines, including MCF7. Preussin was investigated for its cytotoxic and antiproliferative effects in breast cancer cell lines (MCF7, SKBR3, and MDA-MB-231), representatives of major breast cancers subtypes, and in a non-tumor cell line (MCF12A). Preussin was first tested in 2D (monolayer), and then in 3D (multicellular aggregates), cultures, using a multi-endpoint approach for cytotoxicity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), resazurin and lactate dehydrogenase (LDH)) and proliferative (5-bromo-2′-deoxyuridine (BrdU)) assays, as well as the analysis of cell morphology by optical/electron microscopy and immunocytochemistry for caspase-3 and ki67. Preussin affected cell viability and proliferation in 2D and 3D cultures in all cell lines tested. The results in the 3D culture showed the same tendency as in the 2D culture, however, cells in the 3D culture were less responsive. The effects were observed at different concentrations of preussin, depending on the cell line and assay method. Morphological study of preussin-exposed cells revealed cell death, which was confirmed by caspase-3 immunostaining. In view of the data, we recommend a multi-endpoint approach, including histological evaluation, in future assays with the tested 3D models. Our data showed cytotoxic and antiproliferative activities of preussin in breast cancer cell lines in 2D and 3D cultures, warranting further studies for its anticancer potential. Full article
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19 pages, 1655 KiB  
Article
In Vitro and In Silico Approaches to Generating and Identifying Angiotensin-Converting Enzyme I Inhibitory Peptides from Green Macroalga Ulva lactuca
by Marco Garcia-Vaquero, Leticia Mora and Maria Hayes
Mar. Drugs 2019, 17(4), 204; https://doi.org/10.3390/md17040204 - 30 Mar 2019
Cited by 64 | Viewed by 8278
Abstract
A protein extract was generated from the macroalga Ulva lactuca, which was subsequently hydrolysed using the food-grade enzyme papain and angiotensin-converting Enzyme I and renin inhibitory peptides identified using a combination of enrichment strategies employing molecular weight cutoff filtration and mass spectrometry [...] Read more.
A protein extract was generated from the macroalga Ulva lactuca, which was subsequently hydrolysed using the food-grade enzyme papain and angiotensin-converting Enzyme I and renin inhibitory peptides identified using a combination of enrichment strategies employing molecular weight cutoff filtration and mass spectrometry analysis. The generated hydrolysates with the most promising in vitro activity were further purified using preparative RP-HPLC and characterised. The 1 kDa hydrolysate (1 kDa-UFH), purified and collected by preparative RP-HPLC at minutes 41‒44 (Fr41‒44), displayed statistically higher ACE-I inhibitory activities ranging from 96.91% to 98.06%. A total of 48 novel peptides were identified from these four fractions by LC-MS/MS. A simulated gastrointestinal digestion of the identified peptide sequences was carried out using in silico enzyme cleavage simulation tools, resulting in 86 peptide sequences that were further assessed for their potential activity, toxicity and allergenicity using multiple predictive approaches. All the peptides obtained in this study were predicted to be non-toxic. However, 28 out of the 86 novel peptides released after the in silico gastrointestinal digestion were identified as potential allergens. The potential allergenicity of these peptides should be further explored to comply with the current labelling regulations in formulated food products containing U. lactuca protein hydrolysates. Full article
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16 pages, 1811 KiB  
Article
Antioxidant and Neuroprotective Potential of the Brown Seaweed Bifurcaria bifurcata in an in vitro Parkinson’s Disease Model
by Joana Silva, Celso Alves, Rafaela Freitas, Alice Martins, Susete Pinteus, Joana Ribeiro, Helena Gaspar, Amparo Alfonso and Rui Pedrosa
Mar. Drugs 2019, 17(2), 85; https://doi.org/10.3390/md17020085 - 1 Feb 2019
Cited by 67 | Viewed by 6419
Abstract
Bifurcaria bifurcata is a marine brown seaweed mainly found on the Atlantic coast. Herein, we report the antioxidant and neuroprotective activities of seven fractions (F1–F7) obtained by normal phase chromatography from the B. bifurcata dichloromethane extract, as well as of its two major [...] Read more.
