Marine Pharmacology in 2014–2015: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, Antiviral, and Anthelmintic Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

The systematic review of the marine pharmacology literature from 2014 to 2015 was completed in a manner consistent with the 1998–2013 reviews of this series. Research in marine pharmacology during 2014–2015, which was reported by investigators in 43 countries, described novel findings on the preclinical pharmacology of 301 marine compounds. These observations included antibacterial, antifungal, antiprotozoal, antituberculosis, antiviral, and anthelmintic pharmacological activities for 133 marine natural products, 85 marine compounds with antidiabetic, and anti-inflammatory activities, as well as those that affected the immune and nervous system, and 83 marine compounds that displayed miscellaneous mechanisms of action, and may probably contribute to novel pharmacological classes upon further research. Thus, in 2014–2015, the preclinical marine natural product pharmacology pipeline provided novel pharmacology as well as new lead compounds for the clinical marine pharmaceutical pipeline, and thus continued to contribute to ongoing global research for alternative therapeutic approaches to many disease categories.


Introduction
The aim of the present review is to consolidate 2014-2015 preclinical marine pharmacology, with a format similar to the previous nine reviews of this series, which cover the period 1998-2013 [1][2][3][4][5][6][7][8][9]. The peer-reviewed articles were retrieved from searches in the following databases: MarinLit, PubMed, Chemical Abstracts ® , ISI Web of Knowledge, and Google Scholar. As in our previous work, we have limited our review to include bioactivity and/or pharmacology of structurally characterized marine Table 1 presents 2014-2015 preclinical pharmacological research on the antibacterial, antifungal, antiprotozoal, antituberculosis, antiviral, and anthelmintic activities of marine natural products  shown in Figure 1. Table 1. Marine pharmacology in 2014-2015: marine compounds with antibacterial, antifungal, antituberculosis, antiprotozoal, antiviral, and anthelmintic activities.

Drug Class
Compound/Organism a Chemistry Pharmacologic Activity IC 50 b

Antibacterial Activity
During 2014-2015, 48 studies reported antibacterial marine natural products (1-64) isolated from bacteria, fungi, tunicates, sponges, soft corals, sea snakes, fish, and algae; a research enterprise focused on the discovery of novel chemical leads to treat emerging drug-resistant bacterial infections.
As shown in Table 1 and Figure 1, nine publications reported on the mode of action of marinederived antibacterial compounds. Rodríguez and colleagues reported on "a practical synthesis of the axinellamines" (1, 2), as well as their broad spectrum Gram-positive and Gram-negative antibacterial activity, probably resulting from "secondary membrane destabilization…consistent with the inhibition of normal septum formation" [24]. Moon and colleagues characterized a new pentacyclic antibiotic, buanmycin (3), isolated from a Korean marine Streptomyces strain, which was active towards Gram-native Salmonella enterica that causes salmonellosis, by inhibiting sortase A, an enzyme involved in bacterial adhesion and proposed as a "promising target for antibiotic discovery" [25]. Wei and colleagues discovered a novel peptide cathelicidin (4) from the Chinese sea snake Hydrophis

