ABSTRACT
In our continuing study for structurally and biogenetically interesting natural products from marine organisms, Okinawan marine sponges Agelas spp. were investigated, resulting in the isolation of 18 unique alkaloids including five dimeric bromopyrrole alkaloids (1-5), ten monomeric bromopyrrole alkaloids (6-15), and three conjugates of monomeric bromopyrrole alkaloid and hydroxykynurenine (16-18). In this mini-review, the isolation, structure elucidation, and antimicrobial activities of these alkaloids are summarized.
Subject(s)
Agelas/chemistry , Alkaloids/pharmacology , Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Bacteria/drug effects , Fungi/drug effects , Alkaloids/chemistry , Alkaloids/isolation & purification , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Microbial Sensitivity Tests , Molecular StructureABSTRACT
Six new prenylated benzophenones, (-)-nemorosonol (1) and trijapins A-E (2-6), were isolated from the aerial parts of Triadenum japonicum. (-)-Nemorosonol (1) and trijapins A-C (2-4) have a common tricyclo[4.3.1.0(3,7)]decane skeleton, while 1 is an enantiomer of (+)-nemorosonol previously isolated from Clusia nemorosa. The absolute configuration of (-)-nemorosonol (1) was assigned by ECD spectroscopy. Trijapins A-C (2-4) are analogues of 1 possessing an additional tetrahydrofuran ring. Trijapins D (5) and E (6) are prenylated benzophenones with a 1,2-dioxane moiety and a hydroperoxy group, respectively. (-)-Nemorosonol (1) exhibited antimicrobial activity against Escherichia coli (MIC, 8 µg/mL), Staphylococcus aureus (MIC, 16 µg/mL), Bacillus subtilis (MIC, 16 µg/mL), Micrococcus luteus (MIC, 32 µg/mL), Aspergillus niger (IC50, 16 µg/mL), Trichophyton mentagrophytes (IC50, 8 µg/mL), and Candida albicans (IC50, 32 µg/mL), while trijapin D (5) showed antimicrobial activity against C. albicans (IC50, 8 µg/mL).
Subject(s)
Anti-Bacterial Agents/isolation & purification , Benzophenones/isolation & purification , Hypericum/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Aspergillus niger/drug effects , Bacillus subtilis/drug effects , Benzophenones/chemistry , Benzophenones/pharmacology , Candida albicans/drug effects , Escherichia coli/drug effects , Japan , Microbial Sensitivity Tests , Micrococcus luteus/drug effects , Molecular Structure , Plant Components, Aerial/chemistry , Prenylation , Staphylococcus aureus/drug effects , Stereoisomerism , Trichophyton/drug effectsABSTRACT
Three structurally unique bromopyrrole alkaloids, agelamadins C-E (1-3), were isolated from a marine sponge Agelas sp. Agelamadin C (1) possesses a hybrid structure of oroidin and 3-hydroxykynurenine connected through a dihydro-1,4-oxazine moiety. Agelamadins D (2) and E (3) are a C-9/C-10 diastereomer and a 10-epimer of 1, respectively. The structures of 1-3 were elucidated on the basis of spectroscopic analysis as well as application of a PGME method and a TDDFT ECD calculation. Antimicrobial activity of 1-3 was evaluated.
Subject(s)
Agelas/chemistry , Alkaloids/isolation & purification , Anti-Infective Agents/isolation & purification , Hydrocarbons, Brominated/isolation & purification , Pyrroles/chemistry , Alkaloids/chemistry , Alkaloids/pharmacology , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Cryptococcus neoformans/drug effects , Hydrocarbons, Brominated/chemistry , Hydrocarbons, Brominated/pharmacology , Kynurenine/analogs & derivatives , Kynurenine/chemistry , Microbial Sensitivity Tests , Molecular Structure , Nuclear Magnetic Resonance, BiomolecularABSTRACT
Two structurally unique dimeric bromopyrrole alkaloids, agelamadins A (1) and B (2), were isolated from a marine sponge Agelas sp. Agelamadins A (1) and B (2) have a structure consisting of an agelastatin-like tetracyclic moiety and an oroidin-like linear moiety in common. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis. The antimicrobial activity and cytotoxicity of agelamadins A (1) and B (2) were evaluated.
Subject(s)
Agelas/chemistry , Alkaloids/isolation & purification , Hydrocarbons, Brominated/isolation & purification , Alkaloids/chemistry , Alkaloids/pharmacology , Animals , Bacillus subtilis/drug effects , Cryptococcus neoformans/drug effects , Drug Screening Assays, Antitumor , Humans , Hydrocarbons, Brominated/chemistry , Hydrocarbons, Brominated/pharmacology , KB Cells , Mice , Microbial Sensitivity Tests , Micrococcus luteus/drug effects , Molecular Structure , Nuclear Magnetic Resonance, BiomolecularABSTRACT
Five new bromopyrrole alkaloids, 2-bromokeramadine (1), 2-bromo-9,10-dihydrokeramadine (2), tauroacidins C (3) and D (4), and mukanadin G (5), were isolated from an Okinawan marine sponge Agelas sp. The structures of 1-5 were elucidated on the basis of spectroscopic data and conformational analysis. Mukanadin G (5) has a tricyclic skeleton consisting of a fused tetrahydrobenzaminoimidazole and 2,5-dioxopyrrolidine moieties. Antimicrobial activities of 1-3, and 5 as well as three related known bromopyrrole alkaloids, keramadine (6), tauroacidin A (7), and taurodispacamide A (8) were evaluated.
Subject(s)
Alkaloids/pharmacology , Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Hydrocarbons, Brominated/pharmacology , Porifera/chemistry , Pyrroles/pharmacology , Alkaloids/chemistry , Alkaloids/isolation & purification , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Bacteria/drug effects , Dose-Response Relationship, Drug , Fungi/drug effects , Hydrocarbons, Brominated/chemistry , Hydrocarbons, Brominated/isolation & purification , Microbial Sensitivity Tests , Molecular Structure , Pyrroles/chemistry , Pyrroles/isolation & purification , Structure-Activity RelationshipABSTRACT
Three new dimeric bromopyrrole alkaloids, nagelamides X-Z (1-3), were isolated from a marine sponge Agelas sp. Nagelamides X (1) and Y (2) possess a novel tricyclic skeleton consisting of spiro-bonded tetrahydrobenzaminoimidazole and aminoimidazolidine moieties. Nagelamide Z (3) is the first dimeric bromopyrrole alkaloid involving the C-8 position in dimerization. The structures of 1-3 were elucidated on the basis of spectroscopic data. Nagelamides X-Z (1-3) exhibited antimicrobial activity.
