Simultaneous determination of five main active constituents of Erigeron multiradiatus by HPLC-DAD-MS

The complete chloroplast genome sequence of Erigeron breviscapus and Erigeron multiradiatus (Asteraceae)

The complete chloroplast genomes of Erigeron breviscapus (Vant.) Hand-Mazz and Erigeron multiradiatus (Lindl.) Benth were reported in this study. The complete chloroplast genomes were 152,367 bp and 152,281 bp for E. breviscapus and E. multiradiatus, respectively. Erigeron breviscapus including two inverted repeat (IRs, 24,692 bp) regions, one large singe copy region (LSC) and one small singe copy region (SSC) of 84,881 bp and 18,102 bp, whereas E. multiradiatus contained IRs of 24,691 bp, LSC of 84,789 bp and SSC of 18,110 bp. The chloroplast genomes both contained 129 genes, including 84 protein-coding genes, 37 tRNA genes, and 8 rRNA genes.

Analysis of the transcriptome of Erigeron breviscapus uncovers putative scutellarin and chlorogenic acids biosynthetic genes and genetic markers

Background

Erigeron breviscapus (Vant.) Hand-Mazz. is a famous medicinal plant. Scutellarin and chlorogenic acids are the primary active components in this herb. However, the mechanisms of biosynthesis and regulation for scutellarin and chlorogenic acids in E. breviscapus are considerably unknown. In addition, genomic information of this herb is also unavailable.

Principal Findings

Using Illumina sequencing on GAIIx platform, a total of 64,605,972 raw sequencing reads were generated and assembled into 73,092 non-redundant unigenes. Among them, 44,855 unigenes (61.37%) were annotated in the public databases Nr, Swiss-Prot, KEGG, and COG. The transcripts encoding the known enzymes involved in flavonoids and in chlorogenic acids biosynthesis were discovered in the Illumina dataset. Three candidate cytochrome P450 genes were discovered which might encode flavone 6-hydroase converting apigenin to scutellarein. Furthermore, 4 unigenes encoding the homologues of maize P1 (R2R3-MYB transcription factors) were defined, which might regulate the biosynthesis of scutellarin. Additionally, a total of 11,077 simple sequence repeat (SSR) were identified from 9,255 unigenes. Of SSRs, tri-nucleotide motifs were the most abundant motif. Thirty-six primer pairs for SSRs were randomly selected for validation of the amplification and polymorphism. The result revealed that 34 (94.40%) primer pairs were successfully amplified and 19 (52.78%) primer pairs exhibited polymorphisms.

Conclusion

Using next generation sequencing (NGS) technology, this study firstly provides abundant genomic data for E. breviscapus. The candidate genes involved in the biosynthesis and transcriptional regulation of scutellarin and chlorogenic acids were obtained in this study. Additionally, a plenty of genetic makers were generated by identification of SSRs, which is a powerful tool for molecular breeding and genetics applications in this herb.

Separation and purification of two flavone glucuronides from Erigeron multiradiatus (Lindl.) Benth with macroporous resins

Scutellarein-7-O-beta-D-glucuronide (SG) and apigenin-7-O-beta-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R(2) > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials.