Total steroidal alkaloids from Veratrum patulum L. Inhibit platelet aggregation, thrombi formation and decrease bleeding time in rats

Comparative transcriptome analysis of Veratrum maackii and Veratrum nigrum reveals multiple candidate genes involved in steroidal alkaloid biosynthesis

Veratrum (Melanthiaceae; Liliales) is a genus of perennial herbs known for the production of unique bioactive steroidal alkaloids. However, the biosynthesis of these compounds is incompletely understood because many of the downstream enzymatic steps have yet to be resolved. RNA-Seq is a powerful method that can be used to identify candidate genes involved in metabolic pathways by comparing the transcriptomes of metabolically active tissues to controls lacking the pathway of interest. The root and leaf transcriptomes of wild Veratrum maackii and Veratrum nigrum plants were sequenced and 437,820 clean reads were assembled into 203,912 unigenes, 47.67% of which were annotated. We identified 235 differentially expressed unigenes potentially involved in the synthesis of steroidal alkaloids. Twenty unigenes, including new candidate cytochrome P450 monooxygenases and transcription factors, were selected for validation by quantitative real-time PCR. Most candidate genes were expressed at higher levels in roots than leaves but showed a consistent profile across both species. Among the 20 unigenes putatively involved in the synthesis of steroidal alkaloids, 14 were already known. We identified three new CYP450 candidates (CYP76A2, CYP76B6 and CYP76AH1) and three new transcription factor candidates (ERF1A, bHLH13 and bHLH66). We propose that ERF1A, CYP90G1-1 and CYP76AH1 are specifically involved in the key steps of steroidal alkaloid biosynthesis in V. maackii roots. Our data represent the first cross-species analysis of steroidal alkaloid biosynthesis in the genus Veratrum and indicate that the metabolic properties of V. maackii and V. nigrum are broadly conserved despite their distinct alkaloid profiles.

The protective effect of rivaroxaban with or without aspirin on inflammation, oxidative stress, and platelet reactivity in isoproterenol-induced cardiac injury in rats

Coronary artery diseases are principal sources of mortality and disability in global human population. Progressively, rivaroxaban is being evaluated for the prevention of atherosclerotic thrombi, particularly with anti-platelet agents. Hence, the current report aimed to investigate the cardioprotective effect of rivaroxaban on isoproterenol (ISO)-induced cardiac injury model in rats and the possible synergistic effect when combined with aspirin. Male Wistar rats were randomly assigned into five different groups. Cardiac injury was induced by subcutaneous injection of ISO (85 mg/kg) for 2 consecutive days. Rat tail bleeding time was performed prior to sacrifice. Cardiac enzymes, platelet activity, inflammatory, and oxidative stress biomarkers levels were measured using enzyme-linked immunoassay (ELISA). Pre-administration of rivaroxaban alone and on combination with aspirin prevented ISO-induced increase in cardiac thiobarbituric acid reactive substances (TBARS), interleukin 6 (IL-6), and thromboxane B2 (TXB2) levels. Moreover, a significant prolongation of bleeding time was demonstrated among aspirin, rivaroxaban, and aspirin plus rivaroxaban treated groups. On the other hand, the combination treatment of aspirin plus rivaroxaban showed no marked difference in these biomarkers and bleeding time relative to either drug administered separately. However, a prominent decrease of cardiac 6-keto prostaglandin F1α (6-Keto-PGF1α) level was displayed in the combination treatment when compared with ISO and rivaroxaban-treated groups, whereas no significant improvement was seen in cardiac glycoprotein V (GPV) levels except in aspirin-treated group. The study results demonstrated that rivaroxaban decreases cardiac oxidative stress, inflammation, and platelets reactivity. However, the addition of rivaroxaban to aspirin did not seem to show synergistic antioxidant, anti-inflammatory, or antiplatelet effect.

