C21 steroidal glycosides from the roots of Cynanchum saccatum
Graphical abstract
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 (1–8) (Fig. 1). For the unknown C21 steroidal glycosides, we adopted the name cynsaccatols A–H (1–8). Herein, the isolation and structural elucidation of these steroids (1–10) 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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Cited by (9)
Review on Pregnane Glycosides and Their Biological Activities
2022, Phytochemistry LettersCitation Excerpt :Eight pregnane glycosides named cynsaccatol (A-G) (182-188) and saccatum A (189) were obtained from the roots of Cynanchum saccatum. These compounds (182-189) were tested for their cytotoxicity in vitro using three human cancer cell lines (HepG2, Hela, and U251), and compounds 182, 185, 186, and 189 showed weak inhibitory activities against different cell lines (Zhang et al., 2015a). Wilfoside C3N (190) and otophylloside B (191) were obtained from roots of Cynanchum otophyllum Schneid.
Synthesis and biological evaluation of 3β-O-neoglycosides of caudatin and its analogues as potential anticancer agents
2022, Bioorganic and Medicinal ChemistryCitation Excerpt :To date, much effort has been made to study the anticancer activities of C21-steroidal glycosides from Cynanchum plants. Preliminary structure–activity relationship (SAR) analysis indicated that the existence of oligosaccharide chain with one to three sugar units at C-3 of C21-steroidal aglycone had more significant anticancer activity,6–11 especially those of caudatin glycosides.12–14 Caudatin (1) is a major C21-steroidal aglycone isolated from Cynanchum wilfordii15 and Cynanchum otophyllum,16 which was reported as a potential anticancer substance.17–19
C<inf>21</inf> steroidal glycosides from Cynanchum auriculatum and their neuroprotective effects against H<inf>2</inf>O<inf>2</inf>-induced damage in PC12 cells
2017, PhytochemistryCitation Excerpt :The HMBC correlations from δH 5.35 (H-12) to C-1′ (δC 165.4) in 22 and from δH 5.05 (H-12) to C-1′ (δC 166.1) in 23 enabled location of a benzoyl group and an ikemaoyl group at C-12 of 22 and 23, respectively. Based on the other NMR data assigned to their aglycones and those in previous isolates, 12-O-benzoyldeacylmetaplexigenin 3-O-β-D-oleandropyranosyl-(1 → 4)-β-D- digitoxopyranoside and caudatin-3-O-β-D-cymaropyranosyl-(1 → 4)-β-D- oleandropyranosyl-(1 → 4)-β-D-cymaropyranoside, the aglycones of 22 and 23 were identified as 12-O-benzoyldeacylmetaplexigenin and caudatin, respectively (Li et al., 2008; Zhang et al., 2015a,b). For their sugar parts, the other signals due to sugar moiety of 22 and 23 were very similar to those of 8, together with the key correlations in HMBC and GC analysis, suggesting that they had the same sugar chain as 8, which were located at C-3, also confirmed by the correlation in HMBC of δH 5.51 (DigitI H-1)/δC 77.7 (C-3).
14,15-Secopregnane-type C<inf>21</inf>-steriosides from the roots of Cynanchum stauntonii
2017, PhytochemistryCitation Excerpt :Pregnane glycosides have been suggested by the phytochemical community to be the major native chemical constituents (Qiu et al., 1989; Shibano et al., 2012; Sugama et al., 1986; Wang et al., 2004a; Yu et al., 2013a; Yu et al., 2013b) of Cynanchum species. The normal four-ring C21-pregnane-type skeleton, the unusual 13,14:14,15-diseco-C21-pregnane-type skeleton and the equally unusual 14,15-seco-C21-pregnane-type skeleton have all been found among pregnane glycosides from Cynanchum species (Bai et al., 2008; Liu et al., 2006; Wang et al., 2004b; Yin et al., 2016; Zhang et al., 2015). It is well known in natural medicinal chemistry that C21-steroids are one class of structurally complex and biologically active compounds.
Seco-pregnane steroidal glycosides from the roots of Cynanchum stauntonii
2016, Phytochemistry LettersCitation Excerpt :C21 steroidal glycosides were mainly abundant in plants of the family Asclepiadaceae, which are widely distributed in tropical and subtropical regions throughout the world (Araya et al., 2012), especially in the genus Cynanchum plants (Zhang et al., 2015).
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Those authors contributed equally to this work.