Bioactive C₂₁ Steroidal Glycosides from the Roots of Cynanchum otophyllum That Suppress the Seizure-like Locomotor Activity of Zebrafish Caused by Pentylenetetrazole

Abstract

Six new C21 steroidal glycosides, cynotophyllosides A-F (1-6), together with 16 known compounds, were isolated from the roots of Cynanchum otophyllum. The structures of the new compounds were elucidated by spectroscopic analysis and chemical methods. The three major components, otophylloside F (15), otophylloside B (17), and rostratamine 3-O-β-D-oleandropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-β-D-cymaropyranoside (18), suppressed the seizure-like locomotor activity caused by pentylenetetrazole in zebrafish. Preliminary structure-activity relation studies revealed that a pregnene skeleton with a C-12 ester group (ikemaoyl > cinnamoyl > hydroxy > p-hydroxybenzoyl) and a C-3 sugar chain consisting of three 2,6-dideoxysaccharide units is essential for this suppressive activity.

Identification and Evaluation of Antiepileptic Activity of C21 Steroidal Glycosides from the Roots of Cynanchum wilfordii

“…Analysis of its 13 C NMR, 1 H− 1 H COSY, HSQC, and HMBC spectra showed the aglycone of 6 to be qingyangshengenin. 24 Two anomeric proton signals at δ H 4.95 (1H, dd, J = 2.1, 9.8 Hz) and 4.56 (1H, dd, J = 2.1, 9.8 Hz) corresponding to two anomeric carbon signals at δ C 95.9 and 100.5 revealed that 6 contained two saccharide moieties with β glycosidic linkages. (Tables 2 and 3), which is in accordance with the molecular mass difference of 14 amu between 9 and 8.…”

“…24,27 Thus, 4 was characterized as caudatin 3-O-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside. Compound 5 gave a sodium adduct ion at m/z 835.4464 in the HRTOFMS, revealing its molecular formula to be C 42 H 68 O 15 .…”

“…The 1 H and 13 C NMR data of the aglycone part of 5 were similar to those of 4 (Tables 1 and 3), except for the absence of signals due to the ikemaoyl group and the shielding of H-12 (δ H 3.70) and C-12 (δ C 69.6), which indicated the aglycone of 5 to be deacetylmetaplexigenin. 24 Three glycosyl units are present in the structure of 5 according to three anomeric proton signals at δ H 4.98 (1H, d, J = 3.6 Hz), 4.83 (1H, dd, J = 2.1, 9.7 Hz), and 4.68 (1H, dd, J = 1.9, 9.9 Hz) and corresponding anomeric carbon resonances at δ C 101.0, 95.8, and 99.2, respectively. The sugar moieties were determined to be two β-cymaropyranosyl and one α-diginopyranosyl by analyzing the coupling constants ( Table 1) Figure S6C, Supporting Information), which indicated the presence of a para-disubstituted benzene ring.…”

“…In our previous work, three C 21 glycosides were found to exhibit more potent antiseizurelike locomotor activity than phenytoin sodium in the zebrafish model. 24 Herein, the isolation and identification of nine new C 21 steroidal glycosides, named cynawilfosides A−I (1−9), along with 12 known ones from the roots of C. wilfordii, as well as the antiepileptic activities of several abundant isolates using the mouse MES test are discussed.…”

Zebrafish Models of Human Disease: Gaining Insight into Human Disease at ZFIN

“…To facilitate a better understanding of epilepsy, zebrafish models of epilepsy have been created by administering pentetrazol to induce seizures (Table 1D). Studies that utilize this method have investigated potential therapeutic compounds to alleviate seizure states as well as to understand changes in gene expression due to seizure events (Barbalho et al 2016; Li et al 2015; Siebel et al 2015). PD is a neurodegenerative disease that results from the loss of dopaminergic cells in the brain (Beitz 2014; Pienaar et al 2010).…”