Comprehensive mass spectrum analysis of two flavone-6,8-C-di-glycosides and its application by high resolution electrospray ionization tandem mass spectroscopy in both negative and positive ion modes / 中国中药杂志

The tandem mass spectrum of apigenin-6,8-C-di-glucoside( 1) and apigenin-6-C-glucose-8-C-rhamnoside( 2) were obtained by high resolution electrospray ionization mass spectrometry( HR-ESI-MS/MS) in both positive and negative ion modes. The elemental composition of each ion was determined according to its accurate mass-to-charge,hence,the fragmentation pathways of each compound were proposed in both negative and positive ion modes. Comprehensive analysis of each ion and its proposed fragmentation pathways of the two compounds was initially conducted in both negative and positive ion mode HR-ESI-MS/MS to explore the diagnostic ions for flavone-6,8-C-di-glycosides and the characteristic ions for each compound and their cleavage rules. The results showed that a family of fragmentation ions with m/z 353,325,311,297 in ESI(-)-MS and m/z 355,325,307,295 in ESI( +)-MS could be the diagnostic ions of flavone-6,8-C-di-glycoside,and characteristic neutral loss could be assigned to glycosyl substitution,for example,neutral losses of C_4H_8O_4( 120),C_3H_6O_3( 90),C_2H_4O_2( 60) for glucoside substitution while neutral losses of C_4H_8O_3(104),C_3H_6O_2( 74),C_2H_4O( 44) for rhamnoside substitution. Furthermore,only one H_2O loss from mother ion( [M-H]-) was observed for 1 & 2 in ESI(-)-MS while five to six H2 O loss from mother ion( [M+H]+) was observed for 1 & 2 in ESI( +)-MS to produce a family of ions by subsequent loss of H_2O,which could be applied for glucosyl difference. The flavone-6,8-C-di-glycosides in both ESI( +)-MS and ESI(-)-MS showed the cleavage similarity at sugar substitutions. However,there were much more differences by the fragmentation pathways and neutral losses between ESI( +)-MS and ESI(-)-MS as following,hyperconjugation ions by subsequent loss of H_2O from precursor ions of flavone-6,8-C-di-glycosides in ESI( +)-MS were not observed in ESI(-)-MS; the subsequent neutral loss of CH_2O in ESI( +)-MS were rarely observed in ESI(-)-MS; the loss of CO only happen at C-ring of flavone ESI( +)-MS other than glycosyl position in ESI(-)-MS; the C4-chain neutral loss of flavone-6,8-C-di-glycosides happened at 8-C-glycosyl position other than at 6-C-glycosyl position. The above cleavage rules and diagnostic ions of ESI( +)-MS were successfully applied for the structure identification of 4 flavone-6 C,8 C-diglycosides from the stem extract of Dendrobium officinale as vicenin Ⅱ,vicenin Ⅰ,isoschaftoside,schaftoside as well as one flavone-O-glysoside named rutin,which were supported by ESI(-)-MS data as well.

Regulatory Effect of Sijunzi Tang and Its Single Herbs on Intestinal Flora in Rats with Spleen Deficiency / 中国实验方剂学杂志

Objective:To investigate the regulatory effect of Sijunzi Tang(SJZT) and its single herbs(Ginseng Radix et Rhizoma, Glycyrrhizae Radix et Rhizoma Praeparata cum Melle, Atractylodis Macrocephalae Rhizoma and Poria) on intestinal flora in spleen-deficient rats. Method:Normal rats were randomly divided into the blank group, model group, Zhengchangsheng granules group, SJZT group and each single herb group, rats were orally administered Sennae Folium decoction to induce diarrhea for ten consecutive days to establish a spleen-deficient model(distilled water for the blank group), then treated with the corresponding drugs for seven consecutive days(distilled water for the blank group and the model group). Fresh feces were collected on pre-modeling(0th day), post-modeling(11th day), and post-treatment(18th day). Short-chain fatty acids(SCFAs) in feces were acidified by sulphuric acid and extracted by diethyl ether, then determined by gas chromatography. The structural change(diversity and similarity) of intestinal flora in feces was analyzed by 16S rDNA-polymerase chain reaction(PCR)-denaturing gel gradient electrophoresis(DGGE) technique. Result:Compared with blank group, the contents of SCFAs as well as diversity and similarity indexes of intestinal flora in feces of all administered groups were significantly decreased on the 11th day(PPth day, compared with model group, the contents of SCFAs as well as diversity and similarity indexes of intestinal flora in feces of Atractylodis Macrocephalae Rhizoma group were significantly increased(PPPPConclusion:Ginseng Radix et Rhizoma, Atractylodis Macrocephalae Rhizoma and Poria are the single herbs responsible for the regulatory effect of SJZT on intestinal flora in spleen-deficient rats, and Atractylodis Macrocephalae Rhizoma may play a major role.