Bifurcaria bifurcata is a marine brown seaweed mainly found on the Atlantic coast. Herein, we report the antioxidant and neuroprotective activities of seven fractions (F1–F7) obtained by normal phase chromatography from the B. bifurcata dichloromethane extract, as well as of its two major isolated diterpenes. Total phenolic content of fractions was determined by the Folin–Ciocalteu method, while antioxidant activity was evaluated by the DPPH, ORAC, and FRAP assays. Neuroprotective effects were evaluated in a neurotoxic model induced by 6-hydroxydopamine (6-OHDA) in a human neuroblastoma cell line (SH-SY5Y), while the mechanisms associated to neuroprotection were investigated by the determination of mitochondrial membrane potential, H2O2 production, Caspase-3 activity, and by observation of DNA fragmentation. Fractions F4 and F5 exhibited the best neuroprotective and antioxidant activities, respectively. F4 fraction prevented changes in mitochondrial potential, and induced a reduction of H2O2 levels production and an increase in cell viability, suggesting that it may contain multi-target compounds acting on different pathways. Hence, this fraction was subjected to purification steps, affording the known diterpenes eleganolone and eleganonal. Both compounds exhibited antioxidant potential, being interesting candidates for further neuroprotective studies. Full article
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12 pages, 1745 KiB  
Article
Anti-Acanthamoeba Activity of Brominated Sesquiterpenes from Laurencia johnstonii
by Sara García-Davis, Ines Sifaoui, María Reyes-Batlle, Ezequiel Viveros-Valdez, José E. Piñero, Jacob Lorenzo-Morales, José J. Fernández and Ana R. Díaz-Marrero
Mar. Drugs 2018, 16(11), 443; https://doi.org/10.3390/md16110443 - 11 Nov 2018
Cited by 27 | Viewed by 5063
Abstract
Focused on our interest to develop novel antiparasistic agents, the present study was aimed to evaluate the biological activity of an extract of Laurencia johnstonii collected in Baja California Sur, Mexico, against an Acantamoeba castellanii Neff strain. Bioassay-guided fractionation allowed us to identify [...] Read more.
Focused on our interest to develop novel antiparasistic agents, the present study was aimed to evaluate the biological activity of an extract of Laurencia johnstonii collected in Baja California Sur, Mexico, against an Acantamoeba castellanii Neff strain. Bioassay-guided fractionation allowed us to identify the amoebicidal diastereoisomers α-bromocuparane (4) and α-isobromocuparane (5). Furthermore, bromination of the inactive laurinterol (1) and isolaurinterol (2) yielded four halogenated derivatives, (6)–(9), which improved the activity of the natural sesquiterpenes. Among them, the most active compound was 3α-bromojohnstane (7), a sesquiterpene derivative which possesses a novel carbon skeleton johnstane. Full article
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8 pages, 788 KiB  
Article
Anti-MRSA Sesquiterpenes from the Semi-Mangrove Plant Myoporum bontioides A. Gray
by Li-Mei Dong, Li-Lan Huang, Hang Dai, Qiao-Lin Xu, Jin-Kui Ouyang, Xu-Chao Jia, Wen-Xiang Gu and Jian-Wen Tan
Mar. Drugs 2018, 16(11), 438; https://doi.org/10.3390/md16110438 - 8 Nov 2018
Cited by 22 | Viewed by 3846
Abstract
The striking rise of methicillin-resistant Staphylococcus aureus (MRSA) infections has become a serious threat to public health worldwide. In an effort to search for new anti-MRSA agents from natural products, a bioassay-guided phytochemical study was conducted on the semi-mangrove plant Myoporum bontioides A. [...] Read more.
The striking rise of methicillin-resistant Staphylococcus aureus (MRSA) infections has become a serious threat to public health worldwide. In an effort to search for new anti-MRSA agents from natural products, a bioassay-guided phytochemical study was conducted on the semi-mangrove plant Myoporum bontioides A. Gray, which led to the isolation of two new sesquiterpene alkaloids (1 and 2) and six known furanosesquiterpenes (38). Their structures were elucidated on the basis of extensive analysis of their 1D, 2D NMR and mass spectroscopic data. These two new alkaloids (1 and 2) displayed potent anti-MRSA activity with MIC value of 6.25 μg/mL. This is the first report of sesquiterpene alkaloids from the plants of Myoporum genus and their anti-MRSA activity. Full article
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8 pages, 1445 KiB  
Article
Cytotoxic Tetrahydroxanthone Dimers from the Mangrove-Associated Fungus Aspergillus versicolor HDN1009
by Guihong Yu, Guangwei Wu, Zichao Sun, Xiaomin Zhang, Qian Che, Qianqun Gu, Tianjiao Zhu, Dehai Li and Guojian Zhang
Mar. Drugs 2018, 16(9), 335; https://doi.org/10.3390/md16090335 - 14 Sep 2018
Cited by 38 | Viewed by 3980
Abstract
Three new tetrahydroxanthone dimers, 5-epi-asperdichrome (1), versixanthones N (2), and O (3), were isolated from the mangrove-derived fungus Aspergillus versicolor HDN1009. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and circular dichroism [...] Read more.
Three new tetrahydroxanthone dimers, 5-epi-asperdichrome (1), versixanthones N (2), and O (3), were isolated from the mangrove-derived fungus Aspergillus versicolor HDN1009. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and circular dichroism (CD) experiments. Among them, compound 1 was the second example of tetrahydroxanthone dimers, which dimerized by a rare diaryl ether linkage and showed promising antibacterial activities against Vibrio parahemolyticus, Bacillus subtilis, Mycobacterium phlei, and Pseudomonas aeruginosa, with MIC values ranging from 100 μM to 200 μM; whilst compounds 2 and 3 exhibited extensive cytotoxicities against five cancer cell lines (HL-60, K562, H1975, MGC803, and HO-8910), with IC50 values ranging from 1.7 μM to 16.1 μM. Full article
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10 pages, 1363 KiB  
Article
Mycophenolic Acid Derivatives with Immunosuppressive Activity from the Coral-Derived Fungus Penicillium bialowiezense
by Qing Zhang, Beiye Yang, Fengli Li, Mengting Liu, Shuang Lin, Jianping Wang, Yongbo Xue, Hucheng Zhu, Weiguang Sun, Zhengxi Hu and Yonghui Zhang
Mar. Drugs 2018, 16(7), 230; https://doi.org/10.3390/md16070230 - 7 Jul 2018
Cited by 17 | Viewed by 6077
Abstract
Mycophenolic acid (MPA) is a potent inosine-5′-monophosphate dehydrogenase (IMPDH) inhibitor for immunosuppressive chemotherapy. Most importantly, as the 2-morpholinoethyl ester prodrug of MPA, mycophenolate mofetil (MMF) is a well-known immunosuppressant used to prevent rejection in organ transplantations. Nevertheless, due to its frequently occurred side [...] Read more.
