Sponge Research Articles

Chemical Component Analysis of Marine Sponge Extract of Potentially Medicinal Based on Solvent Differences

Tracing and characterizing marine natural materials with special medicinal abilities is important to obtain new materials to enrich the diversity of drugs to treat particular diseases. The identification of the chemical components of sponges is interesting, considering the uniqueness and several other abilities possessed by sponges that are thought to have medicinal potential. Searching for chemical components in sponge extracts is suspected to contain secondary metabolic substances with medicinal potential. The study aimed to identify the chemical components of sponge extract with potential medicinal value based on differences in solvents. The first extract on the sponge Clathria (Thalysias) reinwardti Sp.1 (CTR) by maceration method using semi-polar solvents (methanol). The second extraction uses a separating funnel with two types of non-polar solvents (diethyl-ether and n-hexane). The chemical components of the three extracts were analyzed using a gas chromatography-mass spectrophotometer instrument. The identified chemical components of sponge extract generally belong to the class of free fatty acids and cholesterol. Investigation of identified compounds with medicinal value chemical components, for example, Cholestan-3.alpha.-ol, Ergosta-5, Hexadecanoic acid, 1-(2,6-Dichlorophenyl)-2-indolinone and Pyridine-3-carboxamide. Searching for chemical components with medicinal potential from sponge extracts is novelty research based on differences in solvents, a new method. Complementing the data from this research, it is necessary to carry out further and specific searches related to chemical components with medicinal properties, which can be carried out by chromatographic fractionation and testing the activity of the extract against bacteria. pathogens and parasitic fungi.

Biofouling sponges as natural eDNA samplers for marine vertebrate biodiversity monitoring

Environmental DNA (eDNA) analysis has now become a core approach in marine biodiversity research, which typically involves the collection of water or sediment samples. Yet, recently, filter-feeding organisms have received much attention for their potential role as natural eDNA samplers. While the indiscriminate use of living organisms as ‘sampling tools’ might in some cases raise conservation concerns, there are instances in which highly abundant sessile organisms may become a nuisance as biofouling on artificial marine structures. Here we demonstrate how a sea sponge species that colonizes the moorings of the world's largest curtain of hydroacoustic receivers can become a powerful natural collector of fish biodiversity information. By sequencing eDNA extracted from Vazella pourtalesii retrieved from moorings during routine biofouling maintenance, we detected 23 species of marine fish and mammals, compared to 19 and 15 species revealed by surface and bottom water eDNA respectively, and 28 species captured by groundfish survey in the surrounding area, which are more ecologically impactful and involve higher additional costs. Sponge-based species inventories proved at least as informative as those obtained by traditional survey methods, and are also able to detect seasonal differences in fish assemblages. We conclude that opportunistic sampling of marine sponge biofouling may become an efficient way to document and monitor biodiversity in our rapidly changing oceans.

Cytotoxic Activity and Molecular Docking Studies of the Fraction Containing Ergosta-14,22-dien-3-ol (3β, 5α, and 22E) from Dysidea avara Sponges

Background: Cancer is a global health burden, and the discovery of novel therapeutic agents remains a critical pursuit. Marine organisms, including sponges, have emerged as a promising source of structurally diverse natural products with potential anticancer properties. Objectives: In the present study, the cytotoxic activity of the fraction containing Ergosta-14,22-dien-3-ol (3β, 5α, and 22E), a steroid compound derived from Dysidea avara, was evaluated against Jurkat/E6-1 and Hek293 cells. Methods: Multiple analytical techniques, including column chromatography, TLC, and GC-MS, were used to isolate and identify the compound from marine sponges from the Persian Gulf. The XTT assay determined the cytotoxic activity and western blot for P53 expression in the Jurkat/ E6-1 cell line. The compound was also docked within the poly (ADP-ribose) polymerase-1 (PARP1) and E3 ubiquitin-protein ligase (MDM2) to investigate its potential mechanism of action. Furthermore, the pharmacological properties of the compound were predicted using PerADME, SwissADME, and Molinspiration tools. Results: The results showed that Ergosta-14,22-dien-3-ol (3β, 5α, and 22E) exhibited significant cytotoxic activity against Jurkat/E6-1 cells with an IC50 of 26.59 μg/mL. Western blotting analysis demonstrated a noticeable increase in the expression of P53 protein in cells treated with 50 and 100 µg/mL of the compound. In silico analysis revealed adequate binding energy against PARP1 and E3 MDM2 receptors. The compound also demonstrated favorable pharmacokinetic characteristics, specifically in absorption, distribution, metabolism, and excretion (ADME). Conclusions: Ergosta-14,22-dien-3-ol (3β, 5α, and 22E) has the potential to be developed as a promising anti-cancer agent.

