New 3,4-seco-3,19-Dinor- and Spongian-Based Diterpenoid Lactones from the Marine Sponge Spongia sp.

Continuing chemical investigation of the Red Sea sponge Spongia sp. led to the isolation of four new 3,4-seco-3,19-dinorspongian diterpenoid lactones, secodinorspongins A-D (1-4), along with a classical spongian diterpenoid lactone, sponginolide (5). The chemical structures, including the absolute configurations of these compounds, were elucidated using the extensive spectroscopic study composed of 1D and 2D NMR data analyses, and a comparison between calculated-electronic-circular-dichroism (ECD) and experimental-circular-dichroism (CD) spectra. A plausible biosynthetic pathway of 1-4 was also proposed. Furthermore, the cytotoxicity, antibacterial and anti-inflammatory activities of 1-5 were evaluated. Compound 1 was found to exhibit inhibitory activity against the growth of Staphylococcus aureus (S. aureus), and 4 and 5 exhibited suppression of superoxide-anion generation and elastase release in fMLF/CB-induced human neutrophils.

The Chemically Highly Diversified Metabolites from the Red Sea Marine Sponge Spongia sp.

A polyoxygenated and halogenated labdane, spongianol (1); a polyoxygenated steroid, 3ß,5α,9α-trihydroxy-24S-ethylcholest-7-en-6-one (2); a rare seven-membered lactone B ring, (22E,24S)-ergosta-7,22-dien-3ß,5α-diol-6,5-olide (3); and an α,ß-unsaturated fatty acid, (Z)-3-methyl-9-oxodec-2-enoic acid (4) as well as five known compounds, 10-hydroxykahukuene B (5), pacifenol (6), dysidamide (7), 7,7,7-trichloro-3-hydroxy-2,2,6-trimethyl-4-(4,4,4-trichloro-3-methyl-1-oxobu-tylamino)-heptanoic acid methyl ester (8), and the primary metabolite 2'-deoxynucleoside thymidine (9), have been isolated from the Red Sea sponge Spongia sp. The stereoisomer of 3 was discovered in Ganoderma resinaceum, and metabolites 5 and 6, isolated previously from red algae, were characterized unprecedentedly in the sponge. Compounds 7 and 8 have not been found before in the genus Spongia. Compounds 1-9 were also assayed for cytotoxicity as well as antibacterial and anti-inflammatory activities.

Spongenolactones A-C, Bioactive 5,5,6,6,5-Pentacyclic Spongian Diterpenes from the Red Sea Sponge Spongia sp.

Three new 5,5,6,6,5-pentacyclic spongian diterpenes, spongenolactones A-C (1-3), were isolated from a Red Sea sponge Spongia sp. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and the absolute configurations of 1-3 were determined on the basis of comparison of the experimental circular dichroism (CD) and calculated electronic circular dichroism (ECD) spectra. Compounds 1-3 are the first 5,5,6,6,5-pentacyclic spongian diterpenes bearing an ß-hydroxy group at C-1. These metabolites were assayed for their cytotoxic, antibacterial, and anti-inflammatory activities. All three compounds were found to exert inhibitory activity against superoxide anion generation in fMLF/CB-stimulated human neutrophils. Furthermore, 1 showed a higher activity against the growth of Staphylococcus aureus in comparison to 2.

An Anti-Inflammatory 2,4-Cyclized-3,4-Secospongian Diterpenoid and Furanoterpene-Related Metabolites of a Marine Sponge Spongia sp. from the Red Sea.

