Xiao Lin

Effect and mechanism of senkyunolide I as an anti-migraine compound from Ligusticum chuanxiong

Objective  To evaluate the analgesic and anti‐migraine activities of senkyunolide I from Ligusticum chuanxiong.

A polysaccharide, MDG-1, induces S1P1 and bFGF expression and augments survival and angiogenesis in the ischemic heart.

Ophiopogon japonicus is a traditional Chinese medicine used to treat cardiovascular disease. Recent studies have confirmed its beneficial properties, but not the mechanism of action. Herein, we investigate the anti-ischemic properties of a water-soluble beta-d-fructan (MDG-1) from Ophiopogon japonicus, and assess the cytoprotective and proangiogenic effects of MDG-1. MDG-1 protects cardiomyocyte and microvascular endothelial cells (HMEC-1) against oxygen glucose deprivation (OGD)-induced cell death, as well as protect myocardial cells from ischemia-induced death occurring after coronary artery ligation in rats. Meanwhile, MDG-1 stimulates the differentiation of HMEC-1 cells into capillary-like structures in vitro and functions as a chemoattractant in migration assays, and promotes neovascularization in ischemic myocardium. In addition, MDG-1 upregulates sphingosine kinase 1 and sphingosine-1-phosphate (S1P) receptor 1 expression. Both MDG-1 and S1P induce basic fibroblast growth factor (bFGF) expression in HMEC-1 cells. Further study revealed that both MDG-1 and S1P induce Akt and ERK phosphorylation in a dose- and time-dependent manner, an effect that is attenuated by pre-treatment with either the Akt inhibitor wortmannin or the ERK inhibitor PD98059, and MDG-1 can also induce eNOS phosphorylation and increases in production of NO. These data indicate that MDG-1 presented remarkable anti-ischemic activity and protects cardiomyocyte and HMEC-1 cells from ischemia-induced cell damage by inducing S1P1 and bFGF cytoprotective and proangiogenic effects via the S1P/bFGF/Akt/ERK/eNOS signaling pathway.

Poly(ethylene glycol)-Radix Ophiopogonis polysaccharide conjugates: Preparation, characterization, pharmacokinetics and in vitro bioactivity

Radix Ophiopogonis polysaccharide (ROP), a natural graminan-type fructan with Mw of ∼5kDa, had been found to have an excellent anti-myocardial ischemic activity. However, its rapid renal excretion following administration remarkably limits its efficacy and clinical use, which makes necessary the development of an effective delivery system. In this article, the feasibility of PEGylation to solve this problem was examined. A moderate coupling reaction between the hydroxyl-activated ROP and the amino-terminated mPEG was chosen to PEGylate ROP. Five different mPEG-ROP conjugates (with mPEG of molecular mass 2, 5 or 20kDa) were prepared, purified, characterized and evaluated in pharmacokinetics and in vitro bioactivity. Results showed that only when the apparent molecular weight of the conjugate approached to a certain value, would its plasma elimination reduce abruptly. In general, the conjugation caused the reduction in the bioactivity of ROP; however, well-preserved bioactivity was observed when the grafting degree of the conjugate was lower. Among the five conjugates studied, the one with an average 1.3 mPEG (20kDa) residues per single ROP was found to be satisfactory both in plasma retention and in bioactivity. It had a 47.4-fold increased elimination half-life and preserved approximately 74% of the bioactivity of ROP; moreover, the decrease in bioactivity is not significant. These findings demonstrate that PEGylation would be a promising approach for improving the clinical efficacy of ROP by prolonged retention in plasma.

Influence of sulfation on anti-myocardial ischemic activity of Ophiopogon japonicus polysaccharide

Ophiopogon japonicus polysaccharide (FOJ-5) from Radix ophiopogonis has shown anti-myocardial ischemic action in vitro and in vivo in our previous studies. In order to clarify the influence of chemical modifications on the action, a series of sulfated FOJ-5 (FOJ-5-S) with different substitution degrees were prepared and the anti-myocardial ischemic action of the natural FOJ-5 and the FOJ-5-S were studied in vitro and in vivo. Langendorff isolated rat hearts and acute myocardial ischemic rats induced by isoprenaline were employed as myocardial ischemic models in our experiments. The amplitude and frequency of cardiac contraction, coronary blood flow at different time points after ischemia/reperfusion were measured in vitro. The ST segment shift in electrocardiogram and lactate dehydrogenase level in blood plasma were observed on the in vivo model. The results indicated that FOJ-5 and FOJ-5-S had the anti-myocardial ischemic action compared with non-treated vehicle groups. Furthermore, it was found that FOJ-5-S had significant action on the in vivo model compared with FOJ-5 (P < 0.05). And the obtained results from the further study also indicated that only when the degree of substitution was in a certain range, the FOJ-5-S had excellent anti-myocardial ischemic activity.