Antibacterial Activity
During 2014-2015, 48 studies reported antibacterial marine natural products (1-64) isolated from bacteria, fungi, tunicates, sponges, soft corals, sea snakes, fish, and algae; a research enterprise focused on the discovery of novel chemical leads to treat emerging drug-resistant bacterial infections.
As shown in Table 1 and Figure 1, nine publications reported on the mode of action of marine-derived antibacterial compounds. Rodríguez and colleagues reported on "a practical synthesis of the axinellamines" (1, 2), as well as their broad spectrum Gram-positive and Gram-negative antibacterial activity, probably resulting from "secondary membrane destabilization . . . consistent with the inhibition of normal septum formation" [24]. Moon and colleagues characterized a new pentacyclic antibiotic, buanmycin (3), isolated from a Korean marine Streptomyces strain, which was active towards Gram-native Salmonella enterica that causes salmonellosis, by inhibiting sortase A, an enzyme involved in bacterial adhesion and proposed as a "promising target for antibiotic discovery" [25]. Wei and colleagues discovered a novel peptide cathelicidin (4) from the Chinese sea snake Hydrophis cyanocinctus with potent antimicrobial activity against 35 strains of 48 human pathogenic bacteria, probably by a mechanism that involved "disruption of cell membrane and lysis of bacterial cells . . . resulting in cellular disruption of both Gram-positive and Gram-negative bacteria" [26]. Silva and colleagues demonstrated that the antimicrobial peptide clavanin A (5) significantly reduced E. coli and S. aureus-infected mice mortality with concomitant reduction of proinflammatory cytokines, thus proposing that clavalin A " . . . will facilitate studies on the development of novel peptide-based strategies for the treatment of infected wounds and sepsis" [27]. Abdelmohsen and colleagues investigated the new sterol gelliusterol E (6) from the Red sea sponge Callyspongia aff. implexa and showed that it inhibited both the primary infection by Chlamydia trachomatis, an obligate intracellular Gram-negative bacterium, as well as the production of viable progeny, and thus the developmental cycle of this bacterium [28]. Pieri and colleagues described new ianthelliformisamine B and C (7, 8) from the marine sponge Suberea ianthelliformis as antibiotic enhancers against resistant Gram-negative bacteria by a mechanism described as "altered proton homeostasis", and thus probably affecting drug transport [29]. Huang and colleagues showed that the antimicrobial peptide pardaxin (9) isolated from the Red sea flatfish Pardachirus marmoratus protected mice from a lethal dose of methicillin-resistant Staphylococcus aureus, while also accelerating wound healing, increasing monocytes' and macrophages' recruitment, as well as expression of vascular endothelial growth factor [30]. Eom and colleagues described the mechanism of antibacterial activity of the phlorotannin phlorofucofuroeckol-A (10) isolated from the edible brown alga Eisenia bicyclis, which was shown to involve suppression of several mec operon genes in methicillin-resistant Staphylococcus aureus as well as the production of penicillin-binding protein 2a, considered as the "primary cause of methicillin resistance" [31]. Hassan and colleagues reported a new depsipeptide salinamide F (11), isolated from a marine-derived Streptomyces sp. strain CNB-091 that was observed to significantly inhibit RNA polymerase (RNAP) from both Gram-positive and Gram-negative bacteria, but "does not interact with the rifampin binding site on RNAP" [32].
As shown in Table 1 and Figure 1, three reports described antifungal marine chemicals with novel mechanisms of action. Lee and colleagues investigated the new macrocyclic lactone antifungal bahamaolide A (65) isolated from the culture of marine actinomycete Streptomyces sp. CNQ343 [72]. Detailed studies determined that the compound inhibited isocitrate lyase (ICL) mRNA expression, suggesting it might be used for treatment of "C. albicans infections via inhibition of ICL activity". Sugiyama and colleagues characterized the biological activity of the polyene macrolactam heronamide C (66) isolated from a marine-derived Streptomyces sp. [73]. The heronamide C was shown to induce abnormal cell wall morphology by "perturbing membrane microdomains". Wyche and colleagues reported a novel marine-derived polyketide forazoline A (67) isolated from an Actinomadura sp. strain WMMB-499 cultivated from the ascidian Ecteinascidia turbinata [74]. Using chemical genomics, the authors proposed forazoline A worked in vivo in mice against the fungus Candida albicans by affecting cell membrane integrity by a "novel mechanism of action from known antifungal agents".
Malaria, a global disease caused by protozoan genus Plasmodium (P. falciparum, P. ovale, P. vivax and P. malariae), currently affects over 2 billion people worldwide. Contributing to the global search for novel antimalarial drugs, and as presented in Table 1, 11 marine molecules (84-94) isolated from bacteria, molluscs, sponges, and soft corals were shown during 2014-2015 to possess antimalarial activity. Young and colleagues reported a detailed mechanistic study with the marine sesquiterpene isonitrile 7,20-diisocyanoadociane (84) originally isolated from the marine sponge Cymbastela hooperi [87], demonstrating that it inhibited β-hematin (IC 50 = 13nM), and thus interfered with the parasite's heme detoxification pathway.
As shown in Table 1 and Figure 1, thirteen marine compounds (95-107) isolated from bacteria, fungi, sponges, and soft corals were reported to possess bioactivity towards the so-called neglected protozoal diseases: leishmaniasis, caused by the genus Leishmania (L.); amebiasis, trichomoniasis, as well as African sleeping sickness (caused by Trypanosoma (T.) brucei rhodesiense and T. brucei gambiense), and American sleeping sickness or Chagas disease (caused by T. cruzi). Table 1, two reports described two antitrypanosomal marine chemicals (95,96) as well as their mechanisms of action. Oli and colleagues examined the mode of action of plakortide E (95), isolated from the sponge Plakortis halichondrioides, and demonstrated that it inhibited activity of T. brucei by a non-competitive, covalent or "mechanisms leading to slow-binding", reversible inhibition of the parasite's enzyme rhodesain [95]. Santos and colleagues extended the pharmacology of guanidine and pyrimidine alkaloids from the Brazilian marine sponge Monanchora arbuscula, and reported that batzelladine L (96) affected both trypomastigotes of T. cruzi and L. infantum promastigotes, demonstrating that several mechanisms including altered plasma membrane permeability, mitochondrial membrane depolarization, and increased reactive oxygen species, probably contributing to "parasite cell death" [96].

