Phenolic glycosides and monoterpenoids from the roots of Euphorbia ebracteolata and their bioactivities

The bioactive substance investigation of Euphorbia ebracteolata obtained 17 compounds by various chromatographic techniques. Their structures were elucidated using widely spectroscopic data, including ESI-MS, HRESI-MS, CD, 1D- and 2D-NMR, which gave 5 new phenolic glucosides and 4 new monoterpenoids. The phenolic glucosides and monoterpenoids showed the inhibitory effect against the human carboxylesterase-2 (hCE-2) using a fluorescence bioassay in vitro, with the strongest inhibitor compound 4 (IC50 7.17 μM). The antioxidant effects of these isolated compounds were evaluated using a DPPH scavenging assay. All of the phenolic acids displayed the DPPH scavenging effect, especially that eight compounds have better effect than vitamin C, with the IC50 values ranging from 4.52 to 7.52 μM. Additionally, compounds 1-17 showed no cytotoxic effect against five human cancer cell lines by MTT assay.

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