Quantification of permanent positively charged compounds in plasma using one-step dilution to reduce matrix effect in MS.

BACKGROUND: Bioanalysis of conventional methods for compounds with permanent positive charge leads to peak tailing in separation and matrix effects in MS. This study describes a novel, rapid and sensitive method for quinolinium-containing compounds quantification. Results & methodology: A charged surface hybrid chromatography-tandem MS/MS using one-step protein precipitation dilution technique has been developed for determining analytes in plasma. We found symmetric peak and high recoveries for the analytes without matrix effect. All calibration curves had good linearity (r 0.991). The intra- and inter-assay precision was within 15% and the accuracy ranged from 88 to 103%. The method has been successfully applied to the PK study. CONCLUSION: The proposed method was sensitive, reproducible and applicable to other permanent positively charged compounds.

Different molecular complexity of linear-isomaltomegalosaccharides and ß-cyclodextrin on enhancing solubility of azo dye ethyl red: towards dye biodegradation.

Intermolecular interaction of linear-type α-(1 → 6)-glucosyl megalosaccharide rich (L-IMS) and water-insoluble anionic ethyl red was firstly characterized in a comparison with inclusion complexation by cyclodextrins (CDs) to overcome the problem of poor solubility and bioavailability. Phase solubility studies indicated an enhancement of 3- and 9-fold over the solubility in water upon the presence of L-IMS and ß-CD, respectively. (1)H NMR and circular dichrosim spectra revealed the dye forms consisted of 1:1 stoichiometric inclusion complex within the ß-CD cavity, whereas they exhibited non-specific hydrophobic interaction, identified by solvent polarity changes, with L-IMS. The inclusion complex delivered by ß-CD showed an uncompetitive inhibitory-type effect to azoreductase, particularly with high water content that did not promote dye liberation. Addition of the solid dye dispersed into coupled-enzyme reaction system supplied by L-IMS as the dye solubilizer provided usual degradation rate. The dye intermission in series exhibited successful removal with at least 5 cycles was economically feasible.

Bufothionine, a possible effective component in cinobufocini injection for hepatocellular carcinoma.

ETHNOPHARMACOLOGICAL RELEVANCE: Cinobufacini has been traditionally used in China for the treatment of tumor since hundreds years ago. For recent years, its modern preparation,cinobifucini injection has also obtained satisfactory therapeutic functions for cancer. MATERIALS AND METHODS: High performance liquid chromatography (HPLC) analysis was applied to determine the content of cinobufagin, resibufogenin and bufothionine in cinobufacin extract liquid and injection; MTT assay and flow cytometric analysis were also respectively used to study the effect of cinobufacini extract liquid, injection and three chemical structures on cells and cell cycles. RESULTS: HPLC results demonstrated that in cinobufacini extract liquid three ingredients (cinobufagin, resibufogenin and bufothionine) were all monitored while in cinofacini injection only bufothinone was detected; MTT assays showed bufothionine could obviously inhibit the proliferation of human hepatocellular carcinoma cell lines such as SMMC-7721 and BEL-7402 in a dose- and time-dependent manner as well as cinobufagin and resibufogenin; further flow cytometric analysis indicated obvious increases in G2/M phase and decrease in G0/G1 phase when SMMC-7721 cell line exposure to bufothionine (480 µg/ml). CONCLUSIONS: These results suggested bufothionine could be involved in treatment of human cancer for cinobufacini injection and the mechanism might be relative to induce G2/M phase cell cycle arrest.

Anachelin, the siderophore of the cyanobacterium Anabaena cylindrica CCAP 1403/2A.

A catecholate siderophore - anachelin - has been isolated from the cyanobacterium Anabaena cylindrica CCAP 1403/2A. The central part of the siderophore is a tripeptide consisting of L-Thr, D-Ser and L-Ser. Its C-terminus is linked amidically to a 1,1-dimethyl-3-amino-1,2,3,4-tetrahydro-7,8-dihydroxyquinolinium system and its N-terminus to 6-amino-3,5,7-trihydroxyheptanoic acid. The 7-hydroxyl group of the latter is esterified with salicylic acid whose carboxyl group is condensed with the 6-amino group to an oxazoline ring. Anachelin is the first genuine siderophore of a cyanobacterium whose structure has been elucidated.

N-methylquinolinium 2-carboxylate, a defensive betaine from Photuris versicolor fireflies.

From whole body extracts of Photuris versicolor fireflies, the defensive betaine N-methylquinolinium 2-carboxylate (1) was isolated and characterized on the basis of spectroscopic data and comparison with a synthetic sample.

Alkaloids of Thalictrum. XXI. Isolation and characterization of alkaloids from the roots of Thalictrum podocarpum.

Thirteen alkaloids, hernandezine, thalidezine, N-desmethylthalidezine, isothalidezine, thalistyline, thalistyline methodiiodide, N-desemethylthalistyline, berberine, columbamine, jatrorrhizine, palmatine, thalifendine, magnoflorine and the artifact, 8-trichloromethyldihydroberberine were isolated from the roots of Thalictrum podocarpum Humb. In addition, oxyberberine and thaliglucinone were obtained in very minor amounts and identified by tlc. Of these compounds, N-desmethylthalidezine and isothalidezine are new bisbenzylisoquinoline alkaloids. Sucrose was isolated from the alcoholic extract. Hernandezine, thalistyline, thalidezine, thalistyline methodiiodide and N-desmethylthalistyline were found to possess antimicrobial activity against Mycobacterium smegmatis at concentrations of 100 microgram/ml or less.