Towards a scientific rationale for traditional properties of Chinese medicinal plants: “natures” and “flavors”

Objective: According to theory of Chinese medicine property, the ecological environment shapes properties(natures and flavors) of Chinese materia medica(CMM) and there are close relationships between certain natures and flavors. However, to date these observations have not been validated scientifically in the context of the whole flora of a region. The present study aims to address this gap.Methods: We collected geographical distributions of 3637 vascular plant species native to the Xinjiang region of northwest China, of which around 812 are medicinal plants. The CMM property characters of these medicinal plants were also collected. All medicinal plants were then analyzed in the occurrence of their natures(cold, cool, neutral, warm, and hot) and flavors(sweet, bitter, sour, salty, and pungent). Possible correlations between these properties and environmental factors, notably climate, as well as correlations with plant species richness of the wider native flora of Xinjiang were then investigated using permutation test and regression.Results: Cold species(38.5%) were more numerous than warm(21.0%) and neutral(22.3%), while bitter species(43.3%) were more numerous than pungent(25.6%), sweet(22.4%) and sour(6.7%) ones. Species with bitter flavor were most commonly also cold(48.6%) in nature, sour flavor usually coincided with cold(44.2%) or cool nature(26.0%), whereas pungent or sweet species tended to be warm(34.4%, 28.4%) or neutral(27.8%, 28.4%). The percentages of species of cold/cool nature, bitter flavor were higher in mountainous regions, and the percentages of warm/neutral and pungent/sweet/sour were higher in basins. The percentages of species of cold/cool, bitter were positively correlated with actual evapotranspiration(AET),and also plant species richness but had a bell-shaped relationship with potential evapotranspiration(PET),whereas the inverse situation was shown for warm/neutral and pungent/sweet/sour species.Conclusion: Analysis of the data in Xinjiang region of China supports the qualitative observations concerning natures and flavors in traditional theory of Chinese medicine property. Specifically,(i) certain natures and flavors co-occur more frequently than if randomly distributed;(ii) correlations between proportions of natures and flavors and climatic variables suggest a role for the environment in shaping the properties of CMM.

Identification of Dian Ji Xue Teng(Kadsura interior) with DNA barcodes

Objective: To identify Kadsura interior(Dian Ji Xue Teng, Schisandraceae) by using DNA barcoding.Methods: We analyzed five DNA barcodes(ITS, ITS2, psb A-trn H, mat K and rbc L) using DNA barcoding in terms of distance-based,tree-based and character-based identification to distinguish Kadsura interior and its adulterants.Results: In distance-based and tree-based identification, K. interior could be distinguished easily from the species of Schisandra and K. coccinea.In character-based identification, there are two single nucleotide polymorphisms(SNPs) in ITS and one SNP in psb A-trn H which can be used to distinguish K. interior from K. heteroclita and K. longipedunculata.Conclusion: The results indicate that DNA barcoding can be used to identify K. interior. ITS and psb A-trnH sequence can be the most ideal DNA barcode for discriminating K. interior and its adulterants by the combination analysis of distance-based, tree-based and character-based identification(SNPs).

Genome sizes of four important medicinal species in Kadsura by flow cytometry

Objective:Dianjixueteng is a geoherb in Yunnan Province,the source plant of which is Kadsura interior.However,the formation of this geoherb is not clear in genetic mechanism,in which genome size is the first step that should be known on the genomic level.In this study we aimed to estimate the genome sizes of source plants of K.interior and three related herbs K.heteroclita,K.longipedunculata,and K.coccinea by flow cytometry(FCM)and make a comparison.Methods:The genome sizes of K.interior,K.heteroclita,K.longipedunculata and K.coccinea,i.e.,the source plants of Dianjixueteng and its relative medicinal materials,were estimated by FCM.The nuclei of K.interior were isolated using modified LB01 buffer,for the rest species,by the Galbraith’s buffer.Results:The genome sizes of K.interior,K.heteroclita,K.longipedunculata,and K.coccinea were 7.36,7.12,7.01,and 5.15 pg/1 C,respectively.Genome size of K.interior had no significant variation with those of K.heteroclita and K.longipedunculata(P=0.296),which was significantly larger than that of K.coccinea.Conclusion:Genome size can not distinguish K.interior from K.heteroclita and K.longipedunculata,but could distinguish them from K.coccinea,which lays the foundation for future studies on genetic mechanism of the geoherb formation.

Comparing chloroplast genomes of traditional Chinese herbs Schisandra sphenanthera and S.chinensis

Objective:Schisandra sphenanthera and S.chinensis are the two important medicinal plants that have long been used under the names of"Nan-Wuweizi"and"Wuweizi",respectively.The misuse of"NanWuweizi"and"Wuweizi"in herbal medical products calls for an accurate method to distinguish these herbs.Chloroplast(cp)genomes have been widely used in species delimitation and phylogeny due to their uniparental inheritance and lower substitution rates than that of the nuclear genomes.To develop more efficient DNA markers for distinguishing S.sphenanthera,S.chinensis,and the related species,we sequenced the cp genome ofS.sphenanthera and compared it to that of S.chinensis.Methods:The cp genome of S.sphenanthera was sequenced at the lllumina HiSeq platform,and the reference-guided mapping of contigs was obtained with a de novo assembly procedure.Then,comparative analyses of the cp genomes of S.sphenanthera and S.chinensis were carried out.Results:The cp genome of S.sphenanthera was 146853 bp in length and consisted of a large single copy(LSC)region of 95627 bp,a small single copy(SSC)region of 18292 bp,and a pair of inverted repeats(IR)of 16467 bp.GC content was 39.6%.A total of 126 functional genes were predicted,of which 113 genes were unique,including 79 protein-coding genes,30 transfer RNA(tRNA)genes,and four ribosomal RNA(rRNA)genes.Five tRNA,four protein-coding genes,and all rRNA were duplicated in the IR regions.There were 18 intron-containing genes,including six tRNA genes and 12 protein-coding genes.In addition,45 SSRs were detected.The whole cp genome of S.sphenanthera was 123 bp longer than that of S.chinensis.A total of 474 SNPs and 97 InDels were identified.Five genetic regions with high levels of variation(Pi>0.015),trnS-trnG,ccsA-ndhD,psbI-trnS,trnT-psbD and ndhF-rpl32 were revealed.Conclusion:We reported the cp genome ofS.sphenanthera and revealed the SNPs and InDels between the cp genomes of S.sphenanthera and S.chinensis.This study shed light on the species identification and further phylogenetic study within the genus of Schisandra.