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Mar. Drugs, Volume 18, Issue 4 (April 2020) – 51 articles

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Cover Story (view full-size image) Phylum Cnidaria, the oldest extant venomous lineage, is distinguished from other venomous phyla in [...] Read more.
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Open AccessReview
Biological Activities of Rhamnan Sulfate Extract from the Green Algae Monostroma nitidum (Hitoegusa)
Mar. Drugs 2020, 18(4), 228; https://doi.org/10.3390/md18040228 - 24 Apr 2020
Viewed by 560
Abstract
Monostroma nitidum is a green single-cell layered algae that grows on the southwest coast of Japan. It is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. M. nitidum is composed of many cell aggregates, and the various [...] Read more.
Monostroma nitidum is a green single-cell layered algae that grows on the southwest coast of Japan. It is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. M. nitidum is composed of many cell aggregates, and the various substances that fill the intercellular space are dietary fibers, vitamins, and minerals. Rhamnan sulfate (RS), a sulfated polysaccharide, is main the component of the fiber extracted from M. nitidum. Recently, some biological properties of RS have been demonstrated by in vitro and in vivo studies that probably protect human subjects from viruses and ameliorate vascular dysfunction caused by metabolic disorders, especially lifestyle-related diseases. In this review, we focus on the antithrombotic effects of RS and introduce its antiviral and other biological activities. Full article
(This article belongs to the Special Issue Marine Compounds and Inflammation II)
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Open AccessArticle
A New Citrinin Derivative from the Indonesian Marine Sponge-Associated Fungus Penicillium citrinum
Mar. Drugs 2020, 18(4), 227; https://doi.org/10.3390/md18040227 - 24 Apr 2020
Viewed by 503
Abstract
Sponge-associated fungi are attractive targets for the isolation of bioactive natural products with different pharmaceutical purposes. In this investigation, 20 fungi were isolated from 10 different sponge specimens. One isolate, the fungus Penicillium citrinum strain WK-P9, showed activity against Bacillus subtilis JH642 when [...] Read more.
Sponge-associated fungi are attractive targets for the isolation of bioactive natural products with different pharmaceutical purposes. In this investigation, 20 fungi were isolated from 10 different sponge specimens. One isolate, the fungus Penicillium citrinum strain WK-P9, showed activity against Bacillus subtilis JH642 when cultivated in malt extract medium. One new and three known citrinin derivatives were isolated from the extract of this fungus. The structures were elucidated by 1D and 2D NMR spectroscopy, as well as LC-HRMS. Their antibacterial activity against a set of common human pathogenic bacteria and fungi was tested. Compound 2 showed moderate activity against Mycobacterium smegmatis ATCC607 with a minimum inhibitory concentration (MIC) of 32 µg/mL. Compound 4 exhibited moderate growth inhibition against Bacillus subtilis JH642, B. megaterium DSM32, and M. smegmatis ATCC607 with MICs of 16, 16, and 32 µg/mL, respectively. Furthermore, weak activities of 64 µg/mL against B. subtilis DSM10 and S. aureus ATCC25923 were observed for compound 4. Full article
(This article belongs to the Special Issue Marine Antibiotics 2020)
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Open AccessArticle
Chitosan Coated Microparticles Enhance Simvastatin Colon Targeting and Pro-Apoptotic Activity
Mar. Drugs 2020, 18(4), 226; https://doi.org/10.3390/md18040226 - 24 Apr 2020
Viewed by 336
Abstract
This work aimed at improving the targeting and cytotoxicity of simvastatin (SMV) against colon cancer cells. SMV was encapsulated in chitosan polymers, followed by eudragit S100 microparticles. The release of SMV double coated microparticles was dependent on time and pH. At pH 7.4 [...] Read more.
This work aimed at improving the targeting and cytotoxicity of simvastatin (SMV) against colon cancer cells. SMV was encapsulated in chitosan polymers, followed by eudragit S100 microparticles. The release of SMV double coated microparticles was dependent on time and pH. At pH 7.4 maximum release was observed for 6 h. The efficiency of the double coat to target colonic tissues was confirmed using real-time X-ray radiography of iohexol dye. Entrapment efficiency and particle size were used in the characterization of the formula. Cytotoxicity of SMV microparticles against HCT-116 colon cancer cells was significantly improved as compared to raw SMV. Cell cycle analysis by flow cytomeric technique indicated enhanced accumulation of colon cancer cells in the G2/M phase. Additionally, a significantly higher cell fraction was observed in the pre-G phase, which highlighted enhancement of the proapoptotic activity of SMV prepared in the double coat formula. Assessment of annexin V staining was used for confirmation. Cell fraction in early, late and total cell death were significantly elevated. This was accompanied by a significant elevation of cellular caspase 3 activity. In conclusion, SMV-loaded chitosan coated with eudragit S100 formula exhibited improved colon targeting and enhanced cytotoxicity and proapoptotic activity against HCT-116 colon cancer cells. Full article
(This article belongs to the Special Issue Application of Marine Chitin and Chitosan)
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Open AccessFeature PaperArticle
Putative Inhibitors of SARS-CoV-2 Main Protease from A Library of Marine Natural Products: A Virtual Screening and Molecular Modeling Study
Mar. Drugs 2020, 18(4), 225; https://doi.org/10.3390/md18040225 - 23 Apr 2020
Cited by 2 | Viewed by 1939
Abstract
The current emergency due to the worldwide spread of the COVID-19 caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great concern for global public health. Already in the past, the outbreak of severe acute respiratory syndrome (SARS) in [...] Read more.