A sensitive and specific HPGPC-FD method for the study of pharmacokinetics and tissue distribution of Radix Ophiopogonis polysaccharide in rats

Interest in antimyocardial ischemic activity of a graminan-type fructan with a weight average molecular weight of 4.8 kDa extracted from Radix Ophiopogonis (ROP) has necessitated the study of its pharmacokinetics and tissue distribution. For that, a simple HPGPC-FD method was developed for the sensitive and specific determination of FITC-ROP (fluorescein-isothiocyanate-labeled ROP) in plasma and rat tissues (heart, liver, spleen, lung, kidney, brain and stomach). The analyte was separated on a Shodex Sugar KS-802 high-performance gel column with 0.1 M phosphate buffer (pH 7.0) as mobile phase at a flow rate of 0.5 mL/min, and fluorescence detection at lambda(ex) 495 nm and lambda(em) 515 nm. The calibration curve for FITC-ROP was linear over the range 0.25-20.0 or 50.0 microg/mL in all studied biosamples with correlation coefficients > 0.995. The inter-day and intra-day precisions of analysis were not more than 10%, and assay accuracy ranged from 93 to 105% for plasma and from 89 to 108% for tissue homogenates. This method has been confirmed here to be suitable for the study of pharmacokinetics and tissue distribution of ROP and the achieved results are highly instructive for the further pharmaceutical development of ROP, suggesting the promising application of the method to the increasingly important carbohydrate-based drugs.

Development of potential novel cushioning agents for the compaction of coated multi-particulates by co-processing micronized lactose with polymers.

This work aimed to explore the potential of lactose as novel cushioning agents with suitable physicomechanical properties by micronization and co-spray drying with polymers for protecting coated multi-particulates from rupture when they are compressed into tablets. Several commercially available lactose grades, micronized lactose (ML) produced by jet milling, spray-dried ML (SML), and polymer-co-processed SMLs, were evaluated for their material characteristics and tableting properties. Hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and polyvinylpyrrolidone (PVP) at three different levels were evaluated as co-processed polymers for spray drying. Sugar multi-particulates layered with chlorpheniramine maleate followed by an ethylcellulose coat were tableted using various lactose types as fillers. Drug release from compacted multi-particulate tablets was used to evaluate the cushioning effect of the fillers. The results showed that the cushioning effect of lactose principally depended on its particle size. Micronization can effectively enhance the protective action of lactose. Although spray drying led to a small reduction in the cushioning effect of ML, it significantly improved the physicomechanical properties of ML. Co-spray drying with suitable polymers improved both the cushioning effect and the physicomechanical properties of SML to a certain degree. Among the three polymers studied, HPC was the most effective in terms of enhancing the cushioning effect of SML. This was achieved by reducing yield pressure, and enhancing compressibility and compactibility. The combination of micronization and co-spray drying with polymers is a promising method with which new applications for lactose can be developed.

Pharmacokinetics, tissue distribution and metabolism of senkyunolide I, a major bioactive component in Ligusticum chuanxiong Hort. (Umbelliferae)

ETHNOPHARMACOLOGICAL RELEVANCE Ligusticum chuanxiong Hort. (Umbelliferae) is widely prescribed for treatment of cardiovascular diseases in China for centuries. One of the major bioactive components in L. chuanxiong is senkyunolide I (SEI), which shows pharmacological activities in anti-migraine and anti-oxidative damage. MATERIALS AND METHODS The aim of this study was to investigate in vivo pharmacokinetics, tissue distribution and metabolism of SEI in rats. The concentrations of SEI in plasma and tissues were determined by a high performance liquid chromatography (HPLC) method, and the pharmacokinetic parameters were calculated using and non-compartmental analysis. The metabolites were identified using high performance liquid chromatography tandem mass (HPLC-ESI-MS/MS) method. RESULTS After oral and intravenous administration, SEI was quickly eliminated from plasma and its oral bioavailability (BA) was about 37.25%, which was smaller than intraportal BA (81.17%), but similar to intraduodenal BA (36.91%), suggesting that gastric first-pass effect of SEI is negligible, and hepatic first-pass effect was approximately 18.83%. After oral administration, SEI could penetrate blood brain barrier and extensively distribute in tested tissues, with the descending order of AUC being kidney, liver, lung, muscle, brain, heart, thymus, and spleen in rat. The parent compound and nine metabolites were found and identified in rat bile after oral administration of SEI (36 mg/kg). The metabolic mechanism of SEI in rat mainly involves methylation, glucuronidation and glutathione conjugation during the phase II biotransformation pathway in rats. CONCLUSIONS The information gained here may provide a meaningful basis for clinical application of such a bioactive compound of herbal medicines.

