Marine Drugs

2 pages, 177 KiB

Open AccessEditorial

Marine Antibiotics 2020

by Yannick Fleury

Mar. Drugs 2021, 19(6), 351; https://doi.org/10.3390/md19060351 - 21 Jun 2021

Cited by 1 | Viewed by 2117

The range of environmental conditions in marine life is tremendous at different physico-chemical criteria (temperature, light, pressure and salinity) [...] Full article

(This article belongs to the Special Issue Marine Antibiotics 2020)

22 pages, 4080 KiB

Open AccessReview

Microbial Oligosaccharides with Biomedical Applications

by Jian-Lin Xu, Zhi-Feng Liu, Xiao-Wei Zhang, Hai-Li Liu and Yong Wang

Mar. Drugs 2021, 19(6), 350; https://doi.org/10.3390/md19060350 - 21 Jun 2021

Cited by 11 | Viewed by 3688

Abstract

Microbial oligosaccharides have been regarded as one of the most appealing natural products attributable to their potent and selective bioactivities, such as antimicrobial activity, inhibition of α-glucosidases and lipase, interference of cellular recognition and signal transduction, and disruption of cell wall biosynthesis. Accordingly, [...] Read more.

Microbial oligosaccharides have been regarded as one of the most appealing natural products attributable to their potent and selective bioactivities, such as antimicrobial activity, inhibition of α-glucosidases and lipase, interference of cellular recognition and signal transduction, and disruption of cell wall biosynthesis. Accordingly, a handful of bioactive oligosaccharides have been developed for the treatment of bacterial infections and type II diabetes mellitus. Given that naturally occurring oligosaccharides have increasingly gained recognition in recent years, a comprehensive review is needed. The current review highlights the chemical structures, biological activities and divergent biosynthetic origins of three subgroups of oligomers including the acarviosine-containing oligosaccharides, saccharomicins, and orthosomycins. Full article

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14 pages, 3127 KiB

Open AccessArticle

Distribution of the Water-Soluble Astaxanthin Binding Carotenoprotein (AstaP) in Scenedesmaceae

by Hiroki Toyoshima, Ami Miyata, Risako Yoshida, Taichiro Ishige, Shinichi Takaichi and Shinji Kawasaki

Mar. Drugs 2021, 19(6), 349; https://doi.org/10.3390/md19060349 - 20 Jun 2021

Cited by 8 | Viewed by 3070

Abstract

Photooxidative stress-inducible water-soluble astaxanthin-binding proteins, designated as AstaP, were identified in two Scenedesmaceae strains, Coelastrella astaxanthina Ki-4 and Scenedesmus obtusus Oki-4N; both strains were isolated under high light conditions. These AstaPs are classified as a novel family of carotenoprotein and are useful for [...] Read more.

Photooxidative stress-inducible water-soluble astaxanthin-binding proteins, designated as AstaP, were identified in two Scenedesmaceae strains, Coelastrella astaxanthina Ki-4 and Scenedesmus obtusus Oki-4N; both strains were isolated under high light conditions. These AstaPs are classified as a novel family of carotenoprotein and are useful for providing valuable astaxanthin in water-soluble form; however, the distribution of AstaP orthologs in other microalgae remains unknown. Here, we examined the distribution of AstaP orthologs in the family Scenedesmaceae with two model microalgae, Chlamydomonas reinhardtii and Chlorella variabilis. The expression of AstaP orthologs under photooxidative stress conditions was detected in cell extracts of Scenedesmaceae strains, but not in model algal strains. Aqueous orange proteins produced by Scenedesmaceae strains were shown to bind astaxanthin. The protein from Scenedesmus costatus SAG 46.88 was purified. It was named ScosAstaP and found to bind astaxanthin. The deduced amino acid sequence from a gene encoding ScosAstaP showed 62% identity to Ki-4 AstaP. The expression of the genes encoding AstaP orthologs was shown to be inducible under photooxidative stress conditions; however, the production amounts of AstaP orthologs were estimated to be approximately 5 to 10 times lower than that of Ki-4 and Oki-4N. Full article

(This article belongs to the Special Issue Fucoxanthin and Astaxanthin—Production, Biofunction, and Application)

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10 pages, 1937 KiB

Open AccessArticle

Four New Chromones from the Endophytic Fungus Phomopsis asparagi DHS-48 Isolated from the Chinese Mangrove Plant Rhizophora mangle

by Chengwen Wei, Chunxiao Sun, Zhao Feng, Xuexia Zhang and Jing Xu

Mar. Drugs 2021, 19(6), 348; https://doi.org/10.3390/md19060348 - 19 Jun 2021

Cited by 13 | Viewed by 2411

Abstract

Four new chromones, phomochromenones D–G (1–4), along with four known analogues, diaporchromone A (5), diaporchromanone C (6), diaporchromanone D (7), and phomochromenone C (8), were isolated from the culture of Phomopsis [...] Read more.

Four new chromones, phomochromenones D–G (1–4), along with four known analogues, diaporchromone A (5), diaporchromanone C (6), diaporchromanone D (7), and phomochromenone C (8), were isolated from the culture of Phomopsis asparagi DHS-48 from Chinese mangrove Rhizophora mangle. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configurations of 1 and 4 were assigned on the basis of experimental and calculated electronic circular dichroism (ECD) data, and those of enantiomers 2 and 3 were determined by a modified Mosher’s method and basic hydrolysis. To the best of our knowledge, phomochromenones D–F (1–4) possessing a 3-substituted-chroman-4-one skeleton are rarely found in natural sources. Diaporchromone A (5) showed moderate to weak immunosuppressive activity against T and/or B lymphocyte cells with IC₅₀ of 34 μM and 117 μM. Full article

(This article belongs to the Special Issue Marine Natural Product Chemistry: A Themed Issue Dedicated to Prof. Dr. Peter Proksch on His Research Career)

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18 pages, 4946 KiB

Open AccessArticle

Purification, Identification, Activity Evaluation, and Stability of Antioxidant Peptides from Alcalase Hydrolysate of Antarctic Krill (Euphausia superba) Proteins

by Shuang-Yi Zhang, Guo-Xu Zhao, Shi-Kun Suo, Yu-Mei Wang, Chang-Feng Chi and Bin Wang

Mar. Drugs 2021, 19(6), 347; https://doi.org/10.3390/md19060347 - 17 Jun 2021

Cited by 43 | Viewed by 3837

Abstract

For utilizing the largest source of marine proteins, Antarctic krill (Euphausia superba) proteins were defatted and hydrolyzed separately using pepsin, alcalase, papain, trypsin, and netrase, and alcalase hydrolysate (EPAH) showed the highest DPPH radical (DPPH·) and hydroxyl radical (HO·) scavenging activity [...] Read more.