Chemical investigation of a Red Sea Spongia sp. led to the isolation of four new compounds, i.e., 17-dehydroxysponalactone (1), a carboxylic acid, spongiafuranic acid A (2), one hydroxamic acid, spongiafuranohydroxamic acid A (3), and a furanyl trinorsesterpenoid 16-epi-irciformonin G (4), along with three known metabolites (-)-sponalisolide B (5), 18-nor- 3,17-dihydroxy-spongia-3,13(16),14-trien-2-one (6), and cholesta-7-ene-3ß,5α-diol-6-one (7). The biosynthetic pathway for the molecular skeleton of 1 and related compounds was postulated for the first time. Anti-inflammatory activity of these metabolites to inhibit superoxide anion generation and elastase release in N-formyl-methionyl-leucyl phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophil cells and cytotoxicity of these compounds toward three cancer cell lines and one human dermal fibroblast cell line were assayed. Compound 1 was found to significantly reduce the superoxide anion generation and elastase release at a concentration of 10 µM, and compound 5 was also found to display strong inhibitory activity against superoxide anion generation at the same concentration. Due to the noncytotoxic activity and the potent inhibitory effect toward the superoxide anion generation and elastase release, 1 and 5 can be considered to be promising anti-inflammatory agents.

Psammaceratin A: A Cytotoxic Psammaplysin Dimer Featuring an Unprecedented (2Z,3Z)-2,3-Bis(aminomethylene)succinamide Backbone from the Red Sea Sponge Pseudoceratina arabica.

Bioassay-guided partition of the extract of the Red Sea sponge Pseudoceratina arabica and HPLC purification of the active fraction gave a psammaplysin dimer, psammaceratin A (1), along with psammaplysin A (2). The dimer comprises two units of psammaplysin A (2) connected via the terminal amines with an unprecedented (2Z,3Z)-2,3-bis(aminomethylene)succinamide moiety, and it represents the first dimer to be identified among the psammaplysin family. Data from 1D- and 2D-NMR and HRMS supported the chemical structures of the compounds. Psammaceratin A (1) and psammaplysin A (2) exhibited significant growth inhibition of HCT 116, HeLa, and MBA-MB-231 cells down to 3.1 µM.

Hemimycalins C-E; Cytotoxic and Antimicrobial Alkaloids with Hydantoin and 2-Iminoimidazolidin-4-one Backbones from the Red Sea Marine Sponge Hemimycale sp.

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine sponges, we have investigated the sponge Hemimycale sp. The cytotoxic fraction of the organic extract of the sponge afforded three new compounds, hemimycalins C-E (1-3). Their structural assignments were obtained via analyses of their one- and two-dimensional NMR spectra and HRESI mass spectrometry. Hemimycalin C was found to differ from the reported hydantoin compounds in the configuration of the olefinic moiety at C-5-C-6, while hemimycalins D and E were found to contain an 2-iminoimidazolidin-4-one moiety instead of the hydantoin moiety in previously reported compounds from the sponge. Hemimycalins C-E showed significant antimicrobial activity against Escherichia coli and Candida albicans and cytotoxic effects against colorectal carcinoma (HCT 116) and the triple-negative breast cancer (MDA-MB-231) cells.

Magnificines A and B, Antimicrobial Marine Alkaloids Featuring a Tetrahydrooxazolo[3,2-a]azepine-2,5(3H,6H)-dione Backbone from the Red Sea Sponge Negombata magnifica.

Investigation of the Red Sea sponge Negombata magnifica gave two novel alkaloids, magnificines A and B (1 and 2) and a new ß-ionone derivative, (±)-negombaionone (3), together with the known latrunculin B (4) and 16-epi-latrunculin B (5). The analysis of the NMR and HRESIMS spectra supported the planar structures and the relative configurations of the compounds. The absolute configurations of magnificines A and B were determined by the analysis of the predicted and experimental ECD spectra. Magnificines A and B possess a previously unreported tetrahydrooxazolo[3,2-a]azepine-2,5(3H,6H)-dione backbone and represent the first natural compounds in this class. (±)-Negombaionone is the first ß-ionone of a sponge origin. Compounds 1-3 displayed selective activity against Escherichia coli in a disk diffusion assay with inhibition zones up to 22 mm at a concentration of 50 µg/disc and with MIC values down to 8.0 µM. Latrunculin B and 16-epi-latrunculin B inhibited the growth of HeLa cells with IC50 values down to 1.4 µM.

Siphonocholin isolated from red sea sponge Siphonochalina siphonella attenuates quorum sensing controlled virulence and biofilm formation.

