Chemical Constituents from Staminate Flowers of Eucommia ulmoides Oliver and Their Anti-Inflammation Activity in Vitro.

Three new monoterpenoids, named eucomylides A-C (1-3), along with six known compounds (4-9) were isolated from the staminate flowers of Eucommia ulmoides Oliver. The structures were elucidated by extensive analyses of spectroscopic methods, and their absolute configurations were established by time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculation. All the compounds along with previously isolated components (10-14) were tested for their anti-inflammatory effects. Two iridoid glycosides (11 and 12) and a flavonoid glycoside (14) showed potent suppressive effects on nitric oxide (NO) production in RAW 264.7 cells, with IC50 values ranging from 17.11 to 22.26 µM.

Eucommicin A, a ß-truxinate lignan from Eucommia ulmoides, is a selective inhibitor of cancer stem cells.

Cancer stem cells (CSCs) constitute a small population of undifferentiated cells within a tumor that have the ability to self-renew and drive tumor formation, thus behaving as cancer-initiating cancer cells. Therapeutic interventions that eliminate CSCs are necessary to completely cure patients, since CSCs are a crucial source of tumor recurrence and metastasis. An induced CSC-like (iCSCL) model was recently established using induced pluripotent stem cells (iPSCs). In this study, a natural product-eucommicin A-was identified from Eucommia ulmoides leaves by screening for anti-CSC activity using the iCSCL model. Its structure was elucidated by spectroscopic methods as a quinic acid diester of 3,4,3',4'-tetrahydroxy-ß-truxinic acid. Eucommicin A exhibited selective anti-CSC activity and inhibited tumor sphere formation by iCSCL cells. The results of this study suggest that eucommicin A could serve as a lead compound in the development of drugs to abrogate the stemness and self-renewal ability of CSCs.