Structures of steroidal saponins from the tubers of Brodiaea californica and their inhibitory activity on tumor promoter-induced phospholipid metabolism

Anti-inflammatory and antiviral activities of cynanversicoside A and cynanversicoside C isolated from Cynanchun paniculatum in influenza A virus-infected mice pulmonary microvascular endothelial cells

BACKGROUND

Outbreaks of the influenza A virus (IAV) often occur in various avian and mammalian species, including humans, causing serious respiratory injury worldwide. Therapeutic actions are limited to vaccines and a few antiviral drugs. Combination antiviral compounds and anti-inflammatory modulators to control the propagation of viruses would be more efficient therapeutic strategies for infectious diseases.

PURPOSE

This study was designed to isolate anti-inflammatory and antiviral compounds from Cynanchun paniculatum and elucidate their potential molecular mechanisms.

METHODS/STUDY DESIGNS

Bioactivity-guided isolation (via in vitro anti-inflammatory assay) was performed on the ethanolic extract of C. paniculatum, the structures of active compounds were elucidated by comparing spectral data (ESI-MS, ¹H NMR and ¹³C NMR) with literature values. The antiviral activity of active compounds against Influenza A virus (IAV) was determined using the cytopathic effect (CPE) inhibition assay. Inhibitory effects of active compounds on influenza A/FM1/1/47 (H1N1) virus infection were also determined by RT-PCR. Effect of active compounds on NF-kB and MAPK signaling pathways after virus infection was determined by ELISA.

RESULTS

Two compounds that showed great anti-inflammatory activity were isolated from C. paniculatum and elucidated as cynanversicoside A and cynanversicoside C. Cytokine assay demonstrated that cynanversicoside A and cynanversicoside C can suppress the production of TNF-α, IL-6 and IL-1β in Mice Pulmonary Microvascular Endothelial Cells (MPMEC) after Influenza virus A/FM/1/47 infection (p < .05) and also decreased the expressions of p-p65 and p-IκBα in infected cells. Furthermore, the phosphorylation of p38, ERK and JNK was also significantly attenuated. Subsequently, cynanversicoside A and cynanversicoside C treatment resulted in decreased viral replication and viral mRNA synthesis.

CONCLUSIONS

These results indicate that cynanversicoside A isolated from C. paniculatum has potent anti-inflammatory and antiviral effects on IAV-infected MPMEC by the regulation of NF-κB and MAPK signaling pathways.

Activity of two extracts of Cynanchum paniculatum against Ichthyophthirius multifiliis theronts and tomonts

The present study aims to evaluate the antiparasitic activity of active components from Cynanchum paniculatum against Ichthyophthirius multifiliis. The antiparasitic activities of two bioassay-guided fractionationated compounds from C. paniculatum identified as Cynatratoside-A and Cynanversicoside C, by comparing spectral data (NMR and ESI-MS) with literature values, were evaluated by in vitro assay. These showed that both could kill theronts of I. multifiliis at a concentration of 10·0 mg L-1, with the median effective concentration (EC50) values of 4·6 mg L-1 and 5·2 mg L-1 for Cynatratoside-A and Cynanversicoside C, respectively. Encysted tomonts were killed at concentrations of 8·0 mg L-1 with both compounds. In vivo experiments demonstrated that fish treated with both compounds at 15·0 mg L-1 carried significantly fewer parasites than controls (P < 0·05). There were no mortalities among treated fish group compared with 75% mortality of untreated fish. Cynatratoside-A and Cynanversicoside C are therefore potential candidate drugs for use against I. multifiliis.

Steroidal Saponins from Furcraea hexapetala Leaves and Their Phytotoxic Activity

Four new steroidal saponins (1-4) along with 13 known saponins were isolated from the leaves of Furcraea hexapetala. The new compounds were identified as (20R,22R,25R)-3β-hydroxy-5α-spirostan-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-β-d-glucopyranosyl-(1→3)-O-[β-d-glucopyranosyl-(1→3)-O-β-d-glucopyranosyl-(1→2)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (1), (25R)-3β-hydroxy-5α-spirost-20(21)-en-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-β-d-glucopyranosyl-(1→3)-O-[β-d-glucopyranosyl-(1→3)-O-β-d-glucopyranosyl-(1→2)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (2), (25R)-5α-spirostan-3β-ol 3-O-{β-d-glucopyranosyl-(1→2)-O-β-d-glucopyranosyl-(1→2)-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (3), and (25R)-5β-spirostan-3β-ol 3-O-{β-d-glucopyranosyl-(1→6)-O-β-d-galactopyranoside} (4) by spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry, and chemical methods. The phytotoxicity of the isolated compounds against the standard target species Lactuca sativa was evaluated. Structure-activity relationships for these compounds with respect to phytotoxic effects are discussed.