The current emergency due to the worldwide spread of the COVID-19 caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great concern for global public health. Already in the past, the outbreak of severe acute respiratory syndrome (SARS) in 2003 and Middle Eastern respiratory syndrome (MERS) in 2012 demonstrates the potential of coronaviruses to cross-species borders and further underlines the importance of identifying new-targeted drugs. An ideal antiviral agent should target essential proteins involved in the lifecycle of SARS-CoV. Currently, some HIV protease inhibitors (i.e., Lopinavir) are proposed for the treatment of COVID-19, although their effectiveness has not yet been assessed. The main protease (Mpro) provides a highly validated pharmacological target for the discovery and design of inhibitors. We identified potent Mpro inhibitors employing computational techniques that entail the screening of a Marine Natural Product (MNP) library. MNP library was screened by a hyphenated pharmacophore model, and molecular docking approaches. Molecular dynamics and re-docking further confirmed the results obtained by structure-based techniques and allowed this study to highlight some crucial aspects. Seventeen potential SARS-CoV-2 Mpro inhibitors have been identified among the natural substances of marine origin. As these compounds were extensively validated by a consensus approach and by molecular dynamics, the likelihood that at least one of these compounds could be bioactive is excellent. Full article
(This article belongs to the Special Issue Marine Natural Products against Coronaviruses)
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Open AccessArticle
The Comparative Analysis of Antiviral Activity of Native and Modified Fucoidans from Brown Algae Fucus evanescens In Vitro and In Vivo
Mar. Drugs 2020, 18(4), 224; https://doi.org/10.3390/md18040224 - 22 Apr 2020
Cited by 1 | Viewed by 468
Abstract
The enzymatic depolymerization of fucoidans from brown algae allowed the production of their standardized derivatives with different biological activities. This work aimed to compare the antiviral activities of native (FeF) and modified with enzyme (FeHMP) fucoidans from F. evanescens. The cytotoxicity and [...] Read more.
The enzymatic depolymerization of fucoidans from brown algae allowed the production of their standardized derivatives with different biological activities. This work aimed to compare the antiviral activities of native (FeF) and modified with enzyme (FeHMP) fucoidans from F. evanescens. The cytotoxicity and antiviral activities of the FeF and FeHMP against herpes viruses (HSV-1, HSV-2), enterovirus (ECHO-1), and human immunodeficiency virus (HIV-1) in Vero and human MT-4 cell lines were examined by methylthiazolyltetrazolium bromide (MTT) and cytopathic effect (CPE) reduction assays, respectively. The efficacy of fucoidans in vivo was evaluated in the outbred mice model of vaginitis caused by HSV-2. We have shown that both FeF and FeHMP significantly inhibited virus-induced CPE in vitro and were more effective against HSV. FeF exhibited antiviral activity against HSV-2 with a selective index (SI) > 40, and FeHMP with SI ˃ 20, when they were added before virus infection or at the early stages of the HSV-2 lifecycle. Furthermore, in vivo studies showed that after intraperitoneal administration (10 mg/kg), both FeF and FeHMP protected mice from lethal intravaginal HSV-2 infection to approximately the same degree (44–56%). Thus, FeF and FeHMP have comparable potency against several DNA and RNA viruses, allowing us to consider the studied fucoidans as promising broad-spectrum antivirals. Full article
(This article belongs to the Special Issue Marine Antiviral Agents)
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Open AccessArticle
Isolation of Lobane and Prenyleudesmane Diterpenoids from the Soft Coral Lobophytum varium
Mar. Drugs 2020, 18(4), 223; https://doi.org/10.3390/md18040223 - 22 Apr 2020
Viewed by 389
Abstract
Further chemical investigation of the EtOAc extract of the soft coral Lobophytum varium resulted in the discovery of eleven new diterpenoids lobovarols F–P (111) of lobane– and prenyleudesmane–types, along with two known metabolites (12 and 13). The [...] Read more.
Further chemical investigation of the EtOAc extract of the soft coral Lobophytum varium resulted in the discovery of eleven new diterpenoids lobovarols F–P (111) of lobane– and prenyleudesmane–types, along with two known metabolites (12 and 13). The structures of the new metabolites were established by spectroscopic analyses, including 2D NMR experiments. The absolute configuration of 1 was determined using Mosher’s method. The complete assignment of 1H and 13C NMR spectroscopic data of 12 and 13 and the identification of pyran-derived moieties in the prenyleudesmanes were reported for the first time. Anti-inflammatory activities of the isolated compounds in suppressing elastase release and superoxide anion generation in human neutrophils were disclosed for 1, 2, 4, 12, and 13. A stereospecific biosynthesis for lobanes and prenyleudesmanes from the related prenylgermacranes could explain the coexistence of lobanes and prenylgermacranes in L. varium. Full article
(This article belongs to the Special Issue Terpenoids from Marine Organisms II)
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Open AccessArticle
Anti-Inflammatory Effects of Fucoxanthinol in LPS-Induced RAW264.7 Cells through the NAAA-PEA Pathway
Mar. Drugs 2020, 18(4), 222; https://doi.org/10.3390/md18040222 - 21 Apr 2020
Viewed by 497
Abstract
Palmitoylethanolamide (PEA) is an endogenous lipid mediator with powerful anti-inflammatory and analgesic functions. PEA can be hydrolyzed by a lysosomal enzyme N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and other immune cells. The pharmacological inhibition of NAAA activity is a [...] Read more.
Palmitoylethanolamide (PEA) is an endogenous lipid mediator with powerful anti-inflammatory and analgesic functions. PEA can be hydrolyzed by a lysosomal enzyme N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and other immune cells. The pharmacological inhibition of NAAA activity is a potential therapeutic strategy for inflammation-related diseases. Fucoxanthinol (FXOH) is a marine carotenoid from brown seaweeds with various beneficial effects. However, the anti-inflammatory effects and mechanism of action of FXOH in lipopolysaccharide (LPS)-stimulated macrophages remain unclear. This study aimed to explore the role of FXOH in the NAAA–PEA pathway and the anti-inflammatory effects based on this mechanism. In vitro results showed that FXOH can directly bind to the active site of NAAA protein and specifically inhibit the activity of NAAA enzyme. In an LPS-induced inflammatory model in macrophages, FXOH pretreatment significantly reversed the LPS-induced downregulation of PEA levels. FXOH also substantially attenuated the mRNA expression of inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), and markedly reduced the production of TNF-α, IL-6, IL-1β, and nitric oxide (NO). Moreover, the inhibitory effect of FXOH on NO induction was significantly abolished by the peroxisome proliferator-activated receptor α (PPAR-α) inhibitor GW6471. All these findings demonstrated that FXOH can prevent LPS-induced inflammation in macrophages, and its mechanisms may be associated with the regulation of the NAAA-PEA-PPAR-α pathway. Full article
(This article belongs to the collection Marine Polysaccharides) Printed Edition available
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Open AccessArticle
Syntheses and Glycosidase Inhibitory Activities, and in Silico Docking Studies of Pericosine E Analogs Methoxy-Substituted at C6
Mar. Drugs 2020, 18(4), 221; https://doi.org/10.3390/md18040221 - 20 Apr 2020
Viewed by 383
Abstract
Inspired by the significant α-glucosidase inhibitory activities of (+)- and (−)-pericosine E, we herein designed and synthesized 16 analogs of these marine natural products bearing a methoxy group instead of a chlorine atom at C6. Four of these compounds exhibited moderate α-glucosidase inhibitory [...] Read more.
