E. Sun

Metabolite profiles of icariin in rat plasma by ultra-fast liquid chromatography coupled to triple-quadrupole/time-of-flight mass spectrometry

In this work, the metabolite profiles of icariin in rat plasma were qualitatively investigated, and the possible metabolic pathways of icariin were subsequently proposed. After oral administration of icariin, rat plasma samples were collected and pretreated by protein precipitation. Then these pretreated samples were injected into a Venusil ASB-C18 column with mobile phase consisted of 0.1% formic acid water and 0.1% formic acid acetonitrile and detected by Ultra fast liquid chromatography coupled to time-of-flight mass spectrometry (UFLC-TOF/MS). A total of 19 metabolites, namely, icariside I (M1), icaritin (M2), desmethylicaritin and its isomer (M3-M6), icaritin-3-O-gluA (M7), icaritin-7-O-gluA (M8), icariside II and its isomer (M9 and M10), icaritin-3,7-di-O-gluA (M11), 1,3-isoprene alcohol icaritin and its isomer (M12, M13 and M18), 1,3-isoprene alcohol icariside II (M14), allylic alcohol icaritin and its isomer (M15 and M16), 1,3-isoprene icariside II (M17) and icaritin-3-O-rha-7-O-gluA (M19) were detected and tentatively identified, and 9 of them, including M7 and M8 and M12-M18 were reported for the first time. The metabolites profiles in plasma revealed that glucuronide conjugates of isoflavonoids and flavonoid aglycones were the major circulating forms of icariin.

Effect of β-Cyclodextrin Complexation on Solubility and Enzymatic Conversion of Naringin

In the present paper, the effect of β-cyclodextrin (β-CD) inclusion complexation on the solubility and enzymatic hydrolysis of naringin was investigated. The inclusion complex of naringin/β-CD at the molar ratio of 1:1 was obtained by the dropping method and was characterized by differential scanning calorimetry. The solubility of naringin complexes in water at 37 ± 0.1 °C was 15 times greater than that of free naringin. Snailase-involved hydrolysis conditions were tested for the bioconversion of naringin into naringenin using the univariate experimental design. Naringin can be transformed into naringenin by snailase-involved hydrolysis. The optimum conditions for enzymatic hydrolysis were determined as follows: pH 5.0, temperature 37 °C, ratio of snailase/substrate 0.8, substrate concentration 20 mg·mL−1, and reaction time 12 h. Under the optimum conditions, the transforming rate of naringenin from naringin for inclusion complexes and free naringin was 98.7% and 56.2% respectively, suggesting that β-CD complexation can improve the aqueous solubility and consequently the enzymatic hydrolysis rate of naringin.

A nanostructured liquid crystalline formulation of 20(S)-protopanaxadiol with improved oral absorption

As with many other anti-cancer agents, 20(S)-protopanaxadiol (PPD) has a low oral absorption. In this study, in order to improve the oral bioavailability of PPD, the cubic nanoparticles that it contains were used to enhance absorption. Therefore, the cubic nanoparticle loaded PPD were prepared through the fragmentation of the glyceryl monoolein (GMO)/poloxamer 407 bulk cubic gel and were verified by transmission electron microscope, small angle X-ray scattering and differential scanning calorimetry. The in vitro release of 20(S)-protopanaxadiol from these nanoparticles was less than 5% at 12h. And then Caco-2 cell monolayer model was used to evaluate the absorption of PPD in vitro. Meanwhile the rat intestinal perfusion model and bioavailability were also estimated in vivo. The results showed that, in the Caco-2 cell model, the PPD-cubosome could increase the permeability values from the apical (AP) to the basolateral (BL) of PPD at 53%. The result showed that the four-site rat intestinal perfusion model was consistent with the Caco-2 cell model. And the result of a pharmacokinetic study in rats showed that the relative bioavailability of the PPD-cubosome (AUC(0-∞)) compared with the raw PPD (AUC(0-∞)) was 169%. All the results showed that the PPD-cubosome enhanced bioavailability was likely due to the increased absorption by the cubic nanoparticles rather than by the improved release. Hence, the cubic nanoparticles may be a promising oral carrier for the drugs that have a poor oral absorption.

Reactive oxygen species-mediated mitochondrial pathway is involved in Baohuoside I-induced apoptosis in human non-small cell lung cancer.