Latitudinal distribution of freshwater sponge species across European Russia

This study provides original faunistic data on freshwater sponge dispersal across a huge territory of European Russia from north to south, highlighting the northern limits of thermophilic and north-adapted species. The holarctic species Ephydatia muelleri and, especially, Spongilla lacustris were predominant in northern areas, while the cosmopolitan Ephydatia fluviatilis and Eunapius fragilis were less prevalent. Moving to the south, E. fluviatilis took the lead. The distributional pattern of northern sponges aligns with literature data from North Europe, confirming the prevalence of the holarctic species in high latitudes. Tubella (=Trochospongilla) horrida, Eunapius carteri, and Radiospongilla cerebellata are considered to be thermophilic species that could not tolerate the conditions in northern regions. Notable findings include the extension of Eunapius carteri's known range and the first report of R. cerebellata within Russia, which is also the second record for Europe. Three potentially expected species were not found in the studied area, indicating regional rarity. We also provide molecular and morphological evidence for the synonymy of Spongilla arctica and Spongilla lacustris. Finally, we discuss the impacts of climate change and agricultural activities on northern and southern sponge habitats respectively.

3D printed scaffolds of biosilica and spongin from marine sponges: analysis of genotoxicity and cytotoxicity for bone tissue repair.

Biosilica (BS) and spongin (SPG) from marine sponges are highlighted for their potential to promote bone regeneration. Moreover, 3D printing is introduced as a technology for producing bone grafts with optimized porous structures, allowing for better cell attachment, proliferation, and differentiation. Thus, this study aimed to characterize the BS and BS/SPG 3D printed scaffolds and to evaluate the biological effects in vitro. The scaffolds were printed using an ink containing 4 wt.% of sodium alginate. The physicochemical characteristics of BS and BS/SPG 3D printed scaffolds were analyzed by SEM, EDS, FTIR, porosity, evaluation of mass loss, and pH measurement. For in vitro analysis, the cellular viability of the MC3T3-E1 cell lineage was assessed using the AlamarBlue® assay and confocal microscopy, while genotoxicity and mineralization potential were evaluated through the micronucleus assay and Alizarin Red S, respectively. SEM analysis revealed spicules in BS, the fibrillar structure of SPG, and material degradation over the immersion period. FTIR indicated peaks corresponding to silicon oxide in BS samples and carbon oxide and amine in SPG samples. BS-SPG scaffolds exhibited higher porosity, while BS scaffolds displayed greater mass loss. pH measurements indicated a significant decrease induced by BS, which was mitigated by SPG over the experimental periods. In vitro studies demonstrated the biocompatibility and non-cytotoxicity of scaffold extracts. .Also, the scaffolds promoted cellular differentiation. The micronucleus test further confirmed the absence of genotoxicity. These findings suggest that 3D printed BS and BS/SPG scaffolds may possess desirable morphological and physicochemical properties, indicating in vitro biocompatibility.

Ocean Acidification: Effects on Sponges

Approximately 30% of the carbon dioxide (CO2) released into the atmosphere has been absorbed by the world’s oceans. As CO2 emissions increase due to human activities so does the amount of CO2 absorbed by the oceans. Carbon dioxide lowers the pH of the ocean system, causing ocean acidification (OA). The effects of OA on economically and ecologically important aquatic species is a subject of interest. Sponges are important reef-associated species that provide shelter for fish and crustaceans in reef habitats and can also structure ecosystems through bioerosion, water filtration, and colonization of coral reef areas. This publication considers the effects of OA on marine sponges, with a focus on Florida’s coral reef.

