Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis

Context: Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.

Objectives: This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.

Materials and methods: Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.

Results: Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.

Discussion and conclusions: DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.     

Identification of potent anticancer activity in Ximenia americana aqueous extracts used by African traditional medicine

The antineoplastic activity of a plant powder used in African traditional medicine for treating cancer was investigated by analyzing the activity of various extracts in vitro. The most active, aqueous extract was subsequently subjected to a detailed investigation in a panel of 17 tumor cell lines, showing an average IC50 of 49 mg raw powder/ml medium. The sensitivity of the cell lines varied by two orders of magnitude, from 1.7 mg/ml in MCF7 breast cancer cells to 170 mg/ml in AR230 chronic-myeloid leukemia cells. Immortalized, non-tumorigenic cell lines showed a marginal sensitivity. In addition, kinetic and recovery experiments performed in MCF7 and U87-MG cells and a comparison with the antineoplastic activity of miltefosine, gemcitabine, and cisplatinum in MCF7, U87-MG, HEp2, and SAOS2 cells revealed no obvious similarity between the sensitivity profiles of the extract and the three standard agents, suggesting a different mechanism of cytotoxicity. The in vivo antitumor activity was determined in the CC531 colorectal cancer rat model. Significant anticancer activity was found following administration of equitoxic doses of 100 (perorally) and 5 (intraperitoneally) mg raw powder/kg, indicating a 95% reduced activity following intestinal absorption. By sequencing the mitochondrial gene for the large subunit of the ribulose bis-phosphate carboxylase (rbcL) in DNA from the plant material, the source plant was identified as Ximenia americana. A physicochemical characterization showed that the active antineoplastic component(s) of the plant material are proteins with galactose affinity. Moreover, by mass spectrometry, one of these proteins was shown to contain a stretch of 11 amino acids identical to a tryptic peptide from the ribosome-inactivating protein ricin.     

蒙药蜀葵花HPLC指纹图谱及rbcL序列分子鉴定研究

目的 建立蜀葵花HPLC指纹图谱及rbcL序列DNA条形码（barcoding）分子鉴定方法。方法 色谱柱为Welchrom Column C₁₈（300 mm×4.6 mm，5 μm），以乙腈-0.1%甲酸溶液为流动相、梯度洗脱，体积流量1.0 mL/min，柱温35℃，检测波长365 nm，进样量10 μL；采用"中药色谱指纹图谱相似度评价软件（2012版A版）"进行相似度评价；同时以rbcL为引物，对11份蜀葵花进行PCR扩增并测定序列，运用DNDMAN和MEGA7.0及CodonCode Aligner17.0软件进行分析。结果 建立了11份蜀葵花的HPLC指纹图谱，得到21个共有峰，相似度均大于0.88，并标定了金丝桃苷（7号峰）、槲皮素（15号峰）、芹菜素（19号峰）、山柰素（20号峰）4个成分；rbcL序列扩增和测序成功率100%，测序到的长度500 bp，GC含量为44.10%~44.40%，种内遗传距离0~0.004 0，平均遗传距离0.001 4，变异位点数10个，相似度为99.00%。结论 建立的HPLC指纹图谱方法稳定可靠、rbcL序列DNA barcoding分子鉴定方法重复性好，可用于蜀葵花的质量控制。     

博落回本草考证及其鉴定研究

目的 开展博落回及其相似品种的中药鉴定研究。方法 通过查阅历代本草书籍和近现代文献资料,对博落回进行系统梳理与考证;采用传统中药鉴定、显微鉴定、理化鉴定以及分子鉴定等鉴别方法对博落回及其相似品种进行鉴定。结果得到博落回本草考证资料;博落回与小果博落回以及其他相似品种的性状、显微、理化、分子特征均有一定区别;分子鉴定结果显示,博落回rbcL序列长度在600～603 bp,平均GC碱基含量在43.95%～44.28%;博落回与其他相似品种间的变异位点存在较大差异,其中与小果博落回的变异位点最少;博落回与其相似品种的种间遗传距离均大于其最大种内遗传距离;基于rbcL构建的NJ树可对博落回与其他相似品种进行有效区分;博落回与其相似品种在rbcL二级结构上存在显著差异。结论 构建了博落回与小果博落回以及其他相似品种的中药鉴定方法,为博落回的品种鉴定及后续中药资源开发提供实验基础。     

基于DNA条形码鉴别缘毛紫菀及狭苞紫菀

目的 基于ITS2和rbcL序列对来自不同地理环境的缘毛紫菀Aster souliei及狭苞紫菀A. farreri进行分子鉴定。方法 以ITS2和rbcL的特异性引物,扩增缘毛紫菀及狭苞紫菀的ITS2和rbcL的序列并测定,运用MEGA7.0软件进行多重比对分析和种间种内遗传距离分析,构建邻接法(neigbor-joining,NJ)系统发育树。结果 ITS2序列在缘毛紫菀及狭苞紫菀的变异位点较rbcL序列丰富,且种间与种内的变异位点数无交叉;ITS2序列的NJ树可将缘毛紫菀及狭苞紫菀样品进行有效区分,而rbcL序列构建的系统发育树无法使缘毛紫菀及狭苞紫菀样品得到有效的区分;ITS2及rbcL序列的遗传距离结果显示缘毛紫菀之间的遗传距离很近,而狭苞紫菀之间的遗传距离较远。结论 ITS2较rbcL序列更适合用于不同产地的缘毛紫菀及狭苞紫菀样品的鉴定;狭苞紫菀的种内差异较大。     

