Evaluation of oil content and fatty acid composition of five endemic Bupleurum species growing in the Central Anatolia region of Turkey

Quantitative Analysis and Differential Evaluation of Radix Bupleuri Cultivated in Different Regions Based on HPLC-MS and GC-MS Combined with Multivariate Statistical Analysis

The quality of Radix Bupleuri is greatly affected by its growing environment. In this study, Radix Bupleuri samples that were harvested from seven different regions across northwest China were examined by high-performance liquid chromatography (HPLC) and gas chromatography (GC) coupled with mass spectrometry (MS) to reveal significant differences in quality contributed by the cultivation region. An HPLC-MS method was firstly established and used in the multiple reaction monitoring mode for the quantitative analysis of five saikosaponins in Radix Bupleuri so as to evaluate the difference in the absolute content of saikosaponins attributable to the cultivation region. The effect on the components of Radix Bupleuri was further investigated based on the profiles of the representative saponins and volatile compounds, which were extracted from the Radix Bupleuri samples and analyzed by HPLC-MS and GC-MS. Multivariate statistical analysis was employed to differentiate the Radix Bupleuri samples cultivated in different regions and to discover the differential compositions. The developed quantitative method was validated to be accurate, stable, sensitive, and repeatable for the determination of five saikosaponins. Further statistical tests revealed that the collected Radix Bupleuri samples were distinctly different from each other in terms of both saponins and volatile compounds, based on the provinces where they were grown. In addition, twenty-eight saponins and fifty-eight volatile compounds were identified as the differentially accumulated compositions that contributed to the discrimination of the Radix Bupleuri samples. The Radix Bupleuri samples grown in Shouyang county showed the highest content of saikosaponins. All of the results indicated that the cultivation region significantly affected the accumulation and diversity of the main chemical components of Radix Bupleuri. The findings of this research provide insights into the effect of the cultivation region on the quality of Radix Bupleuri and the differentiation of Radix Bupleuri cultivated in different regions based on the use of HPLC-MS and GC-MS combined with multivariate statistical analysis.

Do Compositions of Lipid Fraction Correspond to Species Differentiation in Bupleurum L. (Apiaceae)?

Bupleurum L. has been widely used in various medical systems as an agent with a wide range of activities. The qualitative composition and content of lipid fraction components of the aerial parts of B. longifolium and B. chinense were elucidated in this work. The available data on the fatty acids (FAs) in Bupleurum plants were compiled and compared with species differentiation in the genus. As a result, the content of FAs in the studied Bupleurum plant species only partially corresponded to the species differentiation and, in some cases, contradicted it. The prognostic value of Bupleurum's species differentiation for the identification of the potential composition of FAs was insignificant, and it was limited only by particular groups of species. This suggests that a complete phytochemical study of Bupleurum species needs to be conducted to determine the composition of FAs and to identify which species have a similar composition.

Constituents of Essential Oil and Lipid Fraction from the Aerial Part of Bupleurum scorzonerifolium Willd. (Apiaceae) from Different Habitats

The essential oils and lipid fraction extracted from the aerial parts of Bupleurum scorzonerifolium were determined by a GC-MS method. In total, up to 67 components were identified. cis-β-Ocimene, trans-β-ocimene, limonene, α-pinene, α-copaene, β-elemene, and caryophyllene oxide were recognized as consistent components of the essential oil extracted from the aerial parts of B. scorzonerifolium, regardless of the habitat. The content of these components varied from traces to a significant amount. The volume of the lipid fraction varied from 2.73 to 9.38%. In total, 23 components were identified, including 20 fatty acids, two sterols, and one ketone. The major fatty acid components identified were 16:0, 18:2n9, and 18:1n9. The total content of these fatty acids reached up to 76.19%. The lipid fraction of the aerial parts of B. scorzonerifolium predominantly contained MUFA and PUFA, which confirmed the pharmacological value of the species. The main factors affecting the composition of essential oils and lipid fractions of B. scorzonerifolium are environmental ones that determine the moisture supply to the plants in semiarid and arid areas.

A novel coumarin, (+)-3'-angeloxyloxy-4'-keto-3',4'-dihydroseselin, isolated from Bupleurum malconense (Chaihu) inhibited NF-κB activity

Background

This study aims to identify the major anti-inflammatory components in the petroleum ether extract of Bupleurummalconense (Chaihu), by bioassay-guided fractionation, and to investigate the anti-inflammatory mechanisms of active components in lipopolysaccharide (LPS)-stimulated murine macrophage RAW-Blue cells.