For utilizing the largest source of marine proteins, Antarctic krill (Euphausia superba) proteins were defatted and hydrolyzed separately using pepsin, alcalase, papain, trypsin, and netrase, and alcalase hydrolysate (EPAH) showed the highest DPPH radical (DPPH·) and hydroxyl radical (HO·) scavenging activity among five hydrolysates. Using ultrafiltration and chromatography methods, fifteen antioxidant peptides were purified from EPAH and identified as Asn-Gln-Met (NQM), Trp-Phe-Pro-Met (WFPM), Gln-Asn-Pro-Thr (QNPT), Tyr-Met-Asn-Phe (YMNF), Ser-Gly-Pro-Ala (SGPA), Ser-Leu-Pro-Tyr (SLPY), Gln-Tyr-Pro-Pro-Met-Gln-Tyr (QYPPMQY), Glu-Tyr-Glu-Ala (EYEA), Asn-Trp-Asp-Asp-Met-Arg-Ile-Val-Ala-Val (NWDDMRIVAV), Trp-Asp-Asp-Met-Glu-Arg-Leu-Val-Met-Ile (WDDMERLVMI), Asn-Trp-Asp-Asp-Met-Glu-Pro-Ser-Phe (NWD-DMEPSF), Asn-Gly-Pro-Asp-Pro-Arg-Pro-Ser-Gln-Gln (NGPDPRPSQQ), Ala-Phe-Leu-Trp-Asn (AFLWA), Asn-Val-Pro-Asp-Met (NVPDM), and Thr-Phe-Pro-Ile-Tyr-Asp-Tyr-Pro-Gln (TFPIYDPQ), respectively, using a protein sequencer and ESI/MS. Among fifteen antioxidant peptides, SLPY, QYPPMQY and EYEA showed the highest scavenging activities on DPPH· (EC₅₀ values of 1.18 ± 0.036, 1.547 ± 0.150, and 1.372 ± 0.274 mg/mL, respectively), HO· (EC₅₀ values of 0.826 ± 0.027, 1.022 ± 0.058, and 0.946 ± 0.011 mg/mL, respectively), and superoxide anion radical (EC₅₀ values of 0.789 ± 0.079, 0.913 ± 0.007, and 0.793 ± 0.056 mg/mL, respectively). Moreover, SLPY, QYPPMQY and EYEA showed strong reducing power, protective capability against H₂O₂-damaged plasmid DNA, and lipid peroxidation inhibition ability. Furthermore, SLPY, QYPPMQY, and EYEA had high stability under temperatures lower than 80 °C, pH values ranged from 6–8, and simulated GI digestion for 180 min. The results showed that fifteen antioxidant peptides from alcalase hydrolysate of Antarctic krill proteins, especially SLPY, QYPPMQY and EYEA, might serve as effective antioxidant agents applied in food and health products. Full article

(This article belongs to the Special Issue Marine Drug Research in China: Selected Papers from the 15-NASMD Conference)

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16 pages, 4077 KiB

Open AccessArticle

Astaxanthin Protects Dendritic Cells from Lipopolysaccharide-Induced Immune Dysfunction

by Yinyan Yin, Nuo Xu, Yi Shi, Bangyue Zhou, Dongrui Sun, Bixia Ma, Zhengzhong Xu, Jin Yang and Chunmei Li

Mar. Drugs 2021, 19(6), 346; https://doi.org/10.3390/md19060346 - 17 Jun 2021

Cited by 24 | Viewed by 3345

Abstract

Astaxanthin, originating from seafood, is a naturally occurring red carotenoid pigment. Previous studies have focused on its antioxidant properties; however, whether astaxanthin possesses a desired anti-inflammatory characteristic to regulate the dendritic cells (DCs) for sepsis therapy remains unknown. Here, we explored the effects [...] Read more.

Astaxanthin, originating from seafood, is a naturally occurring red carotenoid pigment. Previous studies have focused on its antioxidant properties; however, whether astaxanthin possesses a desired anti-inflammatory characteristic to regulate the dendritic cells (DCs) for sepsis therapy remains unknown. Here, we explored the effects of astaxanthin on the immune functions of murine DCs. Our results showed that astaxanthin reduced the expressions of LPS-induced inflammatory cytokines (TNF-α, IL-6, and IL-10) and phenotypic markers (MHCII, CD40, CD80, and CD86) by DCs. Moreover, astaxanthin promoted the endocytosis levels in LPS-treated DCs, and hindered the LPS-induced migration of DCs via downregulating CCR7 expression, and then abrogated allogeneic T cell proliferation. Furthermore, we found that astaxanthin inhibited the immune dysfunction of DCs induced by LPS via the activation of the HO-1/Nrf2 axis. Finally, astaxanthin with oral administration remarkably enhanced the survival rate of LPS-challenged mice. These data showed a new approach of astaxanthin for potential sepsis treatment through avoiding the immune dysfunction of DCs. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 2021)

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15 pages, 5505 KiB

Open AccessReview

Marine Polysaccharides as a Versatile Biomass for the Construction of Nano Drug Delivery Systems

by Ying Sun, Xiaoli Ma and Hao Hu

Mar. Drugs 2021, 19(6), 345; https://doi.org/10.3390/md19060345 - 16 Jun 2021

Cited by 59 | Viewed by 6474

Abstract

Marine biomass is a treasure trove of materials. Marine polysaccharides have the characteristics of biocompatibility, biodegradability, non-toxicity, low cost, and abundance. An enormous variety of polysaccharides can be extracted from marine organisms such as algae, crustaceans, and microorganisms. The most studied marine polysaccharides [...] Read more.

Marine biomass is a treasure trove of materials. Marine polysaccharides have the characteristics of biocompatibility, biodegradability, non-toxicity, low cost, and abundance. An enormous variety of polysaccharides can be extracted from marine organisms such as algae, crustaceans, and microorganisms. The most studied marine polysaccharides include chitin, chitosan, alginates, hyaluronic acid, fucoidan, carrageenan, agarose, and Ulva. Marine polysaccharides have a wide range of applications in the field of biomedical materials, such as drug delivery, tissue engineering, wound dressings, and sensors. The drug delivery system (DDS) can comprehensively control the distribution of drugs in the organism in space, time, and dosage, thereby increasing the utilization efficiency of drugs, reducing costs, and reducing toxic side effects. The nano-drug delivery system (NDDS), due to its small size, can function at the subcellular level in vivo. The marine polysaccharide-based DDS combines the advantages of polysaccharide materials and nanotechnology, and is suitable as a carrier for different pharmaceutical preparations. This review summarizes the advantages and drawbacks of using marine polysaccharides to construct the NDDS and describes the preparation methods and modification strategies of marine polysaccharide-based nanocarriers. Full article

(This article belongs to the Special Issue Marine Natural Product Chemistry: A Themed Issue Dedicated to Prof. Dr. Peter Proksch on His Research Career)

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24 pages, 4568 KiB

Open AccessArticle

Agarose Stearate-Carbomer₉₄₀ as Stabilizer and Rheology Modifier for Surfactant-Free Cosmetic Formulations

by Qiong Xiao, Guo Chen, Yong-Hui Zhang, Fu-Quan Chen, Hui-Fen Weng and An-Feng Xiao

Mar. Drugs 2021, 19(6), 344; https://doi.org/10.3390/md19060344 - 16 Jun 2021

Cited by 18 | Viewed by 3834

Abstract

Some commonly used surfactants in cosmetic products raise concerns due to their skin-irritating effects and environmental contamination. Multifunctional, high-performance polymers are good alternatives to overcome these problems. In this study, agarose stearate (AS) with emulsifying, thickening, and gel properties was synthesized. Surfactant-free cosmetic [...] Read more.

