Determination of 13-cis-Retinoic Acid and Its Metabolites in Plasma by Micellar Electrokinetic Chromatography Using Cyclodextrin-Assisted Sweeping for Sample Preconcentration.

The online preconcentration technique, cyclodextrin-assisted sweeping (CD-sweeping), coupled with micellar electrokinetic chromatography (MEKC) was established to determine 13-cis-retinoic acid (13-cis-RA), all-trans-retinoic acid (all-trans-RA) and 4-oxo-13-cis-retinoic acid (4-oxo-13-cis-RA) in human plasma. A CD-sweeping buffer (45 mM borate (pH 9.2), containing 80 mM sodium dodecyl sulfate (SDS) and 22 mM hydroxypropyl ß-CD (HP-ß-CD) was introduced into the capillary and, then, the sample dissolved in 70 mM borate (pH 9.2): methanol = 9:1 (v/v) was injected into capillary by pressure. The separation voltage was 23 kV. Compared to the conventional cyclodextrin-micellar electrokinetic chromatography (CD-MEKC) method, the new technique achieved 224-257-fold sensitivity enrichment of analytes. The limits of detection of 13-cis-RA, all-trans-RA were 1 ng/mL, whereas that of 4-oxo-13-cis-RA was 25 ng/mL in plasma. The linear ranges of 13-cis-RA, all-trans-RA were between 15 and 1000 ng/mL, whereas that of 4-oxo-13-cis-RA was between 75 and 1500 ng/mL. The coefficient of correlation between the concentration of analytes and peak area ratio of analytes and internal standard (2, 4-dihydroxy-benzophenone) for intra-day (n = 3) and inter-day (n = 5) analyses were both greater than 0.999. The optimized experimental conditions were successfully applied to determine 13-cis-retinoic acid and its metabolites in plasma samples from a patient during the administration of 13-cis-RA for treating acne.

Bioactive 6S-styryllactone constituents of Polyalthia parviflora.

Parvistones A-E (1-5), five new styryllactones possessing a rare α,ß-lactone moiety and a 6S configuration, were isolated from a methanolic extract of Polyalthia parviflora leaves. The structures and the absolute configuration of the isolates were elucidated using NMR spectroscopy, specific rotation, circular dichroism, and X-ray single-crystal analysis. Compounds 8, 9, 11, and 12 were isolated for the first time. The results were supported by comparing the data measured to those of 6R-styryllactones. Moreover, a plausible biogenetic pathway of the isolated compounds was proposed. The structure-activity relationship of the compounds in an in vitro anti-inflammatory assay revealed the 6S-styryllactones to be more potent than the 6R derivatives. However, the effect was opposite regarding their cytotoxic activity. In addition, 6S-styrylpyrones isolated showed more potent anti-inflammatory and cytotoxic activity when compared to the 1S-phenylpyranopyrones obtained.

Fast quantification of S-adenosyl-L-methionine in dietary health products utilizing reversed-phase high-performance liquid chromatography: teaching an old method new tricks.

S-adenosyl-L-methionine is a ubiquitous methyl donor in living bodies. It is known to participate in several physiological processes including homocysteine metabolism and glutathione synthesis regulation, and cellular antioxidant mechanism. S-adenosyl-L-methionine containing dietary supplements has been prescribed recently for the treatment of depression, arthritis, and liver diseases with encouraging results. The development of an efficient analytical protocol for S-adenosyl-L-methionine containing dietary supplements is crucial for maintaining product quality and consumer health. In this study, the S-adenosyl-L-methionine content of several yeast products and commercial healthy food product samples was quantitatively analyzed utilizing HPLC. The chromatographic separation was achieved on a reversed-phase column and 2 % acetonitrile with a 98 % ammonium-acetate mobile phase under pH 4.5, with a flow rate of 1.0 mL/min. The wavelength used for detection with the UV detector was 254 nm. The total analysis time was short and the target compound showed a well-defined peak. The correlation coefficient of the regression curve showed good linearity and sensitivity with r = 0.999. All experiments were replicated five times and the relative standard deviations as well as the relative error values were all less than 3 %. Moreover, the achieved precision and accuracy values were high with 97.4-100.9 % recovery. Qualitative determination of S-adenosyl-L-methionine in the tested products was achieved using NMR and LC-MS techniques. The developed protocol is robust, fast, and suitable for the quality control analysis of yeast and commercial S-adenosyl-L-methionine products.