Inspired by the significant α-glucosidase inhibitory activities of (+)- and (−)-pericosine E, we herein designed and synthesized 16 analogs of these marine natural products bearing a methoxy group instead of a chlorine atom at C6. Four of these compounds exhibited moderate α-glucosidase inhibitory activities, which were weaker than those of the corresponding chlorine-containing species. The four compounds could be prepared by coupling reactions utilizing the (−)-pericosine B moiety. An additional in silico docking simulation suggested that the reason of reduced activity of the C6-methoxylated analogs might be an absence of hydrogen bonding between a methoxy group with the surrounding amino acid residues in the active site in α-glucosidase. Full article
(This article belongs to the Special Issue Marine Natural Products and Obesity 2020)
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Open AccessArticle
Fucoidan Induces Apoptosis of HT-29 Cells via the Activation of DR4 and Mitochondrial Pathway
Mar. Drugs 2020, 18(4), 220; https://doi.org/10.3390/md18040220 - 20 Apr 2020
Viewed by 326
Abstract
Fucoidan has a variety of pharmacological activities, but the understanding of the mechanism of fucoidan-induced apoptosis of colorectal cancer cells remains limited. The results of the present study demonstrated that the JNK signaling pathway is involved in the activation of apoptosis in colorectal [...] Read more.
Fucoidan has a variety of pharmacological activities, but the understanding of the mechanism of fucoidan-induced apoptosis of colorectal cancer cells remains limited. The results of the present study demonstrated that the JNK signaling pathway is involved in the activation of apoptosis in colorectal cancer-derived HT-29 cells, and fucoidan induces apoptosis by activation of the DR4 at the transcriptional and protein levels. The survival rate of HT-29 cells was approximately 40% in the presence of 800 μg/mL of fucoidan, but was increased to 70% after DR4 was silenced by siRNA. Additionally, fucoidan has been shown to reduce the mitochondrial membrane potential and destroy the integrity of mitochondrial membrane. In the presence of an inhibitor of cytochrome C inhibitor and DR4 siRNA or the presence of cytochrome C inhibitor only, the cell survival rate was significantly higher than when cells were treated with DR4 siRNA only. These data indicate that both the DR4 and the mitochondrial pathways contribute to fucoidan-induced apoptosis of HT-29 cells, and the extrinsic pathway is upstream of the intrinsic pathway. In conclusion, the current work identified the mechanism of fucoidan-induced apoptosis and provided a novel theoretical basis for the future development of clinical applications of fucoidan as a drug. Full article
(This article belongs to the Special Issue Fucoidans)
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Open AccessArticle
In Vivo Evaluation of the Wound Healing Activity of Extracts and Bioactive Constituents of the Marine Isopod Ceratothoa oestroides
Mar. Drugs 2020, 18(4), 219; https://doi.org/10.3390/md18040219 - 18 Apr 2020
Viewed by 407
Abstract
Wound healing is a fundamental response to tissue injury and a number of natural products has been found to accelerate the healing process. Herein, we report the preparation of a series of different polarity (organic and aqueous) extracts of the marine isopod Ceratothoa [...] Read more.
Wound healing is a fundamental response to tissue injury and a number of natural products has been found to accelerate the healing process. Herein, we report the preparation of a series of different polarity (organic and aqueous) extracts of the marine isopod Ceratothoa oestroides and the in vivo evaluation of their wound healing activity after topical administration of ointments incorporating the various extracts on wounds inflicted on SKH-hr1 hairless mice. The most active extract was fractionated for enrichment in the bioactive constituents and the fractions were further evaluated for their wound healing activity, while their chemical profiles were analyzed. Wound healing was evaluated by clinical assessment, photo-documentation, histopathological analysis and measurement of biophysical skin parameters, such as transepidermal water loss (TEWL), hydration, elasticity, and skin thickness. The highest levels of activity were exerted by treatment of the wounds with a fraction rich in eicosapentaenoic acid (EPA), as well as myristic and palmitoleic acids. Topical application of the bioactive fraction on the wounds of mice resulted in complete wound closure with a skin of almost normal architecture without any inflammatory elements. Full article
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Open AccessArticle
Astaxanthin Attenuates Fish Oil-Related Hepatotoxicity and Oxidative Insult in Juvenile Pacific White Shrimp (Litopenaeus vannamei)
Mar. Drugs 2020, 18(4), 218; https://doi.org/10.3390/md18040218 - 17 Apr 2020
Viewed by 335
Abstract
The present study investigated the effect of dietary astaxanthin (AX) on the growth performance, antioxidant parameters, and repair of hepatopancreas damage in Pacific white shrimp (Litopenaeus vannamei). To evaluate the hepatopancreas protective function of AX in shrimps, we compared the effect [...] Read more.
The present study investigated the effect of dietary astaxanthin (AX) on the growth performance, antioxidant parameters, and repair of hepatopancreas damage in Pacific white shrimp (Litopenaeus vannamei). To evaluate the hepatopancreas protective function of AX in shrimps, we compared the effect of five isonitrogenous and isoenergetic diets under oxidized fish oil conditions with varying AX levels during the 50-day experimental period. The formulated diets were as follows: (i) OFO (oxidized fish oil); (ii) OFO/AX150 (oxidized fish oil + AX150 mg/kg); (iii) OFO/AX250 (oxidized fish oil + AX250 mg/kg); (iv) OFO/AX450 (oxidized fish oil + AX450 mg/kg); and, (v) control group (fresh fish oil). Results showed that the oxidized fish oil with 275.2 meq/kg peroxide value (POV) resulted in a substantial decrease in the final body weight of L. vannamei (P > 0.05) and induced some visible histopathological alterations in the hepatopancreas. Growth performance was significantly higher in shrimps fed with the OFO/AX450 diet than those fed with the OFO diet (p < 0.05). However, no significant difference was observed when the OFO/AX450 diet was compared to the control diet containing fresh fish oil (p > 0.05). Moreover, shrimps under the OFO/AX450 diet displayed a significant improvement in hepatopancreatic health and showed a reduction of malondialdehyde (MDA) compared to those under the OFO diet (p < 0.05). Dietary AX improved the antioxidant capacity of L. vannamei by increasing the catalase (CAT) activity in the hemolymph. Acute salinity change test showed a higher shrimp survival rate under OFO/AX450 diet than the OFO diet (p < 0.05), suggesting that AX can contribute to enhanced stress tolerance. In conclusion, our data suggest that AX confers dose-dependent protection against OFO-induced oxidative insults and hepatopancreatic damage in shrimp. Full article
(This article belongs to the Special Issue Astaxanthin: A Potential Therapeutic Agent)
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Open AccessArticle
Growth-Inhibitory Effect of Chitosan-Coated Liposomes Encapsulating Curcumin on MCF-7 Breast Cancer Cells
Mar. Drugs 2020, 18(4), 217; https://doi.org/10.3390/md18040217 - 17 Apr 2020
Cited by 1 | Viewed by 458
Abstract
Current anticancer drugs exhibit limited efficacy and initiate severe side effects. As such, identifying bioactive anticancer agents that can surpass these limitations is a necessity. One such agent, curcumin, is a polyphenolic compound derived from turmeric, and has been widely investigated for its [...] Read more.
