Two new triterpenoids from the seeds of blackberry (Rubus fructicosus)

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

Keywords:

• Rubus fructicosus
• blackberry
• Rosaceae
• ursane-type triterpenoid
• isopropylidenedioxy
• cytotoxic activity

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).