A new cytotoxic bromotyrosine-derived secondary metabolite, 11-oxoaerothionin [3], was isolated from the Caribbean sea sponge Aplysina lacunosa. The structure of 3 was argued on the basis of detailed spectroscopic analysis and by chemical conversion to the known antibiotic compound 11-hydroxyaerothionin [2]. When screened against a panel of four human cell lines, 11-oxoaerothionin [3] showed pronounced as well as selective antitumor activity toward the human colon (HCT 116) cell line within the limited concentration range of 0.01-0.1 microgram/ml.

Nobiletin is a polymethoxyflavonoid with a remarkable antiproliferative effect. In order to overcome its low aqueous solubility and chemical instability, the use of nanoparticles as carriers has been proposed. This study explores the possibility of binding nobiletin to chitosan nanoparticles, as well as to evaluate their antiproliferative activity. The association and loading efficiencies are 69.1% and 7.0%, respectively. The formation of an imine bond between chitosan amine groups and the carbonyl group of nobiletin, via Schiff-base, is proposed. Nobiletin-loaded chitosan nanoparticles exhibit considerable inhibition (IC50=8 μg/mL) of cancerous cells, revealing their great potential for applications in cancer chemotherapy.

Emission and UV-vis absorption spectra of (hydrotris(pyrazolyl)borato)(triphenylarsine)copper(I), (CuTpAsPh3), (hydrotris(pyrazolyl)borato)(triethylamine)copper(I), (CuTpNEt3), and (hydrotris(pyrazolyl)borato)(triphenylphosphine)copper(I), (CuTpPPh3), are reported. The spectra of the arsine complex contain low-energy bands (with a band maximum at 16,500 cm(-1) in emission and a weak shoulder centered at about 25,000 cm(-1) in absorption) that are not present in the corresponding spectra of the amine or phosphine complexes. The lowest energy electronic transition is assigned to ligand to ligand charge transfer (LLCT) with some contribution from the metal. This assignment is consistent with PM3(tm) molecular orbital calculations that show the HOMO to consist primarily of pi orbitals on the Tp ligand (with some metal orbital character) and the LUMO to be primarily antibonding orbitals on the AsPh3 ligand (also with some metal orbital character). The absorption shoulder shows a strong negative solvatochromism, indicative of a reversal or rotation of electric dipole upon excitation, and consistent with a LLCT. The trends in the energies of the electronic transitions and the role of the metal on the LLCT are discussed.

A recent collection and extraction of the common Caribbean sea whip Eunicea succinea from Puerto Rico has produced four previously undescribed representatives of the cembrane family of diterpenes (2, 3, 4, and 6). A new geranylgeraniol derivative, 8, was also isolated as a minor constituent. The chemical structures of the new compounds were carefully established by spectroscopic and chemical methods in addition to detailed NMR spectral comparisons with known cembranoid models from Eunicea.

A new chemical study of the Caribbean gorgonian Eunicea succinea collected in Puerto Rico afforded seven new cembranolides (1-5, 7, and 8). Excepting 1, the new compounds described here possess an unusual unsaturation at either position C-1, C-6, or C-8, and all but 8 possess the C-12R, C-13S stereochemistry usually ascribed to cembranolides from E. succinea. Their chemical structures were carefully established by a combination of chemical and spectroscopic methods in addition to detailed NMR spectral comparisons with known cembranolide models.