Some commonly used surfactants in cosmetic products raise concerns due to their skin-irritating effects and environmental contamination. Multifunctional, high-performance polymers are good alternatives to overcome these problems. In this study, agarose stearate (AS) with emulsifying, thickening, and gel properties was synthesized. Surfactant-free cosmetic formulations were successfully prepared from AS and carbomer₉₄₀ (CBM₉₄₀) mixed systems. The correlation of rheological parameter with skin feeling was determined to study the usability of the mixed systems in cosmetics. Based on rheological analysis, the surfactant-free cosmetic cream (SFC) stabilized by AS-carbomer₉₄₀ showed shear-thinning behavior and strongly synergistic action. The SFC exhibited a gel-like behavior and had rheological properties similar to commercial cosmetic creams. Scanning electron microscope images proved that the AS-CBM₉₄₀ network played an important role in SFC’s stability. Oil content could reinforce the elastic characteristics of the AS-CBM₉₄₀ matrix. The SFCs showed a good appearance and sensation during and after rubbing into skin. The knowledge gained from this study may be useful for designing surfactant-free cosmetic cream with rheological properties that can be tailored for particular commercial cosmetic applications. They may also be useful for producing medicine products with highly viscous or gel-like textures, such as some ointments and wound dressings. Full article

(This article belongs to the Collection Marine Polysaccharides)

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21 pages, 1708 KiB

Open AccessReview

Bridging Cyanobacteria to Neurodegenerative Diseases: A New Potential Source of Bioactive Compounds against Alzheimer’s Disease

by Andrea Castaneda, Ricardo Ferraz, Mónica Vieira, Isabel Cardoso, Vitor Vasconcelos and Rosário Martins

Mar. Drugs 2021, 19(6), 343; https://doi.org/10.3390/md19060343 - 16 Jun 2021

Cited by 15 | Viewed by 4605

Abstract

Neurodegenerative diseases (NDs) represent a drawback in society given the ageing population. Dementias are the most prevalent NDs, with Alzheimer’s disease (AD) representing around 70% of all cases. The current pharmaceuticals for AD are symptomatic and with no effects on the progression of [...] Read more.

Neurodegenerative diseases (NDs) represent a drawback in society given the ageing population. Dementias are the most prevalent NDs, with Alzheimer’s disease (AD) representing around 70% of all cases. The current pharmaceuticals for AD are symptomatic and with no effects on the progression of the disease. Thus, research on molecules with therapeutic relevance has become a major focus for the scientific community. Cyanobacteria are a group of photosynthetic prokaryotes rich in biomolecules with confirmed activity in pathologies such as cancer, and with feasible potential in NDs such as AD. In this review, we aimed to compile the research works focused in the anti-AD potential of cyanobacteria, namely regarding the inhibition of the enzyme β-secretase (BACE1) as a fundamental enzyme in the generation of β-amyloid (Aβ), the inhibition of the enzyme acetylcholinesterase (AChE) lead to an increase in the availability of the neurotransmitter acetylcholine in the synaptic cleft and the antioxidant and anti-inflammatory effects, as phenomena associated with neurodegeneration mechanisms. Full article

(This article belongs to the Special Issue Bioactive Products from Marine Cyanobacteria and Their Potential Therapeutic Applications)

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26 pages, 1294 KiB

Open AccessReview

Development of Marine-Derived Compounds for Cancer Therapy

by Weimin Zuo and Hang Fai Kwok

Mar. Drugs 2021, 19(6), 342; https://doi.org/10.3390/md19060342 - 15 Jun 2021

Cited by 32 | Viewed by 4944

Abstract

Cancer has always been a threat to human health with its high morbidity and mortality rates. Traditional therapy, including surgery, chemotherapy and radiotherapy, plays a key role in cancer treatment. However, it is not able to prevent tumor recurrence, drug resistance and treatment [...] Read more.

Cancer has always been a threat to human health with its high morbidity and mortality rates. Traditional therapy, including surgery, chemotherapy and radiotherapy, plays a key role in cancer treatment. However, it is not able to prevent tumor recurrence, drug resistance and treatment side effects, which makes it a very attractive challenge to search for new effective and specific anticancer drugs. Nature is a valuable source of multiple pharmaceuticals, and most of the anticancer drugs are natural products or derived from them. Marine-derived compounds, such as nucleotides, proteins, peptides and amides, have also shed light on cancer therapy, and they are receiving a fast-growing interest due to their bioactive properties. Their mechanisms contain anti-angiogenic, anti-proliferative and anti-metastasis activities; cell cycle arrest; and induction of apoptosis. This review provides an overview on the development of marine-derived compounds with anticancer properties, both their applications and mechanisms, and discovered technologies. Full article

(This article belongs to the Special Issue Development and Application of Marine-Sourced Anti-Cancer and Cancer Pain Control Agents II)

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24 pages, 1820 KiB

Open AccessReview

An Overview to the Health Benefits of Seaweeds Consumption

by Silvia Lomartire, João Carlos Marques and Ana M. M. Gonçalves

Mar. Drugs 2021, 19(6), 341; https://doi.org/10.3390/md19060341 - 15 Jun 2021

Cited by 81 | Viewed by 12602

Abstract

Currently, seaweeds are gaining major attention due to the benefits they give to our health. Recent studies demonstrate the high nutritional value of seaweeds and the powerful properties that seaweeds’ bioactive compounds provide. Species of class Phaeophyceae, phylum Rhodophyta and Chlorophyta possess unique [...] Read more.

Currently, seaweeds are gaining major attention due to the benefits they give to our health. Recent studies demonstrate the high nutritional value of seaweeds and the powerful properties that seaweeds’ bioactive compounds provide. Species of class Phaeophyceae, phylum Rhodophyta and Chlorophyta possess unique compounds with several properties that are potential allies of our health, which make them valuable compounds to be involved in biotechnological applications. In this review, the health benefits given by consumption of seaweeds as whole food or by assumption of bioactive compounds trough natural drugs are highlighted. The use of seaweeds in agriculture is also highlighted, as they assure soils and crops free from chemicals; thus, it is advantageous for our health. The addition of seaweed extracts in food, nutraceutical, pharmaceutical and industrial companies will enhance the production and consumption/usage of seaweed-based products. Therefore, there is the need to implement the research on seaweeds, with the aim to identify more bioactive compounds, which may assure benefits to human and animal health. Full article

(This article belongs to the Special Issue Seaweeds Secondary Metabolites: Successes in and/or Probable Therapeutic Applications 3.0)

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10 pages, 1031 KiB

Open AccessArticle

Effects of Ingesting Fucoidan Derived from Cladosiphon okamuranus Tokida on Human NK Cells: A Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Pilot Study

by Makoto Tomori, Takeaki Nagamine, Tomofumi Miyamoto and Masahiko Iha

Mar. Drugs 2021, 19(6), 340; https://doi.org/10.3390/md19060340 - 15 Jun 2021

Cited by 9 | Viewed by 3448

Abstract

The aim of this study was to evaluate the effects of ingesting fucoidan derived from Okinawa mozuku (Cladosiphon okamuranus) on natural killer (NK) cell activity and to assess its safety in healthy adults via a randomized, double-blind, parallel-group, placebo-controlled pilot study. [...] Read more.