Current anticancer drugs exhibit limited efficacy and initiate severe side effects. As such, identifying bioactive anticancer agents that can surpass these limitations is a necessity. One such agent, curcumin, is a polyphenolic compound derived from turmeric, and has been widely investigated for its potential anti-inflammatory and anticancer effects over the last 40 years. However, the poor bioavailability of curcumin, caused by its low absorption, limits its clinical use. In order to solve this issue, in this study, curcumin was encapsulated in chitosan-coated nanoliposomes derived from three natural lecithin sources. Liposomal formulations were all in the nanometric scale (around 120 nm) and negatively charged (around −40 mV). Among the three lecithins, salmon lecithin presented the highest growth-inhibitory effect on MCF-7 cells (two times lower growth than the control group for 12 µM of curcumin and four times lower for 20 µM of curcumin). The soya and rapeseed lecithins showed a similar growth-inhibitory effect on the tumor cells. Moreover, coating nanoliposomes with chitosan enabled a higher loading efficiency of curcumin (88% for coated liposomes compared to 65% for the non-coated liposomes) and a stronger growth-inhibitory effect on MCF-7 breast cancer cells. Full article
(This article belongs to the Special Issue Nano-Marine Drugs: Relevance of Nanoformulations in Cancer Therapies)
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Open AccessArticle
Characterization of Regulatory and Transporter Genes in the Biosynthesis of Anti-Tuberculosis Ilamycins and Production in a Heterologous Host
Mar. Drugs 2020, 18(4), 216; https://doi.org/10.3390/md18040216 - 17 Apr 2020
Viewed by 294
Abstract
Ilamycins are cyclopeptides with novel structures that have been isolated from different Actinomycetes. They showed strong anti-tuberculosis activity and could serve as important anti-tuberculosis drug leads. The functions of the pre-tailoring and the post-tailoring genes in the biosynthesis of ilamycins have been [...] Read more.
Ilamycins are cyclopeptides with novel structures that have been isolated from different Actinomycetes. They showed strong anti-tuberculosis activity and could serve as important anti-tuberculosis drug leads. The functions of the pre-tailoring and the post-tailoring genes in the biosynthesis of ilamycins have been elucidated, but the functions of the regulatory and transporter genes remain elusive. We reported herein the functions of four genes in ilamycin biosynthetic gene cluster (ila BGC) including two regulatory genes (ilaA and ilaB) and two transporter genes (ilaJ and ilaK) and the heterologous expression of ila BGC. The IlaA and IlaB were unambiguously shown to be negative and positive regulator of ilamycins biosynthesis, respectively. Consistent with these roles, inactivation of ilaA and ilaB (independent of each other) was shown to enhance and abolish the production of ilamycins, respectively. Total yields of ilamycins were enhanced 3.0-fold and 1.9-fold by inactivation of ilaA and overexpression of ilaB compared to those of in the Streptomyces atratus SCSIO ZH16, respectively. In addition, the ila BGC was successfully expressed in Streptomyces coelicolor M1152, which indicated that all biosynthetic elements for the construction of ilamycins were included in the PAC7A6. These results not only lay a foundation for further exploration of ilamycins, but also provide the genetic elements for synthetic biology. Full article
(This article belongs to the Special Issue Genetics of Marine Organisms Associated with Human Health)
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Open AccessEditorial
Marine Microbial Diversity as a Source of Bioactive Natural Products
Mar. Drugs 2020, 18(4), 215; https://doi.org/10.3390/md18040215 - 16 Apr 2020
Viewed by 405
(This article belongs to the Special Issue Marine Microbial Diversity as a Source of Bioactive Natural Products)
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Open AccessReview
Marine Collagen from Alternative and Sustainable Sources: Extraction, Processing and Applications
Mar. Drugs 2020, 18(4), 214; https://doi.org/10.3390/md18040214 - 15 Apr 2020
Viewed by 513
Abstract
Due to its unique properties, collagen is used in the growing fields of pharmaceutical and biomedical devices, as well as in the fields of nutraceuticals, cosmeceuticals, food and beverages. Collagen also represents a valid resource for bioplastics and biomaterials, to be used in [...] Read more.
Due to its unique properties, collagen is used in the growing fields of pharmaceutical and biomedical devices, as well as in the fields of nutraceuticals, cosmeceuticals, food and beverages. Collagen also represents a valid resource for bioplastics and biomaterials, to be used in the emerging health sectors. Recently, marine organisms have been considered as promising sources of collagen, because they do not harbor transmissible disease. In particular, fish biomass as well as by-catch organisms, such as undersized fish, jellyfish, sharks, starfish, and sponges, possess a very high collagen content. The use of discarded and underused biomass could contribute to the development of a sustainable process for collagen extraction, with a significantly reduced environmental impact. This addresses the European zero-waste strategy, which supports all three generally accepted goals of sustainability: sustainable economic well-being, environmental protection, and social well-being. A zero-waste strategy would use far fewer new raw materials and send no waste materials to landfills. In this review, we present an overview of the studies carried out on collagen obtained from by-catch organisms and fish wastes. Additionally, we discuss novel technologies based on thermoplastic processes that could be applied, likewise, as marine collagen treatment. Full article
(This article belongs to the Special Issue Papers from MarPipe and Ocean Medicines)
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Open AccessArticle
Laminarin Pretreatment Provides Neuroprotection against Forebrain Ischemia/Reperfusion Injury by Reducing Oxidative Stress and Neuroinflammation in Aged Gerbils
Mar. Drugs 2020, 18(4), 213; https://doi.org/10.3390/md18040213 - 15 Apr 2020
Viewed by 360
Abstract
Laminarin is a polysaccharide isolated from brown algae that has various biological and pharmacological activities, such as antioxidant and anti-inflammatory properties. We recently reported that pretreated laminarin exerted neuroprotection against transient forebrain ischemia/reperfusion (IR) injury when we pretreated with 50 mg/kg of laminarin [...] Read more.