Steroidal alkaloid with unprecedented triheterocyclic architecture

Veratrazine A (1), a steroidal alkaloid with a unique 6/5/5 triheterocyclic scaffold as the side chain, was isolated from Veratrum stenophyllum, and its structure was established via spectroscopic analyses and X-ray diffraction. A plausible biosynthetic pathway for 1 is proposed. Bioassy exhibits moderate anti-inflammatory activities in vitro and in vivo.

New steroidal alkaloids with anti-inflammatory and analgesic effects from Veratrum grandiflorum

ETHNOPHARMACOLOGICAL RELEVANCE

"Li-Lu", the roots and rhizomes of Veratrum grandiflorum (Melianthiaceae), has been historically used as a traditional folk medicine for the treatment of wrist pain, fractures, sores, and inflammation in Yunnan Province, China. However, the anti-inflammatory and analgesic studies of this plant have seldom reported.

AIM OF THE STUDY

To evaluate the anti-inflammatory and analgesic properties related to the traditional usage of V. grandiflorum both in vitro and in vivo, and further explore the accurate bioactive compounds from the medicinal plant.

MATERIALS AND METHODS

Phytochemical investigation was carried out by chromatographic methods and their structures were established based on extensive spectra and comparison with corresponding data in the reported literatures. Anti-inflammatory activities were assessed by the suppression of lipopolysaccharide-activated inflammatory mediators in RAW 264.7 macrophage cells in vitro. Furthermore, anti-inflammatory and analgesic effects were evaluated based on carrageenan-induced paw edema and acetic acid-stimulated writhing in mice.

RESULTS

The methanol extract (ME) of V. grandiflorum significantly alleviated the paw edema caused by carrageenan and the writhing numbers induced by acetic acid. Subsequent phytochemical investigation led to isolated of 21 steroidal alkaloids, including seven new compounds, veragranines C-I (1-7). Anti-inflammatory test indicated that steroidal alkaloids could decrease the expression of cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells at a concentration of 5.0 μg/ml in vitro, comparable to DXM. Moreover, five new steroidal alkaloids (2, 4, 5, 6, and 7) and two major steroidal alkaloids (9 and 13) significantly decreased the numbers of writhing in mice at the doses of 0.5 and/or 1.0 mg/kg (p < 0.01/0.05), roughly comparable to Dolantin™ at 10.0 mg/kg.

CONCLUSIONS

The investigation supported the traditional use of V. grandiflorum and provided new steroidal alkaloids as potent analgesic agents.

Hemostatic and hepatoprotective bioactivity of Junci Medulla Carbonisata-derived Carbon Dots

AIM

To explore the hemostatic and hepatoprotective bioactivity of Junci Medulla Carbonisata-derived Carbon Dots (JMC-CDs).

MATERIALS & METHODS

The JMC-CDs were characterized using transmission electron microscopy, HPLC, Fourier transform IR, UV, fluorescence and x-ray photoelectron spectroscopy. The hemostatic effect of JMC-CDs was evaluated and confirmed by trauma hemorrhagic animal models and internal hemorrhage animal model induced by Deinagkistrodon acutus venom.

RESULTS

The JMC-CDs ranged in diameter from 1.0 to 8 nm and had a yield of 0.12%. Moreover, JMC-CDs not only possessed remarkable hemostatic efficacy but could also prevent hemorrhage-induced liver injury, as demonstrated by the reduced serum levels of biochemical indicators of liver damage such as aspartate aminotransferase, alanine amino transferase, alkaline phosphatase, total bilirubin and direct bilirubin.

CONCLUSION

The JMC-CDs may have great potentials in clinical practice.

New approaches in tail-bleeding assay in mice: improving an important method for designing new anti-thrombotic agents

This report describes a modified, simple, low-cost and more sensitive method to determine bleeding patterns and haemoglobin concentration in a tail-bleeding assay using BALB/c mice and tail tip amputation. The cut tail was immersed in Drabkin's reagent to promote erythrocyte lysis and haemoglobin release, which was monitored over 30 min. The operator was blinded to individual conditions of the mice, which were treated with either saline (NaCl 0.15m), DMSO (0.5%) or clinical anti-thrombotic drugs. Our experimental protocols showed good reproducibility and repeatability of results when using Drabkin's reagent than water. Thus, the use of Drabkin's reagent offered a simple and low-cost method to observe and quantify the bleeding and rebleeding episodes. We also observed the bleeding pattern and total haemoglobin loss using untreated animals or those under anti-coagulant therapy in order to validate the new Drabkin method and thus confirm that it is a useful protocol to quantify haemoglobin concentrations in tail-bleeding assay. This modified method provided a more accurate results for bleeding patterns in mice and for identifying new anti-thrombotic drugs.