The aim of this study was to evaluate the effects of ingesting fucoidan derived from Okinawa mozuku (Cladosiphon okamuranus) on natural killer (NK) cell activity and to assess its safety in healthy adults via a randomized, double-blind, parallel-group, placebo-controlled pilot study. Subjects were randomly divided into two groups—a placebo group (ingesting citric acid, sucralose, and caramel beverages; n = 20; 45.5 ± 7.8 years (mean ± standard deviation)) and a fucoidan group (3.0 g/day from beverages; n = 20; 47.0 ± 7.6 years); after 12 weeks, blood, biochemical, and immunological tests were performed. Clinically adverse events were not observed in any of the tests during the study period. In addition, adverse events due to the test food were not observed. In the immunological tests, NK cell activity was significantly enhanced at 8 weeks in the fucoidan group, compared to before ingestion (0 weeks). In addition, a significantly enhanced NK cell activity was observed in male subjects at 8 weeks, compared with the placebo group. These results confirm that Okinawa mozuku-derived fucoidan enhances NK cell activity and suggest that it is a safe food material. Full article

(This article belongs to the Special Issue Fucoidans Ⅱ: Immunomodulating Activity of Fucoidans)

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11 pages, 797 KiB

Open AccessArticle

Six New Diterpene Glycosides from the Soft Coral Lemnaliabournei

by Xia Yan, Han Ouyang, Te Li, Yutong Shi, Bin Wu, Xiaojun Yan and Shan He

Mar. Drugs 2021, 19(6), 339; https://doi.org/10.3390/md19060339 - 14 Jun 2021

Cited by 7 | Viewed by 2706

Abstract

A chemical study on the extracts of soft coral Lemnalia bournei resulted in the isolation and identification of six new bicyclic diterpene glycosides including three new lemnaboursides E–G (1–3), and three new lemnadiolboursides A–C (4–6), [...] Read more.

A chemical study on the extracts of soft coral Lemnalia bournei resulted in the isolation and identification of six new bicyclic diterpene glycosides including three new lemnaboursides E–G (1–3), and three new lemnadiolboursides A–C (4–6), along with three known lemnaboursides (7–9). Their structures were elucidated by detailed spectroscopic analysis, ECD analysis, chemical methods, and comparison with the literature data. Lemnadiolboursides A–C (4–6) contained a lemnal-1(10)-ene-7,12-diol moiety compared with the lemnaboursides. All these compounds were evaluated for antibacterial activity; cell growth inhibition of A549, Hela, HepG2, and CCRF-CEM cancer cell lines; and inhibition of LPS-induced NO production in RAW264.7 macrophages. The results indicated that compounds 1, 2, and 4–6 exhibited antibacterial activity against Staphylococcus aureus and Bacillus subtilis (MIC 4–16 μg/mL); compounds 1–9 displayed low cytotoxicity on the CCRF-CEM cell lines (IC₅₀ 10.44–27.40 µM); and compounds 1, 2, and 5 showed weak inhibition against LPS-induced NO production (IC₅₀ 21.56–28.06 μM). Full article

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19 pages, 621 KiB

Open AccessArticle

Characterization of Protein Hydrolysates from Fish Discards and By-Products from the North-West Spain Fishing Fleet as Potential Sources of Bioactive Peptides

by Andreia Henriques, José A. Vázquez, Jesus Valcarcel, Rogério Mendes, Narcisa M. Bandarra and Carla Pires

Mar. Drugs 2021, 19(6), 338; https://doi.org/10.3390/md19060338 - 13 Jun 2021

Cited by 42 | Viewed by 5343

Abstract

Fish discards and by-products can be transformed into high value-added products such as fish protein hydrolysates (FPH) containing bioactive peptides. Protein hydrolysates were prepared from different parts (whole fish, skin and head) of several discarded species of the North-West Spain fishing fleet using [...] Read more.

Fish discards and by-products can be transformed into high value-added products such as fish protein hydrolysates (FPH) containing bioactive peptides. Protein hydrolysates were prepared from different parts (whole fish, skin and head) of several discarded species of the North-West Spain fishing fleet using Alcalase. All hydrolysates had moisture and ash contents lower than 10% and 15%, respectively. The fat content of FPH varied between 1.5% and 9.4% and had high protein content (69.8–76.6%). The amino acids profiles of FPH are quite similar and the most abundant amino acids were glutamic and aspartic acids. All FPH exhibited antioxidant activity and those obtained from Atlantic horse mackerel heads presented the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and Cu²⁺ chelating activity. On the other hand, hydrolysates from gurnard heads showed the highest ABTS radical scavenging activity and Fe²⁺ chelating activity. In what concerns the α-amylase inhibitory activity, the IC₅₀ values recorded for FPH ranged between 5.70 and 84.37 mg/mL for blue whiting heads and whole Atlantic horse mackerel, respectively. α-Glucosidase inhibitory activity of FPH was relatively low but all FPH had high Angiotensin Converting Enzyme (ACE) inhibitory activity. Considering the biological activities, these FPH are potential natural additives for functional foods or nutraceuticals. Full article

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8 pages, 1961 KiB

Open AccessArticle

NaCl Promotes the Efficient Formation of Haematococcus pluvialis Nonmotile Cells under Phosphorus Deficiency

by Feng Li, Ning Zhang, Yulei Zhang, Qingsheng Lian, Caiying Qin, Zuyuan Qian, Yanqi Wu, Zhiyuan Yang, Changling Li, Xianghu Huang and Minggang Cai

Mar. Drugs 2021, 19(6), 337; https://doi.org/10.3390/md19060337 - 13 Jun 2021

Cited by 8 | Viewed by 3581

Abstract

Natural astaxanthin helps reduce the negative effects caused by oxidative stress and other related factors, thereby minimizing oxidative damage. Therefore, it has considerable potential and broad application prospects in human health and animal nutrition. Haematococcus pluvialis is considered to be the most promising [...] Read more.

