Secondary metabolites from Andrographis paniculata.

Two new flavonoid glycosides, 5-hydroxy-7,8-dimethoxy (2R)-flavanone-5-O-beta-D-glucopyranoside (1) and 5-hydroxy-7,8,2',5'-tetramethoxy-flavone-5-O-beta-D-glucopyranoside (2), and a new diterpenoid, andrographic acid (3), along with andrographidine A (4) were isolated from Andrographis paniculata, and their structures were determined on the basis of physicochemical and spectroscopic analysis. Compound 3 was evaluated for cytotoxicity to KB cells along with andrographolide, isoandrographolide, neoandrographolide and 14-deoxy-11,12-didehydroandrographolide obtained from A. paniculata in the present study.

Liquid chromatography/electrospray tandem mass spectrometry of terpenoid lactones in Ginkgo biloba.

Ginkgo biloba (ginkgo) is one of most frequently used botanical dietary supplements. The bioactive constituents include the terpenoid lactones consisting of bilobalide and the ginkgolides A, B, C and J. A new assay based on high-performance liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) was developed for the measurement of the terpenoid lactones in ginkgo products such as leaf powder and extracts.

Differential enantioselectivity and product-dependent activation and inhibition in metabolism of verapamil by human CYP3As.

In vitro studies of enantioselective metabolism of R-(+)- and S-(-)verapamil (VER) were conducted using human cDNA-expressed CYP3A isoforms, CYP3A4, CYP3A5, and CYP3A7. N-dealkylated products nor-VER [2,8-bis-(3,4-dimethoxyphenyl)-2-isopropyl-6-azaoctanitrile] and D617 [2-(3,4-dimethoxyphenyl)-5-methylamino-2-isopropylvaleronitrile] were the major metabolites for all CYP3A isoforms regardless of enantiomer. Enantioselectivity of CYP3A4 and CYP3A7 was most similar among the three isoforms.

Identification of caffeic acid derivatives in Actea racemosa (Cimicifuga racemosa, black cohosh) by liquid chromatography/tandem mass spectrometry.

Caffeic acid derivatives occurring in black cohosh [Cimicifuga racemosa (L.) Nutt., Actaea racemosa (Ranunculaceae)], some of which may have pharmacological activity, were analyzed using high-performance liquid chromatography (HPLC) electrospray ionization tandem mass spectrometry (ESI-MS/MS) with the aim of developing a methodology for their rapid identification in a complex plant matrix.

p-Hydroxybenzoic acid alkyl esters in Andrographis paniculata herbs, commercial extracts, and formulated products.

Analysis of two commercial extracts of Andrographis paniculata using high-performance liquid chromatography (HPLC) with photodiode array absorbance detection showed the presence of several unexpected compounds, which were isolated and identified as methyl, ethyl, and propyl esters of p-hydroxybenzoic acid by using high-resolution mass spectrometry and nuclear magnetic resonance. Quantitative analysis using HPLC revealed the presence of 0.22% p-hydroxybenzoic acid methyl ester (methlyparaben) in one commercial extract, and both 0.