Mono-PEGylated radix ophiopogonis polysaccharide for the treatment of myocardial ischemia

This work aimed to improve the clinical application of Radix Ophiopogonis polysaccharide (ROP), a natural anti-myocardial ischemic fructan with Mw of 4.80 kDa, by mono-PEGylation. Three mono-PEGylated ROPs were prepared by a moderate coupling reaction between amino-terminated methoxy-PEG (20-, 30-, or 40-kDa) and excessive hydroxyl-activated ROP. After being fully characterized by proton nuclear magnetic resonance as well as high-performance gel permeation chromatography and anthrone-sulfuric acid colorimetry coupled assay, they were evaluated for pharmacokinetics and anti-myocardial ischemic activities in rats with coronary artery ligation. The results showed that mono-PEGylated ROPs were successfully and effectively prepared. Compared with ROP, the three mono-PEGylated ROPs showed approximately 32-, 85-, and 100-fold prolonged retention in systemic circulation with plasma half-lives reaching 16.1, 42.4, and 49.8 h, respectively. Studies on anti-myocardial ischemic effects of the conjugates showed that administrated at the same molar dose of 4 μ mol/kg per injection as ROP, they could achieve comparable or even better therapeutic effects although their administration intervals were 2- to 6-fold longer than that of ROP. These findings confirm that PEGylation would be a promising approach to markedly reducing the injection-administered frequency of ROP and hence patient compliance without sacrifice of the therapeutic efficacy by significantly improving its pharmacokinetics.

Comparison of tissue distribution of a PEGylated Radix Ophiopogonis polysaccharide in mice with normal and ischemic myocardium

PEGylation was found to be a promising approach to improve the anti-myocardial ischemic activity of Radix Ophiopogonis polysaccharide (ROP) by prolonging its retention in plasma. To fully evaluate the effectiveness and safety of this strategy, the tissue distribution of PEGylated ROP was investigated in this study. A long-circulating and bioactive PEGylated ROP with 1.04 mol 20-kDa mPEG per mol ROP ((1.04)P(20k)-R) was prepared by a moderate coupling reaction between the hydroxyl-activated ROP and the amino-terminated mPEG. Its tissue distribution in mice with normal and ischemic myocardium was studied and compared with ROP. The results show that the descending order of tissue distribution of (1.04)P(20k)-R ranked by AUC was kidney, lung, heart, liver, and brain in normal mice and kidney ≈ lung ≈ heart, liver and brain in mice with myocardial ischemia. With the exception of the heart, myocardial ischemia did not cause obvious changes in the distribution of (1.04)P(20k)-R in the other tissues studied. Owing to the enhanced permeability and retention effect caused by ischemia, the AUC of (1.04)P(20k)-R in ischemic hearts was approximately 1.6-fold greater than in normal hearts. Compared with ROP in rats, the distribution tendency of (1.04)P(20k)-R in mouse kidney, brain, and lung was reduced by approximately 42, 1.6, and 1.3 times, respectively, whereas it was increased by approximately 1.3-fold in the liver. The results of this study are highly instructive for the further pharmaceutical development of PEGylated ROP.

Novel coprocessed excipients composed of lactose, HPMC, and PVPP for tableting and its application.

New coprocessed excipients composed of α-lactose monohydrate (a filler), HPMC E3 (a binder), and PVPP (a superdisintegrant) were developed by spray drying in this study to improve the tableting properties of lactose. Factors affecting the properties of the coprocessed excipients were investigated by a 3 × 3 × 2 factorial design. These factors include lactose grade (90 M, 200 M, and 450 M), percentage of HPMC (3.5%, 7.0%, and 10.5%), and percentage of PVPP (0% and 3.5%). The results show that the compactability of the excipients could be significantly improved by increasing either the percentage of HPMC or the primary particle size of lactose. The addition of 3.5% PVPP had little effect on the compactability, but significantly improved the disintegration ability. The developed coprocessed excipients have much lower yield pressures and much higher working efficiency during tableting compared to the main raw material (α-lactose monohydrate). These improvements are mainly attributed to the addition of HPMC and the proximately 30% amorphous lactose formed during process. Both HPMC and amorphous lactose were homogeneously distributed on the surface of the secondary particles, maximizing their effect. Furthermore, the low hygroscopicity and high glass transition temperature of HPMC led to a high yield. The drug loading capacity of the newly coprocessed excipients is also excellent. In summary, the tri-component coprocessed excipients investigated are promising and worthy of further development.