Natural astaxanthin helps reduce the negative effects caused by oxidative stress and other related factors, thereby minimizing oxidative damage. Therefore, it has considerable potential and broad application prospects in human health and animal nutrition. Haematococcus pluvialis is considered to be the most promising cell factory for the production of natural astaxanthin. Previous studies have confirmed that nonmotile cells of H. pluvialis are more tolerant to high intensity of light than motile cells. Cultivating nonmotile cells as the dominant cell type in the red stage can significantly increase the overall astaxanthin productivity. However, we know very little about how to induce nonmotile cell formation. In this work, we first investigated the effect of phosphorus deficiency on the formation of nonmotile cells of H. pluvialis, and then investigated the effect of NaCl on the formation of nonmotile cells under the conditions of phosphorus deficiency. The results showed that, after three days of treatment with 0.1% NaCl under phosphorus deficiency, more than 80% of motile cells had been transformed into nonmotile cells. The work provides the most efficient method for the cultivation of H. pluvialis nonmotile cells so far, and it significantly improves the production of H. pluvialis astaxanthin. Full article

(This article belongs to the Special Issue Fucoxanthin and Astaxanthin—Production, Biofunction, and Application)

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24 pages, 7538 KiB

Open AccessArticle

Hemolytic Activity in Relation to the Photosynthetic System in Chattonella marina and Chattonella ovata

by Ni Wu, Mengmeng Tong, Siyu Gou, Weiji Zeng, Zhuoyun Xu and Tianjiu Jiang

Mar. Drugs 2021, 19(6), 336; https://doi.org/10.3390/md19060336 - 12 Jun 2021

Cited by 8 | Viewed by 2913

Abstract

Chattonella species, C. marina and C. ovata, are harmful raphidophycean flagellates known to have hemolytic effects on many marine organisms and resulting in massive ecological damage worldwide. However, knowledge of the toxigenic mechanism of these ichthyotoxic flagellates is still limited. Light was [...] Read more.

Chattonella species, C. marina and C. ovata, are harmful raphidophycean flagellates known to have hemolytic effects on many marine organisms and resulting in massive ecological damage worldwide. However, knowledge of the toxigenic mechanism of these ichthyotoxic flagellates is still limited. Light was reported to be responsible for the hemolytic activity (HA) of Chattonella species. Therefore, the response of photoprotective, photosynthetic accessory pigments, the photosystem II (PSII) electron transport chain, as well as HA were investigated in non-axenic C. marina and C. ovata cultures under variable environmental conditions (light, iron and addition of photosynthetic inhibitors). HA and hydrogen peroxide (H₂O₂) were quantified using erythrocytes and pHPA assay. Results confirmed that% HA of Chattonella was initiated by light, but was not always elicited during cell division. Exponential growth of C. marina and C. ovata under the light over 100 µmol m⁻² s⁻¹ or iron-sufficient conditions elicited high hemolytic activity. Inhibitors of PSII reduced the HA of C. marina, but had no effect on C. ovata. The toxicological response indicated that HA in Chattonella was not associated with the photoprotective system, i.e., xanthophyll cycle and regulation of reactive oxygen species, nor the PSII electron transport chain, but most likely occurred during energy transport through the light-harvesting antenna pigments. A positive, highly significant relationship between HA and chlorophyll (chl) biosynthesis pigments, especially chl c2 and chl a, in both species, indicated that hemolytic toxin may be generated during electron/energy transfer through the chl c2 biosynthesis pathway. Full article

(This article belongs to the Special Issue Marine Biotoxins)

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25 pages, 2053 KiB

Open AccessReview

Chemical Diversity and Biological Activity of Secondary Metabolites from Soft Coral Genus Sinularia since 2013

by Xia Yan, Jing Liu, Xue Leng and Han Ouyang

Mar. Drugs 2021, 19(6), 335; https://doi.org/10.3390/md19060335 - 11 Jun 2021

Cited by 40 | Viewed by 3804

Abstract

Sinularia is one of the conspicuous soft coral species widely distributed in the world’s oceans at a depth of about 12 m. Secondary metabolites from the genus Sinularia show great chemical diversity. More than 700 secondary metabolites have been reported to date, including [...] Read more.

Sinularia is one of the conspicuous soft coral species widely distributed in the world’s oceans at a depth of about 12 m. Secondary metabolites from the genus Sinularia show great chemical diversity. More than 700 secondary metabolites have been reported to date, including terpenoids, norterpenoids, steroids/steroidal glycosides, and other types. They showed a broad range of potent biological activities. There were detailed reviews on the terpenoids from Sinularia in 2013, and now, it still plays a vital role in the innovation of lead compounds for drug development. The structures, names, and pharmacological activities of compounds isolated from the genus Sinularia from 2013 to March 2021 are summarized in this review. Full article

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14 pages, 1698 KiB

Open AccessArticle

A Comparative In Vitro Evaluation of the Anti-Inflammatory Effects of a Tisochrysis lutea Extract and Fucoxanthin

by Elisabetta Bigagli, Mario D’Ambrosio, Lorenzo Cinci, Alberto Niccolai, Natascia Biondi, Liliana Rodolfi, Luana Beatriz Dos Santos Nascimiento, Mario R. Tredici and Cristina Luceri

Mar. Drugs 2021, 19(6), 334; https://doi.org/10.3390/md19060334 - 11 Jun 2021

Cited by 22 | Viewed by 3232

Abstract

In this study, we compared the effects of a Tisochrysis lutea (T. lutea) F&M-M36 methanolic extract with those of fucoxanthin (FX) at equivalent concentration, on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The T. lutea F&M-M36 methanolic extract contained 4.7 mg of FX and [...] Read more.

In this study, we compared the effects of a Tisochrysis lutea (T. lutea) F&M-M36 methanolic extract with those of fucoxanthin (FX) at equivalent concentration, on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The T. lutea F&M-M36 methanolic extract contained 4.7 mg of FX and 6.22 mg of gallic acid equivalents of phenols per gram. HPLC analysis revealed the presence of simple phenolic acid derivatives. The T. lutea F&M-M36 extract exhibited a potent and concentration-dependent inhibitory activity against COX-2 dependent PGE2 production compared to FX alone. Compared to LPS, T. lutea F&M-M36 extract and FX reduced the expression of IL-6 and of Arg1 and enhanced that of IL-10 and of HO-1; T. lutea F&M-M36 extract also significantly abated the expression of NLRP3, enhanced mir-223 expression and reduced that of mir-146b, compared to LPS (p < 0.05). These findings indicate that T. lutea F&M-M36 methanolic extract has a peculiar anti-inflammatory activity against COX-2/PGE2 and NLRP3/mir-223 that might be attributable to the known anti-inflammatory effects of simple phenolic compounds found in the extract that may synergize with FX. Our data suggest that T. lutea F&M-M36 may serve as a source of anti-inflammatory compounds to be further evaluated in in vivo models of inflammation. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 2021)

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9 pages, 2271 KiB

Open AccessArticle

Antiproliferative Illudalane Sesquiterpenes from the Marine Sediment Ascomycete Aspergillus oryzae

by Raha Orfali, Shagufta Perveen, Muhammad Farooq Khan, Atallah F. Ahmed, Mohammad A. Wadaan, Areej Mohammad Al-Taweel, Ali S. Alqahtani, Fahd A. Nasr, Sobia Tabassum, Paolo Luciano, Giuseppina Chianese, Jyh-Horng Sheu and Orazio Taglialatela-Scafati

Mar. Drugs 2021, 19(6), 333; https://doi.org/10.3390/md19060333 - 10 Jun 2021

Cited by 9 | Viewed by 3184

Abstract

The new asperorlactone (1), along with the known illudalane sesquiterpene echinolactone D (2), two known pyrones, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (3) and its acetate 4, and 4-hydroxybenzaldehyde (5), were isolated from a culture of Aspergillus [...] Read more.