Baohuoside I (also known as Icariside II) is a flavonoid isolated from Epimedium koreanum Nakai. Although Baohuoside I exhibits anti-inflammatory and anti-cancer activities, its molecular targets/pathways in human lung cancer cells are poorly understood. Therefore, in the present study, we investigated the usefulness of Baohuoside I as a potential apoptosis-inducing cytotoxic agent using human adenocarcinoma alveolar basal epithelial A549 cells as in vitro model. The apoptosis induced by Baohuoside I in A549 cells was confirmed by annexin V/propidium iodide double staining, cell cycle analysis and dUTP nick end labeling. Further research revealed that Baohuoside I accelerated apoptosis through the mitochondrial apoptotic pathway, involving the increment of BAX/Bcl-2 ratio, dissipation of mitochondrial membrane potential, transposition of cytochrome c, caspase 3 and caspase 9 activation, degradation of poly (ADP-ribose) polymerase and the over-production of reactive oxygen species (ROS). A pan-caspase inhibitor, Z-VAD-FMK, only partially prevented apoptosis induced by Baohuoside I, while NAC, a scavenger of ROS, diminished its effect more potently. In addition, the apoptotic effect of Baohuoside I was dependent on the activation of ROS downstream effectors, JNK and p38(MAPK), which could be almost abrogated by using inhibitors SB203580 (an inhibitor of p38(MAPK)) and SP600125 (an inhibitor of JNK). These findings suggested that Baohuoside I might exert its cytotoxic effect via the ROS/MAPK pathway.

A novel drug–phospholipid complex loaded micelle for baohuoside I enhanced oral absorption: in vivo and in vivo evaluations

Baohuoside I is an effective anti-cancer drug currently used for a variety of cancers in vitro. Unfortunately, baohuoside I has a very poor solubility in both water and in organic solvents. Besides that, it is subject to significant efflux. This work therefore aimed at evaluating the ability of mixed micelles to solubilize baohuoside I, increase permeability and inhibit efflux of baohuoside I to promote oral absorption. A novel (TPGS–baohuoside I–phospholipid complex) mixed micelles was formed by phospholipid complex and TPGS to increase the solubility, enhance permeability, and inhibit efflux of baohuoside I. Micelle formation was confirmed by differential scanning calorimetry and transmission electron microscopy. The average diameters and efflux ratio of mixed micelles decreased as the ratio of TPGS increased with a respective increase in solubility of baohuoside I. Nevertheless, a slow release of baohuoside I from loaded micelles was noted. The results showed that at a 1:9 ratio for baohuoside I–phospholipid complex: TPGS in mixed micelles, solubility of baohuoside I increased up to 88 fold while the efflux ratio decreased by 85%. Their smaller size and higher zeta potential values indicated that mixed micelles would be easily absorbed and more stable. The relative bioavailability of the micelles (AUC0-∞) compared with baohuoside I (AUC0-∞) was 533%, demonstrating great potential for clinical application. Hence, the novel micelles formed with phospholipid complex and TPGS considerably increased drug concentration in the media and enhanced absorption.

Preparation and evaluation of icariside II-loaded binary mixed micelles using Solutol HS15 and Pluronic F127 as carriers

Abstract An effective anti-cancer drug, icariside II (IS), has been used to treat a variety of cancers in vitro. However, its poor aqueous solubility and permeability lead to low oral bioavailability. The aim of this work was to use Solutol®HS15 and Pluronic F127 as surfactants to develop novel mixed micelles to enhance the oral bioavailability of IS by improving permeability and inhibiting efflux. The IS-loaded mixed micelles were prepared using the method of ethanol thin-film hydration. The physicochemical properties, dissolution property, oral bioavailability of the male SD rats, permeability and efflux of Caco-2 transport models, and gastrointestinal safety of the mixed micelles were evaluated. The optimized IS-loaded mixed micelles showed that at 4:1 ratio of Solutol®HS15 and Pluronic F127, the particle size was 12.88 nm with an acceptable polydispersity index of 0.172. Entrapment efficiency (94.6%) and drug loading (9.7%) contributed to the high solubility (11.7 mg/mL in water) of IS, which increased about 900-fold. The SF-IS mixed micelle release profile showed a better sustained release property than that of IS. In Caco-2 cell monolayer models, the efflux ratio dramatically decreased by 83.5%, and the relative bioavailability of the mixed micelles (AUC0–∞) compared with that of IS (AUC0–∞) was 317%, indicating potential for clinical application. In addition, a gastrointestinal safety assay also provided reliable clinical evidence for the safe use of this micelle.

