Anti-hepatitis B virus activities of friedelolactones from Viola diffusa Ging.

BACKGROUND: Hepatitis B virus (HBV) infection is the major factor of causing hepatitis B, cirrhosis and liver cancer. Interferon and nucleoside drugs, the main drugs to treat HBV infection, have disadvantages of scavenge difficulty and drug resistance respectively. Viola diffusa Ging is used as a traditional Chinese herbal medicine for the treatment of hepatitis. PURPOSE: The aim of the study is to investigate the chemical constituents of Viola diffusa Ging and their anti-HBV activity. METHODS: Chemical constituents were extracted and purified by ethanol reflux extraction and chromatographic separation technology including D-101 Macroporous resin, silica gel, Sephadex LH-20 and preparative thin-layer chromatography. Their structures were elucidated on the basis of extensive NMR and MS data. Cytotoxicity and inhibiting effects on HBsAg and HBeAg secretion of HepG2.2.15 of all compounds except 10 were studied by MTT method and ELISA method. RESULTS: Three friedelolactones with naturally occurring seco-ring-A friedelane triterpenoids, 2ß-hydroxy-3, 4-seco-friedelolactone-27-oic acid (1), 2ß, 28ß-dihydroxy-3,4-seco-friedelolactone-27-oic acid (2) and 2ß, 30ß-dihydroxy-3,4-seco-friedelolactone-27-lactone (3), and a stigmastane, stigmast-25-ene-3ß,5α,6ß-triol (11) together with nine known compounds were isolated from the whole plant of Viola diffusa G. (Violaceae). Compounds 1-3, 9, 11, 12 exhibited significant activities of blocking both HBsAg and HBeAg secretion, and compound 4, 6, 7, 8 selectively inhibited HBeAg secretion while compound 13 selectively inhibited HBsAg secretion. IC50 values of compounds 1 and 2, 26.2 µM and 33.7 µM for HBsAg, 8.0 µM and 15.2 µM for HBeAg, was significantly lower than that of positive control lamivudine. CONCLUSION: Compounds 1-3, 11 are new compounds never reported before and the promising results demonstrate the potential of compound 1-3, 9, 11, 12 for the treatment of HBV infection.

[Removal of the template molecules from vinblastine-imprinted polymer].

OBJECTIVE: To investigate the optimal condition for complete removal of the template molecules from vinblastine (VLB)-imprinted polymer. METHOD: The prepared polymers were packed into the cartridges of solid-phase extraction column and washed by methanol-glacial acetic acid mixture with different proportions. The contents and recoveries of VLB in the effluents were determined. RESULTS: Polymer extraction with methanol-glacial acetic acid (9:1, V/V) resulted in VLB recovery of 91.73%, but template bleeding was observed because of incomplete VLB removal. Using methanol-glacial acetic acid (6:4, V/V) as the extraction solvent, the recovery of VLB reached 98.03% with less solvents and extract times. The polymers could selectively adsorb VLB through non-covalent interactions and still exhibited strong affinity for the template molecule but not for the structural analogue vincristine after extraction with methanol-glacial acetic acid (6:4, V/V). CONCLUSION: Methanol-glacial acetic acid (6:4, V/V) is an ideal extract solvent for complete template molecule removal from the polymers, and the processed polymers possess stable capacity of specific recognition and selectivity to the template.

[Optimization of the polymerization conditions of vinblastine imprinted polymer by uniform design].

OBJECTIVE: To optimize the polymerization conditions of vinblastine (VLB) imprinted polymer. METHODS: The conditions were optimized by the method of uniform design. The major factors investigated included the amount of functional monomer (MAA) and the cross-linker (EDMA) and the progenic solvent (toluene or acetonitril). The adsorption rate of VLB on the solid-phase extraction (SPE) column packed with MIP was adopted as the response value. RESULTS: The optimal conditions were MAA 0.4 mmol, EDMA 1.6 mmol and using acetonitrile as the solvent. Under the conditions,the VLB imprinted polymer was synthesized and the absorption rate of VLB was 88.20%. The characterizations of the optimal MIP were determined by IR spectrometry and scanning electron microscope (SEM) analysis. CONCLUSION: It is possible to furtherly improve the nature of the polymer by optimizing the polymerization parameters with uniform design. The polymer synthesized under the optimal conditions exhibited high affinity to the target molecule VLB.