As shown in
As shown in Table 1 and Figure 1, eleven additional marine natural products (97-107) exhibited antileishmanial and antiprotozoal activity, although their mechanisms of action remained undetermined. Abdelmohsen and colleagues reported that a new O-glycosylated angucycline actinosporin A (97), isolated from a culture of Actinokineospora sp. strain EG49 cultivated from a Red sea sponge Spheciospongia vagabunda, moderately inhibited the growth of T. brucei brucei [97]. Thao and colleagues isolated the terpenoid astropectenol A (98) from a Vietnamese marine sea star Astropecten polyacanthus, and observed significant activity against T. cruzi and T. brucei brucei [98]. Viegelmann and colleagues identified a new saringosterol derivative (99) from the Irish marine sponge Haliclona simulans, which demonstrated antitrypanosomal activity against T. brucei brucei [99]. Using genome-directed lead discovery, Schulze and colleagues contributed a novel polyene macrolactam lobosamide A (100) from a marine actinobacterium Micronospora sp. that was highly active towards the parasite T. brucei brucei, "likely via a parasite-specific mechanism" that remained undetermined [100]. Thao and colleagues assessed the cembranoid diterpenes lobocrasols A and C (101, 102), and crassumols D and E (104, 105), isolated from several Vietnamese soft corals, and noted that they displayed potent activity against L. donovani amastigotes and T. brucei rhodesiense, respectively [90]. Nakashima and colleagues found a new cyclopentadecane antibiotic mangromicin A (103) separated from the culture broth of the fungus Lechevalieria aerocolonigenes K10-0216 isolated from a Japanese mangrove sediment with potent activity against T. brucei brucei strain GUTat 3.1 [101]. Yang and colleagues characterized a new scalarane sesterterpene sesterstamide (106) isolated from the Paracel islands marine sponge Hyrtios sp. that moderately inhibited L. donovani promastigotes [102]. Von Salm and colleagues contributed a novel tricyclic sesquiterpenoid shagene A (107) from an "undescribed" soft coral collected from the "Scotia Arc in the Southern Ocean" that was moderately active against L. donovani [103].
Drug-resistant strains of the intracellular pathogen Mycobacterium tuberculosis have stimulated a search for novel drug leads with novel mechanisms of action, and, as shown in Table 1 and Figure 1, five novel marine natural products (108-112) isolated from sponges and fungi evidenced promising activity, and thus contributed to the ongoing global search for novel antituberculosis agents during 2014-2015.
Arai and colleagues identified a novel aaptamine class alkaloid, 2-methoxy-3-oxoaaptamine (108), from a marine sponge Aaptos sp. that demonstrated strong inhibitory activity against M. smegmatis in "both active growing and dormancy-inducing hypoxic conditions" [104]. Daletos and colleagues isolated cyclic peptides callyaerins A and B (109,110), from the Indonesian sponge Callyspongia aerizusa, that demonstrated potent antibacterial activity against M. tuberculosis, highlighting the "potential of these compounds as promising anti-TB agents" [105]. Kumar and colleagues established that a new diarylpyrrole alkaloid denigrin C (111) from an extract of the Indian marine sponge Dendrilla nigra exhibited strong M. tuberculosis H 37 Rv activity "with a probable novel mechanism needed for antitubercular drug design . . . " [106]. Lin and colleagues characterized a racemic, prenylated polyketide dimer, oxazinin A (112) from a filamentous fungus isolated from the Papua New Guinea ascidian Lissoclinum patella, which showed activity against M. tuberculosis with modest activity towards human transient receptor potential channels [107].
As shown in Table 1, five reports described antiviral marine chemicals and their mechanisms of action. González-Almela and colleagues extended the pharmacology of pateamine A (113), isolated from the marine sponge Mycale sp. by demonstrating that the compound affected the translation of genomic and subgenomic mRNAs from Sindbis virus, although "subgenomic mRNA translation (was) more resistant to pateamine A inhibition" [108]. León and colleagues identified abyssomicin 2 (114) from a marine-derived actinobacterium Streptomyces sp. that reactivated human immunodeficiency virus type-1 (HIV-1) by a protein kinase C and histone deacetylase-independent mechanism that "remains to be elucidated" [109]. Karadeniz and colleagues reported that the anti-HIV activity of the phlorotannin derivative 8,4"'-dieckol (115) from the Korean brown alga Ecklonia cava included the "ability to act against drug-resistant HIV-1 strains" by a mechanism that involved inhibition of cytopathic effects, as well as inhibition of HIV-1 reverse transcriptase enzyme [110]. Zhao and colleagues established that truncateol M (116) isolated from a culture of the sponge-associated fungus Truncatella angustata demonstrated potent activity against influenza A infections by a mechanism that targeted the virion assembly and release step, putatively becoming "a model structure of antiviral lead for further modification" [111]. Chen and colleagues determined that the alkaloid neoechinulin B (117) isolated from the marine-derived fungus Eurotium rubrum showed potent inhibition of H1N1 influenza A virus by binding to the influenza virion envelope hemagglutin, thus "disrupting its interaction with the sialic acid receptor" on host cells [112].
