In our search for bioactive metabolites from marine organisms, we have investigated the polar fraction of the organic extract of the Red Sea sponge Theonella swinhoei. Successive chromatographic separations and final HPLC purification of the potent antifungal fraction afforded a new bicyclic glycopeptide, theonellamide G (1). The structure of the peptide was determined using extensive 1D and 2D NMR and high-resolution mass spectral determinations. The absolute configuration of theonellamide G was determined by chemical degradation and 2D NMR spectroscopy. Theonellamide G showed potent antifungal activity towards wild and amphotericin B-resistant strains of Candida albicans with IC50 of 4.49 and 2.0 μM, respectively. Additionally, it displayed cytotoxic activity against the human colon adenocarcinoma cell line (HCT-16) with IC50 of 6.0 μM. These findings provide further insight into the chemical diversity and biological activities of this class of compounds.
Certain new nitrogen-substituted derivatives of cyclic imides phthalimide (a), 1, 8-naphthalimide (b), and diphenimide (c), were synthesized aiming to obtain potent hypolipidemic agents. Thus, 2-(N-imido) propanoic acids, 2-(N-phthalimido)-2-methylpropionic acid, and their ethyl esters were synthesized (Target derivative A). Also their corresponding N-substituted-2-(N-imido) propionamides and 2-(N-phthalimido)-2-methylpropionamides were prepared (Target derivative B). In addition, N-phthalimidomethyleneoxy acetate was prepared. Some of the newly prepared compounds were subjected to 3D studies and were found to be superimposed on Clofibrate, which is the first generation of fibrate drugs. The preliminary evaluation of hypolipidemic activity of the newly prepared compounds against triton WR-1339-induced hyperlipidemia in rat showed that several derivatives have demonstrated significant lowering of serum total cholesterol and triglyceride levels at dose of 150 mg/kg/i.p. comparing with Fenofibrate which is one of the second generations of fibrate drugs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.