Laminarin is a polysaccharide isolated from brown algae that has various biological and pharmacological activities, such as antioxidant and anti-inflammatory properties. We recently reported that pretreated laminarin exerted neuroprotection against transient forebrain ischemia/reperfusion (IR) injury when we pretreated with 50 mg/kg of laminarin once a day for seven days in adult gerbils. However, there have been no studies regarding a neuroprotective effect of pretreated laminarin against IR injury in aged animals and its related mechanisms. Therefore, in this study, we intraperitoneally inject laminarin (50 mg/kg) once a day to aged gerbils for seven days before IR (5-min transient ischemia) surgery and examine the neuroprotective effect of laminarin treatment and the mechanisms in the gerbil hippocampus. IR injury in vehicle-treated gerbils causes loss (death) of pyramidal neurons in the hippocampal CA1 field at five days post-IR. Pretreatment with laminarin effectively protects the CA1 pyramidal neurons from IR injury. Regarding the laminarin-treated gerbils, production of superoxide anions, 4-hydroxy-2-nonenal expression and pro-inflammatory cytokines [interleukin(IL)-1β and tumor necrosis factor-α] expressions are significantly decreased in the CA1 pyramidal neurons after IR. Additionally, laminarin treatment significantly increases expressions of superoxide dismutase and anti-inflammatory cytokines (IL-4 and IL-13) in the CA1 pyramidal neurons before and after IR. Taken together, these findings indicate that laminarin can protect neurons from ischemic brain injury in an aged population by attenuating IR-induced oxidative stress and neuroinflammation. Full article
(This article belongs to the Special Issue Marine Anti-inflammatory Agents 2020)
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Open AccessArticle
Antioxidant Potential of Sulfated Polysaccharides from Padina boryana; Protective Effect against Oxidative Stress in In Vitro and In Vivo Zebrafish Model
Mar. Drugs 2020, 18(4), 212; https://doi.org/10.3390/md18040212 - 14 Apr 2020
Viewed by 461
Abstract
Elevated levels of reactive oxygen species (ROS) damage the internal cell components. Padina boryana, a brown alga from the Maldives, was subjected to polysaccharide extraction. The Celluclast enzyme assisted extract (PBE) and ethanol precipitation (PBP) of P. boryana were assessed against hydrogen [...] Read more.
Elevated levels of reactive oxygen species (ROS) damage the internal cell components. Padina boryana, a brown alga from the Maldives, was subjected to polysaccharide extraction. The Celluclast enzyme assisted extract (PBE) and ethanol precipitation (PBP) of P. boryana were assessed against hydrogen peroxide (H2O2) induced cell damage and zebra fish models. PBP which contains the majority of sulfated polysaccharides based on fucoidan, showed outstanding extracellular ROS scavenging potential against H2O2. PBP significantly declined the intracellular ROS levels, and exhibited protection against apoptosis. The study revealed PBPs’ ability to activate the Nrf2/Keap1 signaling pathway, consequently initiating downstream elements such that catalase (CAT) and superoxide dismutase (SOD). Further, ROS levels, lipid peroxidation values in zebrafish studies were declined with the pre-treatment of PBP. Collectively, the results obtained in the study suggest the polysaccharides from P. boryana might be a potent source of water soluble natural antioxidants that could be sustainably utilized in the industrial applications. Full article
(This article belongs to the Special Issue Fucoidans)
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Open AccessArticle
Effects of Bioactive Marine-Derived Liposomes on Two Human Breast Cancer Cell Lines
Mar. Drugs 2020, 18(4), 211; https://doi.org/10.3390/md18040211 - 13 Apr 2020
Cited by 2 | Viewed by 508
Abstract
Breast cancer is the leading cause of death from cancer among women. Higher consumption of dietary marine n-3 long-chain polyunsaturated fatty acids (LC-PUFAs) is associated with a lower risk of breast cancer. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two n-3 LC-PUFAs [...] Read more.
Breast cancer is the leading cause of death from cancer among women. Higher consumption of dietary marine n-3 long-chain polyunsaturated fatty acids (LC-PUFAs) is associated with a lower risk of breast cancer. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two n-3 LC-PUFAs found in fish and exert anticancer effects. In this study, natural marine-derived lecithin that is rich in various polyunsaturated fatty acids (PUFAs) was extracted from salmon heads and transformed into nanoliposomes. These nanoliposomes were characterized and cultured with two breast cancer lines (MCF-7 and MDA-MB-231). The nanoliposomes decreased the proliferation and the stiffness of both cancer cell types. These results suggest that marine-derived lecithin possesses anticancer properties, which may have an impact on developing new liposomal delivery strategies for breast cancer treatment. Full article
(This article belongs to the Special Issue Nano-Marine Drugs: Relevance of Nanoformulations in Cancer Therapies)
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Open AccessArticle
Cytotoxic Activity of Aplykurodin A Isolated From Aplysia kurodai against AXIN1-Mutated Hepatocellular Carcinoma Cells by Promoting Oncogenic β-Catenin Degradation
Mar. Drugs 2020, 18(4), 210; https://doi.org/10.3390/md18040210 - 13 Apr 2020
Viewed by 397
Abstract
Dysregulation of the Wnt/β-catenin signaling pathway is involved in the development of human hepatocellular carcinoma and has thus emerged as a therapeutic target for this malignant tumor. In this study, we employed sensitive cell-based assays to identify aplykurodin A isolated from Aplysia kurodai [...] Read more.