An additional 15 marine natural products (118)(119)(120)(121)(122)(123)(124)(125)(126)(127)(128)(129)(130)(131)(132), listed in Table 1 and shown in Figure 1, demonstrated antiviral activity, but the mechanism of action of these compounds remained undetermined at the time of publication. Li and colleagues isolated a novel khayanolide, thaixylomolin I (118) from the seeds of the Trang (South Thailand) mangrove plant Xylocarpus moluccensis, which inhibited potent activity against influenza virus strain H1N1 [113]. Chen and colleagues contributed a new prenylated dihydroquinolone derivative 22-O-(N-Me-L-valyl)-21-epi-aflaquinolone B (119), produced by the mycelia of an Aspergillus sp. fungus derived from a South China Sea gorgonian Muricella abnormaliz, that inhibited respiratory syncytial virus influenza A virus H1N1 "with a high therapeutic ratio" [114]. Nong and colleagues found that two novel lactones territrem D and arisugacin A (120, 121) from a fungus Aspergillus terreus SCSGAF0162 derived from a South China sea gorgonian Echinogorgia aurantiaca exhibited HSV-1 activity "under non-cytotoxic concentrations" [115]. Li and colleagues isolated a novel isoindolinone-type alkaloid chartarutine B (122) from the marine sponge-associated fungus Stachybotrys chartarum, which displayed moderate inhibitory activity HIV-1, noting that "side chain variation directly affected the inhibitory effects" [116]. Gupta and colleagues purified debromoaplysiatoxin (123) from the marine Singaporan cyanobacterium Trichodesmium erythraeum, which inhibited Chikungunya virus with "minimal cytotoxicity", and probably targeted the viral replication cycle after "viral entry" [117]. Pardo-Vargas and colleagues reported that the new diterpene dolabelladienol A (124) isolated from the Brazilian marine brown alga Dictyota pfaffii had potent activity against HIV-1 and, owing to "low cytotoxicity", appeared to be a "promising anti-HIV-1 agent" [118]. Cheng and colleagues noted that one of the dolastane diterpenes isolated from the South China sea brown alga Dictyota plectens, namely 13-deacetoxyamijidictyol (125), showed inhibitory activity against wild-type HIV-1 replication, thus proposing that "Dictyota algae may be a potential source of antiviral lead compounds" [119]. Yamashita and colleagues investigated the effect of two polybrominated diphenyl ethers (22,23) isolated from the Indonesian marine sponge Dysidea granulosa on the hepatitis B virus (HBV) core promoter activity, as well as the production of HBV DNA, suggesting that they may become "candidate lead compounds for the development of anti-HBV drugs" [120].
Cao and colleagues discovered that a new steroid echrebsteroid C (126) from the South China sea gorgonian Echinogorgia rebekka evidenced high activity against respiratory syncytial virus, a common cause of lower respiratory tract disease in infants and children, as well as a high therapeutic index, thus "suggesting it might be useful as a potential antiviral agent" [121]. Jia and colleagues showed that one of two enantiomeric dimers, namely (+)-pestaloxazine A (127), isolated from a Pestalotiopsis sp. fungus derived from a soft coral, showed potent antiviral activity towards enterovirus 71, a small, single-stranded RNA virus that may cause hand, foot, and mouth disease associated with neurological complications in children and infants [122]. Eom and colleagues evaluated phlorofucofuroeckol-A (10), isolated from the edible brown alga Eisenia bicyclis against murine norovirus, a leading cause of gastroenteritis, noting that, because of its strong anti-norovirus activity and high therapeutic index, it appeared "phlorotannins could be used as a potential source of natural antiviral agents" [123]. Cheng and colleagues discovered a new seco-cembranoid secocrassumol (128) from the marine soft coral Lobophytum crassum, which showed significant activity against human cytomegalovirus, a common herpesvirus infection in humans [124]. Using ligand-based pharmacophore mapping, Dineshkumar and colleagues demonstrated that the polycyclic macrolide sporolide B (129) isolated from the marine actinomycete Salinispora tropica showed significant inhibition of the HIV-1 reverse transcriptase, and thus "could be a possible drug candidate for HIV" [125]. Shin and colleagues isolated two new depsipeptides stellettapeptins A and B (130,131) from an extract of the Australian marine sponge Stelletta sp. with significant HIV-inhibitory properties, suggesting that "this class of peptides may hold promise as anti-HIV agents" [126]. Sun and colleagues characterized a new tetramic acid derivative trichobotrysin A (132) isolated from the culture of South China sea Trichobotrys effuse DFFSCS021 that inhibited herpes simplex virus type-1, responsible for lifelong oral infections in humans [127].

