[Saponins of anemarrhenae rhizoma]

Two New Compounds from Allii Macrostemonis Bulbus and Their In Vitro Antioxidant Activities

Two new compounds named 4,4'-bis(β-D-glucopyranosyloxy)biphenyl (1) and spirostane-25(27)-en-2α,3β-diol-3-O-β-D-xylopyranosyl(1→3)-β-D-glucopyranosyl(1→4)-β-D-galactopyranoside (2) were isolated from n-butanol extraction part of 80% ethanol extract of Allii Macrostemonis Bulbus. Alongside these, ten known compounds (3-12) were also identified, including a flavonoid glycoside (3), seven steroids (4-10), a nucleoside (11), and a phenylpropanoid glycoside (12) were found. Notably, compounds 3-6 were isolated from this plant for the first time. The structures of all compounds were confirmed using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D, and 2D NMR spectroscopy. Some of these compounds showed strong antioxidant activity, and compound 1 demonstrated the most potent reduction of ferric ions (Fe3+) with an IC50 value of 0.59 ± 0.18 mg/mL. Compounds 2 and 3 exhibited the highest scavenging activity against superoxide anion radicals (O2-·) with an IC50 value of 0.02 ± 0.01 mg/mL. Additionally, compound 3 displayed substantial scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) with IC50 values of 0.21 ± 0.17 mg/mL and 0.02 ± 0.01 mg/mL, respectively. The discovery of these two new compounds is a reference for identifying Allii Macrostemonis Bulbus quality markers. Moreover, their exceptional antioxidant activity offers a promising avenue for uncovering novel natural antioxidants.

Steroidal Saponins from the Rhizomes of Anemarrhena asphodeloides

Four new steroid saponins 1-4 were isolated from the rhizomes of Anemarrhena asphodeloides (Asparagaceae), as well as four known saponins: anemarsaponin B (5) timosaponin D (6), timosaponin E1 (7) anemarsaponin B II (8). Their structures were established through UV and NMR as well as MS data. All the compounds were evaluated for cytotoxicity against HepG2 and SGC7901 human cancer lines. Compounds 3 and 7 displayed medium antiproliferative activities on HepG2 and SGC7901 cells, with IC50 values of 43.90 and 57.90 μM, respectively.

Cytotoxic activities of chemical constituents from rhizomes of Anemarrhena asphodeloides and their analogues

Seven steroidal saponins (1-7) and two xanthones (8, 9) were isolated from the rhizomes of Anemarrhena asphodeloides. Then in order to discover more analogues, which may possess good biological activity, the structural modifications of 2 and 9 were performed by acid hydrolysis and acetylation. Consequently, one novel steroidal saponin (2d, timosaponin BII-d), three compounds (2c, 2e and 2f) which were also the new products prepared by the diluted acid hydrolysis of 3 by our group previously, and four known compounds (2a, 2b, 9a and 9b) were obtained. The structures were elucidated by analyses of NMR and MS data. All the compounds were evaluated for their cytotoxicities against BEL-7402, HT-29, HeLa and MDA-MB-468 cell lines in vitro by Sulforhodamine protein coloration method. Compounds 1, 2, 2b, 4-6, 9a and 9b showed certain anti-proliferative activities against the four cell lines, in which compounds 2, 4 and 9b exhibited especially more potent activities. The structure-activity relationships of these compounds were simply discussed.

Steroidal glycosides from the underground parts of Yucca glauca and their cytotoxic activities

Six steroidal glycosides and 14 known compounds were isolated from the underground parts of Yucca glauca (Agavaceae). Their structures were determined from extensive spectroscopic analysis, including analysis of two-dimensional NMR data, and from chemical transformations. The compounds were also evaluated for cytotoxic activities against HL-60 human leukemia cells and A549 human lung adenocarcinoma cells. Four spirostanol glycosides and three furostanol glycosides exhibited cytotoxic activities against both HL-60 and A549 cells. Two of the compounds induced apoptosis in HL-60 cells.

Enzymatic synthesis of alpha-glucosyl-timosaponin BII catalyzed by the extremely thermophilic enzyme: Toruzyme 3.0L

Timosaponin BII (BII), a steroidal saponin showing potential anti-dementia activity, was converted into its glucosylation derivatives by Toruzyme 3.0L. Nine products with different degrees of glucosylation were purified and their structures were elucidated on the basis of (13)C NMR, HR-ESI-MS, and FAB-MS spectra data. The active enzyme in Toruzyme 3.0L was purified to electrophoretic homogeneity by tracking BII-glycosylase activity and was identified as Cyclodextrin-glycosyltransferase (CGTase, EC 2.4.1.19) by ESI-Q-TOF MS/MS. In this work, we found that the active enzyme catalyzed the synthesis of alpha-(1-->4)-linked glucosyl-BII when dextrin instead of an expensive activated sugar was used as the donor and showed a high thermal tolerance with the most favorable enzymatic activity at 100 degrees C. In addition, we also found that the alpha-amylases and CGTase, that is, GH13 family enzymes, all exhibited similar activities, which were able to catalyze glucosylation in steroidal saponins. But other kinds of amylases, such as gamma-amylase (GH15 family), had no such activity under the same reaction conditions.

