Toussaintines A–E: Antimicrobial indolidinoids, a cinnamoylhydrobenzofuranoid and a cinnamoylcyclohexenoid from Toussaintia orientalis leaves

The indolidinoids 1– 3, the cinnamoyl hydrobenzofuranoid 4 and the cyclohexenoid 5 have been isolated as antibacterial and antifungal constituents of Toussaintia orientalis (Annonaceae) leaves and the structures established on analysis of spectroscopic data. [Display omitted] ► Metabolites of unprecedented indolidinoid, benzofuranoid and cyclohexanoid systems. ► Metabolites derived from leaves of near extinct Toussaintia orientalis (Annonaceae). ► Metabolites formed through mixed biosynthesis of N-cinnamoyl and tetraketide units. ► Metabolites with antibacterial (MIC 20–5 μg/mL) and antifungal activity at 40 μg/mL. Toussaintine A ( N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-2,7-dione), toussaintine B ( N-cinnamoyl-5,6-dehydro-4,7-dihydroxyindolidin-2-one), toussaintine C ( N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-7-one), toussaintine D ( N-cinnamoyl-2-amino-4-hydroxy-7-oxo-2,3,8,9-tetrahydrobenzofuran) and toussaintine E ( N-cinnamoyl-1-acetoxymethyl-2-amino-1-hydroxycyclox-5-en-4-one) were isolated as antibacterial and antifungal constituents of the leaves of Toussaintia orientalis Verdc. (Annonaceae) and their structures established from analysis of spectroscopic data . The compounds belong to a series of variously cyclized aminocinnamoyl tetraketide derivatives, showing the importance of rarely occurring Annonaceae species as sources of structurally diverse natural products.