Anthelmintic Activity
As shown in Table 1, only one report was published during 2014-2015 on the anthelmintic pharmacology of marine natural products. Farrugia and colleagues isolated a 6-N-acyladenine alkaloid, phorioadenine A (133), from the southern Australian marine sponge Phoriospongia sp., which displayed " . . . nematocidal activity against H. contortus . . . slightly weaker than commercial anthelmintics levamisole and closantel", perhaps suggesting that this compound may become a promising lead compound for the development of new anthelmintics [128]. Table 2 presents the 2014-2015 preclinical pharmacology of marine chemicals , which demonstrated either antidiabetic or anti-inflammatory activity, as well as affected the immune or nervous system, and whose structures are depicted in Figure 2.                (198) 6-bromohypaphorine (199) piscidin

Antidiabetic Activity
As shown in Table 2 and Figure 2, four publications reported on the mode of action of marinederived antidiabetic compounds (10, 134-136). Kang and colleagues contributed to the pharmacology of diabetes by noting that the marine carotenoid fucoxanthin (134), isolated from the marine brown alga Ishige okamurae, protected cells and organs from oxidative damage induced by high glucose both in vitro and in vivo, concluding that "fucoxanthin may prove to be an effective mediator to control oxidative stress in hyperglycemia" [155]. Maeda and colleagues observed that fucoxanthin and its metabolite, fucoxanthinol (135), improved obesity-induced inflammation in adipocyte cells with concomitant suppression of tumor necrosis factor-α and monocyte chemotactic protein-1 RNA expression, thus concluding that fucoxanthin "ameliorates glucose tolerance in the diabetic mice model" [154]. Lee and colleagues reported that octaphlorethol A (136) isolated from the marine brown alga Ishige foliacea showed a potent anti-hyperglycemic effect in mice by potently binding to α-glucosidase, an enzyme that plays a role in blood glucose control, thus demonstrating its potential use "for treatment of type 2 diabetes mellitus" [156]. You and colleagues showed that the phlorotannin phlorofucofuroeckol-A (10) isolated from the brown alga Ecklonia cava alleviated postprandial hyperglycemia in diabetic mice by a mechanism that involved significant inhibition of α-glucosidase and α-amylase, thus proposing this natural product "as a nutraceutical for diabetic individuals" [157].
An additional six marine natural products (137)(138)(139)(140)(141)(142), listed in Table 2 and shown Figure 2, demonstrated antidiabetic activity, but the mechanism of action of these compounds remained undetermined at the time of publication. Safavi-Hemami and colleagues described a specialized insulin Con-Ins G1 (137) used for chemical warfare by the fish-hunting cone snail Conus geographus,

Antidiabetic Activity
As shown in Table 2 and Figure 2, four publications reported on the mode of action of marine-derived antidiabetic compounds (10, 134-136). Kang and colleagues contributed to the pharmacology of diabetes by noting that the marine carotenoid fucoxanthin (134), isolated from the marine brown alga Ishige okamurae, protected cells and organs from oxidative damage induced by high glucose both in vitro and in vivo, concluding that "fucoxanthin may prove to be an effective mediator to control oxidative stress in hyperglycemia" [155]. Maeda and colleagues observed that fucoxanthin and its metabolite, fucoxanthinol (135), improved obesity-induced inflammation in adipocyte cells with concomitant suppression of tumor necrosis factor-α and monocyte chemotactic protein-1 RNA expression, thus concluding that fucoxanthin "ameliorates glucose tolerance in the diabetic mice model" [154]. Lee and colleagues reported that octaphlorethol A (136) isolated from the marine brown alga Ishige foliacea showed a potent anti-hyperglycemic effect in mice by potently binding to α-glucosidase, an enzyme that plays a role in blood glucose control, thus demonstrating its potential use "for treatment of type 2 diabetes mellitus" [156]. You and colleagues showed that the phlorotannin phlorofucofuroeckol-A (10) isolated from the brown alga Ecklonia cava alleviated postprandial hyperglycemia in diabetic mice by a mechanism that involved significant inhibition of α-glucosidase and α-amylase, thus proposing this natural product "as a nutraceutical for diabetic individuals" [157].
An additional six marine natural products (137)(138)(139)(140)(141)(142), listed in Table 2 and shown Figure 2, demonstrated antidiabetic activity, but the mechanism of action of these compounds remained undetermined at the time of publication. Safavi-Hemami and colleagues described a specialized insulin Con-Ins G1 (137) used for chemical warfare by the fish-hunting cone snail Conus geographus, which appear to have "evolved to act rapidly and potently to cause severe hypoglycemia" [158].
Yamazaki and colleagues found that the sesquiterpene dehydroeuryspongin A (138) isolated from the Japanese marine sponge Euryspongia sp. inhibited the protein tyrosine phosphatase 1B, considered a key enzyme involved in type II diabetes and obesity because it plays a role in the dephosphorylation of insulin and leptin receptors [159]. Xia and colleagues contributed a new isopimarane diterpene (139) isolated from the culture of the fungus Epicoccum sp. associated with the marine sea cucumber Apostichopus japonicus that potently inhibited α-glucosidase [160]. Shin and colleagues isolated a new benzothioate glycoside suncheonoside A (140) from a Korean marine-derived Streptomyces strain that promoted adiponectin production during adipogenesis in vitro, thus "suggesting antidiabetic potential" [161]. You and colleagues reported that the lumazine-containing peptide terrelumamide A (141), isolated from the culture broth of the Korean marine-derived fungus Aspergillus terreus, improved insulin sensitivity and adiponectin production in an in vitro human adipogenesis model [162]. He and colleagues characterized a polyunsaturated lipid (142) from the Chinese marine sponge Xestospongia testudinaria, which was shown to inhibit protein tyrosine phosphatase 1B, considered as a significant target for the "treatment of type II diabetes and obesity" [163].