Irciniaplysins A-D: New Psammaplysin Derivatives from Philippine Marine Sponge Ircinia sp.

Four new psammaplysin derivatives (1-4) with fatty acyl substituents, designated irciniaplysins A-D, and three known psammaplysins (5-7) were isolated from a marine sponge Ircinia sp. Their structures were elucidated using extensive spectroscopic analyses. The positions of the double bonds and the branch points of the fatty acyl side chains were determined by GC-MS analysis of their fatty acid methyl ester (FAME) derivatives. Irciniaplysins A (1) and B (2) contained an unusual long-chain fatty acyl substituent with a 5,9-diene unit. The isolated compounds were evaluated for their cytotoxic activity against the human colorectal carcinoma (HCT 116) cells, however, none of these compounds showed significant activity.

Halenaquinol Blocks Staphylococcal Protein A Anchoring on Cell Wall Surface by Inhibiting Sortase A in Staphylococcus aureus.

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (1-6) were isolated from the marine sponge Xestospongia sp., and their structures were elucidated using spectroscopic techniques and by comparing them to previously reported data. Among them, halenaquinol (2) was found to be the most potent SrtA inhibitor, with an IC50 of 13.94 μM (4.66 μg/mL). Semi-quantitative reverse transcription PCR data suggest that halenaquinol does not inhibit the transcription of srtA and spA, while Western blot analysis and immunofluorescence microscopy images suggest that it blocks the cell wall surface anchoring of SpA by inhibiting the activity of SrtA. The onset and magnitude of the inhibition of SpA anchoring on the cell wall surface in S. aureus that has been treated with halenaquinol at a value 8× that of the IC50 of SrtA are comparable to those for an srtA-deletion mutant. These findings contribute to the understanding of the mechanism by which marine-derived pentacyclic polyketides inhibit SrtA, highlighting their potential as anti-infective agents targeting S. aureus virulence.

A Screening of 10,240 NatureBank Fractions Identifies Nematicidal Activity in Agelasine-Containing Extracts from Sponges.

Nematode infections affect a fifth of the human population, livestock, and crops worldwide, imposing a burden to global public health and economies, particularly in developing nations. Resistance to commercial anthelmintics has increased over the years in livestock infections and driven the pursuit for new drugs. We herein present a rapid, cost-effective, and automated assay for nematicide discovery using the free-living nematode Caenorhabditis elegans to screen a highly diverse natural product library enriched in bioactive molecules. Screening of 10,240 fractions obtained from extracts of various biological sources allowed the identification of 7 promising hit fractions, all from marine sponges. These fractions were further assayed for nematicidal activity against the sheep nematode parasite Haemonchus contortus and for innocuity in zebrafish. The most active extracts against parasites and innocuous toward vertebrates belong to two chemotypes. High-performance liquid chromatography (HPLC) coupled with nuclear magnetic resonance (NMR) revealed that the most abundant compound in one chemotype is halaminol A, an aminoalcohol previously identified in a small screen against H. contortus. Terpene-nucleotide hybrids known as agelasines predominate in the other chemotype. This study reinforces the power of C. elegans for nematicide discovery from large collections and the potential of the chemical diversity derived from marine invertebrate biota.

Dynamics, diversity, and roles of bacterial transmission modes during the first asexual life stages of the freshwater sponge Spongilla lacustris

