Triplinones I–O: Arylalkenyl α,β-Unsaturated-δ-Lactones Isolated from the Leaves of Australian Rainforest Plant <i>Cryptocarya triplinervis</i> (Lauraceae) Displaying Anti-Inflammatory Activity

Seven new arylalkenyl α,β-unsaturated-δ-lactones, triplinones I-O (<b>1</b>-<b>7</b>), were isolated from the leaves of the Australian rainforest plant <i>Cryptocarya triplinervis</i> B. Hyland (Lauraceae). The chemical structures of these compounds were established by NMR spectroscopic data analysis, while their relative and absolute configurations were established using a combination of Mosher ester analysis utilizing both Riguera's and Kishi's methods and CD experiments. Compounds <b>2</b> and <b>4</b> were identified as epimers, where the relative stereochemistry of the 1,3-diol moiety in both structures was first confirmed by Kishi's method, followed by their absolute configuration determination using Riguera's method. Compounds <b>1</b>-<b>7</b> exhibited good inhibitory activities toward nitric oxide (NO) production in lipopolysaccharide (LPS) and interferon (IFN)-γ-induced RAW 264.7 macrophages, in particular compounds <b>6</b>, <b>2</b>, and <b>4</b>, with IC₅₀ values of 2.1 ± 1.4, 8.5 ± 0.6, and 8.5 ± 0.7 μM, respectively.