Cytotoxic 2,3-Secoaromadendrane-Type Sesquiterpenoids from the Liverwort Plagiochila ovalifolia

Abstract

The ether extract of the Japanese liverwort, Plagiochila ovalifolia Mitt. (Plagiochilaceae) yielded three 2,3-secoaro-madendrane-type sesquiterpenoids, plagiochiline-A-15-yl octanoate, 14-hydroxyplagiochiline-A-15-yl 2E,4E-dodecadienoate and 14-hydroxyplagiochiline-A-15-yl 2E,4E,8Z-tetradecatrienoate. The two latter compounds were first isolated from the Plagiochila species. The structures of the new compounds were elucidated by spectroscopy. Plagiochiline-A-15-yl octanoate and 14-hydroxyplagiochiline-A-15-yl 2E,4E-dodecadienoate showed significant cytotoxicity against P-388 murine leukemia tumor cells, both compounds exhibiting an ID₅₀ of 0.05 µg/ml. Plagiochiline A also showed cytotoxic activity. The ID₅₀ was 3.0 µg/ml.