BackgroundSponge-associated bacteria play important roles in the physiology of their host, whose recruitment processes are crucial to maintain symbiotic associations. However, the acquisition of bacterial communities within freshwater sponges is still under explored. Spongilla lacustris is a model sponge widely distributed in European rivers and lakes, producing dormant cysts (named gemmules) for their asexual reproduction, before winter. Through an in vitro experiment, this study aims to describe the dynamics of bacterial communities and their transmission modes following the hatching of these gemmules.ResultsAn overall change of bacterial β-diversity was observed through the ontology of the juvenile sponges. These temporal differences were potentially linked, first to the osculum acquisition and the development of a canal system, and then, the increasing colonization of the Chlorella-like photosymbionts. Gemmules hatching with a sterilized surface were found to have a more dispersed and less diverse microbiome, revealing the importance of gemmule epibacteria for the whole holobiont stability. These epibacteria were suggested to be vertically transmitted from the maternal tissues to the gemmule surface. Vertical transmission through the incorporation of bacterial communities inside of the gemmule, was also found as a dominant transmission mode, especially with the nitrogen fixers Terasakiellaceae. Finally, we showed that almost no ASVs were shared between the free-living community and the juveniles, suggesting that horizontal recruitment is unlikely to happen during the first stages of development. However, the free-living bacteria filtered are probably used as a source of nutrients, allowing an enrichment of copiotrophic bacteria already present within its microbiome.ConclusionsThis study brings new insight for a better understanding of the microbiome acquisition during the first stages of freshwater sponge development. We showed the importance of epibacterial communities on gemmules for the whole holobiont stability, and demonstrated the near absence of recruitment of free-living bacteria during the first stages.

Marcytoglobosins A and B, Cytochalasans From a Marine Sponge Associated Chaetomium globosum 162105 Fungus.

Two new cytochalasans, marcytoglobosins A (1) and B (2) were isolated from the marine sponge associated fungus Chaetomium globosum 162105, along with six known compounds (3-8). The complete structures of two new compounds were determined based on 1D/2D NMR and HR-MS spectroscopic analyses coupled with ECD calculations. All eight isolates were evaluated for their antibacterial activity. Among them, compounds 3-8 displayed antibacterial effects against Staphylococcus epidermidis, Bacillus thuringiensis, Pseudomonas syringae pv. Actinidiae, Vibrio alginolyticus, and Edwardsiella piscicida with minimum inhibitory concentration (MIC) values ranging from 10 to 25 μg/mL.

Previously unknown diversity: the marine sponge (Porifera) fauna from Rio Grande do Norte State, NE Brazil

Previously unknown diversity: the marine sponge (Porifera) fauna from Rio Grande do Norte State, NE Brazil

Engineered bacteria that self-assemble "bioglass" polysilicate coatings display enhanced light focusing.

Photonic devices are cutting-edge optical materials that produce narrow, intense beams of light, but their synthesis typically requires toxic, complex methodology. Here we employ a synthetic biology approach to produce environmentally-friendly, living microlenses with tunable structural properties. We engineered Escherichia coli bacteria to display the silica biomineralization enzyme silicatein from aquatic sea sponges. Our silicatein-expressing bacteria can self-assemble a shell of polysilicate "bioglass" around themselves. Remarkably, the polysilicate-encapsulated bacteria can focus light into intense nanojets that are nearly an order of magnitude brighter than unmodified bacteria. Polysilicate-encapsulated bacteria are metabolically active for up to four months, potentially allowing them to sense and respond to stimuli over time. Our data demonstrate that engineered bacterial particles have the potential to revolutionize the development of multiple optical and photonic technologies.

Chemical and Biological Characterization of the Ethyl Acetate Fraction from the Red Sea Marine Sponge Hymedesmia sp.

Hymedesmiidae is one of the largest families of marine sponges and stands out as an exceptional source of variable metabolites with diverse biological activities. In this study, the ethyl acetate fraction (HE) of a Hymedesmia sp. marine sponge from the Red Sea, Egypt, was analyzed for the first time using Ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis. The analysis tentatively identified 29 compounds in this fraction, including the isolation and identification of six compounds (two pyrimidine nucleosides, one purine, and two pyrimidine bases in addition to one cerebroside) for the first time. The structures of the isolated compounds were established by 1D and 2D NMR (nuclear magnetic resonance), MS (mass spectrometry), and IR (infrared) spectroscopy. Furthermore, the cytotoxic, antioxidant, and antimicrobial activities of the ethyl acetate fraction were evaluated in vitro. The fraction exhibited strong DPPH scavenging activity with an IC50 of 78.7 µg/mL, compared to ascorbic acid as a positive control with an IC50 of 10.6 µg/mL. It also demonstrated significant cytotoxic activity with IC50 values of 13.5 µg/mL and 25.3 µg/mL against HCT-116 and HEP-2 cell lines, respectively, compared to vinblastine as a positive control with IC50 values of 2.34 µg/mL and 6.61 µg/mL against HCT-116 and HEP-2, respectively. Additionally, the ethyl acetate fraction displayed promising antibacterial activity against S. aureus with a MIC value of 62.5 µg/mL, compared to ciprofloxacin as a positive control with MIC values of 1.56 µg/mL for Gram-positive bacteria and 3.125 µg/mL for Gram-negative bacteria. It also exhibited activity against E. coli and P. aeruginosa with MIC values of 250 µg/mL and 500 µg/mL, respectively. Briefly, this is the first report on the biological activities and secondary metabolite content of the ethyl acetate fraction of Hymedesmia sp. marine sponge, emphasizing the potential for further research against resistant bacterial and fungal strains, as well as different cancer cell lines. The ethyl acetate fraction of Hymedesmia sp. is a promising source of safe and unique natural drugs with potential therapeutic and pharmaceutical benefits.