Novel furostanol saponins from the bulbs of Allium macrostemon B. and their bioactivity on [Ca2+]i increase induced by KCl

Chemical reinvestigation of the ethanol extract of the dried bulbs of Allium macrostemon B. led to the isolation of two novel furostanol saponins, named macrostemonoside M (1) and macrostemonoside N (2), together with six known saponins. The structures of new compounds were elucidated on the basis of extensive spectroscopic analysis including 1D and 2D NMR as (25R)-22-hydroxy-5beta-furostane-1beta,2beta,3beta,6alpha-tetraol-26-O-beta-D-glucopyranoside and 22-hydroxy-5beta-furost-25-(27)-ene-1beta,2beta,3beta,6alpha-tetraol-26-O-beta-D-glucopyranoside, respectively. The pharmacological activities of all the saponins on [Ca2+]i increase induced by KCl were evaluated.

Potent apoptotic effects of saponins from Liliaceae plants in L1210 cells

We isolated eight saponins, a hexacyclic lanosterol tetraglycoside (1), a 27-norlanosterol tetraglycoside (2) and six spirostanol oligoglycosides (3-8), from the plants of the family Liliaceae. In murine leukaemic L1210 cells, saponins 5 and 7 at a concentration of 1 microM showed potent cytotoxic activity and the activities were in the following decreasing order: 5, 7, 1, 3, 2, 8, 4, 6. At a concentration of 10 microM, not only 5 and 7 but also 3 and 8 markedly caused cell death. The flow cytometric analysis indicated that 7 and 8 caused a concentration- and time-dependent apoptosis of L1210 cells (EC50 value = approximately 5 microM). The morphological observation using a light microscope revealed that both 7 and 8 induced shrinkage in cell soma and chromatin condensation, suggesting apoptotic cell death. Moreover, in agarose gel electrophoretic analysis, a typical apoptotic DNA ladder pattern was observed after treatment with both 7 and 8. These results suggest that 7 and 8 caused the death of L1210 cells through the apoptotic process. These compounds may become powerful pharmacological tools for studying the molecular mechanism of apoptosis.

Spirostanols obtained by cyclization of pseudosaponin derivatives and comparison of anti-platelet agglutination activities of spirostanol glycosides

Naturally occurring saponins 3 and 4 have a normal type F ring and alpha-arranged CH(3)-21 group. Treatments of pseudosaponin peracetates 18 and 19 derived from 3 and 4, respectively, with alcoholic KOH, followed by acidification with acetic acid, gave spirostanols 20 and 22 having iso type F rings as major products. Structural analyses of sapogenins and saponins derived from pseudo derivatives 11, 12, 18 and 19 were performed by comparisons of their 1H-NMR spectral data and the X-ray analytical data of 3-O-p-bromobenzoyl sarsasapogenin 7, 3-O-acetyl diosgenin 13 and saponin 20. The mechanisms of ring-closure reaction of the side chain at C-22 of pseudosapogenins and pseudosaponins were deduced using stereomodels of the spirostanols derived from 11 under various reaction conditions. Inhibitory activities of saponin diglycosides 3, 4, 20, 21 and 25 on human platelet agglutinations induced by ADP and ristocetin were compared.

Effect of timosaponin E1 and E2 on superoxide generation induced by various stimuli in human neutrophils and on platelet aggregation in human blood

We have reported that six steroidal saponins isolated from Anemarrhenae rhizoma had various effects on stimulus-induced superoxide generation in human neutrophils. In this paper, two novel steroidal saponins, timosaponins E1 and E2 were isolated from Anemarrhenae rhizoma, and the effects of these steroidal saponins on superoxide generation in human neutrophils were investigated. Timosaponins E1 and E2 significantly inhibited N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide generation in a concentration-dependent manner, but not that induced by arachidonic acid (AA). On the other hand, both compounds enhanced superoxide generation induced by phorbol 12-myristate 13-acetate (PMA) in a concentration-dependent manner. The superoxide generation induced by PMA with timosaponins E1 and E2 was suppressed by staurosporine, an inhibitor of protein kinase C, but was not suppressed by genistein, an inhibitor of protein tyrosine kinase. Tyrosyl phosphorylation of a 58 kDa protein, which was increased by fMLP, was inhibited by timosaponins E1 and E2. Timosaponins E1 and E2 also inhibited the generation of a 47 kDa protein and platelet aggregation in human blood. The results suggest that protein tyrosine kinase participates in fMLP-mediated superoxide generation by timosaponin E1- and E2-treated human neutrophils.

Effect of six steroidal saponins isolated from anemarrhenae rhizoma on platelet aggregation and hemolysis in human blood

Six steroidal saponins were isolated from Anemarrhena asphodeloides Bunge (Liliaceae), a traditional chinese medicine, and named anemarrhenasaponin I (An-I), anemarrhenasaponin Ia (An-Ia), timosaponin B-I (TB-I), timosaponin B-II (TB-II), timosaponin B-III (TB-III), and timosaponin A-III (TA-III). The effects of these six compounds on platelet aggregation and hemolysis in human blood were studied. All these compounds provoked remarkable inhibiting effect on platelet aggregation, and activated partial thromboplastin times (APTT) are sensitive to the presence of these six compounds. Using an in vitro system, APTT was delayed with the increment of the concentrations of these six compounds. In these six compounds, only timosaponin A-III appeared a strong effect on hemolysis, and anemarrhenasaponin Ia had a slight effect on hemolysis, other had no effect on hemolysis. These results suggested that these steroidal saponins isolated from Anemarrhena asphodeloides Bunge (Liliaceae) might be used as a novel antithrombotic therapeutic agents in post-myocardial infarction.