The new asperorlactone (1), along with the known illudalane sesquiterpene echinolactone D (2), two known pyrones, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (3) and its acetate 4, and 4-hydroxybenzaldehyde (5), were isolated from a culture of Aspergillus oryzae, collected from Red Sea marine sediments. The structure of asperorlactone (1) was elucidated by HR-ESIMS, 1D, and 2D NMR, and a comparison between experimental and DFT calculated electronic circular dichroism (ECD) spectra. This is the first report of illudalane sesquiterpenoids from Aspergillus fungi and, more in general, from ascomycetes. Asperorlactone (1) exhibited antiproliferative activity against human lung, liver, and breast carcinoma cell lines, with IC₅₀ values < 100 µM. All the isolated compounds were also evaluated for their toxicity using the zebrafish embryo model. Full article

(This article belongs to the Special Issue Marine Natural Product Chemistry: A Themed Issue Dedicated to Prof. Dr. Peter Proksch on His Research Career)

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7 pages, 550 KiB

Open AccessCommunication

Secondary Metabolite Production Potential of Mangrove-Derived Streptomyces olivaceus

by Dini Hu, Simon Ming-Yuen Lee, Kai Li and Kai Meng Mok

Mar. Drugs 2021, 19(6), 332; https://doi.org/10.3390/md19060332 - 8 Jun 2021

Cited by 3 | Viewed by 3352

Abstract

Mangroves are intertidal extreme environments with rich microbial communities. Actinobacteria are well known for producing antibiotics. The search for biosynthetic potential of Actinobacteria from mangrove environments could provide more possibilities for useful secondary metabolites. In this study, whole genome sequencing and MS/MS analysis [...] Read more.

Mangroves are intertidal extreme environments with rich microbial communities. Actinobacteria are well known for producing antibiotics. The search for biosynthetic potential of Actinobacteria from mangrove environments could provide more possibilities for useful secondary metabolites. In this study, whole genome sequencing and MS/MS analysis were used to explore the secondary metabolite production potential of one actinobacterial strain of Streptomyces olivaceus sp., isolated from a mangrove in Macau, China. The results showed that a total of 105 gene clusters were found in the genome of S. olivaceus sp., and 53 known secondary metabolites, including bioactive compounds, peptides, and other products, were predicted by genome mining. There were 28 secondary metabolites classified as antibiotics, which were not previously known from S. olivaceus. ISP medium 2 was then used to ferment the S. olivaceus sp. to determine which predicted secondary metabolite could be truly produced. The chemical analysis revealed that ectoine, melanin, and the antibiotic of validamycin A could be observed in the fermentation broth. This was the first observation that these three compounds can be produced by a strain of S. olivaceus. Therefore, it can be concluded that Actinobacteria isolated from the mangrove environment have unknown potential to produce bioactive secondary metabolites. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Streptomyces)

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6 pages, 208 KiB

Open AccessEditorial

Current Trend of Marine Carbohydrate-Containing Compounds with Medicinal Properties

by Irina M. Yermak and Viktoria N. Davydova

Mar. Drugs 2021, 19(6), 331; https://doi.org/10.3390/md19060331 - 8 Jun 2021

Cited by 2 | Viewed by 2577

Abstract

Carbohydrates are most abundant biomolecules on Earth and, also, the most complex biomolecules in terms of structure [...] Full article

(This article belongs to the Special Issue Marine Carbohydrate-Based Compounds with Medicinal Properties)

31 pages, 3866 KiB

Open AccessReview

Sphingolipids of Asteroidea and Holothuroidea: Structures and Biological Activities

by Timofey V. Malyarenko, Alla A. Kicha, Valentin A. Stonik and Natalia V. Ivanchina

Mar. Drugs 2021, 19(6), 330; https://doi.org/10.3390/md19060330 - 8 Jun 2021

Cited by 15 | Viewed by 4241

Abstract

Sphingolipids are complex lipids widespread in nature as structural components of biomembranes. Commonly, the sphingolipids of marine organisms differ from those of terrestrial animals and plants. The gangliosides are the most complex sphingolipids characteristic of vertebrates that have been found in only the [...] Read more.

Sphingolipids are complex lipids widespread in nature as structural components of biomembranes. Commonly, the sphingolipids of marine organisms differ from those of terrestrial animals and plants. The gangliosides are the most complex sphingolipids characteristic of vertebrates that have been found in only the Echinodermata (echinoderms) phylum of invertebrates. Sphingolipids of the representatives of the Asteroidea and Holothuroidea classes are the most studied among all echinoderms. In this review, we have summarized the data on sphingolipids of these two classes of marine invertebrates over the past two decades. Recently established structures, properties, and peculiarities of biogenesis of ceramides, cerebrosides, and gangliosides from starfishes and holothurians are discussed. The purpose of this review is to provide the most complete information on the chemical structures, structural features, and biological activities of sphingolipids of the Asteroidea and Holothuroidea classes. Full article

(This article belongs to the Special Issue Echinoderms Metabolites: Structure, Functions and Biomedical Perspectives II)

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16 pages, 4582 KiB

Open AccessArticle

Spray Drying of Chitosan Acid Salts: Process Development, Scaling Up and Physicochemical Material Characterization

by Nilia de la Paz, Mirna Fernández, Orestes López, Caridad Garcia, Antonio Nogueira, Leonid Torres, Wilfredo Turiño and Jyrki Heinämäki

Mar. Drugs 2021, 19(6), 329; https://doi.org/10.3390/md19060329 - 6 Jun 2021

Cited by 2 | Viewed by 2847

Abstract

We investigated a spray drying process for preparing water-soluble salts of high molecular weight chitosan (CH) intended for pharmaceutical excipient applications. CH was derived from chitin of marine lobster origin (Panulirus argus). The effects of organic acid (acetic or lactic acid) [...] Read more.

We investigated a spray drying process for preparing water-soluble salts of high molecular weight chitosan (CH) intended for pharmaceutical excipient applications. CH was derived from chitin of marine lobster origin (Panulirus argus). The effects of organic acid (acetic or lactic acid) and the ratio (difference) of inlet/outlet air temperature (140/90 °C or 160/100 °C) on spray drying were studied. The yield of spray-dried CH salt powders ranged from 50% to 99% in laboratory and industrial-scale processes. The spray-dried dry powder of CH salts consisted of spherical agglomerated particles with an average diameter of 36.2 ± 7.0 µm (CH acetate) and 108.6 ± 11.5 µm (CH lactate). After dispersing the spray-dried CH salt powder samples in purified water, the mean particle sizes obtained for the CH acetate salts were 31.4 nm (batch A001), 33.0 nm (A002) and 44.2 nm (A003), and for the CH lactate salts 100.8 nm (batch L001), 103.2 nm (L002) and 121.8 nm (L003). The optimum process conditions for spray drying were found: an inlet air temperature of 160 ± 5 °C, an outlet temperature of 100 ± 5 °C and an atomizer disk rotational speed of 18,200 min⁻¹. The X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) results confirmed the amorphous state of the CH salts. The ¹H nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra of CH acetate and lactate salts verified that the spray drying process does not affect the polymer backbone. In conclusion, both laboratory and industrial-scale spray drying methods for preparing water-soluble acid salts of CH are reproducible, and the physicochemical properties of the corresponding CH acid salts are uniform. Full article

(This article belongs to the Special Issue Pharmaceutical Formulation of Marine Drugs)

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21 pages, 3309 KiB

Open AccessArticle

Genome Mining for Antimicrobial Compounds in Wild Marine Animals-Associated Enterococci

by Janira Prichula, Muriel Primon-Barros, Romeu C. Z. Luz, Ícaro M. S. Castro, Thiago G. S. Paim, Maurício Tavares, Rodrigo Ligabue-Braun, Pedro A. d’Azevedo, Jeverson Frazzon, Ana P. G. Frazzon, Adriana Seixas and Michael S. Gilmore

Mar. Drugs 2021, 19(6), 328; https://doi.org/10.3390/md19060328 - 6 Jun 2021

Cited by 18 | Viewed by 4975

Abstract

New ecosystems are being actively mined for new bioactive compounds. Because of the large amount of unexplored biodiversity, bacteria from marine environments are especially promising. Further, host-associated microbes are of special interest because of their low toxicity and compatibility with host health. Here, [...] Read more.