Methods

A QUANTI-Blue assay was used to guide fractionation of B.malconense root extract. The petroleum ether extract which exerted significant secreted embryonic alkaline phosphatase (SEAP) inhibition effect was purified by silica gel column chromatography and assisted with reverse phase HPLC. The major bioactive compound which significantly inhibited SEAP activity was obtained and its anti-inflammatory effects in LPS-induced RAW-Blue cells were measured by the overproduction of NO (Griess method), gene expression of Il-1β, Tnf-α and iNos (real-time PCR). In parallel, protein expressions of COX-2, iNOS and IκB-α were determined by western blot.

Results

In bioassay-guided fractionation using LPS-stimulated mouse macrophage RAW-Blue cells, (+)-3′-angeloxyloxy-4′-keto-3′,4′-dihydroseselin (Pd-Ib) was identified by MS and NMR spectral analyses. Pd-Ib (5, 10, 20 μg/mL) suppressed the gene expression of Il-1β (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations), Tnf-α (P = 0.006, P = 0.001, P < 0.0001 for three respective concentrations) and iNos (P = 0.009, P < 0.0001, P < 0.0001 for three respective concentrations) in LPS-stimulated macrophages. The production of cyclooxygenase-2 (P = 0.019, P = 0.002, P < 0.0001), iNOS (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations) and NO (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations) significantly decreased when macrophages were treated with Pd-Ib (5, 10, 20 μg/mL) in the presence of LPS. Pd-Ib (5, 10, 20 μg/mL) suppressed the nuclear activation of NF-κB while it up-regulated the IκB-α level (P = 0.028, P = 0.013, P = 0.005 for three respective concentrations) in LPS-stimulated macrophages.

Conclusions

Pd-Ib isolated from B.malconense suppressed LPS-induced inflammatory responses in macrophages by inhibiting NF-κB activity and reducing the expression of iNOS, COX-2 as well as pro-inflammatory cytokines.

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-016-0077-x) contains supplementary material, which is available to authorized users.

Comparison of root transcriptomes and expressions of genes involved in main medicinal secondary metabolites from Bupleurum chinense and Bupleurum scorzonerifolium, the two Chinese official Radix bupleuri source species

Radix bupleuri, roots of Bupleurum species, is a widely used traditional Chinese medicine. Here, we compared the root transcriptomes of both Bupleurum chinense DC. and Bupleurum scorzonerifolium Willd. A total of 313 483 and 342 263 high quality expressed sequence tags were obtained, respectively. In addition, 17 117 (59.2%) and 19 416 (62.8%) unigenes for B. chinense and B. scorzonerifolium had homologous genes in the opposite dataset. For B. chinense, Kyoto Encyclopedia of Genes and Genomes database (KEGG) annotation identified carbohydrate metabolism, energy metabolism and amino acid metabolism as the three highest groups in the metabolism category. For B. scorzonerifolium, the lipid metabolism group had the most unigenes. Genes that may participate in the biosynthesis of terpenoid, triterpenoid, sterol, lignan and flavonoids were identified according to their annotations. (Tri)terpenoid-related genes were predominantly found in B. chinense. The expressions of certain genes were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in the roots of the two species. A total of 558 putative transcription factors (TFs) and 137 transcriptional regulators (TRs) among 1364 TFs and 327 TRs, and 610 TFs and 129 TRs among 1600 TFs and 323 TRs were specific for B. chinense and B. scorzonerifolium, respectively. Our transcriptome comparison reflects the different types and proportions of metabolites synthesized by the two species. The data, especially, those genes involved in the biosynthesis of particular types of metabolites, will provide the basis for further investigations of the secondary metabolite repertoire of the two Bupleurum species, as well as other species from the genus of Bupleurum.

Traditional Use, Pharmacology, Toxicology, and Quality Control of Species in Genus Bupleurum L

Many species of genus Bupleurum L. have been pharmaceutically used mainly in Asia and Europe for thousand years. Their roots are the most popular ingredients in Chinese materia medica prescriptions for the treatment of inflammatory diseases and auto-immune diseases. A plenty of chemical constituents have been isolated and identified from the species in Bupleurum L., such as saikosaponins, polysaccharides, volatile oils, flavonoids, polyacetylenes, lignins, and coumarins, most of which possess a variety of biological activities, especially for the hepatoprotective effect, antitumor activity, immunoregulation, and febrifuge efficacy. Therefore, the species in genus Bupleurum L. could be potential herbs of immunomodulator, antineoplastic, anti-oxidant, etc. Meanwhile, as potential toxicities have been discovered in some constituents, it is urgent to establish a comprehensive quality evaluation system to ensure the safety and efficiency of herbs. This paper reviews on the phytochemical and pharmacological studies, especially for the toxicology and quality control of the species in Bupleurum L., which is a reference for the species in this genus for safe usage and further development.