Four cucurbitane glycosides taimordisins A-D with novel furopyranone skeletons isolated from the fruits of .

Four novel triterpene glycosides, taimordisins A-D (-), were discovered from fresh fruits of Taiwanese . The chemical framework and relative stereochemistry of these four natural products were isolated, purified, and determined by using various separation and spectroscopy techniques. Each of them features a unique bicyclic-fused or trifuso-centro-fused ring system. Notably, and are cucurbitane-based compounds possessing a new C-24 and C-2″ carbon-carbon linkage with 5-hydroxy-2-(hydroxymethyl)tetrahydro-4-pyran-4-one and 6-(hydroxymethyl)tetrahydro-4-pyran-3,4,4-triol units, respectively, and represented an unprecedented molecular skeleton. In terms of biosynthesis, they all originate from a common precursor 3-hydroxycucurbita-5,24-dien-19-al-7,23-di---glucopyranoside. Of two sugar moieties, the one at 23---glucopyranoside grants each individual congener uniqueness likely through microbial symbiont-mediated intramolecular transformation into two major types of furo[2,3-]pyranone and furo[3,2-]pyranone derivatives. These new products possess desirable anti-inflammatory biological activities in addition to being generally regarded as safe.