Antiparasitic effect of cynatratoside-C from Cynanchum atratum against Ichthyophthirius multifiliis on grass carp

Ichthyophthirius multifiliis (Ich), a fish ectoparasite, comprises an important challenge in the aquaculture industry. In this study, a steroidal glycoside, cynatratoside-C, isolated from Cynanchum atratum roots by bioassay-guided fractionation was used to treat I. multifiliis. The cynatratoside-C at 0.25 mg/L demonstrated a 100% mortality of I. multifiliis in vitro after 5 h exposure. The 5 h median effective concentration (EC50) of cynatratoside-C to nonencysted tomonts was 0.083 mg/L. In addition, cynatratoside-C at concentrations of 0.125 and 0.06 mg/L could completely terminate the reproduction of encysted tomonts. The cynatratoside-C at 2 mg/L could cure the infected grass carp within 48 h. The exact mechanism of cynatratoside-C for killing I. multifiliis is unknown, but it manifests itself microscopically through loss of membrane integrity of nonencysted tomonts or through releasing immature theronts from encysted tomonts. The immature theronts finally died before infecting fish. On the basis of these results, cynatratoside-C could be used as a natural anti-I. multifiliis agent.

DT-13 suppresses MDA-MB-435 cell adhesion and invasion by inhibiting MMP-2/9 via the p38 MAPK pathway

Previous research has shown that the Dwarf lilyturf tuber has antitumor effects. The antitumor ability of DT-13, a saponin monomer isolated from the roots of the Dwarf lilyturf tuber, is discussed in this study. The results showed that DT-13 inhibited the proliferation, adhesion and invasion of MDA-MB-435 cells. DT-13 decreased the excretion and expression of MMP-2/9. Furthermore, DT-13 inhibited the phosphorylation of p38 in MDA-MB-435 cells. In conclusion, the results suggest that DT-13 possesses anticancer and antimetastatic properties by inhibiting the invasion of cancer cells.

Effects of Saponin Monomer 13 of Dwarf Lilyturf Tuber on L-Type Calcium Currents in Adult Rat Ventricular Myocytes

The saponin monomer 13 of dwarf lilyturf tuber (DT-13), one of the saponin monomers of dwarf lilyturf tuber, has been found to have potent cardioprotective effects. In order to investigate the effect of DT-13 on L-type calcium currents ( I Ca,L ), exploring the mechanisms of DT-13's cardioprotective effects, we directly measured the I Ca,L in the adult rat cardiac myocytes exposed to DT-13 using standard whole-cell patch-clamp recording technique. Our results showed that DT-13 exerted inhibitory effects on the I Ca,L of the single adult rat cardiac myocytes. The current density was reduced by about 38% after exposure of the cells to DT-13 (0.1 μM) for 10 minutes, from the control value of 7.46 ± 1.31 pA/pF to 4.25 ± 0.35 pA/pF ( n = 6, p < 0.05). This I Ca,L -inhibiting action of DT-13 was concentration-dependent. DT-13 up-shifted the current-voltage (I-V) curve, but did not significantly affect the half activation potential (V0.5). V0.5 was from -11.8 ± 0.9 mV in the control to -12.6 ± 1.9 mV in the presence of DT-13 at 0.1 μmol/L. DT-13 at 0.1 μM did not markedly affect the activation of I Ca,L , but shifted the inactivation curve of I Ca,L to the left. In combination with previous reports, these results suggest that there might be a close relationship between the cardioprotective effects of dwarf lilyturf tuber and the inhibitory effects of DT-13 on L-type calcium currents.

The saponin monomer of dwarf lilyturf tuber, DT-13, reduces human breast cancer cell adhesion and migration during hypoxia via regulation of tissue factor