Increasing incidence of multi-drug resistant bacterial pathogens, especially in clinical settings, has been developed into a grave health situation. The drug resistance problem demands the necessity for alternative unique therapeutic policies. One such tactic is targeting the quorum sensing (QS) controlled virulence and biofilm production. In this study, we evaluated a marine steroid Siphonocholin (Syph-1) isolated from Siphonochalina siphonella against Chromobacterium violaceum (CV) 12472, Pseudomonas aeruginosa (PAO1), Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (BAA) for biofilm and pellicle formation inhibition, and anti-QS property. MIC of Syph-1 against MRSA, CV, PAO1 was found as 64 µg/mL and 256 µg/mL against BAA. At selected sub-MICs, Syph-1 significantly (P ≤ 0.05) decreased the production of QS regulated virulence functions of CV12472 (violacein) and PAO1 [elastase, total protease, pyocyanin, chitinase, exopolysaccharides, and swarming motility]. The Syph-1 significantly decreased (p = 0.005) biofilm formation ability of tested bacterial pathogens, at sub-MIC level (PAO1 > MRSA > CV > BAA) and pellicle formation in A. baumannii (at 128 µg/mL). Molecular docking and simulation results indicated that Siph-1 was bound at the active site of BfmR N-terminal domain with high affinity. This study highlights the anti-QS and anti-biofilm activity of Syph-1 against bacterial pathogens reflecting its broad spectrum anti-infective potential.

Antiproliferative Scalarane-Based Metabolites from the Red Sea Sponge Hyrtios erectus.

Two new sesterterpenes analogs, namely, 12-acetoxy,16-epi-hyrtiolide (1) and 12ß-acetoxy,16ß-methoxy,20α-hydroxy-17-scalaren-19,20-olide (2), containing a scalarane-based framework along with seven previously reported scalarane-type sesterterpenes (3-9) have been isolated from the sponge Hyrtios erectus (order Dictyoceratida) collected from the Red Sea, Egypt. The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and comparison with reported NMR data. Compounds 1-9 exhibited considerable antiproliferative activity against breast adenocarcinoma (MCF-7), colorectal carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG2). Compounds 3, 5 and 9 were selected for subsequent investigations regarding their mechanism of cell death induction (differential apoptosis/necrosis assessment) and their influence on cell cycle distribution.

Cytotoxic Compounds from the Saudi Red Sea Sponge Xestospongia testudinaria.

Bioassay-guided fractionation of the organic extract of the Red Sea sponge Xestospongia testudinaria led to the isolation of 13 compounds including two new sterol esters, xestosterol palmitate (2) and xestosterol ester of l6'-bromo-(7'E,11'E,l5'E)-hexadeca-7',11',l5'-triene-5',13'-diynoic acid (4), together with eleven known compounds: xestosterol (1), xestosterol ester of 18'-bromooctadeca-7'E,9'E-diene-7',15'-diynoic acid (3), and the brominated acetylenic fatty acid derivatives, (5E,11E,15E,19E)-20-bromoeicosa-5,11,15,19-tetraene-9,17-diynoic acid (5), 18,18-dibromo-(9E)-octadeca-9,17-diene-5,7-diynoic acid (6), 18-bromooctadeca-(9E,17E)-diene-7,15-diynoic acid (7), 18-bromooctadeca-(9E,13E,17E)-triene-7,15-diynoic acid (8), l6-bromo (7E,11E,l5E)hexadeca-7,11,l5-triene-5,13-diynoic acid (9), 2-methylmaleimide-5-oxime (10), maleimide-5-oxime (11), tetillapyrone (12), and nortetillapyrone (13). The chemical structures of the isolated compounds were accomplished using one- and two-dimensional NMR, infrared and high-resolution electron impact mass spectroscopy (1D, 2D NMR, IR and HREIMS), and by comparison with the data of the known compounds. The total alcoholic and n-hexane extracts showed remarkable cytotoxic activity against human cervical cancer (HeLa), human hepatocellular carcinoma (HepG-2), and human medulloblastoma (Daoy) cancer cell lines. Interestingly, the dibrominated C18-acetylenic fatty acid (6) exhibited the most potent growth inhibitory activity against these cancer cell lines followed by Compounds 7 and 9. Apparently, the dibromination of the terminal olefinic moiety has an enhanced effect on the cytotoxic activity.