Red Sea Sponge Callyspongia siphonella Extract Induced Growth Inhibition and Apoptosis in Breast MCF-7 and Hepatic HepG-2 Cancer Cell Lines in 2D and 3D Cell Cultures.

The increasing incidence of cancer diseases necessitates the urgent exploration of new bioactive compounds. One of the trends in drug discovery is marine sponges which is gaining significant support due to the abundant production of natural pharmaceutical compounds obtained from marine ecosystems. This study evaluates the anticancer properties of an organic extract from the Red Sea sponge Callyspongia siphonella (C. siphonella) on HepG-2 and MCF-7 cancer cell lines. C. siphonella was collected, freeze-dried, and extracted using a methanol-dichloromethane mixture. The extract was analyzed via Liquid Chromatography-Mass Spectrometry. Cytotoxic effects were assessed through cell viability assays, apoptosis detection, cell cycle analysis, mitochondrial membrane potential assays, scratch-wound healing assays, and 3D cell culture assays. Fifteen compounds were identified in the C. siphonella extract. The extract showed moderate cytotoxicity against MCF-7 and HepG-2 cells, with IC50 values of 35.6 ± 6.9 μg/mL and 64.4 ± 8 μg/mL, respectively, after 48 hours of treatment. It induced cell cycle arrest at the G2/M phase in MCF-7 cells and the S phase in HepG-2 cells. Apoptosis increased significantly in both cell lines, accompanied by reduced mitochondrial membrane potential. The extract inhibited cell migration, with notable reductions after 24 and 48 hours. In 3D cell cultures, the extract had IC50 values of 5.1 ± 2 μg/mL for MCF-7 and 166.4 ± 27 μg/mL for HepG-2 after 7 days of treatment, showing greater potency in MCF-7 spheres compared to HepG-2 spheres. The anticancer activity is attributed to the bioactive compounds. The C. siphonella extract's ability to induce apoptosis, disrupt mitochondrial membrane potential, and arrest the cell cycle highlights its potential as a novel anticancer agent. Additional research is required to investigate the underlying mechanism by which this extract functions as a highly effective anticancer agent.

Multicentric retrospective study on the treatment characteristics, efficacy and safety of eribulin in Slovenian patients with breast cancer.