Anti-Inflammatory Activity
As shown in Table 2 and Figure 2, there was a remarkable increase in anti-inflammatory pharmacology of marine compounds  during 2014-2015. The molecular mechanism of action of marine natural products  was assessed in both in vitro and in vivo preclinical pharmacological studies in twenty-two papers that used several in vitro models: the murine RAW 264.7 macrophages, a human keratinocyte cell line, a human hepatocarcinoma HepG2 cell line, primary rat brain microglia, and a murine microglia BV-2 cell line.
Taira and colleagues evaluated the anti-inflammatory properties of alcyonolide and its congener (143,144), isolated from the Okinawan soft coral Cespitularia sp. in lipopolysaccharide (LPS)-stimulated RAW264.7, observing inhibition of NO as well as gene expression of the proinflammatory genes inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 mRNA [164]. Guo and colleagues extended the pharmacology of the terpenoid astaxanthin (145) by reporting that a reduction of oxidative stress in an in vivo model of rat burn injury was concomitant with a decrease in the level of malondialdehyde, an indicator of lipid peroxidation, as well as an increase of antioxidant enzymes superoxide dismutase and catalase, a "protective effect" that held "potential as a new drug treatment of severely burned patients . . . " [165]. Yang and colleagues reported that the polyketide 8, 8 -bieckol (146), isolated from the edible marine brown alga Ecklonia cava, significantly inhibited both pro-inflammatory NO, prostaglandin E 2 (PGE 2 ), and interleukin 6 (IL-6) production, as well as gene expression by downregulating NF-κB signaling pathway and ROS accumulation in both LPS-stimulated primary macrophages and RAW 264.7 macrophages, thus demonstrating the compound's "anti-inflammatory potential . . . in systemic inflammatory conditions such as sepsis" [166]. Fernandes and colleagues studied convolutamydine A (147), isolated from marine bryozoan Amathia convoluta, and two synthesized analogs, and determined that they exhibited significant in vivo and in vitro anti-inflammatory activity by a mechanism that involved reduced leukocyte migration as well as inhibition of the production of the cytokine IL-6, PGE 2 , and NO [167]. Phan and colleagues isolated a new bicyclogermacrene capgermacrene A (148) from the Bornean soft coral Capnella sp. and observed significant in vitro inhibition of NO production by RAW 264.7 macrophages by inhibition of iNOS expression, proposing this compound as a "promising iNOS inhibiting agent" [168]. Jiménez-Romero and colleagues investigated the effect of the diterpene dactyloditerpenol acetate (149) extracted from the Puerto Rican tropical sea hare Aplysia dactylomela on E. coli LPS-activated rat neonatal microglia in vitro, observing the potent inhibition of both thromboxane B 2 and superoxide anion (O 2 − ) generation, proinflammatory mediators associated with neuroinflammation, concluding that the data "support further development" of this compound [169]. Two studies extended the anti-inflammatory pharmacology of dieckol (150) isolated from the brown alga Ecklonia cava: Choi and colleagues demonstrated the compound inhibited LPS-induced iNOS expression by affecting mitogen-activated protein kinases (MAPK), "significantly p38MAPK" in the mouse macrophage 264.7 cell line in vitro [170], while Kang and colleagues demonstrated that dieckol suppressed production of macrophage-derived chemokine, C-C motif chemokine 22, an inflammatory chemokine that controls leukocyte movements by down-regulating the activation of the signal transducer and activator of transcription (STAT)1 signaling pathway in human keratinocytes [171]. Lin and colleagues characterized the anti-inflammatory effects of the diterpene excavatolide B (151) isolated from the cultured Formosan marine gorgonian Briareum excavatum and observed that, in vitro, it inhibited iNOS and COX-2 mRNA expression in LPS-treated murine RAW 264.7 macrophages, while in vivo it attenuated carrageenan-induced rat paw inflammation and pain, thus concluding that "excavatolide B may serve as a useful therapeutic agent for the treatment of acute inflammation" [172]. Chen and colleagues investigated the antinociceptive properties of flexibilide (152), isolated from the Australian soft coral Sinularia flexibilis in the rat chronic injury model of neuropathic pain, observing significant analgesic effects concomitant with suppression of iNOS expression in microglia and astrocytes in the spinal dorsal horn, accompanied with upregulation of transforming growth factor-β1 (TGF-β1), "suggesting involvement of TGF-β1 in the anti-neuroinflammatory and analgesic effects" [173]. Kim and colleagues reported that a polyhydroxyflavone (153) isolated from the marine alga Hizikia fusiforme suppressed LPS-stimulated RAW 264.7 cells' release of pro-inflammatory cytokines, as well as both iNOS and COX-2 expression, by attenuating nuclear transcription factor-κB (NF-κB) translocation, and thus might become a "potential therapeutic agent for patients with, or at risk of, septic shock or other inflammatory diseases" [174]. Wijesinghe and colleagues evaluated 5β-hydroxypalisadin B (154), a brominated secondary metabolite isolated from the Malaysian marine red alga Laurencia snackeyi, on LPS-stimulated RAW 264.7 macrophages and observed significant reduction of several pro-inflammatory cytokines, NO, and PGE 2 generation, and thus concluded that the compound might help development of "an active ingredient in pharmaceutical, nutraceutical . . . " applications [175]. Huang and colleagues characterized two novel biscembranes glaucumolides A and B (155,156) from the cultured soft coral Sarcophyton glaucum that significantly inhibited O 2 generation and elastase release in human neutrophils, while also reducing expression of iNOS and COX-2 in LPS-treated murine RAW 264.7 macrophages, concluding that these two compounds "might be useful for future biomedical applications" [176]. Yu and colleagues determined that the effects of phlorofucofuroeckol-B (157), isolated from the marine alga Ecklonia stolonifera, on the decreased production of pro-inflammatory mediators by LPS-stimulated BV-2 microglia cells, as well as reduced COX-2 and iNOS expression, resulted from inhibition of the iκB-α/NF-κB and Akt/ERK/JNK pathways, thus proposing that this compound might be "considered as a therapeutic agent against neuroinflammation" [177]. Babskota and colleagues isolated a new phosphatidylglycerol (158) from an extract of the marine red alga Palmaria palmata, also commonly known as dulse, which strongly inhibited NO release from LPS treated murine RAW 264.7 macrophages, probably by a mechanism that down-regulated iNOS, thus suggesting that "consumption of dulse as a functional food may help to reduce inflammation associated with various diseases" [178].
Itoh and coleagues showed that reduced scytonemin (159) isolated from the cosmopolitan colonial cyanobacterium Nostoc commune strongly inhibited LPS and interferon-γ-induced NO production in murine macrophage RAW 264.7 macrophages, by generating reactive oxygen species by activation of the phosphatidylinositol-3-kinase/Akt and the p38 mitogen-activated protein kinase/nuclear factor erythroid 2-related factor 2 signaling pathways [179]. Lillsunde and colleagues reported that a norcembranoid sinuleptolide (160) isolated from the Indian soft coral Sinularia kavarattiensis potently modulated both morphology and release of pro-inflammatory and anti-inflammatory mediators by LPS-treated rat primary microglial cells in vitro, thus decreasing microglia activation, which has been hypothesized to be involved in the "progression of chronic neurodegenerative diseases.. and central nervous system (CNS) homeostasis" [180]. Thao and colleagues contributed a new polyhydroxylated steroid sarcopanol A (161) from the Vietnamese soft coral Sarcophyton pauciplicatum that inhibited tumor necrosis factor (TNF)-α and interferon (IFN)γ-induced expression of COX-2, iNOS, and intercellular adhesion molecule-1 (ICAM-1) in the spontaneously transformed immortal human keratinocyte cell line HaCaT via inhibition of NF-κB signaling pathway activation [181]. Thao and colleagues investigated the diterpenoid sinumaximol (162), isolated from the marine soft coral Sinularia maxima, and determined that it significantly inhibited TNF-α-induced NF-κB transcriptional activity in a human hepatocarcinoma HepG2 cell line, while concomitantly inhibiting the expression of pro-inflammatory iNOS and ICAM-1mRNA expression, thus supporting the "therapeutic potential as anti-inflammatory" of this compound [182]. Quang con colleagues determined that tanzawaic acid A (163), isolated from a marine fungus Penicillium sp. SF-6013 derived from the Pacific sea urchin Brisaster latifrons, inhibited both NO and PGE 2 production from LPS-activated murine BV-2 microglia cells and RAW 264.7 murine macrophages, while suppressing iNOS and COX-2 expression and inhibiting protein tyrosine phosphatase 1B [183].