A Novel Reduplicate Strategy for Tracing Hemostatic Compounds from Heating Products of the Flavonoid Extract in Platycladi cacumen by Spectrum-Effect Relationships and Column Chromatography

Platycladi cacumen and its processed product have been utilized as a Chinese medicine to treat hemorrhages. In this study, the base peak chromatogram fingerprints of heating products of total flavonoids in Platycladi cacumen were established by high performance liquid chromatography coupled with mass spectroscopy/mass spectroscopy (HPLC-MS/MS), and the hemostatic activities were studied by hemostatic screening tests in vivo. The spectrum-effect relationships between fingerprints and hemostatic activities were analyzed by using canonical correlation analysis to trace the peaks responsible for the significant hemostatic effects. Peak 10 and peak 12 were correlated most closely, thus probably being the main hemostatic compounds. To confirm the reliability of this strategy, the targeted unknown peak was obtained by bioactivity-guided isolation, characterized by MS, ¹H-NMR, ¹³C-NMR, and 2D-NMR spectroscopies, and referred to as cecarbon as a new compound. In addition, the isolated compound exhibited hemostatic effect in a dose-dependent manner with different potencies in vitro and existed in Platycladi cacumen Carbonisatus. A novel dereplication strategy was employed to trace and identify the active compounds of other herbs that have bioactivity enhancement after processing using spectrum–effect relationships and column chromatography.

Antiplatelet and antithrombotic effect of Phyllostachys pubescens leaves and Mume Fructus combination

Background

Agents currently used for the treatment and prevention of thrombosis have a number of side effects. We conducted this study to develop antithrombotic agents from herbs that are used in food.

Methods

The 80% (v/v) ethanol extracts of Phyllostachys pubescens leaf (PL) and Mume Fructus (MF) and their combinations—2:1 (PM21), 1:1 (PM11), and 1:2 (PM12)—were evaluated on rat platelet aggregation induced by adenosine diphosphate (ADP) in vitro and on arteriovenous shunt thrombosis after 3 days of oral treatment in rats in vivo.

Results

At 100 μg/mL, PM21 and PM11 inhibited in vitro ADP-induced aggregation by 44.0 ± 4.3% and 30.0 ± 3.2%, respectively, whereas PL, MF, and PM12 weakly or scarcely inhibited ADP-induced aggregation by 3.9 ± 3.2%, 13.0 ± 2.7%, and 5.2 ± 1.3%, respectively. The IC₅₀ values of PM21 on ADP-, collagen-, and thrombin-induced platelet aggregations were 135.6 ± 7.4 μg/mL, 142.7 ± 5.8 μg/mL, and 186.5 ± 9.7 μg/mL, respectively. In an in vivo rat arteriovenous-shunt thrombosis model, thrombus weight was significantly decreased after the oral administration of 400 mg/kg PL (27.8 ± 3.0%, p < 0.01) or MF (35.2 ± 2.1%, p < 0.01), and with a good accord to the in vitro results, the combination of PL and MF in the ratio of 2:1, PM21 (60.9 ± 1.2%, p < 0.001), showed a superior antithrombotic effect to those of individual extracts. At dosages of 200 mg/kg, 100 mg/kg, and 50 mg/kg, PM21 dose-dependently decreased thrombosis weight (ED₅₀, 314 mg/kg).

Conclusion

These results suggest that combination preparations of PL and MF, especially their 2:1 combination, can increase antiplatelet and antithromboticeffects more than PL and MF alone, offering evidence for a potential novel combination antithrombotic therapy.