Enhanced oral absorption of 20(S)-protopanaxadiol by self-assembled liquid crystalline nanoparticles containing piperine: in vitro and in vivo studies

Background 20(S)-protopanaxadiol (PPD), similar to several other anticancer agents, has low oral absorption and is extensively metabolized. These factors limit the use of PPD for treatment of human diseases. Methods In this study, we used cubic nanoparticles containing piperine to improve the oral bioavailability of PPD and to enhance its absorption and inhibit its metabolism. Cubic nanoparticles loaded with PPD and piperine were prepared by fragmentation of glyceryl monoolein (GMO)/poloxamer 407 bulk cubic gel and verified using transmission electron microscopy and differential scanning calorimetry. We evaluated the in vitro release of PPD from these nanoparticles and its absorption across the Caco-2 cell monolayer model, and subsequently, we examined the bioavailability and metabolism of PPD and its nanoparticles in vivo. Results The in vitro release of PPD from these nanoparticles was less than 5% at 12 hours. PPD-cubosome and PPD-cubosome loaded with piperine (molar ratio PPD/piperine, 1:3) increased the apical to basolateral permeability values of PPD across the Caco-2 cell monolayer from 53% to 64%, respectively. In addition, the results of a pharmacokinetic study in rats showed that the relative bioavailabilities of PPD-cubosome [area under concentration–time curve (AUC)0–∞] and PPD-cubosome containing piperine (AUC0–∞) compared to that of raw PPD (AUC0–∞) were 166% and 248%, respectively. Conclusion The increased bioavailability of PPD-cubosome loaded with piperine is due to an increase in absorption and inhibition of metabolism of PPD by cubic nanoparticles containing piperine rather than because of improved release of PPD. The cubic nanoparticles containing piperine may be a promising oral carrier for anticancer drugs with poor oral absorption and that undergo extensive metabolism by cytochrome P450.

Metabolite profiles of epimedin B in rats by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

In this work, the metabolite profiles of epimedin B in rat feces, bile, urine, and plasma were qualitatively investigated, and the possible metabolic pathways of epimedin B were subsequently proposed. After oral administration of epimedin B at a single dose of 80 mg/kg, rat biological samples were collected and pretreated by protein precipitation. Then, these pretreated samples were injected into an Acquity ultraperformance liquid chromatography BEH C₁₈ column with mobile phase consisting of 0.1% formic acid-water and 0.1% formic acid-acetonitrile and detected by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry. In all, 43 metabolites were identified in the biosamples. Of these, 13, including F5, F7, F16-F18, D5-D7, D9, N5, N7, M1, and M3, were to our knowledge reported for the first time. The results indicated that epimedin B was metabolized via desugarization, dehydrogenation, hydrogenation, hydroxylation, demethylation, glucuronidation, and glycosylation pathways in vivo. Specific hydrolysis of 7-O-glucosides in the gut lumen and glucuronic acid conjugation in the liver were considered as the main physiologic processes of epimedin B. This study revealed the possible metabolite profiles of epimedin B in rats.

Metabolite Profiling of Four Major Flavonoids of Herba Epimdii in Zebrafish

The zebrafish model organism was applied first in a metabolic study of icariin, baohuoside I, epimedin A and epimedin C, which are flavonoids in Herba Epimedii. Metabolites of these compounds in zebrafish after exposure for 24 h were identified by HPLC-ESI-MS, whereby the separation was performed with a Zorbax C-18 column using a gradient elution of 0.05% formic acid acetonitrile-0.05% formic acid water. The quasi-molecular ions of compounds were detected in simultaneous negative and positive ionization modes. Metabolic products of icariin and epimedin C via cleavage of glucose residue instead of rhamnose residues were found, which coincided with the results using regular metabolic analysis methods. In addition, the zebrafish model was used to predict the metabolism of the trace component epimedin A, whose metabolic mechanisms haven’t been clearly elucidated with the current metabolism model. The metabolic pathway of epimedin A in zebrafish was similar to those of its homologue icariin and epimedin C. Our study demonstrated that the zebrafish model can successfully imitate the current models in elucidating metabolic pathways of model flavonoids, which has advantages of lower cost, far less amount of compound needed, easy set up and high performance. This novel model can also be applied in quickly predicting the metabolism of Chinese herb components, especially trace compounds.

Improvement in oral bioavailability and dissolution of tanshinone IIA by preparation of solid dispersions with porous silica

This study aims to evaluate the oral bioavailability and dissolution of tanshinone IIA (tanIIA) by preparation of solid dispersions (SDs) with porous silica.