A New Friedelane Type Triterpene from Euonymus hederaceus

Euonymus hederaceus is distributed widely in the south of China; its stems and leaves have been used as folk medicines to treat many diseases such as renal deficiency and chronic diarrhea, traumatic injury, and abnormal menstruation. Chemical investigation of the leaves and stems of Euonymus hederaceus resulted in the isolation for the first time and characterization of a new friedelane type triterpene with a molecular mass of 472 and molecular formula of C30H48O4 by high resolution mass spectrometry. The 1H-NMR 13C-NMR and DEPT1350 spectra matched the characteristic data of the proposed triterpene skeleton. The compound was finally identified as 28-hydroxyfriedelan-3-one-29-oic acid on the basis of spectroscopic evidence, including two dimensional nuclear magnetic resonance as well as its IR spectrum.


Introduction
Celastraceae plants have been the subject of continued and growing interest due to the range of biological activities shown by many members of this family. Pharmaceutical studies and clinical practice have demonstrated that their sesquiterpenes and triterpenes possess notable antibacterial, anti-tumor, insect antifeedant and cytotoxic activities. More than 100 compounds have been isolated OPEN ACCESS and purified from three species, including Celastrus hypoleucus (Oliv.) Warb [1], Celastrus hypoleucus [2], and Microtropis triflora Merr [3] belonging to the Celastraceae family. The structures were determined by IR, UV, MS, and NMR, respectively, and 13 of them were new compounds. Friedelin ring triterpenes are a very important class, and so far, these compounds were reported to display a lot of biological activity. For example, 28,30-dihydroxyfriedelan-3-one showed good anti-tumor activity against P388 [4].

General
The IR spectrum was recorded in KBr pellets on a Nicolet NEXUS-470 FT-IR spectrometer. NMR spectra were recorded on a Bruker Avance DMX 500 NMR Instrument (Bruker Analytik, GmbH, Germany). The chemical shift values are given in ppm using pyridine-D 5 as solvent and TMS as the internal standard. Mass spectra were performed on an Apex III (7.0 Tesla) Fourier transformation ion cyclotron resonance mass spectrometer (FT-ICRMS) equipped with electrospray ionization source (ESI) (Bruker, Billerica, MA, USA).

Plant material
The

Extraction and isolation
The shade-dried, powdered root barks, stem barks and leaves of Euonymus hederaceus (5.0 kg) were extracted three times with 95% EtOH (20 L) at room temperature for seven days. After removal of the solvent in vacuo, the extract was dissolved in H 2 O (0.5 L) and extracted with EtOAc (2 L). The concentrated EtOAc extract (75 g) was subjected to column chromatography (CC) on silica gel, eluting with petroleum ether and increasing proportions of EtOAc. The eluate with 1:9 (petroleum ether/EtOAc) give the new pure compound 1 (10 mg).

Conclusions
A new friedelane type triterpene was isolated from Euonymus hederaceus, its structure was determined to be 28-hydroxy-friedelan-3-one-29-oic acid by spectroscopic methods, including FT-ICRMS and NMR experiments, in combination to the comparison with known compounds. In addition, its stereo structure was proposed on the basis of the reference data.