Elsevier

Steroids

Volume 101, September 2015, Pages 28-36
Steroids

C21 steroidal glycosides from the roots of Cynanchum saccatum

https://doi.org/10.1016/j.steroids.2015.05.009Get rights and content

Highlights

  • Eight new C21 steroidal glycosides were isolated from the roots of Cynanchum saccatum.

  • The structures of those steroids were determined on the basis of analysis of 1D and 2D NMR, as well as HRESIMS.

  • Some compounds showed weak cytotoxicity against three human cancer cell lines (HepG2, Hela and U251), respectively.

Abstract

Eight new C21 steroidal glycosides, named cynsaccatols A–H (18), along with two known analogs (910), were isolated from the roots of Cynanchum saccatum. Their structures were determined on the basis of detailed spectroscopic analysis, as well as HRESIMS. All compounds (110) were tested for their cytotoxicity in vitro using three human cancer cell lines (HepG2, Hela and U251), and compounds 1, 4, 5, 9, 10 showed weak inhibitory activities against different cell lines, respectively.

Introduction

Cynanchum saccatum W.T. Wang ex Tsiang et P.T., belonging to the family Asclepiadaceae, is a perennial liana that is mainly distributed in the southwest of China [1], such as Yunnan, Sichuan, Xizang. As one of species in the genus Cynanchum, which is abundant in the constituents of C21 steroids, showing varieties of biological activities, including antitumor, antiepileptic, immunoregulatory, antioxidant, and antiviral effects [2], [3], [4], the chemical and bioactive researches of C. saccatum were very limited. Previous chemical investigations on that plant reported that only two common steroids and three other simple molecules have been present [5]. In order to discover more biologically active C21 steroids, the chemical constituents of two species from Cynanchum have been studied systematically by our group. As results, five new C21 steroids and three new analogs have been isolated from Cynanchum otophyllum [6], [7] and C. saccatum [8], respectively. In current research, another ten C21 steroidal glycosides with six different aglycones were isolated from C. saccatum, including eight new compounds (18) (Fig. 1). For the unknown C21 steroidal glycosides, we adopted the name cynsaccatols A–H (18). Herein, the isolation and structural elucidation of these steroids (110) were described, as well as their cytotoxicity for three human cancer cell lines (HepG2, Hela and U251).

Section snippets

General methods

Melting points were measured on an X-4 digital display micromelting apparatus and are uncorrected. Optical rotations were obtained using a JASCO P-1020 polarimeter. NMR spectra were performed in C5D5N, recorded on Bruker DRX-500 and Bruker DRX-600 instruments, respectively. UV spectra were recorded on a Shimadzu UV-2450 spectropolarimeter. MS data were detected on a Agilent LC-MSD TOF spectrometer. Silica gel GF254 prepared for TLC were obtained from Qingdao Marine Chemical Company, Qingdao,

Results and discussion

The aims of our study were systematical isolation of C21 steroids and elucidation of their structures from C. saccatum. Ten C21 steroids were purified and identified by NMR technique, as well as HRESIMS. In addition, the sugar part after acid hydrolysis of each compound was further confirmed by co-TLC comparison with authentic compounds. And the absolute configurations of the monosaccharides in the hydrolysates were also elucidated by comparing their optical rotation (OR) data with those

Acknowledgement

This work was supported by the National Natural Science Foundation of China (No. 31160065).

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