Euphorane C, an unusual C17-norabietane diterpenoid from Euphorbia dracunculoides induces cell cycle arrest and apoptosis in human leukemia K562 cells

Four new polycyclic diterpenoids euphoranes A -D (1-4), together with 12 known ter-penoids (5-16) were isolated from the whole plants of Euphorbia dracunculoides. Compound 2 rep-resents the first example of aromatic 15,16,17-trinorabietane diterpenoid in Euphorbia species, and euphorane C (3) is an unusual 17-norabietane diterpenoid. The absolute configurations of 1, 2, and 4 were determined by single crystal X-ray diffraction, while that of 3 was established with the aid of ECD and 1D NMR quantum chemical calculation. Moreover, the absolute stereochemistry of 11 was demonstrated for the first time by crystallographic data. Compounds 1-16 were screened for antiproliferative activities against five human cancer cell lines, and 3 showed significant cytotoxicity against the human leukemia K562 cells with IC50 value of 3.59 lM. Preliminary mechanistic inves-tigation revealed that 3 could induce cell cycle arrest at G0/G1 phase and apoptosis in K562 cells.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Four new polycyclic diterpenoids, including two with novel chemical structures, were isolated from the whole plants of Euphorbia dracunculoides. One of the compounds showed significant anticancer activity.