Abstract
Two new ursane-type triterpenoids (1, 2) attached to isopropylidenedioxy group were isolated from the seeds of blackberry (Rubus fructicosus L., Rosaceae) along with two known ursane-type triterpenoids, 2,3-O-isopropylidenyl-2α,3α,19α-trihydroxyurs-12-en-28-oic acid (3) and 1β-hydroxyeuscaphic acid (4). The chemical structures of 1 and 2 were determined to be 2,3-O-isopropylidene-1β,2β,3β,19α-tetrahydroxyurs-12-en-28-oic acid and 1,2-O-isopropylidene-1β,2α,3α,19α-tetrahydroxyurs-12-en-28-oic acid, respectively, based on spectroscopic data. Additionally, their cytotoxic activity towards HL-60 human leukaemia cells was evaluated. Among them, 3 demonstrated a clear cytotoxic activity with 72.8 μM of IC50 value.
Graphical abstract
![](/cms/asset/1be66c50-a5d2-4fe1-ac2e-f8e1f3207a2f/gnpl_a_1076820_uf0001_oc.jpg)
Disclosure statement
No potential conflict of interest was reported by the authors.
Acknowledgments
We express our appreciation to Mr. H. Harazono of Fukuoka University for the measurement of the FAB-MS. This research was supported in part by a Grant-in-Aid for Scientific Research (C) [JSPS KAKENHI grant numbers. 24590022] from Japan Society for the Promotion of Science. A part of this work was also supported by Research and Study Project of Tokai University Educational System General Research Organisation (Kanagawa, Japan).