Agesasines A and B, Bromopyrrole Alkaloids from Marine Sponges Agelas spp.

Exploration for specialized metabolites of Okinawan marine sponges Agelas spp. resulted in the isolation of five new bromopyrrole alkaloids, agesasines A (1) and B (2), 9-hydroxydihydrodispacamide (3), 9-hydroxydihydrooroidin (4), and 9E-keramadine (5). Their structures were elucidated on the basis of spectroscopic analyses. Agesasines A (1) and B (2) were assigned as rare bromopyrrole alkaloids lacking an aminoimidazole moiety, while 3–5 were elucidated to be linear bromopyrrole alkaloids with either aminoimidazolone, aminoimidazole, or N-methylated aminoimidazole moieties

Hitorins A and B, Hexacyclic C₂₅ Terpenoids from <i>Chloranthus japonicus</i>

Two novel C₂₅ terpenoids with a 6/5/5/5/5/3 hexacyclic skeleton including one γ-lactone ring and two tetrahydrofuran rings, hitorins A (<b>1</b>) and B (<b>2</b>), were isolated from the aerial parts of <i>Chloranthus japonicus.</i> The structures of <b>1</b> and <b>2</b> were elucidated on the basis of spectroscopic analyses as well as TDDFT ECD calculations. Hitorins A (<b>1</b>) and B (<b>2</b>) might be biogenetically derived from eudesmane sesquiterpene and thujane monoterpene

Prenylated Benzophenones from <i>Triadenum japonicum</i>

Six new prenylated benzophenones, (−)-nemorosonol (<b>1</b>) and trijapins A–E (<b>2</b>–<b>6</b>), were isolated from the aerial parts of <i>Triadenum japonicum</i>. (−)-Nemorosonol (<b>1</b>) and trijapins A–C (<b>2</b>–<b>4</b>) have a common tricyclo­[4.3.1.0^3,7]­decane skeleton, while <b>1</b> is an enantiomer of (+)-nemorosonol previously isolated from <i>Clusia nemorosa</i>. The absolute configuration of (−)-nemorosonol (<b>1</b>) was assigned by ECD spectroscopy. Trijapins A–C (<b>2</b>–<b>4</b>) are analogues of <b>1</b> possessing an additional tetrahydrofuran ring. Trijapins D (<b>5</b>) and E (<b>6</b>) are prenylated benzophenones with a 1,2-dioxane moiety and a hydroperoxy group, respectively. (−)-Nemorosonol (<b>1</b>) exhibited antimicrobial activity against <i>Escherichia coli</i> (MIC, 8 μg/mL), <i>Staphylococcus aureus</i> (MIC, 16 μg/mL), <i>Bacillus subtilis</i> (MIC, 16 μg/mL), <i>Micrococcus luteus</i> (MIC, 32 μg/mL), <i>Aspergillus niger</i> (IC₅₀, 16 μg/mL), <i>Trichophyton mentagrophytes</i> (IC₅₀, 8 μg/mL), and <i>Candida albicans</i> (IC₅₀, 32 μg/mL), while trijapin D (<b>5</b>) showed antimicrobial activity against <i>C. albicans</i> (IC₅₀, 8 μg/mL)