Dysregulation of the Wnt/β-catenin signaling pathway is involved in the development of human hepatocellular carcinoma and has thus emerged as a therapeutic target for this malignant tumor. In this study, we employed sensitive cell-based assays to identify aplykurodin A isolated from Aplysia kurodai as an antagonist of Wnt/β-catenin signaling. Aplykurodin A inhibited β-catenin responsive transcription, which was stimulated by a Wnt3a-conditioned medium or a glycogen synthase kinase 3β inhibitor by accelerating intracellular β-catenin degradation. Aplykurodin A downregulated the level of oncogenic β-catenin and decreased the expression of β-catenin-dependent gene, leading to inhibition of human hepatoma Hep3B and SNU475 cell proliferation. Moreover, apoptosis and autophagy were elicited by aplykurodin A, as indicated by an increase the number of Annexin V-FITC-stained cells and the formation of microtubule-associated protein 1 light chain 3 puncta, respectively, in Hep3B and SNU475 cells. Our findings suggest that aplykurodin A provides a novel therapeutic strategy for human hepatocellular carcinoma via stimulation of oncogenic β-catenin degradation. Full article
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Open AccessArticle
Identification of an LPS-Induced Chemo-Attractive Peptide from Ciona robusta
Mar. Drugs 2020, 18(4), 209; https://doi.org/10.3390/md18040209 - 12 Apr 2020
Viewed by 431
Abstract
Background: Previously published work has demonstrated that the LPS injection of Ciona robusta leads to the overexpression of a truncated form of an immune-related mRNA (C8short) by means of Ciona robusta (CR) alternative polyadenylation (APA) (CR-APA). Methods: The 3D structure of the C8short-derived [...] Read more.
Background: Previously published work has demonstrated that the LPS injection of Ciona robusta leads to the overexpression of a truncated form of an immune-related mRNA (C8short) by means of Ciona robusta (CR) alternative polyadenylation (APA) (CR-APA). Methods: The 3D structure of the C8short-derived Ciona robusta chemo-attractive peptide (CrCP) was evaluated by homology modeling. The biological activity of the CrCP was studied in vitro using a primary human dermal cell line (HuDe). Real-Time PCR was used to investigate the expression levels of genes involved in cell motility. NF-κB signaling was studied by western blotting. Results: In silico modeling showed that CrCP displayed structural characteristics already reported for a short domain of the vertebrate CRK gene, suggesting its possible involvement in cell migration mechanisms. In vitro assays demonstrated that CrCP was capable of inducing the motility of HuDe cells in both wound healing and chemo-attractive experiments. qPCR demonstrated the capability of CrCP to modulate the expression of the matrix metalloproteinase-7 (MMP-7) and E-cadherin genes. Finally, western blot analysis demonstrated that treatment with CrCP induced activation of the NF-κB signaling pathway. Conclusion: Our results describe the characterization of the 3D structure and chemo-attractive activity of an LPS-induced CrCP peptide from Ciona robusta. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
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Open AccessArticle
Enzymatic Hydrolysis of Marine Collagen and Fibrinogen Proteins in the Presence of Thrombin
Mar. Drugs 2020, 18(4), 208; https://doi.org/10.3390/md18040208 - 11 Apr 2020
Viewed by 367
Abstract
Enzymatic hydrolysis of native collagen and fibrinogen was carried out under comparable conditions at room temperature. The molecular weight parameters of proteins before and after hydrolysis by thrombin were monitored by gel-penetrating chromatography (GPC). An analysis of the experiment results shows that the [...] Read more.
Enzymatic hydrolysis of native collagen and fibrinogen was carried out under comparable conditions at room temperature. The molecular weight parameters of proteins before and after hydrolysis by thrombin were monitored by gel-penetrating chromatography (GPC). An analysis of the experiment results shows that the molecular weight parameters of the initial fibrinogen (Fn) and cod collagen (CC) are very similar. High molecular CC decays within the first minute, forming two low molecular fractions. The main part (~80%) falls on the fraction with a value of Mw less than 10 kDa. The initial high molecular fraction of Fn with Mw ~320–340 kDa is not completely hydrolyzed even after three days of control. The presence of low molecular fractions with Mw ~17 and Mw ~10 kDa in the solution slightly increases within an hour and noticeably increases for three days. The destruction of macromolecules of high molecular collagen to hydrolysis products appears almost completely within the first minute mainly to the polymer with Mw ~10 kDa, and enzymatic hydrolysis of fibrinogen proceeds slower than that of collagen, but also mainly to the polymer with Mw ~10 kDa. Comparative photos of the surfaces of native collagen, fibrinogen and the scaffold based on them were obtained. Full article
(This article belongs to the Special Issue Marine Collagen: A Promising Biomaterial for Biomedical Applications)
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Open AccessArticle
Meroterpenoids from the Brown Alga Cystoseira usneoides as Potential Anti-Inflammatory and Lung Anticancer Agents
Mar. Drugs 2020, 18(4), 207; https://doi.org/10.3390/md18040207 - 11 Apr 2020
Viewed by 764
Abstract
The anti-inflammatory and anticancer properties of eight meroterpenoids isolated from the brown seaweed Cystoseira usneoides have been evaluated. The algal meroterpenoids (AMTs) 1–8 were tested for their inhibitory effects on the production of the pro-inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and [...] Read more.
The anti-inflammatory and anticancer properties of eight meroterpenoids isolated from the brown seaweed Cystoseira usneoides have been evaluated. The algal meroterpenoids (AMTs) 1–8 were tested for their inhibitory effects on the production of the pro-inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β), and the expression of cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in LPS-stimulated THP-1 human macrophages. The anticancer effects were assessed by cytotoxicity assays against human lung adenocarcinoma A549 cells and normal lung fibroblastic MRC-5 cells, together with flow cytometry analysis of the effects of these AMTs on different phases of the cell cycle. The AMTs 18 significantly reduced the production of TNF-α, IL-6, and IL-1β, and suppressed the COX-2 and iNOS expression, in LPS-stimulated cells (p < 0.05). The AMTs 18 displayed higher cytotoxic activities against A549 cancer cells than against MRC-5 normal lung cells. Cell cycle analyses indicated that most of the AMTs caused the arrest of A549 cells at the G2/M and S phases. The AMTs 2 and 5 stand out by combining significant anti-inflammatory and anticancer activities, while 3 and 4 showed interesting selective anticancer effects. These findings suggest that the AMTs produced by C. usneoides may have therapeutic potential in inflammatory diseases and lung cancer. Full article
(This article belongs to the Special Issue Marine Compounds and Inflammation II)
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Open AccessArticle
Lack of Acute Toxicity and Mutagenicity from Recombinant Epinephelus lanceolatus Piscidin Expressed in Pichia pastoris
Mar. Drugs 2020, 18(4), 206; https://doi.org/10.3390/md18040206 - 11 Apr 2020
Viewed by 386
Abstract
The antimicrobial peptide (AMP) piscidin was identified from Epinephelus lanceolatus and demonstrated to possess antimicrobial and immune-related functions. Supplementation of feed with recombinant Epinephelus lanceolatus piscidin (rEP)-expressing yeast pellets may minimize the excessive use of antibiotics and control pathogens in aquaculture or animal [...] Read more.