Mycophenolic acid (MPA) is a potent inosine-5′-monophosphate dehydrogenase (IMPDH) inhibitor for immunosuppressive chemotherapy. Most importantly, as the 2-morpholinoethyl ester prodrug of MPA, mycophenolate mofetil (MMF) is a well-known immunosuppressant used to prevent rejection in organ transplantations. Nevertheless, due to its frequently occurred side effects, searching for new therapeutic agents is ongoing. In our current work, by virtue of efficient bioassay-guided fractionation and purification, eleven mycophenolic acid derivatives, including five previously unreported metabolites (37) and six known compounds (1, 2, and 811), were obtained from the coral-derived fungus Penicillium bialowiezense. Their structures were elucidated by means of extensive spectroscopic analyses (including 1D and 2D NMR and HRESIMS data) and comparison of the NMR and other physical data with those reported in the literature in the case of the known compounds. All the isolates 111 were evaluated for the immunosuppressive activity, and 13 showed potent IMPDH2 inhibitory potency with IC50 values of 0.84–0.95 μM, which were comparable to that of MPA (the positive control), while 410 showed significant inhibitory potency with IC50 values of 3.27–24.68 μM. All the MPA derivatives showed promising immunosuppressive activity, endowing them as potential drug leads for organ transplantations and autoimmune related diseases. Full article
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Review

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26 pages, 4467 KiB  
Review
Bioactive Compounds Isolated from Marine-Derived Microbes in China: 2009–2018
by Weiwei Sun, Wenhui Wu, Xueling Liu, Diana A. Zaleta-Pinet and Benjamin R. Clark
Mar. Drugs 2019, 17(6), 339; https://doi.org/10.3390/md17060339 - 6 Jun 2019
Cited by 48 | Viewed by 8371
Abstract
This review outlines the research that was carried out regarding the isolation of bioactive compounds from marine-derived bacteria and fungi by China-based research groups from 2009–2018, with 897 publications being surveyed. Endophytic organisms featured heavily, with endophytes from mangroves, marine invertebrates, and marine [...] Read more.
This review outlines the research that was carried out regarding the isolation of bioactive compounds from marine-derived bacteria and fungi by China-based research groups from 2009–2018, with 897 publications being surveyed. Endophytic organisms featured heavily, with endophytes from mangroves, marine invertebrates, and marine algae making up more than 60% of the microbial strains investigated. There was also a strong focus on fungi as a source of active compounds, with 80% of publications focusing on this area. The rapid increase in the number of publications in the field is perhaps most notable, which have increased more than sevenfold over the past decade, and suggests that China-based researchers will play a major role in marine microbial natural products drug discovery in years to come. Full article
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31 pages, 393 KiB  
Review
Current Screening Methodologies in Drug Discovery for Selected Human Diseases
by Olga Maria Lage, María C. Ramos, Rita Calisto, Eduarda Almeida, Vitor Vasconcelos and Francisca Vicente
Mar. Drugs 2018, 16(8), 279; https://doi.org/10.3390/md16080279 - 14 Aug 2018
Cited by 87 | Viewed by 10869
Abstract
The increase of many deadly diseases like infections by multidrug-resistant bacteria implies re-inventing the wheel on drug discovery. A better comprehension of the metabolisms and regulation of diseases, the increase in knowledge based on the study of disease-born microorganisms’ genomes, the development of [...] Read more.
The increase of many deadly diseases like infections by multidrug-resistant bacteria implies re-inventing the wheel on drug discovery. A better comprehension of the metabolisms and regulation of diseases, the increase in knowledge based on the study of disease-born microorganisms’ genomes, the development of more representative disease models and improvement of techniques, technologies, and computation applied to biology are advances that will foster drug discovery in upcoming years. In this paper, several aspects of current methodologies for drug discovery of antibacterial and antifungals, anti-tropical diseases, antibiofilm and antiquorum sensing, anticancer and neuroprotectors are considered. For drug discovery, two different complementary approaches can be applied: classical pharmacology, also known as phenotypic drug discovery, which is the historical basis of drug discovery, and reverse pharmacology, also designated target-based drug discovery. Screening methods based on phenotypic drug discovery have been used to discover new natural products mainly from terrestrial origin. Examples of the discovery of marine natural products are provided. A section on future trends provides a comprehensive overview on recent advances that will foster the pharmaceutical industry. Full article
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