Adhesion and migration of tumor cells are crucial steps in tumor invasion and metastasis. In the present study, we investigated the effects of saponin monomer 13 of dwarf lilyturf tuber (DT-13) on metastasis of human breast cancer cells (MDA-MB-435) during hypoxia. The effects and molecular mechanisms of DT-13 on MDA-MB-435 cells metastatic phenotype in vitro and in vivo were evaluated by RNA interference; quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays. DT-13 had no significant effects on cell adhesion and migration under normoxia conditions. Under hypoxic conditions, MDA-MB-435 adhesion to vitronectin was inhibited by about 43.5% or 60.8% after exposure of the cells to DT-13 at 1 microM or 10 microM, respectively. DT-13 decreased the migratory response by hypoxia at 1 or 10 microM, and inhibition ratios were 20% and 30%, respectively. DT-13 inhibited hypoxia-induced expression of alphavbeta3 integrin, tissue factor (TF) and early growth response gene-1 (Egr-1) and decreased excretion of matrix metalloproteinase 9 (MMP-9) of MDA-MB-435 cells under hypoxic conditions. After Egr-1 short interference RNA (siRNA) treatment, DT-13 could still inhibit the up-regulation of TF mRNA and protein levels and its pro-coagulant activity (PCA) under hypoxia. In nude mice, DT-13 decreased extravasation of MDA-MB-435 cells in the lung after tail vein injection. Our data suggest that DT-13 inhibits MDA-MB-435 cells metastasis during hypoxia via regulation of TF, and the effect of DT-13 on TF is partly mediated by Egr-1.

Unusual 22S-spirostane Steroids from Dracaena cambodiana

From the methanol extract of Dracaena cambodiana roots two unusual 22S-spirostane steroids (1β,3β,14α,20R,22S,25R)-spirost-5-ene-1,3, 14-triol (1) and (1β,3β,14α,15α,20R,22S,25R)-spirost-5-ene-tetrol (2) have been isolated, together with a known 22R-spirostane compound, namogenin B (3). Their structures were elucidated by spectroscopic and spectrometric methods, including HRMS and extensive 1D and 2D NMR spectroscopy. Compound 1 showed significant antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Fusarium oxysporum, with MIC values of 45.0, 25.0 and 50.0 μg/mL, respectively.

The saponin monomer of dwarf lilyturf tuber, DT-13, reduces L-type calcium currents during hypoxia in adult rat ventricular myocytes

The saponin monomer 13 of dwarf lilyturf tuber (DT-13), one of the saponin monomers of dwarf lilyturf tuber, has been found to have potent cardioprotective effects. In order to investigate the effects of DT-13 on L-type calcium currents (I(Ca,L)), exploring the mechanisms of DT-13's cardioprotective effects in the condition of pathophysiology, we directly measured the I(Ca,L) during hypoxia in the adult rat cardiac myocytes exposed to DT-13 using standard whole-cell patch-clamp recording technique. Our previous results showed that DT-13 exerted decreasing effects on the I(Ca,L) of the single adult rat cardiac myocytes. In the condition of hypoxia, the current density was inhibited by about 29% after exposure of the cells to DT-13 (0.1 micromol L(-1)) for 10 min, from 6.96+/-1.05 pA/pF to 4.38+/-0.35 pA/pF (n=5, P<0.05). This I(Ca,L)-inhibiting action of DT-13 was concentration-dependent and showed no frequency-dependence. DT-13 up-shifted the current-voltage (I-V) curve. Steady-state activation of I(Ca,L) was not affected markedly, and the half activation potential (V(0.5)) in the presence of DT-13 (0.1 micromol L(-1)) was also not significantly different. DT-13 at 0.1 micromol L(-1) markedly accelerated the voltage-dependent steady-state inactivation of calcium current and shifted the steady-state inactivation curve of I(Ca,L) to the left. In combination with previous reports, these results suggest that there might be a close relationship between the cardioprotective effects of DT-13 and L-type calcium channels in the condition of hypoxia.

The bioactivity of saponins: triterpenoid and steroidal glycosides

Triterpenoid and steroidal glycosides, referred to collectively as saponins, are bioactive compounds present naturally in many plants. They have considerable potential as pharmaceutical and/or nutraceutical agents in natural or synthetic form. Saponins, from a variety of sources, have been shown to have hypocholesterolemic, anti-coagulant, anticarcinogenic, hepatoprotective, hypoglycemic, immunomodulatory, neuroprotective, anti-inflammatory and anti-oxidant activity. This paper reviews saponin research of the last decade, focussing on developments in understanding their mechanism of action and structure-activity relationships. Virtually all of this work has used animal and in vitro models. To date there are very few human data.

Dependence of the 1H NMR chemical shifts of ring F resonances on the orientation of the 27-methyl group of spirostane-type steroidal sapogenins

A relationship between the 1H NMR chemical shifts of the ring F resonances and orientation of the H3-27 group has been derived for the establishment of 25R- and 25S-stereochemistry in spirostane type of steroidal sapogenins.