Determination of quetiapine and its metabolites in plasma by field-enhanced sample stacking.

Quetiapine is an atypical antipsychotic drug that can be used to treat mental disorders, including schizophrenia, bipolar disorder and Alzheimer's disease. Quetiapine is mainly converted into the active metabolites of norquetiapine and 7-hydroxyquetiapine by the liver enzymes CYP3A4 and CYP2D6. In this study, liquid-liquid extraction (LLE) was used as a sample pretreatment method to eliminate interferences in plasma. tert-Butyl methyl ether was chosen as the extraction solvent. Field-enhanced sample injection (FESS), an online preconcentration technique, was used to analyze quetiapine and its metabolites norquetiapine and 7-hydroxyquetiapine in plasma. The optimal separation condition was 120 mM phosphate (pH 4.0) containing 0.005% (w/v) polyvinyl pyrrolidone and 40% (v/v) methanol. The methanol plug was 0.3 psi for 6 s, the sample was electrokinetic injection by 10 kV for 60 s at positive polarity, and the separation voltage was set at 26 kV. In this experiment, quetiapine, norquetiapine and 7-hydroxyquetiapine were successfully extracted from plasma by the LLE method and stacking and separated by FESS within 15 min. The limits of detection (S/N = 3) of quetiapine, norquetiapine and 7-hydroxyquetiapine were 0.25 ng/mL, 0.50 ng/mL and 1.00 ng/mL, respectively. The linear ranges of quetiapine, norquetiapine and 7-hydroxyquetiapine were 3-120 ng/mL and the correlation coefficients were 0.999. Compared with that of the traditional capillary zone electrophoresis method, the sensitivity enrichment of analytes was 463-835-fold. The optimal experimental conditions were successfully applied to the analysis of plasma samples from patients taking quetiapine for the treatment of schizophrenia.

Acetogenins from Annonaceae.

In recent decades, annonaceous acetogenins have become highly studied plant secondary metabolites in terms of their isolation, structure elucidation, synthesis, biological evaluation, mechanism of action, and toxicity. The aim of the present contribution is to summarize chemical and biological reports published since 1997 on annonaceous acetogenins and synthetic acetogenin mimics. The compounds are considered biologically in terms of their cytotoxicity for cancer cell lines, neurotoxicity, pesticidal effects, and miscellaneous activities.

Constituents of the Leaves of Pandanus utilis.

Nineteen compounds, including seven triterpenoids (1-7), five steroids (8-12), four cyclohexenone derivatives (13-16), two benzenoid glycosides (17 and 18) and one lignan (19), were isolated and separated from the leaves of Pandanus utilis through bioactivity-guided fractionation. Among them, one new lanosterol- type triterpenoid was found and named as (24R)-24-methyl-5a-4-demethyllanosta-9(11),25-dien-3ß-ol (1). The structures of the isolates were determined by mass and spectroscopic analyses, and the compounds were subjected to anti-inflammatory, anti-oxidative and cytotoxic assays.

Rapid HPLC Quantification Approach for Detection of Active Constituents in Modern Combinatorial Formula, San-Huang-Xie-Xin-Tang (SHXXT).

