Leptanoine D, a New Quinoline Alkaloid from the Australian Tree Pitaviaster haplophyllus (Rutaceae)

One new furoquinoline alkaloid, leptanoine D (1) and nine known alkaloids 2–10 were isolated from Pitaviaster haplophyllus. Leptanoine D (1) contains a typically unstable vinyl ether moiety and was structurally elucidated based on 2D NMR, (+)-HR-ESI-MS, and ECD data. The structures of the known furoquinoline alkaloids leptanoine A (11) and B (12) have also been revised. Compounds 1–10 were screened against three species of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli), however they showed no activity at the highest dose tested (32 µg mL−1). The compounds were also evaluated for anti-proliferative action against PC-3 and WPMY-1 cells, with 7–9 displaying weak activity at 100 μM.