A Rapid and Feasible 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedra Herbal Preparations.

A highly specific and sensitive proton nuclear magnetic resonance (1H-NMR) method has been developed for the quantification of ephedrine alkaloid derivatives in Ephedra herbal commercial prescriptions. At the region of δ 4.0 to 5.0 ppm in the 1H NMR spectrum, the characteristic signals are separated well from each other, and six analogues in total, methylephedrine (ME), ephedrine (EP), norephedrine (NE), norpseudoephedrine (NP), pseudoephedrine (PE), and methylpseudoephedrine (MP) could be identified. The quantities of these compounds are calculated by the relative ratio of the integral values of the target peak for each compound to the known concentrations of the internal standard anthracene. The present method allows for a rapid and simple quantification of ephedrine alkaloid derivatives in Ephedra-related commercial prescriptions without any preliminary purification steps and standard compounds, and accordingly it can be a powerful tool to verify different Ephedra species. In comparison to conventional chromatographic methods, the advantages of this method include the fact that no standard compounds are required, the quantification can be directly performed on the crude extracts, a better selectivity for various ephedrine alkaloid derivatives, and the fact that a very significant time-gain may be achieved.

Chemical constituents from the stems of Machilus philippinensis Merr. and the neuroprotective activity of cinnamophilin.

The Machilus genus (Lauraceae) had been extensively utilized in folk medicine due to its broad range of bioactivities. In the present study, a series of chromatographic separations of the methanol extract of stems of M. philippinensis led to the identification of thirty eight compounds totally. Among these, biscinnamophilin (1), machilupins A-C (2-4), machilutone A (5), and machilusoxide A (6) were new compounds reported for the first time. In addition, 5 was characterized with a unprecedented carbon skeleton. Other known compounds, including the major compounds cinnamophilin (7) and meso-dihydroguaiaretic acid (8), are identified by comparison of their physical and spectroscopic data with reported values. One of the reported compounds, cinnamophilin A (10), should be revised as dehydroguaiaretic acid (9) after careful comparison of all the 1H and 13C NMR data. Moreover, the neuroprotective activity of cinnamophilin (7) was examined in a primary cortical neuron culture and the results indicated that 7 was effective against glutamate induced excitotoxicity.

Isolation of substances with antiproliferative and apoptosis-inducing activities against leukemia cells from the leaves of Zanthoxylum ailanthoides Sieb. & Zucc.

Extraction of the leaves of Zanthoxylum ailanthoides Sieb. & Zucc. affords extracts and four isolated compounds which exhibit activities against leukemia cells. The chloroform-soluble fraction (ZAC) of the crude extract of this plant showed cytotoxic activity against human promyelocytic leukemia (HL-60) and myelomonocytic leukemia (WEHI-3) cells with IC(50) values of 73.06 and 42.22 µg/mL, respectively. The active ZAC was further separated to yield pheophorbide-a methyl ester (1), pheophorbide-b methyl ester (2), 13(2)-hydroxyl (13(2)-S) pheophorbide-a methyl ester (3) and 13(2)-hydroxyl (13(2)-R) pheophorbide-b methyl ester (4) whose structures were confirmed by spectroscopic methods. Compounds 2-4 showed cytotoxic activities against both leukemia cells with IC(50) value in the range of 46.76-79.43 nM, whereas compound 1 exhibited only weak cytotoxic activity. The extracts and compounds 1-4 also induced apoptosis and DNA damage in leukemia cells after treatment. The results suggested that the Z. ailanthoides is biologically active against leukemia cells.

New diterpenoids and the bioactivity of Erythrophleum fordii.

A phytochemical investigation of the leaves of Erythrophleum fordii Oliv. has led to the isolation of three new cassaine-type diterpenoids, erythrofordin A (1), erythrofordin B (2) and erythrofordin C (3), as well as a norcassaine diterpenoid with a novel skeleton, norerythrofordin A (4), and 27 known compounds (5-31). The structures of 1-4 were elucidated on the basis of spectroscopic analysis. Selected compounds from this plant were examined for anti-inflammatory activity. Taraxerol (16) displayed potent NO-reducing activity in microglial cells, and gallic acid (27) exhibited excellent DPPH radical-scavenging effects.

Anti-inflammatory activities of furanoditerpenoids and other constituents from Fibraurea tinctoria.

Five new furanoditerpenoids, epi-8-hydroxycolumbin (1), fibaruretin B (2), C (3), E (5), and F (6), were isolated from the stems of Fibraurea tinctoria, as well as fibaruretin D (4) from the natural source for the first time, and 39 known compounds. The structures (1-6) were elucidated on the basis of spectroscopic analysis. All the isolated furanoditerpenoids (1-16) were examined for their in vitro activity and some were in vivo anti-inflammatory activity. Compounds 8 and 9 showed significant anti-inflammatory action administered at a dose of 100mg/kg of reducing carrageenan mice paw edema, whereas compound 7, 9, 10, 14, and 16 were more potent to inhibit NO production. The inhibitory effects of these compounds are dose-dependent (1-4 microg/ml).

Acetophenone derivatives from Acronychia pedunculata.

Chemical investigation on the stem and root bark of Acronychia pedunculata has resulted in the isolation of five new acetophenones, namely, acronyculatins A (1), B (2), C (3), D (4), and E (5). The structures of these metabolites were established on the basis of their 1D and 2D NMR spectroscopic and mass spectrometric data and by CD spectroscopy. The antioxidant and antityrosinase activities of these five metabolites and acrovestone (6) were evaluated. Among these compounds, 6 showed marginal antioxidant and antityrosinase activities.

Triterpenoids from Rubia yunnanensis.

Five new triterpenoids, rubiarbonones D (1), E (5), and F (2), and rubiarbosides F (3) and G (4), together with nine known compounds, were isolated from the roots of Rubia yunnanensis. The structures of 1-12 were elucidated by spectroscopic methods. The antiplatelet aggregation activities of rubiarbonone A (6) and rubiarbonol A (8) and B (9) were investigated with a standard protocol.

Constituents of the roots of Rubia yunnanensis.

Four new naphthohydroquinones, rubinaphthins A (1), B (2), C (3), and D (4), together with 11 known compounds were isolated and characterized from the roots of Rubia yunnanensis. The structures of 1-4 were elucidated by spectral analysis and chemical transformation.