Mirabolides A and B; New Cytotoxic Glycerides from the Red Sea Sponge Theonella mirabilis.

As a part of our continuing work to find out bioactive lead molecules from marine invertebrates, the CHCl3 fraction of the organic extract of the Red Sea sponge Theonella mirabilis showed cytotoxic activity in our primary screen. Bioassay-guided purification of the active fractions of the sponge's extract resulted in the isolation of two new glycerides, mirabolides A and B (1 and 2), together with the reported 4-methylene sterols, conicasterol (3) and swinhosterol B (4). The structures of the compounds were assigned by interpretation of their 1D (¹H, (13)C), 2D (COSY, HSQC, HMBC, ROESY) NMR spectral data and high-resolution mass determinations. Compounds 1-4 displayed marked cytotoxic activity against human breast adenocarcinoma cell line (MCF-7) with IC50 values of 16.4, 5.18, 6.23 and 3.0 µg/mL, respectively, compared to 5.4 µg/mL observed by doxorubicin as reference drug.

A New Bioactive Metabolite Isolated from the Red Sea Marine Sponge Hyrtios erectus.

Chemical investigation of the lipophilic fraction of Hyrtios erectus, a Red Sea sponge, yielded a new pentacyclic nitrogen-containing scalarane; 24-methoxypetrosaspongia C (1), together with the previously reported scalaranes sesterstatin 3 (2), 12-deacetyl-12-epi-scalaradial (3) and 12-deacetyl-12,18-di-epi-scalaradial (4). The compounds were identified using HRESIMS, 1D and 2D NMR experiments. The isolated compounds showed growth inhibitory activity against hepatocellular carcinoma (HepG2), colorectal carcinoma (HCT-116) and breast adenocarcinoma cells (MCF-7).

Bioactive Hydantoin Alkaloids from the Red Sea Marine Sponge Hemimycale arabica.

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Hemimycale arabica. The antimicrobial fraction of an organic extract of the sponge afforded two new hydantoin alkaloids, hemimycalins A and B (2 and 3), together with the previously reported compound (Z)-5-(4-hydroxybenzylidene)imidazolidine-2,4-dione (1). The structures of the compounds were determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determinations. Hemimycalins A (2) and B (3) represent the first examples of the natural N-alkylated hydantoins from the sponge Hemimycale arabica. Compounds 1-3 displayed variable antimicrobial activities against E. coli, S. aureus, and C. albicans. In addition, compound 1 displayed moderate antiproliferative activity against the human cervical carcinoma (HeLa) cell line. These findings provide further insight into the chemical diversity as well as the biological activity of this class of compounds.

Red Sea Sponge Extract Callyspongia siphonella and its Metabolites Induced Anticancer Activity in 2D and 3D Culture of Colon Cancer Cells.

Colorectal Cancer (CRC) significantly contributes to global cancer-related mortality and morbidity. Callyspongia siphonella (Callyspongia sp.), a Red Sea sponge, has shown promising activity as an anticancer extract and a source of anticancer-active compounds. This study sought to determine the effects of Callyspongia siphonella and its metabolites on HCT-116 colon cancer cells. Cell viability assays showed that Callyspongia sp. inhibited in a dose-dependent manner, the growth of HCT-116 cell lines with IC50 values of 64.8±17 ug/ml on 2D culture and 141.1±6.8 ug/ml on 3D culture. The purified compounds Sipholenol-A and Sipholenone-A have an IC50 of 48.9±2.2 uM and 47.1±1.2 uM respectively. Following Callyspongia sp. treatment of HCT-116, cell cycle analysis showed arrest at G2/M.flow cytometry analysis showed an increase in total apoptosis due to Callyspongia sp treatment. Moreover, mitochondria membrane potential has been reported to be depolarized due to Callyspongia sp. which is an extra sign of apoptosis. Further investigations are needed to explain the particular underlying mechanisms of Callyspongia sp. extract and its metabolites Sipholenol-A and Sipholenone-A to explore their therapeutic potential in treating colon cancer.