Marine Compounds with Activity on the Immune System
As shown in Table 2 and Figure 2, the preclinical pharmacology of marine compounds that affected the immune system showed a decline, as previously reported in this series.
Kwan and colleagues reported that the peptide grassypeptolide A (192), isolated from the marine cyanobacterium Lyngbya confervoides, inhibited IL-2 production and proliferation of activated T cells by inhibiting the protease dipeptidyl peptidase 8, probably by binding at inner cavity of the enzyme at two distinct sites [208]. Wang and colleagues isolated a pair of novel bisheterocyclic quinolone-imidazole alkaloids (+)-and ( _ ) spiroreticulatine (193) from the South China sea sponge Fascaplysinopsis reticulata, which showed inhibition of IL-2 production by Jurkat T cells [209]. Kicha and colleagues determined that the cyclic steroid glycoside luzonicoside A (194), isolated from the starfish Echinaster luzonicus, potently enhanced lysosomal activity, ROS level elevation, and NO synthesis in RAW 264.7 murine macrophages, thus seeming "promising for further investigation as a potent immunomodulatory agent" [210]. Pislyagin and colleagues investigated a triterpene glycoside typicoside C 1 (195), isolated from the sea cucumber Actinocucumis typica, and observed that it demonstrated strong immunostimulatory effect on ROS formation in mouse peritoneal macrophages in vitro, with concomitant low cytotoxicity [211].
Four marine compounds were shown to bind nicotinic acetylcholine receptors (nACHR) (199,207,210) and potassium (K + ) channels (208). Kasheverov and colleagues determined the effect of 6-bromohypaphorine (6-BHP) (199), isolated from the marine nudibranch mollusk Hermissenda crassicornis, on different nAChR, demonstrating that, because 6-BHP competed with α-bungarotoxin for binding to the human α7 nAChR, it was the "first low-molecular weight compound from (a) marine source which (was) an agonist of the nACHR subtype" [215]. Bourne and colleagues conducted detailed studies to determine the molecular pharmacology of the macrocylic imine phycotoxin pinnatoxin A (207), originally isolated from the digestive glands of the mollusk Pinna attenuata, towards neuronal α7nACHR, observing that the bicyclic EF-ketal ring was a novel binding determinant for mediating polar versus non-polar interactions, and thus is able to "confer nAChR subtype selectivity . . . (of) these prevalent marine biotoxins" [223]. Rodríguez and colleagues discovered a novel peptide PhcrTx1 (208) from the sea anemone Phymanthus crucifer that inhibited voltage-gated K + ion channels, including acid-sensing ion channel (ASIC) (IC 50 = 100 nM), and that would represent "the first member of a new structural group of sea anemone toxins acting on ASIC" [224]. Aráoz and colleagues extended the pharmacology of the "fast-acting" lipophilic marine toxin 13,19-desmethyl spirolide C (210), extracted from cultures of the dinoflagellate Alexandrium ostenfeldii, defining the mode of action and molecular targets using in vitro electrophysiological experiments, and thus showing that the toxin blocked human neuronal nACHR (IC 50 = 0.2 nM) with high affinity, observations supported by molecular docking experiments "highlighting the nicotinic basis of the neurotoxicity of (this toxin) to mammal(ian) . . . .peripheral and central nervous system" [227].
Three studies extended the pharmacology of conopeptides (201)(202)(203). Wang and colleagues discovered a novel α-conotoxin Mr1.7 (201) in the venom of the marine snail Conus marmoreus that inhibited α3β2, α9α10, and α6/α3β2β3 nACHR subtypes (IC 50 = 53.1, 185.7, and 284.2 nM, respectively), noting that the PE residues at the N-terminal sequence of Mr1.7 were "important for modulating activity and selectivity" [217]. Zhou and colleagues reported the expression and sodium channel activity of peptide It16a (202), a novel framework XVI conotoxin from the M-superfamily isolated from the worm-hunting snail C. litteratus, and, using a variety of electrophysiological techniques, demonstrated that it preferentially inhibited voltage-gated Na + channels (apparent IC 50 = 1 µM) in mammalian sensory neurons, with the authors noting "It16a . . . has similar function as µ-conotoxins" [218]. Li and colleagues extended the pharmacology of Vt3.1 conotoxin (203), isolated from the venom of the marine cone snail C. vitulinus, and demonstrated that it preferentially inhibited large conductance, voltage, and Ca 2+ activated K + (BK) channels containing the β4 subunit (IC 5 = 8.5 µM), which appears to be present in brain and neuronal functions by a mechanism that required electrostatic interactions with the channel protein, making it an excellent tool "uniquely suited in neuroscience involving BK channels" [219].
Two studies reported marine compounds (198,200) that contributed to nociceptive pharmacology. Cavalcante-Silva and colleagues assessed the mechanism involved in in vivo antinociception produced by the bisindole alkaloid caulerpine (198), isolated from the marine alga Caulerpa, demonstrating that, in the in vivo murine writhing test, the effect was likely mediated by "pathways involving α2-adrenoceptors and 5-HT3 receptors", thus proposing cualerpine as a possible "dual-action analgesic drug(s)" [214]. Chen and colleagues investigated the anti-neuropathic properties of the antimicrobial peptide piscidin (200) and observed that the compound demonstrated in vivo anti-nociceptive effects in a rat model of neuropathy by a signaling mechanism that suppressed up-regulation of interleukin-1 in microglia and phosphorylated mammalian target of rapamycin in astrocytes, concluding it "may have potential for development as an alternative pain-alleviating agent" [216].
The neuroprotective activity of marine compounds (196,197,205,206,211) was reported in five studies.
Hjornevik and colleagues completed an extensive in vitro "neurotoxicological" study with the marine algal toxin azaspiracid-1 (197) and observed rat PC12 cells' differentiation-related morphological changes associated with the expression of the PC12-associated neuronal differentiation marker peripherin on neurite-like processes, suggesting this molecule "triggers a differentiation process" [213]. Yamagishi and colleagues explored the structure-activity relationship of LLG-3 (205), a ganglioside isolated from the starfish Linchia laevigata, and discovered that the methyl group at C8 of the terminal sialic acid residue was of critical significance for neuritogenic activity. Furthermore, detailed signaling studies revealed the "activation of mitogen-activated protein kinase signaling pathway" [221]. Cassiano and colleagues, using chemical proteomics, noted that the terpenoid heteronemin (206), isolated from the marine sponge Hyrtios sp., targeted TDP-43, a major component of inclusions that characterize amyotrophic lateral sclerosis and front-temporal lobar degeneration, by lowering its affinity "towards nucleic acids", and thus becoming a "relevant chemical tool in the study of TDP-43 related processes" [222]. Shimizu and colleagues provided the "first report" that the pro-electrophilic sesquiterpene zonarol (211), isolated from the Japanese brown alga Dictyopteris undulata, provided neuroprotection by activating the nuclear factor (erythroid-derived-2)-like 2/antioxidant responsive element Nrf2/ARE pathway, inducing phase-2 enzymes and providing oxidative stress protection to cerebrocortical neurons in vitro, concluding that the compound "represents a lead compound for the treatment of chronic neurodegenerative diseases associated with oxidative stress" [228].
As shown in Table 2, three marine compounds were shown to modulate other molecular targets, that is, γ-aminobutyric acid (GABA) receptor (209), and the acetylcholinesterase (204) and butyrylcholinesterase enzyme (10). Lee and colleagues discovered that the pigment echinochrome A (204), isolated from the sea urchin Scaphechinus, inhibited acetylcholinesterase (IC 50 = 16.4 µM) by an irreversible and uncompetitive mechanism that might be useful in "treating acetylcholine-limited diseases", such as Alzheimer's disease and "other forms of dementia" [220]. Eltahawy and colleagues isolated of a new ceramide (209) from the Red sea soft coral Sarcophyton auritum, which demonstrated antiepileptic activity in vivo with a central nervous system depressing mechanism that appeared to involve "GABA receptor modulation rather than serotonin receptor inhibition" [226]. Choi and colleagues reported that the polyphenol phlorofucofuroeckol-A (10), isolated from the Korean brown alga Ecklonia cava, potently inhibited butyrylcholinesterase, a novel target for Alzheimer's disease, suggesting that "phlorotannins . . . to be very promising medicinal compounds" [225].