e13123 Background: Eribulin mesylate (eribulin) is a microtubule inhibitor and a synthetic analog of halichondrin B, a natural product isolated from the marine sponge Halichondria okadai. Eribulin was approved based on the randomized Phase 3 EMBRACE clinical trial, which showed an improvement in survival compared to chemotherapy (CT) of the physician's choice. The efficacy and safety of eribulin treatment in real-world settings has been reported in several studies: Korean and Chinese multicenter retrospective studies and a meta-analysis from 2020. Methods: We included all patients treated with eribulin between January 24, 2013 and September 14, 2022 at the Institute of Oncology Ljubljana (85.4% of patients) and University Medical Centre Maribor (14.6%). Clinical data were collected retrospectively from paper and electronic patient records. The primary endpoints were median progression-free survival (PFS), overall survival (OS), response rates and safety. We performed a descriptive statistical analysis and a survival analysis using the Kaplan-Meier method. Results: 205 patients, whose average age was 58.6 (29-88) years, were included in the study. The majority (79%) had a hormone receptor (HR+) positive tumor, 12.2% were HER2 positive and 16.6% were triple negative. 32/205 (15.6%) were primary metastatic. Of the remaining 173 patients, 160/173 (92.4%) received adjuvant therapy, of which 15% received hormone therapy, 23.1% received CT and 61.9% received both. At the start of treatment with eribulin, 84.9% had visceral tumors and 14.6% had tumors in the CNS. The median number of all treatment lines was 6 (range 2–15) and the median number of CT lines was 4 (0–13). The ECOG performance status was: 0 in 4.9%, 1 in 53.2%, 2 in 35.1% and 3 in 4.9% and 4 in 0.5% of patients. The objective response rate was 7.3% and clinical benefit was achieved in 27.3%. The median CT line in which eribulin was used was the fourth (1–10). Eribulin was used as the last CT line in half of the patients. The median PFS was 3.01 months (95% confidence interval 2.56–3.47) and the median OS was 6.68 months (95% confidence interval 5.60–7.77). Patients who received eribulin in the first 3 lines of treatment had a better OS than those who received eribulin in later lines. Adverse events (AEs) occurred in 52.7%. Eribulin therapy was discontinued due to AEs in 18.5% of patients. The most common AE was fatigue (25.9%), followed by neuropathy and neutropenia (22.9% and 18%). Conclusions: In our retrospective analysis, we found significantly worse results of treatment with eribulin than in previous studies. In our population, eribulin was used in the late stages of treatment and in older patients with poorer performance status. The proportion of patients with visceral and CNS tumors was higher. The side effects were comparable.

Identification and expression of MarCE, a marine carboxylesterase with synthetic ester-degrading activity.

Carboxylic ester hydrolases with the capacity to degrade polyesters are currently highly sought after for their potential use in the biological degradation of PET and other chemically synthesized polymers. Here, we describe MarCE, a carboxylesterase family protein identified via genome mining of a Maribacter sp. isolate from the marine sponge Stelligera stuposa. Based on phylogenetic analysis, MarCE and its closest relatives belong to marine-associated genera from the Cytophaga-Flavobacterium-Bacteroides taxonomic group and appear evolutionarily distinct to any homologous carboxylesterases that have been studied to date in terms of structure or function. Molecular docking revealed putative binding of BHET, a short-chain PET derivative, onto the predicted MarCE three-dimensional structure. The synthetic ester-degrading activity of MarCE was subsequently confirmed by MarCE-mediated hydrolysis of 2 mM BHET substrate, indicated by the release of its breakdown products MHET and TPA, which were measured, respectively, as 1.28 and 0.12 mM following 2-h incubation at 30°C. The findings of this study provide further insight into marine carboxylic ester hydrolases, which have the potential to display unique functional plasticity resulting from their adaptation to complex and fluctuating marine environmentsw.

Combined inhibition of class 1-PI3K-alpha and delta isoforms causes senolysis by inducing p21WAF1/CIP1 proteasomal degradation in senescent cells

The targeted elimination of radio- or chemotherapy-induced senescent cells by so-called senolytic substances represents a promising approach to reduce tumor relapse as well as therapeutic side effects such as fibrosis. We screened an in-house library of 178 substances derived from marine sponges, endophytic fungi, and higher plants, and determined their senolytic activities towards DNA damage-induced senescent HCT116 colon carcinoma cells. The Pan-PI3K-inhibitor wortmannin and its clinical derivative, PX-866, were identified to act as senolytics. PX-866 potently induced apoptotic cell death in senescent HCT116, MCF-7 mammary carcinoma, and A549 lung carcinoma cells, independently of whether senescence was induced by ionizing radiation or by chemotherapeutics, but not in proliferating cells. Other Pan-PI3K inhibitors, such as the FDA-approved drug BAY80-6946 (Copanlisib, Aliqopa®), also efficiently and specifically eliminated senescent cells. Interestingly, only the simultaneous inhibition of both PI3K class I alpha (with BYL-719 (Alpelisib, Piqray®)) and delta (with CAL-101 (Idelalisib, Zydelig®)) isoforms was sufficient to induce senolysis, whereas single application of these inhibitors had no effect. On the molecular level, inhibition of PI3Ks resulted in an increased proteasomal degradation of the CDK inhibitor p21WAF1/CIP1 in all tumor cell lines analyzed. This led to a timely induction of apoptosis in senescent tumor cells. Taken together, the senolytic properties of PI3K-inhibitors reveal a novel dimension of these promising compounds, which holds particular potential when employed alongside DNA damaging agents in combination tumor therapies.

