Picrajavanicins H–M, new quassinoids from Picrasma javanica collected in Myanmar and their antiproliferative activities

Six new tetracyclic quassinoids, picrajavanicins H–M, along with two known analogues were isolated from the CHCl3 soluble extract of Picrasma javanica bark collected in Myanmar. The structures of these compounds were elucidated using spectroscopic techniques, including 1D and 2D NMR. The absolute configuration at C-4 of picrajavanicin L was determined to be R by the modified Mosher method. In contrast, the absolute structures of picrajavanicin H and picrasin A were determined by the X-ray diffraction analyses. The antiproliferative activities of the isolated compounds were evaluated against a panel of five different human cancer cell lines. All isolates exhibited potent and selective antiproliferative activities against human pancreatic cancer PANC-1 cells, with IC50 values ranging from 3.25 to 17.41 μM.

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