牛奶菜属植物及其近缘植物的ITS2、rbcL序列分析

目的 分析ITS2、rbcL序列在牛奶菜属植物及其近缘植物间的鉴别能力,并对牛奶菜属植物及其近缘植物的系统进化进行初步分析.方法 采用直接测序法测定所分析样品的ITS2、rbcL序列,获得的序列采用软件CodonCode Aligner人工校正,Contig软件拼接,用MEGA 4.0软件分析比对并进行遗传距离等分析,用NJ法对比对的序列构建系统分支树.结果 ITS2、rbcL序列对牛奶菜属植物及其他所分析样品有较好的鉴别能力,且鉴别能力ITS2优于rbcL;南山藤属、匙羹藤属植物与牛奶菜属植物间的亲缘关系非常相近.结论 条形码ITS2、rbcL序列能很好地区分牛奶菜属植物,且鉴别能力ITS2优于rbcL;建议将南山藤属、匙羹藤属等小属植物归入牛奶菜属内.     

石斛属植物rbcL基因序列变异和系统发育初步研究

目的 探讨10种石斛植物叶绿体rbcL基因序列变异和系统发育关系.方法 根据Genebank已经公布的植物rbcL基因序列设计一对引物,用于石斛rbcL基因PCR扩增.基因序列排列用Clustal X软件完成,应用Seqnconverter软件分析序列的长度、GC含量、GpC量、GCskew值等;用Mega 4.1软件分析转换值、颠换值、转换/颠换比;采用最大简约法(maximum parsimony method)获得最大简约系统树;应用自展法(bootstrap)检验系统树,自展次数为1 000次.结果 10种石斛植物叶绿体rbcL基因的长度范围为944～950 bp,其中536 bp为保守位点,466 bp为变异位点,439 bp为具有系统发育信息的信息位点.基因中GC含量为40.61%～41.37%,GpC含量为4.03%～4.78%,GCskew 值为0.043 2～0.082 1.序列转换/颠换比(Si/Sv)为0.9.结论 利用PCR和核酸测序方法可以获得rbcL基因的核苷酸序列,能为石斛植物的系统发育研究提供核苷酸序列方面的资料.     

Detection of plant-based adulterants in turmeric powder using DNA barcoding

Abstract

Context: In its powdered form, turmeric [Curcuma longa L. (Zingiberaceae)], a spice of medical importance, is often adulterated lowering its quality.

Objective: The study sought to detect plant-based adulterants in traded turmeric powder using DNA barcoding.

Materials and methods: Accessions of Curcuma longa L., Curcuma zedoaria Rosc. (Zingiberaceae), and cassava starch served as reference samples. Three barcoding loci, namely ITS, rbcL, and matK, were used for PCR amplification of the reference samples and commercial samples representing 10 different companies. PCR success rate, sequencing efficiency, occurrence of SNPs, and BLAST analysis were used to assess the potential of the barcoding loci in authenticating the traded samples of turmeric.

Results: The PCR and sequencing success of the loci rbcL and ITS were found to be 100%, whereas matK showed no amplification. ITS proved to be the ideal locus because it showed greater variability than rbcL in discriminating the Curcuma species. The presence of C. zedoaria could be detected in one of the samples whereas cassava starch, wheat, barley, and rye in other two samples although the label claimed nothing other than turmeric powder in the samples.

Discussion and conclusion: Unlabeled materials in turmeric powder are considered as adulterants or fillers, added to increase the bulk weight and starch content of the commodity for economic gains. These adulterants pose potential health hazards to consumers who are allergic to these plants, lowering the product's medicinal value and belying the claim that the product is gluten free. The study proved DNA barcoding as an efficient tool for testing the integrity and the authenticity of commercial products of turmeric.     

栀子叶绿体DNA条形码的研究

目的评价3个叶绿体DNA(cpDNA)条形码候选序列对茜草科植物栀子属的鉴别能力,探索栀子属植物鉴定的新方法。方法使用matK、rbcL和psbA候选序列的通用引物对栀子属植物cpDNA进行PCR扩增和测序,比较各序列的扩增成功率、长度、种内和种间变异、barcoding gap,并采用BLAST和DNA MAN进行分析评价。结果 matK、rbcL、psbA序列对栀子属3个物种、5个样本的扩增成功率均为100%,其中通用引物matK扩增的序列种内种间变异差异、barcoding gap较psbA、rbcL序列具有更明显的优势,其鉴定成功率相对较高。结论 matK是适合栀子属植物鉴别的较好cpDNA条形码。