New ecosystems are being actively mined for new bioactive compounds. Because of the large amount of unexplored biodiversity, bacteria from marine environments are especially promising. Further, host-associated microbes are of special interest because of their low toxicity and compatibility with host health. Here, we identified and characterized biosynthetic gene clusters encoding antimicrobial compounds in host-associated enterococci recovered from fecal samples of wild marine animals remote from human-affected ecosystems. Putative biosynthetic gene clusters in the genomes of 22 Enterococcus strains of marine origin were predicted using antiSMASH5 and Bagel4 bioinformatic software. At least one gene cluster encoding a putative bioactive compound precursor was identified in each genome. Collectively, 73 putative antimicrobial compounds were identified, including 61 bacteriocins (83.56%), 10 terpenes (13.70%), and 2 (2.74%) related to putative nonribosomal peptides (NRPs). Two of the species studied, Enterococcus avium and Enterococcus mundtti, are rare causes of human disease and were found to lack any known pathogenic determinants but yet possessed bacteriocin biosynthetic genes, suggesting possible additional utility as probiotics. Wild marine animal-associated enterococci from human-remote ecosystems provide a potentially rich source for new antimicrobial compounds of therapeutic and industrial value and potential probiotic application. Full article

(This article belongs to the Special Issue Natural Product Genomics and Metabolomics of Marine Bacteria)

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40 pages, 15087 KiB

Open AccessReview

Malabaricane and Isomalabaricane Triterpenoids, Including Their Glycoconjugated Forms

by Valentin A. Stonik and Sophia A. Kolesnikova

Mar. Drugs 2021, 19(6), 327; https://doi.org/10.3390/md19060327 - 5 Jun 2021

Cited by 17 | Viewed by 3918

Abstract

In this review, we discuss structural diversity, taxonomic distribution, biological activities, biogenesis, and synthesis of a rare group of terpenoids, the so-called malabaricane and isomalabaricane triterpenoids, as well as some compounds derived from them. Representatives of these groups were found in some higher [...] Read more.

In this review, we discuss structural diversity, taxonomic distribution, biological activities, biogenesis, and synthesis of a rare group of terpenoids, the so-called malabaricane and isomalabaricane triterpenoids, as well as some compounds derived from them. Representatives of these groups were found in some higher and lower terrestrial plants, as well as in some fungi, and in a relatively small group of marine sponges. The skeletal systems of malabaricanes and isomalabaricanes are similar to each other, but differ principally in the stereochemistry of their tricyclic core fragments, consisting of two six-membered and one five-membered rings. Evolution of these triterpenoids provides variety of rearranged, oxidized, and glycoconjugated products. These natural compounds have attracted a lot of attention for their biosynthetic origin and biological activity, especially for their extremely high cytotoxicity against tumor cells as well as promising neuroprotective properties in nanomolar concentrations. Full article

(This article belongs to the Special Issue Carbohydrate-Containing Marine Compounds of Mixed Biogenesis)

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20 pages, 4464 KiB

Open AccessArticle

In Vitro and In Silico Characterization of G-Protein Coupled Receptor (GPCR) Targets of Phlorofucofuroeckol-A and Dieckol

by Pradeep Paudel, Su Hui Seong, Se Eun Park, Jong Hoon Ryu, Hyun Ah Jung and Jae Sue Choi

Mar. Drugs 2021, 19(6), 326; https://doi.org/10.3390/md19060326 - 4 Jun 2021

Cited by 7 | Viewed by 3379

Abstract

Phlorotannins are polyphenolic compounds in marine alga, especially the brown algae. Among numerous phlorotannins, dieckol and phlorofucofuroeckol-A (PFF-A) are the major ones and despite a wider biological activity profile, knowledge of the G protein-coupled receptor (GPCR) targets of these phlorotannins is lacking. This [...] Read more.

Phlorotannins are polyphenolic compounds in marine alga, especially the brown algae. Among numerous phlorotannins, dieckol and phlorofucofuroeckol-A (PFF-A) are the major ones and despite a wider biological activity profile, knowledge of the G protein-coupled receptor (GPCR) targets of these phlorotannins is lacking. This study explores prime GPCR targets of the two phlorotannins. In silico proteocheminformatics modeling predicted twenty major protein targets and in vitro functional assays showed a good agonist effect at the α2C adrenergic receptor (α_2CAR) and an antagonist effect at the adenosine 2A receptor (A_2AR), δ-opioid receptor (δ-OPR), glucagon-like peptide-1 receptor (GLP-1R), and 5-hydroxytryptamine 1A receptor (5-TH_1AR) of both phlorotannins. Besides, dieckol showed an antagonist effect at the vasopressin 1A receptor (V_1AR) and PFF-A showed a promising agonist effect at the cannabinoid 1 receptor and an antagonist effect at V_1AR. In silico molecular docking simulation enabled us to investigate and identify distinct binding features of these phlorotannins to the target proteins. The docking results suggested that dieckol and PFF-A bind to the crystal structures of the proteins with good affinity involving key interacting amino acid residues comparable to reference ligands. Overall, the present study suggests α_2CAR, A_2AR, δ-OPR, GLP-1R, 5-TH_1AR, CB₁R, and V_1AR as prime receptor targets of dieckol and PFF-A. Full article

(This article belongs to the Special Issue Marine Drug Discovery through Computer-Aided Approaches)

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22 pages, 16275 KiB

Open AccessArticle

Dermacozine N, the First Natural Linear Pentacyclic Oxazinophenazine with UV–Vis Absorption Maxima in the Near Infrared Region, along with Dermacozines O and P Isolated from the Mariana Trench Sediment Strain Dermacoccus abyssi MT 1.1^T

by Bertalan Juhasz, Dawrin Pech-Puch, Jioji N. Tabudravu, Bastien Cautain, Fernando Reyes, Carlos Jiménez, Kwaku Kyeremeh and Marcel Jaspars

Mar. Drugs 2021, 19(6), 325; https://doi.org/10.3390/md19060325 - 3 Jun 2021

Cited by 6 | Viewed by 4141

Abstract

Three dermacozines, dermacozines N–P (1–3), were isolated from the piezotolerant Actinomycete strain Dermacoccus abyssi MT 1.1^T, which was isolated from a Mariana Trench sediment in 2006. Herein, we report the elucidation of their structures using a combination [...] Read more.

