How many names for a beloved genus? - Coalescent-based species delimitation in Xanthium L. (Ambrosiinae, Asteraceae).

The species category is the fundamental unit in biology. In the last decades, several studies have been carried out, using sequence information and phylogenies to resolve issues in taxonomically problematic groups. The multispecies coalescent theory, and the species-delimitation methods developed in the last years based on that, offer powerful and objective tools to determine species boundaries using sequence data. The genus Xanthium is a morphologically variable complex with several local forms, nowadays become cosmopolitan due to human-mediated dispersal. Past taxonomic treatments of the genus were based essentially on the burr morphology. They varied considerably in number of recognized species, depending on the importance that the different authors gave to burr traits such as burr size, pubescence, number and length of spines in the burrs, and the degree to which those are hooked. We used sequence information from two plastid regions (the intergenic spacer regions psbA-trnH and trnQ-rps16) and two nuclear ones (ITS1-5.8 S-ITS2 rDNA, and the single-copy nuclear marker D35). Two of the most advanced coalescent-based species delimitation methods (BP&P and STACEY) were applied, in order to objectively determine species boundaries in Xanthium. Results from the species-delimitation methods strongly support scenarios with a reduced number of species. Prior on the effective population size parameter (θ) had a strong influence on BP&P results. Analyses with large and small θ prior supported species delimitation scenarios with four and five species, respectively. STACEY recognized five cluster in the dataset, all supported by high posterior probability values. Five species are identified in Xanthium, in a great extent corresponding to the infrageneric classification given for the genus in past taxonomic revisions.

Phylogenetic Analysis and Molecular Characterization of Xanthium sibiricum Using DNA Barcoding, PCR-RFLP, and Specific Primers.

The fruits of Xanthium sibiricum have been widely used in traditional Chinese medicine for the treatment of nasal sinusitis and headaches. The genus Xanthium (cocklebur) is a taxonomically complex genus. Different taxonomic concepts have been proposed, some including several species, others lumping the different taxa in a few extremely polymorphic species. Due to the morphological similarities between species, the correct authentication of X. sibiricum is very difficult. Therefore, we established a polymerase chain reaction-restriction fragment length polymorphism method and diagnostic PCR based on nuclear internal transcribed spacer and chloroplast trnQ-rps16 barcodes to differentiate X. sibirium from related species.Results from the phylogenetic analyses based on sequence information from four marker regions (plastidal psbA-trnH and trnQ-rps16 and nuclear ITS and D35) support those taxonomic concepts accepting a reduced number of species, as four to five major clades are revealed in the phylogenetic reconstructions. X. sibiricum, together with some accessions from closely related taxa, is always supported as monophyletic, constituting a well-defined genetic entity. Allele-specific primer pairs for ITS and trnQ-rps16 were designed to amplify diagnostic products from the genomic DNA of X. sibiricum. Specific PCR in combination with digestion using the restriction enzyme MseI allowed for the identification of X. sibiricum by producing specific restriction patterns. The results demonstrate that the applied techniques provide effective and accurate authentication of X. sibiricum.

[Herbal textural research on species of Xanthii Fructus].

Xanthii Fructus is a traditional medicine for the treatment of nasal diseases in clinic, mainly come from the burs of Xanthium sibiricum with a worldwide distribution. By sorting and studying literature of Chinese medicine and comparing different figures recorded with the morphological description of several species from Xanthium (Asteraceae) in the Flora of China, combining the biological investigation in resource survey, the article pointed out that the burs or the whole herbs of X. mongolicum, as well as X. sibiricum, has been used by the traditional Chinese medicine in ancient time. It provides a reference for further studies in the future.

[Optimization of processing technology for xanthii fructus by UPLC fingerprint technique and contents of toxicity ingredient].

