Effect of Hepatocyte Targeting Nanopreparation Syringopicroside on Duck Hepatitis B Virus and Evaluation of Its Safety.

Syringopicroside is a kind of iridoid monomer compound isolated from Syringa oblata exhibiting a potent effect against hepatitis B virus (HBV). The therapeutic effect and safety of syringopicroside-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (SYR-NP) were studied on the model of HBV-infected ducklings and on cultured HepG2.2.15 cells. HBV DNA in ducklings was assessed by fluorescence quantitative PCR. In HepG2.2.15 cells, the content of HBsAg and HBeAg were assayed. Acute toxicity of SYR-NP was studied in ICR mice in 12 h and 7 days after SYR-NP administration. The serum levels of HBV DNA in ducklings treated with SYR-NP in a high dose was significantly lower than in the control. In HepG2.2.15 cells treated with different doses of SYR-NP, the concentrations of HBsAg and HBeAg were significantly below the control. Acute toxicity test showed high safety of SYR-NP. Thus, SYR-NP can inhibit replication of HBV DNA and protect the liver tissue.

Effect of Syringopicroside Extracted from Syringa oblata Lindl on the Biofilm Formation of Streptococcus suis.

Syringopicroside is a natural drug with antibacterial activity, which is the main ingredient of Syringa oblata Lindl (S. oblata). In order to further develop the application of S. oblata and evaluate the ability of syringopicroside against Streptococcus suis (S. suis), this investigation first applied an ultrasonic-assisted method to extract syringopicroside, and then response surface methodology (RSM) was performed to get the optimum condition. Based on RSM analysis, a second-order polynomial equation about the syringopicroside yield and four variables, including ultrasonic power, time, temperature, and liquid-to-solid ratio, was purposed. Through RSM prediction and model verification experiments, the optimum conditions were determined, as follows: ultrasonic time was 63 min, temperature was 60 °C, a liquid-to-solid ratio was set to 63 mL/g, and ultrasonic power was 835 W. Under this condition, a high syringopicroside yield was obtained (3.07 ± 0.13 mg/g), which was not significantly different with a predicated value. After separation and purification by HPD 500 microporous resin, then mass spectrum was applied to identify the main ingredient in aqueous extract. A minimal inhibitory concentration (MIC) assay revealed the value against S. suis of syringopicroside was 2.56 µg/µL and syringopicroside with sub-inhibitory concentrations that could effectively inhibit biofilm formation of S. suis. Besides, scanning electron microscopy analysis indicated syringopicroside could destroy the multi-layered aggregation structure of S. suis. Finally, molecular docking analysis confirmed that syringopicroside was combined with Orfy protein of S. suis through hydrogen bonds, hydrophobic interaction, and π-π stacking.

Preparation and Characterization of Syringopicroside Solid Lipid Nanoparticles / 中国药房

OBJECTIVE： To prepare Syringopicroside solid lipid nanoparticles （SYR-SLN）， and optimize the formula and characterize SYR-SLN. METHODS： SYR-SLN were prepared by emulsion evaporation method. Using entrapment efficiency as index， based on single factor， orthogonal design was adopted to optimize the mass ratio of lecithin-monoglyceride， volume ratio of organ phase to water phase， poloxamer 188 （F68） concentration and drug dosage. The optimal formula technology was established to investigate entrapment efficiency， drug-loading amount， morphology， particle size， Zeta potential， stability， etc. RESULTS： The mass ratio of lecithin-monoglyceride was 3 ∶ 1； the volume ratio of organic phase to water phase was 1 ∶ 2； the concentration of F68 was 0.4％； drug dosage was 10 mg. The optimal formula included that monoglyceride 80 mg， lecithin 240 mg， 0.4％ F68， syringopicroside 10 mg， absolute ethyl alcohol 5 mL， distilled water 10 mL， emulsification temperature at 65℃ and stirring at 600 r/min. Encapsulation efficiency of SYR-SLN was （42.35±0.60）％ （n＝3）； drug-loading amount was （5.33±0.03）％ （n＝3）； SYR-SLN had a spherical morphology and was evenly distributed. The average particle size was （180.30±5.31） nm with Zeta potential of （－41.9±0.8） mV， and the SYR-SLN could maintain stable for 15 days at 4℃. CONCLUSIONS： SYR-SLN is prepared successfully， and the technology is simple with high encapsulation efficiency.

Study on Cellular Uptake Mechanism of HepG2.2.15 Cells to Nanoparticles Co-loaded with Syringopicroside and Hydroxytyrosol / 中国中医药信息杂志

Objective To investigate the uptake mechanism of HepG2.2.15 cells to the nanoparticles co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). Methods The nanoparticles were prepared by using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol. The uptake mechanism of HepG2.2.15 cells to SH-NPs was studied by fluorescence microscopy and flow cytometry using fluoresceineisothiocyanate (FITC) as a fluorescent marker. Results With colchicine as the inhibitor, the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 1.9% to 56.4%; When the drug concentration was 125, 250 μg/mL and 500 μg/mL, the positive cell percentages were 4.9%, 3.4% and 3.9%. With chloroquine as the inhibitor; the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 7.4% to 55.4%; When the drug concentration was 125, 250 and 500 μg/mL, the percentage of positive cells was 19.5%, 22.5% and 27.6%. Conclusion Colchicine and chloroquine have an inhibitory effect on HepG2.2.15 cells uptake, and the uptake of SH-NPs in HepG2.2.15 cells was positively correlated with drug concentration and incubation time. It can be concluded that the uptake mechanism of HepG2.2.15 cells to SH-NPs was nonspecific adsorption endocytosis.

The antibacterial activity of syringopicroside, its metabolites and natural analogues from Syringae Folium.

In the present study, the in vitro antibacterial activity of an effective fraction (ESF) from Syringae Folium (SF) on Methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and then its in vivo activity was evaluated by using the MRSA-infected mouse peritonitis model. The ESF showed a significant in vitro and in vivo activity on decreasing the Minimum Inhibitory Concentrations (MICs) and increasing the survival rate of mouse from 42.8% to 100%. Six iridoid glucosides (IGs) of ESF were characterized by UPLC-TOF-MS method and also isolated by column chromatography. Most of them showed in vitro anti MRSA activity. Syringopicroside (Sy), the major compound of IGs, was found to increase the survival rate from 42.8% to 92.8% of the MRSA-infected mouse, which revealed Sy is also the main active components of ESF. In order to know why the effect of oral administration of SF is better than its injections in clinic and the metabolites of Sy, seven metabolites of Sy were isolated from rat urine and identified on the basis of NMR and MS spectra. Most of metabolites possessed stronger in vitro anti-MRSA activity than that of Sy, which furtherly proved the clinical result.

Chemical constituents from rhizomes of Cyperus rotundus / 中草药

Objective: To study the chemical components from the rhizomes of Cyperus rotundus. Methods: The compounds were isolated and purified by chromatographic techniques, and their structures were elucidated by spectral methods. Results: A new isoflavonoid, 5, 7, 4'-trihydroxy-2'-methoxy-3'-prenylisoflavone (1), along with nine phenolic compounds, 6-O-p-hydroxybenzoyl- 6-epi-aucubin (2), 6-O-p-hydroxybenzoyl-6-epi-monomelittoside (3), verproside (4), syringopicroside B (5), syringopicroside C (6), oleuropeinic acid (7), oleuroside (8), 10-hydroxyoleuropein (9), and senburiside I (10), were obtained from the rhizomes of C. rotundus. Conclusion: Compound 1 is a new isoflavone, named cyperotundone A, and compounds 2-10 are isolated from this plant for the first time.