Acetogenins: Polyketides of up to a few dozen carbons in length, formed by chain extension of multiple PROPIONATES and oxygenated to form tetrahydrofuran and lactone rings along the length of the chain. They are found in ANNONACEAE and other PLANTS. Related compounds cyclize to MACROLIDES.Annona: A plant genus of the family ANNONACEAE. It has edible fruit and seeds which contain acetogenins and benzoquinazoline and other alkaloids.Annonaceae: The custard-apple plant family of the order Magnoliales, subclass Magnoliidae, class Magnoliopsida. Some members provide large pulpy fruits and commercial timber. Leaves and wood are often fragrant. Leaves are simple, with smooth margins, and alternately arranged in two rows along the stems.Furans: Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.Uvaria: A plant genus of the family ANNONACEAE. Members contain uvarigrin, uvarigrandin, chamuvaritin and other acetogenins and benzylisoquinoline alkaloids.Benzethonium: Bactericidal cationic quaternary ammonium surfactant used as a topical anti-infective agent. It is an ingredient in medicaments, deodorants, mouthwashes, etc., and is used to disinfect apparatus, etc., in the food processing and pharmaceutical industries, in surgery, and also as a preservative. The compound is toxic orally as a result of neuromuscular blockade.Lactones: Cyclic esters of hydroxy carboxylic acids, containing a 1-oxacycloalkan-2-one structure. Large cyclic lactones of over a dozen atoms are MACROLIDES.Laurencia: A genus of RED ALGAE in the family Rhodomelaceae. Some species are a rich source of chlorine-and bromine-containing metabolites which show significant antibacterial activity.Electron Transport Complex I: A flavoprotein and iron sulfur-containing oxidoreductase complex that catalyzes the conversion of UBIQUINONE to ubiquinol. In MITOCHONDRIA the complex also couples its reaction to the transport of PROTONS across the internal mitochondrial membrane. The NADH DEHYDROGENASE component of the complex can be isolated and is listed as EC 220.127.116.11.