The experiment's aim was to optimize the processing technology of Xanthii Fructus which through comparing the difference of UPLC fingerprint and contents of toxicity ingredient in water extract of 16 batches of processed sample. The determination condition of UPLC chromatographic and contents of toxicity ingredient were as follows. UPLC chromatographic: ACQUITY BEH C18 column (2.1 mm x 100 mm, 1.7 microm) eluted with the mobile phases of acetonitrile and 0.1% phosphoric acidwater in gradient mode, the flow rate was 0.25 mL x min(-1) and the detection wavelength was set at 327 nm. Contents of toxicity ingredient: Agilent TC-C18 column (4.6 mm x 250 mm, 5 microm), mobile phase was methanol-0.01 mol x L(-1) sodium dihydrogen phosphate (35: 65), flow rate was 1.0 mL x min(-1), and detection wavelength was 203 nm. The chromatographic fingerprints 16 batches of samples were analyzed in using the similarity evaluation system of chromatographic, fingerprint of traditional Chinese medicine, SPSS16.0 and SIMCA13.0 software, respectively. The similarity degrees of the 16 batches samples were more than 0.97, all the samples were classified into four categories, and the PCA showed that the peak area of chlorogenic acid, 3,5-dicaffeoylquinic acid and caffeic acid were significantly effect index in fingerprint of processed Xanthii Fructus sample. The outcome of determination showed that the toxicity ingredient contents of all samples reduced significantly after processing. This method can be used in optimizing the processing technology of Xanthii Fructus.

Effects of extraction methods of phenolic compounds from Xanthium strumarium L. and their antioxidant activity / Efeito de métodos de extração de compostos fenólicos de Xanthium strumarium L. e suas atividades antioxidantes

Foram avaliados os efeitos de métodos de extração e de solventes sobre o rendimento de extrato, conteúdo de fenólicos totais, atividade antioxidante, e composição dos compostos fenólicos de Xanthium strumarium L. A atividade antioxidante foi determinada pelo método do radical 2,2-difenil-1-picrilhidrazila (DPPH), e a composição dos compostos fenólicos foi determinada por cromatografia líquida de alta eficiência e por espectrometria de massas com ionização por electrospray. Todos os resultados foram afetados pelo método de extração e, principalmente pelo solvente utilizado, sendo que os melhores resultados foram obtidos com o solvente metanol. Os extratos metanólico e etanólico apresentaram forte ação antioxidante e os principais compostos fenólicos encontrados nos extratos foram os ácidos ferúlico e clorogênico.

The effect of extraction methods and solvents on overall yield, total phenolic content, antioxidant activity, and the composition of the phenolic compounds in Xanthium strumarium extracts were studied. The antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), and the composition of the phenolic compounds was determined by HPLC-DAD and LC/MS. All results were affected by the extraction method, especially by the solvent used, and the best results were obtained with the methanol extract. The methanolic and ethanolic extracts exhibited strong antioxidant activity, and the chlorogenic and ferulic acids were the most abundant phenolic compounds in the extracts.

Correlation between the genetic diversity and variation of total phenolic acids contents in Fructus Xanthii from different populations in China.

Fructus Xanthii (Cang-Er-Zi) is a traditional Chinese medicine that is used in curing nasal diseases and headache according to the Chinese Pharmacopoeia. For the effective quality control of its medicinal values, reflected by chemical variation patterns, in addition to the relationship with genetic diversity, analyses based on UV spectrophotometry, HPLC fingerprinting and inter-simple sequence repeat (ISSR) molecular markers were carried out, involving 16 Xanthium populations from different locations in China. The HPLC data showed considerable variation of chemical constituents among the 16 Xanthium populations, and they were classified to three chemotypes by hierarchical clustering analysis. Abundant genetic diversity was detected among the Xanthium populations, which were also clustered into three groups based on their ISSR data and varied according to different species. Combining the genetic divergence and chemical differences showed an important result that, in the two chemotypes, the higher contents of total phenolic acids (TPA) in Fructus Xanthii showed greater genetic diversity (I). We suggest that genetic diversity affects the contents of TPA. Since variable phenolic acid contents may affect therapeutic efficacy, it is important to point out that combining the use of genetic base with chemotype will help control the favourable chemotypes and breed new cultivars with more desirable chemical constituents.

[Identification of medicinal plant Xanthium L. produced in China].

OBJECTIVE: To gain a clear idea on the resources and pharmacognostic identification of medicinal plant Xanthium in China. METHOD: Identification of botanical origin, analysis of fruit shapes and properties, microscopic characteristics, TLC and UV. RESULT: Identification criteria have been worked out for Xanthium and its confused species. CONCLUSION: The resources of medicinal plant Xanthium may be appropriately expanded.