Advances in biotransformation of protopanaxatriol rare ginsenoside / 中草药

Ginseng is a traditional medicine in Asian countries. Ginsenoside has the main active ingredient, exhibit cardiovascular, tumor, and central nervous system activities. In particular, protopanaxatriol-type ginsenosides Rh1, exhibits anti-inflammatory, anti-allergic, and memory improvement activities. Ginsenoside Rh1 is only found in trace amounts in Panax ginseng, Panax pseudoginseng var. notoginseng, and Panax quinquefolius. Biotransformation of rare ginsenosides has become an effective way. In this paper, the research progress of transformation of ginsenoside saponins by biotransformation to produce rare ginsenoside Rh1 is reviewed, which provides a useful reference for the further development and preparation of ginsenoside Rh1.

The metabolic fingerprint of the compatibility of Radix Aconite and Radix Paeoniae Alba and its effect on CYP450 enzymes / 药学学报

Using a UPLC-MS/MS (MRM) and cocktail probe substrates method, the metabolic fingerprint of the compatibility of Radix Aconite (RA) and Radix Paeoniae Alba (RPA) and its effect on CYP450 enzymes were investigated. These main CYP isoforms include CYP 1A2, CYP 2C, CYP 2E1, CYP 2D and CYP 3A. Compared with the inhibition effect of RA decoctions on CYP450 isoforms, their co-decoctions of RA and RPA with different proportions can decrease RA' inhibition on CYP3A, CYP2D, CYP2C and CYP1A2, but can not reduce RA' effect on CYP2E1. The metabolic fingerprints of RA decoction and co-decoctions with different proportions of RPA in CYP450 of rat liver were analyzed by UPLC-MS. Compared with the metabolic fingerprints of RA decoction, the intensity of diester-diterpenoid aconitum alkaloids decreased significantly, while the intensity of monoester-diterpenoid alkaloids significantly increased in the metabolic fingerprints of co-decoctions of RA and RPA. The results suggest that RA coadministration with RPA increased the degradation of toxic alkaloid and show the effect of toxicity reducing and efficacy enhancing.

Effects of six kinds of Chinese herb extracts on the activities of rat liver microsomes in vitro / 药学学报

Effects of six kinds of Chinese herb extracts, including Folium Crataegi extract, Herba Epimedii extract, Folium Acanthopanacis Senticosi extract, Trifolium pratense L. extract, Folium Ginkgo extract and Radix Puerariae extract, on the activities of CYP450 isozymes (CYP1A2, CYP2C, CYP2E1, CYP2D, CYP3A) in rat hepatic microsomals were studied by using a UPLC-MS/MS (MRM) and cocktail probe substrates method. The results showed that effects of six kinds of Chinese herb extracts on each CYP450 isozyme activity were inhibitory. The IC50 of Folium Crataegi extract for the inhibition of rat microsomal CYP2D activity was only for 4.04 microg x mL(-1), which showed the highest inhibition; Trifolium pratense L. extract had strong inhibitory action to CYP2D, the IC50 value was 5.73 microg x mL(-1); Folium Crataegi extract also had strong inhibitory action on CYP2E1, the IC50 value was 10.91 microg x mL(-1). Furthermore, the IC50 of Folium Ginkgo extract for the inhibition of rat microsomal CYP3A, 2D, 2E1 activities were 45.12, 35.45 and 22.41 microg x mL(-1), respectively, and the IC50 of Folium Acanthopanacis Senticosi extract on the inhibition of rat microsomal CYP2E1 activity was 32.89 microg x mL(-1). In addition, mechanism of inhibition experimental results showed that the inhibiting abilities of Folium Crataegi extract and Radix Puerariae extract on each CYP450 isozyme increased with the increasing of the preincubation time, therefore, the inhibitory effects were a mechanism-based inhibition.

Metabolites and metabolic pathways of mesaconitine in rat liver microsomal investigated by using UPLC-MS/MS method in vitro / 药学学报

Mesaconitine was incubated with rat liver microsomes in vitro. The metabolites of mesaconitine in rat liver microsomes were identified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method with high resolution power. A typical reaction mixture of 100 mol L-1 Tris-HCI buffer (pH 7.4) containing 0.5 gL-1 microsomal protein and 50 micro molL-1 mesaconitine was prepared. The above reaction mixture was divided into six groups, and the volume of each group was 200 micro L. The incubation mixture was pre-incubated at 37 degrees C for 2 min and the reactions were initiated by adding NADPH generating system. After 90 min incubation at 37 degrees C, 200 micro L of acetonitrile was added to each group to stop the reaction. The metabolites of mesaconitine were investigated by UPLC-MS/MS method. Mesaconitine and 6 metabolites M1-M6 were found in the incubation system. The structures were characterized according to the data from MS/MS spectra and literatures. The metabolic reactions of mesaconitine in rat liver microsomes included the demethylation, deacetylation, dehydrogenation and hydroxylation. The major metabolic pathways of mesaconitine in rat liver microsomes were determined by UPLC-MS/MS on multiple reaction monitoring (MRM) mode combined with specific inhibitors of cytochrome P450 (CYP) isoforms, including alpha-naphthoflavone (CYP1A2), quinine (CYP2D), diethyldithiocarbamate (CYP2E1), ketoconazole (CYP3A) and sulfaphenazole (CYP2C), separately. Mesaconitine was mainly metabolized by CYP3A. CYP2C and CYP2D were also more important CYP isoforms for the metabolism reactions of mesaconitine, but CYP1A2 and CYP2E1 haven't any contribution to MA metabolism in rat liver microsomes.