The antimicrobial peptide (AMP) piscidin was identified from Epinephelus lanceolatus and demonstrated to possess antimicrobial and immune-related functions. Supplementation of feed with recombinant Epinephelus lanceolatus piscidin (rEP)-expressing yeast pellets may minimize the excessive use of antibiotics and control pathogens in aquaculture or animal husbandry. However, before implementing rEP as a supplement, it is necessary to understand whether it harbors any toxicity. Since toxicological information on the topic is scarce, the present investigation was carried out to test whether rEP exhibits allergenic and/or toxic effects. In an oral acute toxicity test (OECD 425), Sprague Dawley (SD) rats were administered rEP dissolved in reverse osmosis water, yielding an LD50 > 5000 mg/kg (no observed animal death). The compound was therefore classified as non-toxic by oral administration. In an acute respiratory toxicity test (OECD 403), heads and noses of SD rats were exposed to liquid aerosol for 4 h (the highest concentration that could be administered without causing any animal death), and a lethal concentration (LC50) > 0.88 mg/L was obtained. The mass medium aerodynamics diameter (MMAD) of rEP aerosol particles was 8.18 μm and mass medium aerodynamics diameter (GSD) was 3.04, which meant that 25.90% could enter the airway (<4 μm) of a rat, and 58.06% (<10 μm) could be inhaled by humans. An ocular irritation test (OECD 405) with rEP powder was performed on New Zealand White (NZW) rabbits. Signs of irritation included conjunctival swelling and diffuse flushing 1 h after administration. The signs were less apparent after 24 h and disappeared after 72 h. The classification assigned to the powder was mild eye irritation. Skin sensitization was performed for a local lymphoproliferative test (OECD 442B) using BALB/c mice, with the highest soluble concentration of the rEP considered to be 100% test substance; formulations were diluted to 50% and 25%, and bromodeoxyuridine (BrdU) incorporation was used to measure the degree of lymphocyte proliferation. The stimulation indexes (SIs) were 1.06 (100%), 0.44 (50%), and 0.77 (25%), all of which were less than the cutoff value for a positive sensitization result (1.6). Negative response was also seen in the bacterial reverse mutation test (OECD 471), and no chromosomal effects on Chinese hamster ovary (CHO)-K1 cells were observed (OECD 487). Based on these six toxicity tests, rEP showed neither acute toxic effects in experimental animals nor mutagenicity. Thus, rEP can be considered safe for use in subsequent research on its application as a feed additive for poultry, cattle, or aquatic animals. Full article
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Open AccessCommunication
Cladodionen Is a Potential Quorum Sensing Inhibitor Against Pseudomonas aeruginosa
Mar. Drugs 2020, 18(4), 205; https://doi.org/10.3390/md18040205 - 10 Apr 2020
Viewed by 438
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen using virulence factors and biofilm regulated by quorum sensing (QS) systems to infect patients and protect itself from environmental stress and antibiotics. Interfering with QS systems is a novel approach to combat P. aeruginosa infections without killing [...] Read more.
Pseudomonas aeruginosa is an opportunistic pathogen using virulence factors and biofilm regulated by quorum sensing (QS) systems to infect patients and protect itself from environmental stress and antibiotics. Interfering with QS systems is a novel approach to combat P. aeruginosa infections without killing the bacteria, meaning that it is much harder for bacteria to develop drug resistance. A marine fungus Cladosporium sp. Z148 with anti-QS activity was obtained from Jiaozhou Bay, China. Cladodionen, a novel QS inhibitor, was isolated from the extracts of this fungus. Cladodionen had a better inhibitory effect than pyocyanin on the production of elastase and rhamnolipid. It also inhibited biofilm formation and motilities. The mRNA expressions of QS-related genes, including receptor proteins (lasR, rhlR and pqsR), autoinducer synthases (lasI, rhlI and pqsA) and virulence factors (lasB and rhlA) were down-regulated by cladodionen. Molecular docking analysis showed that cladodionen had better binding affinity to LasR and PqsR than natural ligands. Moreover, the binding affinity of cladodionen to LasR was higher than to PqsR. Cladodionen exhibits potential as a QS inhibitor against P. aeruginosa, and its structure–activity relationships should be further studied to illustrate the mode of action, optimize its structure and improve anti-QS activity. Full article
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Open AccessArticle
Azaphilones from the Red Sea Fungus Aspergillus falconensis
Mar. Drugs 2020, 18(4), 204; https://doi.org/10.3390/md18040204 - 10 Apr 2020
Viewed by 463
Abstract
The marine-derived fungus Aspergillus falconensis, isolated from sediment collected from the Canyon at Dahab, Red Sea, yielded two new chlorinated azaphilones, falconensins O and P (1 and 2) in addition to four known azaphilone derivatives (36) [...] Read more.
The marine-derived fungus Aspergillus falconensis, isolated from sediment collected from the Canyon at Dahab, Red Sea, yielded two new chlorinated azaphilones, falconensins O and P (1 and 2) in addition to four known azaphilone derivatives (36) following fermentation of the fungus on solid rice medium containing 3.5% NaCl. Replacing NaCl with 3.5% NaBr induced accumulation of three additional new azaphilones, falconensins Q−S (79) including two brominated derivatives (7 and 8) together with three known analogues (1012). The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopy and HRESIMS data as well as by comparison with the literature. The absolute configuration of the azaphilone derivatives was established based on single-crystal X-ray diffraction analysis of 5, comparison of NMR data and optical rotations as well as on biogenetic considerations. Compounds 1, 39, and 11 showed NF-κB inhibitory activity against the triple negative breast cancer cell line MDA-MB-231 with IC50 values ranging from 11.9 to 72.0 µM. Full article
(This article belongs to the Special Issue Bioactive Natural Products from the Red Sea)
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Open AccessReview
Naturally Occurring Oxazole-Containing Peptides
Mar. Drugs 2020, 18(4), 203; https://doi.org/10.3390/md18040203 - 10 Apr 2020
Viewed by 374
Abstract
Oxazole-containing peptides are mostly of marine origin and they form an intriguing family with a broad range of biological activities. Here we classify these peptides on the basis of their chemical structure and discuss a number of representatives of each class that reflect [...] Read more.