Three dermacozines, dermacozines N–P (1–3), were isolated from the piezotolerant Actinomycete strain Dermacoccus abyssi MT 1.1^T, which was isolated from a Mariana Trench sediment in 2006. Herein, we report the elucidation of their structures using a combination of 1D/2D NMR, LC-HRESI-MSⁿ, UV–Visible, and IR spectroscopy. Further confirmation of the structures was achieved through the analysis of data from density functional theory (DFT)–UV–Visible spectral calculations and statistical analysis such as two tailed t-test, linear regression-, and multiple linear regression analysis applied to either solely experimental or to experimental and calculated ¹³C-NMR chemical shift data. Dermacozine N (1) bears a novel linear pentacyclic phenoxazine framework that has never been reported as a natural product. Dermacozine O (2) is a constitutional isomer of the known dermacozine F while dermacozine P (3) is 8-benzoyl-6-carbamoylphenazine-1-carboxylic acid. Dermacozine N (1) is unique among phenoxazines due to its near infrared (NIR) absorption maxima, which would make this compound an excellent candidate for research in biosensing chemistry, photodynamic therapy (PDT), opto-electronic applications, and metabolic mapping at the cellular level. Furthermore, dermacozine N (1) possesses weak cytotoxic activity against melanoma (A2058) and hepatocellular carcinoma cells (HepG2) with IC₅₀ values of 51 and 38 μM, respectively. Full article

(This article belongs to the Special Issue Bioactive Molecules from Extreme Environments II)

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75 pages, 14661 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

by Valery M. Dembitsky, Tatyana A. Gloriozova and Vladimir V. Poroikov

Mar. Drugs 2021, 19(6), 324; https://doi.org/10.3390/md19060324 - 3 Jun 2021

Cited by 9 | Viewed by 5011

Abstract

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is [...] Read more.

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds. Full article

(This article belongs to the Special Issue Pharmacological Activity and Biomedical Potential of Marine Antitumor Agents)

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21 pages, 1858 KiB

Open AccessArticle

Salmon (Salmo salar) Side Streams as a Bioresource to Obtain Potential Antioxidant Peptides after Applying Pressurized Liquid Extraction (PLE)

by Beatriz de la Fuente, Noelia Pallarés, Houda Berrada and Francisco J. Barba

Mar. Drugs 2021, 19(6), 323; https://doi.org/10.3390/md19060323 - 3 Jun 2021

Cited by 20 | Viewed by 4404

Abstract

The pressurized liquid extraction (PLE) technique was used to obtain protein extracts with antioxidant capacity from salmon muscle remains, heads, viscera, skin, and tailfins. A protein recovery percentage ≈28% was obtained for all samples except for viscera, which was ≈92%. These values represented [...] Read more.

The pressurized liquid extraction (PLE) technique was used to obtain protein extracts with antioxidant capacity from salmon muscle remains, heads, viscera, skin, and tailfins. A protein recovery percentage ≈28% was obtained for all samples except for viscera, which was ≈92%. These values represented an increase of 1.5–4.8-fold compared to stirring extraction (control). Different SDS-PAGE profiles in control and PLE extracts revealed that extraction conditions affected the protein molecular weight distribution of the obtained extracts. Both TEAC (Trolox equivalent antioxidant capacity) and ORAC (oxygen radical antioxidant capacity) assays showed an outstanding antioxidant activity for viscera PLE extract. Through liquid chromatography coupled with electrospray ionization triple time-of-flight (nanoESI qQTOF) mass spectrometry, 137 and 67 peptides were identified in control and PLE extracts from salmon viscera, respectively None of these peptides was found among the antioxidant peptides inputted in the BIOPEP-UMP database. However, bioinformatics analysis showed several antioxidant small peptides encrypted in amino acid sequences of viscera extracts, especially GPP (glycine-proline-proline) and GAA (glycine-alanine-alanine) for PLE extracts. Further research on the relationship between antioxidant activity and specific peptides from salmon viscera PLE extracts is required. In addition, the salmon side streams studied presented non-toxic levels of As, Hg, Cd, and Pb, as well as the absence of mycotoxins or related metabolites. Overall, these results confirm the feasible use of farmed salmon processing side streams as alternative sources of protein and bioactive compounds for human consumption. Full article

(This article belongs to the Special Issue Fishery Discards, Processing Waste and Marine By-Products Valorization in the Era of Zero Waste: From Discovery to Profit 2.0)

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19 pages, 3874 KiB

Open AccessArticle

Okadaic Acid Exposure Induced Neural Tube Defects in Chicken (Gallus gallus) Embryos

by Yuhu Jiao, Guang Wang, Dawei Li, Hongye Li, Jiesheng Liu, Xuesong Yang and Weidong Yang

Mar. Drugs 2021, 19(6), 322; https://doi.org/10.3390/md19060322 - 2 Jun 2021

Cited by 12 | Viewed by 4066

Abstract

Okadaic acid (OA) is an important liposoluble shellfish toxin distributed worldwide, and is mainly responsible for diarrheic shellfish poisoning in human beings. It has a variety of toxicities, including cytotoxicity, embryonic toxicity, neurotoxicity, and even genotoxicity. However, there is no direct evidence of [...] Read more.

Okadaic acid (OA) is an important liposoluble shellfish toxin distributed worldwide, and is mainly responsible for diarrheic shellfish poisoning in human beings. It has a variety of toxicities, including cytotoxicity, embryonic toxicity, neurotoxicity, and even genotoxicity. However, there is no direct evidence of its developmental toxicity in human offspring. In this study, using the chicken (Gallus gallus) embryo as the animal model, we investigated the effects of OA exposure on neurogenesis and the incidence of neural tube defects (NTDs). We found that OA exposure could cause NTDs and inhibit the neuronal differentiation. Immunofluorescent staining of pHI3 and c-Caspase3 demonstrated that OA exposure could promote cell proliferation and inhibit cell apoptosis on the developing neural tube. Besides, the down-regulation of Nrf2 and increase in reactive oxygen species (ROS) content and superoxide dismutase (SOD) activity in the OA-exposed chicken embryos indicated that OA could result in oxidative stress in early chick embryos, which might enhance the risk of the subsequent NTDs. The inhibition of bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) expression in the dorsal neural tube suggested that OA could also affect the formation of dorsolateral hinge points, which might ultimately hinder the closure of the neural tube. Transcriptome and qPCR analysis showed the expression of lipopolysaccharide-binding protein (LBP), transcription factor AP-1 (JUN), proto-oncogene protein c-fos (FOS), and C-C motif chemokine 4 (CCL4) in the Toll-like receptor signaling pathway was significantly increased in the OA-exposed embryos, suggesting that the NTDs induced by OA might be associated with the Toll-like receptor signaling pathway. Taken together, our findings could advance the understanding of the embryo–fetal developmental toxicity of OA on human gestation. Full article

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Mar. Drugs, Volume 19, Issue 6 (June 2021) – 69 articles

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