Cheng-Qi Xiong

Characterization of steroidal glycosides from the extract of Paris Polyphylla var. Yunnanensis by UPLC/Q-TOF MSE.

Steroidal saponins in Rhizoma Paridis attract scientific attentions for their structural diversity and significant bioactivities. In this work, an ultra performance liquid chromatography coupled with a hybrid quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) was used to rapidly separate and identify steroidal saponins from the extract of the rhizome of Paris polyphylla var. yunnanensis (PPY). The fragment ions from glycosidic and cross-ring cleavages offered a wealth of structural information that is indicative to the aglycones, sugar types and the connecting sequence of sugar units. Based on the exact mass information, the fragmentation characteristics, and the LC retention times of 21 reference steroidal saponin standards, 98 constituents were tentatively identified with their structures proposed, which covered more than 30 types of steroidal aglycones. The 98 constituents consist of 22 pairs of structural isomers, and 40 steroidal glycosides that are identified for the first time from the nature.

Characterization and identification of steroidal saponins from the seeds of Trigonella foenum-graecum by ultra high-performance liquid chromatography and hybrid time-of-flight mass spectrometry

Ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadrupole time-of-flight mass spectrometry (Qtof MS(E)) was used to rapidly separate and identify steroidal saponins from the crude extract of the seeds of Trigonella foenum-graecum (TFG). By using the UHPLC/Qtof MS(E) data acquisition strategy, both intact precursor and fragment ion information were obtained from a single injection. Fragmentation rules for five major groups of saponins from TFG are summarized, and possible fragmentation pathways are proposed. Accurate mass measurements of molecular ions and fragment ions as well as retention times permitted the identification or tentative identification of a total of ninety-five saponins based on comparison with reference standards. This included twenty-two pairs of isomers. Thirty of these saponins were identified for the first time.

Steroidal glycosides from the rhizomes of Anemarrhena asphodeloides and their antiplatelet aggregation activity.

Five new steroidal glycosides, timosaponin J ( 1), timosaponin K ( 2), (25 S)-karatavioside C ( 5), timosaponin L ( 6), and (25 S)-officinalisnin-I ( 8), together with eight known steroidal saponins, timosaponin E (1) ( 3), purpureagitosid ( 4), timosaponin BII ( 7), timosaponin B III ( 9), anemarrhenasaponin I ( 10), anemarrhenasaponin III ( 11), anemarrhenasaponin A (2) ( 12), and timosaponin A III ( 13), were isolated from the rhizomes of Anemarrhena asphodeloides. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The aglycones of compounds 1 and 2 are new aglycones. Compounds 1- 13 were evaluated for their platelet aggregation activities, and compound 13 exhibited the strongest inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation.

Analytical and semipreparative separation of 25 (R/S)‐spirostanol saponin diastereomers using supercritical fluid chromatography

Spirostanol saponins are a class of steroidal saponins with many pharmacological activities. The structural complexity of the spirostanol saponins presents a daunting challenge in separating their 25 R/S diastereomers. Using two CHIRALPAK IC columns coupled in series, six 25 (R/S)-spirostanol saponin diastereomers from the Trigonella foenum-graecum L. seed were successfully separated using supercritical fluid chromatography (SFC) for the first time. In addition, three 25 (R/S)-spirostanol saponin diastereomers were isolated into their respective individual isomers. The structures of the isolated isomers were unambiguously confirmed by NMR analysis. The SFC method development strategy and its associated underlying principles presented in this paper are generally applicable. SFC is a viable addition to the natural product research toolbox, especially for stereoselective analysis and purification.

Steroidal saponins from Tribulus terrestris.

Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-2α,3β,22α,26-tetrol-12-one (terrestrinin C), 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin D), 26-O-β-d-glucopyranosyl-(25S)-furost-4-en-22α,26-diol-3,6,12-trione (terrestrinin E), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-3β,22α,26-triol-12-one (terrestrinin F), 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-12β,22α,26-triol-3-one (terrestrinin G), 26-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin H), and 24-O-β-d-glucopyranosyl-(25S)-5α-spirostan-3β,24β-diol-12-one-3-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation.

Polyhydroxylated Steroidal Glycosides from Paris polyphylla

Three new steroidal saponins, parisyunnanosides G-I (1-3), one new C(21) steroidal glycoside, parisyunnanoside J (4), and three known compounds, padelaoside B (5), pinnatasterone (6), and 20-hydroxyecdyson (7), were isolated from the rhizomes of Paris polyphylla Smith var. yunnanensis. Compounds 1 and 3 have unique trisdesmoside structures that include a C-21 β-d-galactopyranose moiety. All compounds were evaluated for their cytotoxicity against human CCRF leukemia cells.

Steroidal saponins from the tuber of Ophiopogon japonicus.

Eight novel steroidal saponins, ophiopogonins H-O (1-8), along with seven known steroidal saponins (9-15) were isolated from the tubers of Ophiopogon japonicus. The structures of these new compounds were determined by detailed spectroscopic analysis, including extensive 1D and 2D NMR data, and the analysis of hydrolytic reaction products. For the first time, rare furostanol saponins with disaccharide moiety linked at position C-26 of the aglycone were reported to be isolated from a natural source.

Spirostanol saponins derivated from the seeds of Trigonella foenum-graecum by β-glucosidase hydrolysis and their inhibitory effects on rat platelet aggregation.

Nine spirostanol saponins (1-9) and seven mixtures of 25 R and 25 S spirostanol saponin isomers (10-16) were obtained from the seeds of Trigonella foenum-graecum after enzymatic hydrolysis of the furostanol saponin fraction by β-glucosidase. Their structures were determined by NMR and MS spectroscopy. Among them, 1- 4, 6, 8, and 9 were new compounds and five, 11B, 12A, 13B, 14A, and 14B, were new structures observed from seven mixtures. In addition, the inhibitory effects of all saponins on rat platelet aggregation were evaluated.

Rapid isolation of new furostanol saponins from fenugreek seeds based on ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry.

An ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry method was established to rapidly identify and guide the isolation of target saponins from fenugreek seeds. Based on the online screening performance, totally forty-six furostanol saponins were detected and elucidated. Among them, twenty compounds were predicted to be new. To rapidly obtain new furostanol saponins from these seeds, a further phytochemical study was carried out under the guidance of the ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry. Finally, six new furostanol saponins, named as trigoneosides XIV (1), XV (2), XVI (3), XVIIa (4), XVIIb (5), and XIV (6), together with one known furostanol saponin, parvifloside (7), were rapidly obtained, and their definitive structures were determined by NMR and chemical evidence.

New polyoxypregnane glycosides from the roots of Marsdenia tenacissima

For the first time, a systematic phytochemical study was performed on the roots of Marsdenia tenacissima. Finally, sixteen new polyoxypregnane glycosides, marstenacissides A1-A7 (1-7) and marstenacissides B1-B9 (8-16), were isolated from M. tenacissima roots. The structures of these new compounds were established by various spectroscopic techniques, including 1D and 2D NMR spectroscopy and mass spectrometry.