Oxazole-containing peptides are mostly of marine origin and they form an intriguing family with a broad range of biological activities. Here we classify these peptides on the basis of their chemical structure and discuss a number of representatives of each class that reflect the extraordinary potential of this family as a source of new drugs. Full article
(This article belongs to the Special Issue Aromatic Marine Natural Products: Chemistry and Bioactivity)
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Open AccessReview
Characterising Functional Venom Profiles of Anthozoans and Medusozoans within Their Ecological Context
Mar. Drugs 2020, 18(4), 202; https://doi.org/10.3390/md18040202 - 09 Apr 2020
Viewed by 714
Abstract
This review examines the current state of knowledge regarding toxins from anthozoans (sea anemones, coral, zoanthids, corallimorphs, sea pens and tube anemones). We provide an overview of venom from phylum Cnidaria and review the diversity of venom composition between the two major clades [...] Read more.
This review examines the current state of knowledge regarding toxins from anthozoans (sea anemones, coral, zoanthids, corallimorphs, sea pens and tube anemones). We provide an overview of venom from phylum Cnidaria and review the diversity of venom composition between the two major clades (Medusozoa and Anthozoa). We highlight that the functional and ecological context of venom has implications for the temporal and spatial expression of protein and peptide toxins within class Anthozoa. Understanding the nuances in the regulation of venom arsenals has been made possible by recent advances in analytical technologies that allow characterisation of the spatial distributions of toxins. Furthermore, anthozoans are unique in that ecological roles can be assigned using tissue expression data, thereby circumventing some of the challenges related to pharmacological screening. Full article
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Open AccessArticle
In Situ Gel Loaded with Chitosan-Coated Simvastatin Nanoparticles: Promising Delivery for Effective Anti-Proliferative Activity against Tongue Carcinoma
Mar. Drugs 2020, 18(4), 201; https://doi.org/10.3390/md18040201 - 09 Apr 2020
Viewed by 322
Abstract
The goal of this study is to develop optimized chitosan-coated Simvastatin (SIM) nanoparticles (NPs) loaded in an in situ gel (ISG) formulation via a face-centered central composite design (FCCCD). Coated SIM-NPs were doped with Quercetin (QRC) using a modified nanoprecipitation method. The concentrations [...] Read more.
The goal of this study is to develop optimized chitosan-coated Simvastatin (SIM) nanoparticles (NPs) loaded in an in situ gel (ISG) formulation via a face-centered central composite design (FCCCD). Coated SIM-NPs were doped with Quercetin (QRC) using a modified nanoprecipitation method. The concentrations of poloxamer 188 (A) and chitosan (B) at five different levels, plus/minus alpha (+1.414 and −1.414: axial points), plus/minus 1 (factorial points) and the center point were optimized for particle size (PS-Y1), entrapment efficacy (EE-Y2) and stability index (SI-Y3). Based on the desirability approach, a formulation containing poloxamer 188 0.24% and chitosan 0.43% renders the prerequisites of optimum formulation for preparing SIM–QRC NP-loaded ISG. Scanning microscopy showed spherical SIM-NPs, indicating monodispersity in the range of 0.50 ± 0.04 nm with a charge of +32.42 mV. The optimized formulation indicated the highest EE 79.67% and better stability at 4 °C. Drug release from SIM–QRC NP-loaded ISG was slower to plateau by up to 96 h and, at the end of 168 h, only 65.12% of SIM was released in a more controlled manner in comparison to SIM–QRC NPs and plain SIM. ISG formulation showed a considerable increase in apoptosis occurrence through caspase-3 mediation and it also enhanced the tumor suppressor protein levels. Enhanced biological activity of SIM was observed due to QRC enabling promising drug and polymer synergistic interaction. The proposed formulation can provide a breakthrough in localized therapy, overcoming the potential drawbacks of systemic chemotherapy for tongue carcinoma. Full article
(This article belongs to the Special Issue Application of Marine Chitin and Chitosan)
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Open AccessReview
The Phylum Bryozoa: From Biology to Biomedical Potential
Mar. Drugs 2020, 18(4), 200; https://doi.org/10.3390/md18040200 - 09 Apr 2020
Viewed by 720
Abstract
Less than one percent of marine natural products characterized since 1963 have been obtained from the phylum Bryozoa which, therefore, still represents a huge reservoir for the discovery of bioactive metabolites with its ~6000 described species. The current review is designed to highlight [...] Read more.
Less than one percent of marine natural products characterized since 1963 have been obtained from the phylum Bryozoa which, therefore, still represents a huge reservoir for the discovery of bioactive metabolites with its ~6000 described species. The current review is designed to highlight how bryozoans use sophisticated chemical defenses against their numerous predators and competitors, and which can be harbored for medicinal uses. This review collates all currently available chemoecological data about bryozoans and lists potential applications/benefits for human health. The core of the current review relates to the potential of bryozoan metabolites in human diseases with particular attention to viral, brain, and parasitic diseases. It additionally weighs the pros and cons of total syntheses of some bryozoan metabolites versus the synthesis of non-natural analogues, and explores the hopes put into the development of biotechnological approaches to provide sustainable amounts of bryozoan metabolites without harming the natural environment. Full article
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Open AccessReview
Genome Mining as New Challenge in Natural Products Discovery
Mar. Drugs 2020, 18(4), 199; https://doi.org/10.3390/md18040199 - 09 Apr 2020
Viewed by 550
Abstract
Drug discovery is based on bioactivity screening of natural sources, traditionally represented by bacteria fungi and plants. Bioactive natural products and their secondary metabolites have represented the main source for new therapeutic agents, used as drug leads for new antibiotics and anticancer agents. [...] Read more.
Drug discovery is based on bioactivity screening of natural sources, traditionally represented by bacteria fungi and plants. Bioactive natural products and their secondary metabolites have represented the main source for new therapeutic agents, used as drug leads for new antibiotics and anticancer agents. After the discovery of the first biosynthetic genes in the last decades, the researchers had in their hands the tool to understand the biosynthetic logic and genetic basis leading to the production of these compounds. Furthermore, in the genomic era, in which the number of available genomes is increasing, genome mining joined to synthetic biology are offering a significant help in drug discovery. In the present review we discuss the importance of genome mining and synthetic biology approaches to identify new natural products, also underlining considering the possible advantages and disadvantages of this technique. Moreover, we debate the associated techniques that can be applied following to genome mining for validation of data. Finally, we review on the literature describing all novel natural drugs isolated from bacteria, fungi, and other living organisms, not only from the marine environment, by a genome-mining approach, focusing on the literature available in the last ten years. Full article
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