Probing the Antiplasmodial Properties of Plakortinic Acids C and D: An Uncommon Pair of Marine Peroxide-Polyketides Isolated from a Two-Sponge Association of Plakortis symbiotica and Xetospongia deweerdtae Collected near Puerto Rico.

Plakortinic acids C (1) and D (2), an unseparable pair of endoperoxide polyketides isolated and purified from the symbiotic association of Caribbean Sea sponges Plakortis symbiotica-Xestospongia deweerdtae, underwent in vitro evaluation for antiplasmodial activity against the malaria parasite Plasmodium berghei using a drug luminescence assay. Initial screening at 10 µM revealed 50% in vitro parasite growth inhibition. The title compounds displayed antiplasmodial activity with an EC50 of 5.3 µM toward P. berghei parasites. The lytic activity against erythrocytes was assessed through an erythrocyte cell lysis assay, which showed non-lytic activity at lower concentrations ranging from 1.95 to 3.91 µM. The antiplasmodial activity and the absence of hemolytic activity support the potential of plakortinic acids C (1) and D (2) as promising lead compounds. Moreover, drug-likeness (ADMET) properties assessed through the pkCSM server predicted high intestinal absorption, hepatic metabolism, and volume of distribution, indicating favorable pharmacokinetic profiles for oral administration. These findings suggest the potential suitability of these metabolites for further investigations of antiplasmodial activity in multiple parasitic stages in the mosquito and Plasmodium falciparum. Notably, this study represents the first report of a marine natural product exhibiting the unique 7,8-dioxatricyclo[4.2.2.02,5]dec-9-ene motif being evaluated against malaria.

Characterization of antibiofilm compound from marine sponge Stylissa carteri.

The fouling phenomenon grabbed global attention and caused huge economic losses specifically in marine-related industries. Sessile behavior exposed the sponge to the risk of fouling. However, their bodies remained free from foulers, which were attributed to the chemical defense system. The objectives of this study were to determine the antibiofilm activity of the marine sponge, Stylissa carteri, and to characterize the isolated compound involved. The antibiofilm activity of S. carteri methanolic crude extract (MCE) and fractions was tested against biofilm-producing bacteria, Pseudomonas aeruginosa, using two different modes of crystal violet biofilm assays: preventive and detachment. Besides that, the disc-diffusion test was conducted to screen the antibacterial activity against gram-positive and gram-negative bacteria while a cytotoxicity assay was conducted on the HepG2 cell line. Bioassay-guided fractionation was carried out using vacuum liquid chromatography (VLC) and solid phase extraction using a C18 Sep-Pak Cartridge. The crystal compound was isolated and characterized through thin-layer chromatography (TLC), Fourier transform infrared (FTIR) spectroscopy, liquid chromatography-mass spectrometry (LCMS), and nuclear magnetic resonance (NMR) spectroscopy. The S. carteri MCE showed a promising result with a half-maximal inhibitory concentration (IC50) of 20.22μg/mL in the preventive assay, while no IC50 was determined in the detachment assay since all inhibitions < 50%. The S. carteri MCE exhibited broad-spectrum antibacterial activity and displayed a non-cytotoxic effect. Fraction 4 from MCE of S. carteri (IC50 = 2.40μg/mL) reduced the biofilm in the preventive assay at all concentrations and exhibited no antibacterial activity indicating the independence of antibiofilm from antibacterial properties. Based on the data obtained, an alkaloid named debromohymenialdisine (DBH) was identified from Fraction 4 of S. carteri MCE. In conclusion, S. carteri was able to reduce the establishment of the biofilm formed by P. aeruginosa and could serve as a prominent source of natural antifouling agents.