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.

Introduction: 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. Methods: 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. Results: 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. Discussion and Conclusion: 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.

Evaluation of Cytotoxicity of the Methanolic Extract of Red Sea Marine Sponge Xestospongia Testudinaria and Its Related Compounds Against MCF-7 Human Breast Cancer Cells.

Background: Breast cancer is a leading cause of death and one of the most common fatal medical conditions in the world. Chemical compounds of various types have been identified in the Red Sea marine sponge Xestospongia testudinaria, including sterol esters, sterols, indole alkaloids, and brominated polyunsaturated fatty acids. These compounds have demonstrated promising biological features, which in cludes anti-inflammatory, cancer preventive, and antioxidant capacities. Methods: The cytotoxic potential of Xestospongia testudinaria was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and morphological alterations in MCF-7 cell line. Furthermore, the flow cytometry was also utilized to assess apoptosis and identify changes in the cell cycle; besides, cell migration was assessed by scratch wound-healing assay. Results: A significant dose-dependent decrease in the percentage of MCF-7 cell viability was observed with IC50 39.8 ug/mL. Functional studies were performed on MCF-7 to show that Xestospongia testudinaria raises apoptotic cell death and induces growth arrest at the G1/G0 while inhibiting cell migration in scratch assay. Conclusion: These results demonstrated that Xestospongia testudinaria extract has an inhibitory effect on breast cancer cells proliferation, migration and induce apoptosis. Thus, it holds great promise as a potential treatment for breast cancer.

Cytotoxic activity of alkyl benzoate and fatty acids from the red sea sponge Hyrtios erectus.

The chemical investigation of the methylene chloride fraction of marine sponge Hyrtios erectus led to the isolation of the known oxysterol (2) along with a new alkyl benzoate compound identified by spectroscopic methods (NMR and MS) as 4'-methylheptyl benzoate (1), whilst the n-butanol fraction afforded the known indole 3-carbaldehyde and ß-carboline derivatives. Moreover, the hexane fraction was analysed by GC-MS for their fatty acids (FAs). A total of 17 FAs with chain lengths between 14 and 25 carbons were identified. Methyl-branched FAs are predominated suggesting the presence of bacterial symbionts in the H. erectus sponge. Furthermore, compounds 1 and 2 displayed significant cytotoxicity against breast adenocarcinoma (MCF-7) with IC50 values of 2.4 and 3.8 µM, respectively, since compound 2 was also shown to have potent cytotoxic effect against hepatocellular carcinoma cells (HepG 2) with IC50 value of 1.3 µM.

Callyptide A, a new cytotoxic peptide from the Red Sea marine sponge Callyspongia species.

In the course of our continuing efforts to allocate bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Callyspongia species. The cytotoxic dichloromethane fraction of the methanolic extract of the sponge afforded a new cytotoxic peptide named callyptide A (1). Its structure was determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determination. The configuration of the amino acids was determined by Marfey's analysis. Callyptide A was found to exhibit growth inhibitory activity when tested against different cancer cell lines.

New fatty acids from the Red Sea sponge Mycale euplectellioides.

Chemical investigation of the Red Sea sponge Mycale euplectellioides afforded two new compounds; hexacosa-(6Z,10Z)-dienoic acid methyl ester (1) and hexacosa-(6Z,10Z)-dienoic acid (2), along with two known compounds: icosa-(8Z,11Z)-dienoic acid methyl ester (3) and ß-sitosterol (4). The structures were elucidated by the interpretation of their spectral data. The total methanol extract (TME) of the sponge exhibited potent antimicrobial activity against the different strains at a concentration of 100 mg/mL. All tested fractions did not exhibit any activity against Serratia marcescens and tested fungal strains. The TME and different fractions displayed anti-inflammatory and antipyretic activities at doses of 100 and 200 mg/kg compared with indomethacin (8 mg). The TME exhibited a remarkable hepato-protective effect in CCl4-induced liver damage compared with silymarin. Furthermore, compounds 1 and 2 displayed weak activity against A549 non-small cell lung cancer, the U373 glioblastoma and the PC-3 prostate cancer cell lines.