Marine Compounds with Miscellaneous Mechanisms of Action
The 2014-2015 preclinical pharmacology of 83 marine compounds (219-300) with miscellaneous mechanisms of action is shown in Table 3, with their corresponding structures presented in Figure 3. Because, at the time of publication, a comprehensive pharmacological characterization of these compounds remained unavailable, their assignment to a particular drug class will probably require further investigation.

Reviews on Marine Pharmacology and Pharmaceuticals
In 2014-2015, several reviews covered general and/or specific areas of marine preclinical pharmacology: (a) Marine pharmacology and marine pharmaceuticals: new marine natural products and relevant biological activities published in 2014 and 2015 [311,312]; marine peptides, bioactivities and applications [313]; bioactive terpenes from marine-derived fungi [314]; bioactive marine natural products from actinobacteria with unique chemical structures [315]; Baltic cyanobacteria as a source of biologically active compounds [316]; biological targets of marine cyanobacteria natural products [317]; marine mussels as a source for bioactive compounds for human health [318]; pharmacological potential of cephalopod ink in drug discovery [319]; pharmacologically active Brazilian octocorals [320]; bioactive natural products isolated from marine microorganisms from Brazil [321]; statistical analysis of marine natural product bioactivity from 1985-2012 [322]; metagenomics and marine natural products drug discovery [323]; new horizons for selected marine natural products as drug leads [324]; marine-sourced agents in clinical and late preclinical development [325]; the global marine pharmaceutical pipeline in 2019: approved compounds and those in Phase I, II, and III of clinical development https://www.midwestern.edu/departments/marinepharmacology.xml. (b) Antimicrobial marine pharmacology: biophysical properties of anti-lipopolysaccharide antimicrobial peptides isolated from marine fish [326]; marine peptides and their anti-microbial activities [327]; marine membrane-active peptides as antimicrobials [328]; marine fungi antibacterial compounds [329]. (c) Antiviral marine pharmacology: marine natural products with antiviral potential [330]; antiviral activity in marine fungi-derived natural products [331]. (d) Antiprotozoal and antimalarial marine pharmacology: antiprotozoal activity in marine natural products isolated from marine algae [332]; marine indole alkaloids as potential leads for antiprotozoal drugs [333]; antimalarial potency of the manzamine β-carboline alkaloids [334]. (e) Immuno-and anti-inflammatory marine pharmacology: marine diterpenoids as potential anti-inflammatory agents [335]; microalgae bioactive compounds for inflammation and cancer [336]. (f) Cardiovascular and antidiabetic marine pharmacology: marinederived natural products as a source of cardiovascular protective agents [337]; antioxidant phlorotannins derived from marine algae [338]; antioxidant carotenoids isolated from marine Grampositive bacteria [339]; brown alga-derived fucoxanthin for diabetes therapy [340]; bioactive compounds from seaweed for diabetes [341]. (g) Nervous system marine pharmacology: astaxanthin as a potential neuroprotective agent [342]; origin, distribution, toxicity, and therapeutic uses of the marine neurotoxin tetrodotoxin [343]; marine natural products with neuroprotective activity [344]; marine-

Reviews on Marine Pharmacology and Pharmaceuticals
In 2014-2015, several reviews covered general and/or specific areas of marine preclinical pharmacology: (a) Marine pharmacology and marine pharmaceuticals: new marine natural products and relevant biological activities published in 2014 and 2015 [311,312]; marine peptides, bioactivities and applications [313]; bioactive terpenes from marine-derived fungi [314]; bioactive marine natural products from actinobacteria with unique chemical structures [315]; Baltic cyanobacteria as a source of biologically active compounds [316]; biological targets of marine cyanobacteria natural products [317]; marine mussels as a source for bioactive compounds for human health [318]; pharmacological potential of cephalopod ink in drug discovery [319]; pharmacologically active Brazilian octocorals [320]; bioactive natural products isolated from marine microorganisms from Brazil [321]; statistical analysis of marine natural product bioactivity from 1985-2012 [322]; metagenomics and marine natural products drug discovery [323]; new horizons for selected marine natural products as drug leads [324]; marine-sourced agents in clinical and late preclinical development [325]; the global marine pharmaceutical pipeline in 2019: approved compounds and those in Phase I, II, and III of clinical development https://www.midwestern.edu/departments/marinepharmacology.xml. (b) Antimicrobial marine pharmacology: biophysical properties of anti-lipopolysaccharide antimicrobial peptides isolated from marine fish [326]; marine peptides and their anti-microbial activities [327]; marine membrane-active peptides as antimicrobials [328]; marine fungi antibacterial compounds [329]. (c) Antiviral marine pharmacology: marine natural products with antiviral potential [330]; antiviral activity in marine fungi-derived natural products [331]. (d) Antiprotozoal and antimalarial marine pharmacology: antiprotozoal activity in marine natural products isolated from marine algae [332]; marine indole alkaloids as potential leads for antiprotozoal drugs [333]; antimalarial potency of the manzamine β-carboline alkaloids [334]. (e) Immuno-and anti-inflammatory marine pharmacology: marine diterpenoids as potential anti-inflammatory agents [335]; microalgae bioactive compounds for inflammation and cancer [336]. (f) Cardiovascular and antidiabetic marine pharmacology: marine-derived natural products as a source of cardiovascular protective agents [337]; antioxidant phlorotannins derived from marine algae [338]; antioxidant carotenoids isolated from marine Gram-positive bacteria [339]; brown alga-derived fucoxanthin for diabetes therapy [340]; bioactive compounds from seaweed for diabetes [341]. (g) Nervous system marine pharmacology: astaxanthin as a potential neuroprotective agent [342]; origin, distribution, toxicity, and therapeutic uses of the marine neurotoxin tetrodotoxin [343]; marine natural products with neuroprotective activity [344]; marine-terpenoid gracilins as promising compounds for Alzheimer's disease [345]; new marine drugs for Alzheimer's disease treatment [346]. (h) Miscellaneous molecular targets and uses: matrix metalloproteinase inhibitors isolated from edible marine algae [347]; marine natural products that targeting apoptosis signaling pathways [348]; scytonemin and emerging biomedical applications [349]; antiobesity effects of the carotenoid fucoxanthin [350]; therapeutic potential of astaxanthin [351]; pharmacological properties of marine coumarins [352].

Conclusions
The current marine pharmacology 2014-2015 review is a sequel to the marine preclinical pharmacology pipeline review series initiated in 1998 [1][2][3][4][5][6][7][8][9], and consolidates the peer-reviewed preclinical marine pharmacological literature published during 2014-2015. The global preclinical marine pharmacology research involved chemists and pharmacologists from 43 countries, namely, Australia, Austria, Bangladesh, Belgium, Brazil, Canada, China, Colombia, Costa Rica, Cuba, Denmark, Egypt, Finland, France, French Polynesia, Germany, Hungary, India, Indonesia, Ireland, Israel, Italy, Japan, Malaysia, Mexico, the Netherlands, New Zealand, Norway, Papua New Guinea, Portugal, Russian Federation, Saudi Arabia, Singapore, South Africa, South Korea, Spain, Sri Lanka, Switzerland, Taiwan, Thailand, United Kingdom, Vietnam, and the United States. Thus, during 2014-2015, the marine preclinical pharmaceutical pipeline continued to provide novel pharmacology that provided novel leads for the marine clinical pharmaceutical pipeline. As shown at the global marine pharmaceutical pipeline website, https://www.midwestern.edu/departments/marinepharmacology.xml, there are currently 9 approved marine-derived pharmaceuticals, and an additional 31 compounds are either in Phase I, II, and III of clinical pharmaceutical development.