San-Huang-Xie-Xin-Tang (SHXXT), one of the most important traditional Chinese medicinal formulas, is comprised by three herbal medicines, the rhizome of Rheum officinale [or Rheum tanguticum (Polygonaceae) (Dahuang in Chinese)], the root of Scutellaria baicalensis (Labiatae) (Huangqin in Chinese), and the rhizome of Coptis chinensis (Ranunculaceae) (Huanglian in Chinese) in the ratios of 2:1:1 or 1:1:1. This study is aimed to quantitate and qualify of SHXXT, by a rapid, convenient, and effective HPLC-PDA approach associated with LC-MS technique. Of which method, nine chosen major bioactive components in SHXXT, including aloe-emodin (Ale), baicalin (Ba), berberine (Be), coptisine (Co), palmatine (Pa), resveratroloside (Res), rhein (Rh), sennoside A (Se-A), and wogonin (Wo), were evaluated within 30 min. The nine chemical markers were monitored in a high sensitivity with a low detection limit of 0.01-0.55 µg/mL and the correlation coefficient of the regression curve revealed a good linearity with R2 > 0.99. Moreover, the extraction solution system and the HPLC elution conditions were also optimized in the present study. This present developed protocol was then successfully applied to quantify nine chemical markers of 10 SHXXT products from eight Taiwanese TCM pharmaceutical companies. In quantitative results, Res was found as the major compound in SHXXT-1~5 and 8 with significantly higher amounts than those in other products, indicating the products SHXXT-1~5 and 8 may use R. tanguticum as the raw material, which possessed a higher concentration of the bioactive composition Res, instead of R. officinale. Simultaneously, Ale, Rh, and Wo were < 2% in these 10 products. Different chemical profiles of commercial products indicated that, probably, each product with the same named formula might be regarded as a sole medicine and need to be investigated individually. Importantly, it is never too much to emphasize the importance of quality control in TCM development.

Insights on the isolation, biological activity and synthetic protocols of enyne derivatives.

Enyne derivatives isolated from terrestrial plants and fungi have recently attracted attention due to their interesting biological activities. It was found that these derivatives possess in general potent antiinflammatory activity which was attributed to the structural similarity of enynes with the natural antiinflammatory agents secreted in the human body. The biosynthesis of some of the isolated enynes has been proposed based on detailed isotope labeling studies. Computational calculations have been utilized to analyze the conformational preferences and forces affecting interaction of some enynes with the target binding sites. Synthesis of enynes has been achieved using several coupling techniques. In the current review we shed some light on the isolation, biological activity, and biosynthetic routes of enynes. We also recount different synthetic methodologies developed for the synthesis of compounds containing enyne functional group.

1,5-Diphenylpent-3-en-1-ynes and methyl naphthalene carboxylates from Lawsonia inermis and their anti-inflammatory activity.

Lawsonia inermis (Lythraceae) known as henna is one of the most popular and ancient plants used in cosmetics and hair dying. It is cultivated for its leaves but other parts such as seeds, flowers, stem bark and roots are also used in traditional medicine for millennia. Henna tattoo paste also proved to be beneficial for wound healing and in several skin diseases suggesting potent anti-inflammatory activity. To evaluate henna anti-inflammatory activity, 31 compounds, including three 1,5-diphenylpent-3-en-1-yne derivatives, lawsochylin A-C and three methyl naphthalene carboxylates, lawsonaphthoate A-C, were isolated from the stems and leaves of henna utilizing a bioassay-guided fractionation. The structures of the compounds were elucidated by spectroscopic data. Two compounds, lawsochylin A and lawsonaphthoate A showed potent anti-inflammatory activity by inhibition of superoxide anion generation (IC(50)=1.80 and 1.90 µg/ml) and elastase release (IC(50)=1.58 and 3.17 µg/ml) of human neutrophils in response to fMLP or cytochalasin B. Moreover, the known compounds, luteolin, apigenin, 4S-4-hydroxy-α-tetralone, and 2-butoxysuccinic acid, also showed potent inhibition of superoxide anion generation (IC(50)=0.75-1.78 µg/ml) and elastase release (IC(50)=1.62-3.61 µg/ml).