Antiplasmodial activity, structure-activity relationship and studies on the action of novel benzimidazole derivatives.

Malaria cases and deaths keep being excessively high every year. Some inroads gained in the last two decades have been eroded especially due to the surge of resistance to most antimalarials. The search for new molecules that can replace the ones currently in use cannot stop.

Structure modification, antialgal, antiplasmodial, and toxic evaluations of a series of new marine-derived 14-membered resorcylic acid lactone derivatives.

Unlabelled: Marine natural products play critical roles in the chemical defense of many marine organisms and are essential, reputable sources of successful drug leads. Sixty-seven 14-membered resorcylic acid lactone derivatives - and - of the natural product zeaenol () isolated from the marine-derived fungus were semisynthesized by chlorination, acylation, esterification, and acetalization in one to three steps. The structures of these new derivatives were established by HRESIMS and NMR techniques.

Semisynthesis, Antiplasmodial Activity, and Mechanism of Action Studies of Isocoumarin Derivatives.

In this study, eight natural isocoumarins (-) were isolated from a marine-derived sp. fungus. To explore their structure-activity relationship and discover potent antimalarial leads, a small library of 22 new derivatives (-, , -, -, and ) were semisynthesized by varying the substituents of the aromatic ring and the aliphatic side chains.

Pumilacidins from the Octocoral-Associated sp. DT001 Display Anti-Proliferative Effects in .

Chemical examination of the octocoral-associated species (sp.) DT001 led to the isolation of pumilacidins A () and C (). We investigated the effect of these compounds on the viability of and the mechanism of pumilacidin-induced death.

Discovery, Semisynthesis, Antiparasitic and Cytotoxic Evaluation of 14-Membered Resorcylic Acid Lactones and Their Derivatives.

Ten antifouling 14-membered resorcylic acid lactones 1-10 were isolated previously with low or trace natural abundance from the zoanthid-derived Cochliobolus lunatus fungus. Further optimization of fermentation conditions led to the isolation of two major natural compounds 7 and 8 with multi-gram quantities. By one or two steps, we semisynthesized the six trace natural compounds 1-6 and a series of derivatives 11-27 of compounds 7 and 8 with high yields (65-95%).

Coibacins A-D, antileishmanial marine cyanobacterial polyketides with intriguing biosynthetic origins.

Four unsaturated polyketide lactone derivatives, coibacins A-D, were isolated from a Panamanian marine cyanobacterium, cf. Oscillatoria sp. The two different types of termini observed in these co-occurring metabolites, either a methyl cyclopropyl ring as seen in curacin A or a methyl vinyl chloride similar to that observed in the jamaicamides, suggest an intriguing flexibility in the "beta branch" forming biosynthetic process.