Marine Sponge Biemna Research Articles

Antibacterial Activity of Steroids Isolated from the Madagascar Marine Sponge Biemna laboutei: Δ7 Steroids as New Potential Agents Against Pathogenic Bacteria

Background: Nowadays, the efficiency of antibiotics is endangered by the development of resistant bacterial strains. Consequently, novel bioactive agents are intensively searched. Marine sponges are well-known for being major sources of bioactive compounds, including unusual sterols. Until now, among sterols, noteworthy antibacterial activity has been reported exclusively for Δ5 sterols. Objectives: This study aims to describe the steroid composition of the marine sponge Biemna laboutei collected in the North coast of Madagascar, and the antibacterial activity of steroid mixture against human pathogenic strains. Methods: Sponge was extracted in CHCl3/MeOH. Free steroids were separated from other lipids by column chromatography with dichloromethane as specific eluent. Free sterols/steroids and sterol acetates were analysed by gas chromatography coupled with mass spectrometry. Antibacterial activity of steroid fractions was assessed for eight strains using agar diffusion with cellulose disks. Results: Neutral lipids were the major lipid class (79.1% of total lipids). The dichloromethane eluted fraction contained only free steroids giving rise to the identification of eleven compounds. These components presented exclusively Δ7 unsaturation, including lathosterol as the major one (38.4%) and four 3-oxo-steroids (11.8%). The steroid fraction of B. laboutei has exhibited inhibitory activity against pathogenic strains but more particularly against gram(+) Bacillus cereus (MIC of 12.5 μg/mL) and Staphylococcus aureus (MIC of 25 μg/mL) strains. This latter bacterium causes several illnesses, some of those strains being antibiotic-resistant and this becomes a worldwide health problem. Conclusion: This is the first report for an antibacterial activity of a mixture of Δ7 steroids against a resistant strain of S. aureus to many antibiotics.

ChemInform Abstract: Two Cell Differentiation Inducing Pyridoacridines from a Marine Sponge Biemna sp. and Their Chemical Conversions.

AbstractTwo pyridoacridines, N‐hydroxymethylisocystodamine (I) and neolabuanine A (II) together with six known compounds are isolated from the title sponge.

Two cell differentiation inducing pyridoacridines from a marine sponge Biemna sp. and their chemical conversions

Two pyridoacridines, N-hydroxymethylisocystodamine (1) and neolabuanine A (2), together with the known ecionine A (3), ecionine B (4), isocystodamine (5), N-methylisocystodamine (6), 9-hydroxyisoascididemin (7), and biemnadin (8), were isolated from a marine sponge Biemna sp. Several of these compounds were shown to induce cell differentiation of K562 leukemia cells into erythrocytes. Following inspection of the NMR data, and comparison of these data with literature values, we demonstrated that neolabuanine A (2) had the structure previously reported as labuanine A (2), and that the compound initially reported under the name of labuanine A possessed the structure assigned to ecionine A (3). We found that both neolabuanine A (2) and ecionine A (3) were gradually converted to 9-hydroxyisoascididemin (7), indicating that 2 and 3 can be considered both as precursors of 7.

Cell differentiation inducers from a marine sponge Biemna sp.

Two pyridoacridines closely related to the known isocystodamine were isolated from the marine sponge Biemna sp. together with isocystodamine. Their structures were determined on the basis of spectroscopic data. They induce the erythroid differentiation of human leukemia K562 cells with an ED 50 value of 5 nM each.

ChemInform Abstract: Two New Polycyclic Aromatic Alkaloids from the Okinawan Marine Sponge Biemna sp.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

5α, 8α-Epidioxysterol from the marine sponge Biemna Triraphis Topsent

5α, 8α-Epidioxy-24( S)-ethylcholest-6-en-3β-ol (1) was isolated from the marine sponge Biemna triraphis Topsent collected at Andavadoaka, near Toliary (west coast of Madagascar-Indian Ocean). The structure was elucidated from NMR spectroscopic data. This is the first report of this compound in a marine sponge belonging to the Biemna genus.

Netamines A—G: Seven New Tricyclic Guanidine Alkaloids from the Marine Sponge Biemna laboutei.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Fortisterol, a novel steroid with an unusual seven-membered lactone ring B from the Chinese marine sponge Biemna fortis Topsent

Fortisterol (1), a novel steroid with a rare seven-membered lactone ring B, has been isolated from the marine sponge Biemna fortis and its structure gas been elucidated on the basis of spectroscopic data.

Netamines A–G: seven new tricyclic guanidine alkaloids from the marine sponge Biemna laboutei

In our continuing program to identify bioactive compounds from marine invertebrates, the MeOH/EtOAc (1:1) extract of three collections of the Madagascar sponge, Biemna laboutei, was found to be cytotoxic to a series of human tumor cells. From the two sponges, seven new guanidine alkaloids, designated netamines A–G ( 1– 7), have been isolated and their structures elucidated. Compounds 3 and 4 were found to be cytotoxic against three tumor cells with GI 50 values in the micromolar range.

Pyridoacridine Alkaloids Inducing Neuronal Differentiation in a Neuroblastoma Cell Line, from Marine Sponge Biemna fortis

AbstractFor Abstract see ChemInform Abstract in Full Text.

Pyridoacridine Alkaloids Inducing Neuronal Differentiation in a Neuroblastoma Cell Line, from Marine Sponge Biemna fortis

A new and three known pyridoacridine alkaloids were isolated from the Indonesian marine sponge Biemna fortis as neuronal differentiation inducers against a murine neuroblastoma cell line, Neuro 2A. The chemical structure of the new compound, labuanine A ( 1), was determined by spectroscopic study and chemical conversion. These pyridoacridine alkaloids induced multipolar neuritogenesis in more than 50% of cells at 0.03–3 μM concentration. Compound 3, which showed the strongest neuritogenic activity among them, also induced increase of acetylcholinesterase, a neuronal marker in Neuro 2A and arrested cell cycle at the G2/M phase.

Biemnasterol, a new cytotoxic sterol with the rare 22,25-diene side chain, isolated from the marine sponge Biemna sp.

Biemnasterol [2], a new sterol with a 22,25-diene side chain possessing cytotoxic activity, has been isolated from the Okinawan marine sponge Biemna sp. and the structure elucidated on the basis of spectroscopic data and chemical means.

Two new polycyclic aromatic alkaloids from the Okinawan marine sponge Biemna sp.

Two new polycyclic aromatic alkaloids, biemnadin ( 1) and 8,9-dihydro-11-hydroxyascididemin ( 2), have been isolated from the Okinawan marine sponge Biemna sp. The X-ray diffraction analysis of 1 has established its octacyclic structure and the structure of 2 elucidated on the basis of extensive spectroscopic and chemical studies.