Kallopterolides A-I, a New Subclass of seco-Diterpenes Isolated from the Southwestern Caribbean Sea Plume Antillogorgia kallos.

Kallopterolides A-I (1-9), a family of nine diterpenoids possessing either a cleaved pseudopterane or a severed cembrane skeleton, along with several known compounds were isolated from the Caribbean Sea plume Antillogorgia kallos. The structures and relative configurations of 1-9 were characterized by analysis of HR-MS, IR, UV, and NMR spectroscopic data in addition to computational methods and side-by-side comparisons with published NMR data of related congeners. An investigation was conducted as to the potential of the kallopterolides as plausible in vitro anti-inflammatory, antiprotozoal, and antituberculosis agents.

Kallolide A acetate pyrazoline.

IN THE CRYSTAL STRUCTURE OF KALLOLIDE A ACETATE PYRAZOLINE [SYSTEMATIC NAME: 7-methyl-16-oxo-4,10-bis-(prop-1-en-2-yl)-17,18-dioxa-14,15-diaza-tetra-cyclo-[9.4.2.1(6,9).0(1,12)]octa-deca-6,8,14-trien-5-yl acetate], C(23)H(28)N(2)O(5), there is a 12-member-ed carbon macrocyclic structure. In addition, there is a tris-ubstituted furan ring, an approximately planar γ-lactone ring [maximum deviation of 0.057 (3) Å] and a pyraz-oline ring, the latter in an envelope conformation. The pyrazoline and the γ-lactone rings are fused in a cis configuration. In the crystal, mol-ecules are linked by weak C-H⋯O inter-actions, forming a two-dimensional network parallel to (001). An intra-molecular C-H⋯O hydrogen bond is also present.

Bipinnatins K-Q, minor cembrane-type diterpenes from the West Indian Gorgonian Pseudopterogorgia kallos: isolation, structure assignment, and evaluation of biological activities.

An extensive chemical study of the secondary metabolites found in the crude organic extract of the gorgonian octocoral Pseudopterogorgia kallos has led to the isolation of seven new cembranolides, bipinnatins K-Q ( 2- 8), and one known compound, bipinnatin E ( 9). The molecular structures of compounds 2- 8, many of which contain unusual structural features, were assigned mainly by 2D NMR spectroscopic methods and X-ray crystallographic analysis. The discovery of compounds 2- 8 may lend support to previously proposed mechanisms for the biosynthesis of recently isolated bioactive natural products from the same gorgonian specimen. The in vitro cytotoxicity of bipinnatins 4, 6, and 7 against the NCI tumor cells MCF breast cancer, NCI-H460 non-small cell lung cancer, and SF-268 CNS cancer was evaluated. However, only bipinnatin Q ( 6) displayed significant cytotoxic activity. Some of the compounds isolated proved to be inhibitors of acetylcholine receptors.

Intricarene, an unprecedented trispiropentacyclic diterpene from the Caribbean Sea plume Pseudopterogorgia kallos.

[structure: see text] A novel trispiropentacyclic diterpene, intricarene (1), was isolated from the hexane extract of the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly entangled structure was established by interpretation of NMR, IR, UV, and HREIMS data and subsequently confirmed by X-ray diffraction analysis. The unprecedented carbon skeleton of 1 constitutes a new addition to the already impressive architectural diversity of the diterpene class of marine secondary metabolites.

Bielschowskysin, a gorgonian-derived biologically active diterpene with an unprecedented carbon skeleton.

Bielschowskysin is a naturally occurring diterpene isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly oxygenated hexacyclic structure is based on a previously undescribed tricyclo[9.3.0.0(2,10)]tetradecane ring system that was established through spectroscopic analysis and X-ray crystallographic analysis. Bielschowskysin was shown to exhibit antimalarial activity against Plasmodium falciparum as well as strong anticancer activity against two human cancer cell lines.

Isolation and structure of providencin: a highly oxygenated diterpene possessing a unique bicyclo[12.2.0]hexadecane ring system from the sea plume Pseudopterogorgia kallos.

[structure: see text] Providencin (1) is a naturally occurring cytotoxin isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly oxygenated hexacyclic structure is based on a previously undescribed bicyclo[12.2.0]hexadecane ring system and was established through spectroscopic analysis and X-ray crystallographic analysis. Providencin (1) was shown to exhibit modest anticancer activity against human breast (MCF7), lung (NCI-H460), and CNS (SF-268) cancer cell lines.

Isolation and characterization of kallosin A, a novel rearranged pseudopterane diterpenoid from the Caribbean sea plume Pseudopterogorgia kallos (Bielschowsky).

The Caribbean alcyonacean Pseudopterogorgia kallos is shown to contain a novel rearranged pseudopterane diterpene, kallosin A (1), possessing several unusual structural features. In addition to having two distinct 2(3H)- and 2(5H)-furanone moieties, kallosin A is based on a new carbon skeleton. The structural assignment of 1 was based mainly on 1D and 2D NMR spectral data and was further supported by accurate mass measurement and single-crystal X-ray diffraction analysis.