Simultaneous determination and pharmacokinetic study of gambogic acid and gambogenic acid in rat plasma after oral administration of Garcinia hanburyi extracts by LC‐MS/MS

Gambogic acid and gambogenic acid are two major bioactive components of Garcinia hanburyi, and play a pivotal role in biologic activity. In this study, a specific and sensitive liquid chromatography–tandem mass spectrometry was developed and validated for simultaneous determination of gambogic acid and gambogenic acid in rat plasma. Chromatographic separation was achieved on a C₁₈ column using an isocratic elution with methanol–10 m m ammonium acetate buffer–acetic acid (90:10:0.1, v/v/v) as the mobile phase. The detection was performed on a triple–quadrupole tandem mass spectrometer equipped with electrospray positive ionization using multiple reaction monitoring modes. The transitions monitored were m/z 629.3 [M + H]⁺ → 573.2 for gambogic acid, m/z 631.2 [M + H]⁺ → 507.2 for gambogenic acid and m/z 444.2 [M + NH₄]⁺ → 83.1 for IS. Linear calibration curves were obtained in the concentration range of 2.00–1000 ng/mL for gambogic acid and 0.500–250 ng/mL for gambogenic acid. The lower limits of quantification of gambogic acid and gambogenic acid in rat plasma were 2.00 and 0.500 ng/mL, respectively. The intra‐ and inter‐day precision (RSD) values were <11.7% and accuracy (RE) was ?10.6–12.4% at three QC levels for both analytes. The assay was successfully applied to evaluate pharmacokinetics behavior in rats after oral administration of Garcinia hanburyi extracts. Copyright © 2014 John Wiley & Sons, Ltd.     

Phloroglucinols, depsidones and xanthones from the twigs of Garcinia parvifolia

Seven phloroglucinols, named parvifoliols A-G (1-7), two depsidones, named parvifolidones A, B (8, 9), and three xanthones, named parvifolixanthones A-C (10-12), were isolated from the twigs of Garcinia parvifolia along with seven known compounds: garcidepsidone B, mangostinone, rubraxanthone, dulxanthone D, 1,3,5,6-tetrahydroxyxanthone, norathyriol, and (2E,6E,10E)-(+)-4β-hydroxy-3-methyl-5β-(3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenyl)cyclohex-2-en-1-one. Their structures were proposed on the basis of spectroscopic data. The antibacterial and antioxidation activities were evaluated.     

藤黄科植物中具有桥环结构的天然产物全合成研究进展

藤黄科植物中含桥环的天然产物具有独特的化学结构和明显的生物活性. 综述了近年来这类天然产物的全合成研究进展.     

山竹的微量元素含量分析

用电感耦合等离子体发射光谱仪(ICP-AES)测定了市售进口越南山竹中微量元素的含量,发现其磷、硫、镁、钙、锌等元素的含量比较丰富,并讨论了这些有益元素与人体健康的关系。     

Oxygenated xanthones and biflavanoids from the twigs of Garcinia xanthochymus

Three new xanthones, xanthochymones A–C (1–3), together with six known compounds including two xanthones, three biflavanoids, and one mellein derivative are isolated from the methanol extract of the twigs of Garcinia xanthochymus. Their structures are identified on the basis of their spectroscopic data. Compound 3 displays moderate antibacterial activity against Staphylococcus aureus while compounds 2 and 3 are weakly active against methicillin-resistant S. aureus.     

Xanthones from the green branch of Garcinia dulcis

Two new prenylated xanthones, namely dulcisxanthone H and dulcisxanthone I along with garciniaxanthone C, were isolated from the dichloromethane extract of the green branch of Garcinia dulcis. Their structures were elucidated by the analysis of 1-D and 2-D NMR spectral data. Their antibacterial activities were also examined.     

Structure elucidation and NMR spectral assignment of five new xanthones from the bark of Garcinia xanthochymus

Five new xanthones, namely Garcinexanthones A-E (1-5), were isolated from the barks of Garcinia xanthochymus. Their structures were elucidated by spectral analysis, primarily NMR, MS, and UV. The complete assignments of the (1)H NMR and (13)C NMR chemical shifts for the compounds were achieved by using 1D and 2D NMR techniques, including DEPT, HSQC, and HMBC NMR experiments.     

A new cytotoxic polycyclic polyprenylated acylphloroglucinol from Garcinia nujiangensis screened by the LC-PDA and LC-MS

Abstract

A new polycyclic polyprenylated acylphloroglucinol (1), nujiangefolin D, together with five known analogues (2–6), were isolated from the fruits of Garcinia nujiangensis. Compound 1 was screened by the LC-MS and LC-PDA. The structure of 1 was elucidated on the basis of extensive spectroscopic techniques including 1?D and 2?D NMR and MS analyses. The compounds isolated were evaluated for their cytotoxic activities against three cancer cell lines, 1 showed moderate cytotoxic activity against Hela, PANC-1, and MDA-MB-231 cell lines with IC₅₀ values of 5.6?±?0.1, 9.1?±?0.2, and 8.3?±?0.2?μM, respectively. The antitumor mechanism was explained via virtual docking of 1 to the main sites in the human serine/threonine-protein kinase mTOR (mTOR) crystal structure (PDB code: 4DRI). Furthermore, 1 may inhibit Hela cell proliferation through mTOR by the western blotting analysis. Taken together, 1 may be a potential mTOR inhibitor used for the treatment of cervical cancer.     

Further rearranged prenylxanthones and benzophenones from Garcinia bracteata

New rearranged polyprenylxanthones, namely garcibracteatone, neoisobractatins A and B, and xerophenone C were isolated from the leaves and bark of a vietnamese Garcinia, Garcinia bracteata, together with 5-O-methylxanthone V₁, bracteaxanthones I and II, and the known nemorosonol and simple xanthones. Neoisobractatins A and B exhibit a significant cytotoxic activity on KB cells. A biogenetic hypothesis is proposed, which explains the possible origin of these so-called cage-xanthanoids.     

Analogues of the Quararibea metabolite chiral enolic-γ-lactone from (2S,3S)- and (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylic acids

Reaction of dialkyl (2S,3S)- or (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylates with POCl₃ in pyridine followed by diazomethane resulted in the isolation of dialkyl 2S-4-methoxy-5-oxo-2,5-dihydro-2,3-furandicarboxylates, which are analogues of the Quararibea metabolite chiral enolic-γ-lactone (3-hydroxy-4,5-(R)-dimethyl-2(5H)-furanone). An unusual α-hydroxylation of γ-butyrolactone takes place involving POCl₃ in pyridine. When the dehydration was facilitated with methanesulfonyl chloride in triethylamine, instead of POCl₃, aromatic dialkyl 5-[(methylsulfonyl)oxy]-2,3-furandicarboxylates were obtained.