DNA barcoding and TLC as tools to properly identify natural populations of the Mexican medicinal species Galphimia glauca Cav

Deoxyribonucleic Acid Barcoding for the Identification of Botanicals

The Natural Herbal Products industry uses botanicals or herbs as raw materials for production of herbal products or dietary supplements. Recently, the demand for natural herbal products has increased tremendously and this has led to adulteration and to counterfeit herbal products. The present chapter deals with currently used molecular methods from "simple" single genomic regions to high-throughput whole genome or transcriptome sequencing methods used in the identification of botanicals.

Identification of Putative Candidate Genes from Galphimia spp. Encoding Enzymes of the Galphimines Triterpenoids Synthesis Pathway with Anxiolytic and Sedative Effects

Galphimia spp. is popularly used in Mexican traditional medicine. Some populations of Galphimia exert anxiolytic and sedative effects due to the presence of the modified triterpenoids galphimines. However, the galphimine synthesis pathway has not yet been elucidated. Hence, in this study, a comparative transcriptome analysis between two contrasting populations of Galphimia spp., a galphimine-producer, and a non-galphimine-producer, is performed using RNA-Seq in the Illumina Next Seq 550 platform to identify putative candidates genes that encode enzymes of this metabolic pathway. Transcriptome functional annotation was performed using the Blast2GO in levels of gene ontology. For differential expression analysis, edgeR, pheatmap, and Genie3 library were used. To validate transcriptome data, qPCR was conducted. In producer and non-producer plants of both populations of Galphimia spp., most of the transcripts were grouped in the Molecular Function level of gene ontology. A total of 680 differentially expressed transcripts between producer and non-producer plants were detected. In galphimine-producer plants, a larger number of highly expressed transcripts related to acyclic and polycyclic terpene synthesis were identified. As putative candidate genes involved in the galphimine synthesis pathway, P450 family members and enzymes with kinase activity were identified.

Multi-methodological approach for the Quality assessment of Senecionis scandentis Herba (Qianliguang) in the herbal market

We set forth to assess the quality of an herbal medicine sold in Hong Kong called Qianliguang by employing a multi-methodological approach. The quality is set by its identity, chemical composition, and bioactivities, among others. Qianliguang (Senecionis scandentis Herba, Senecio scandens Buch.-Ham. ex D.Don) has known antibacterial properties. However, it is poisonous and overconsumption can result in liver damage. Eighteen Qianliguang samples were purchased from herbal shops at various districts in Hong Kong. Samples were first authenticated organoleptically. DNA barcoding at the psbA-trnH, ITS2, and rbcL loci was then conducted to confirm the species. HPLC-UV was performed to screen for the presence of the chemical compounds and to quantify the flavonoid hyperoside. UPLC-MS was used to quantify the amount of the toxic pyrrolizidine alkaloid (PA) adonifoline. Microdilution assay was performed to show the antibacterial effect on Streptococcus aureus and S. pneumoniae. Results showed that five samples were found to be substituted by species belonging to the genus Lespedeza; four samples were mixtures containing not only Qianliguang but also Achyranthes aspera L., Lonicera confusa DC., or Solanum nigrum L. HPLC-UV showed that only ten contained enough hyperoside to meet the standard requirement. In addition, nine samples had adonifoline that exceeded the toxicity standard requirement. In the microdilution assay, samples containing Qianliguang showed inhibition on S. aureus and S. pneumoniae, while among the five Lespedeza sp. samples the antibacterial effects on S. aureus were not detectable; only one sample showed inhibition to S. pneumoniae. Our study illustrated the necessity of using a multi-methodological approach for herbal medicine quality assessment. We also showed that Qianliguang samples in the Hong Kong market were either toxic or adulterated. It is therefore essential to improve the quality control of Qianliguang and probably other herbs in the herbal market.

Verification of Thai ethnobotanical medicine "Kamlang Suea Khrong" driven by multiplex PCR and powerful TLC techniques

Kamlang Suea Khrong (KSK) crude drug, a traditional Thai medicine used for oral tonic and analgesic purposes, is obtained from three origins: the inner stem bark of Betula alnoides (BA) or the stems of Strychnos axillaris (SA) or Ziziphus attopensis (ZA). According to the previous reports, SA contains strychnine-type alkaloids that probably cause poisoning; however, only organoleptic approaches are insufficient to differentiate SA from the other plant materials. To ensure the botanical origin of KSK crude drug, powerful and reliable tools are desperately needed. Therefore, molecular and chemical identification methods, DNA barcoding and thin-layer chromatography (TLC), were investigated. Reference databases, i.e., the ITS region and phytochemical profile of the authentic plant species, were conducted. In case of molecular analysis, multiplex polymerase chain reaction (PCR) based on species-specific primers was applied. Regarding species-specific primers designation, the suitability of three candidate barcode regions (ITS, ITS1, and ITS2) was evaluated by genetic distance using K2P model. ITS2 presented the highest interspecific variability was verified its discrimination power by tree topology. Accordingly, ITS2 was used to create primers that successfully specified plant species of authentic samples. For chemical analysis, TLC with toluene:ethyl acetate:ammonia (1:9:0.025) and hierarchical clustering were operated to identify the authentic crude drugs. The developed multiplex PCR and TLC methods were then applied to identify five commercial KSK crude drugs (CK1-CK5). Both methods correspondingly indicated that CK1-CK2 and CK3-CK5 were originated from BA and ZA, respectively. Molecular and chemical approaches are convenient and effective identification methods that can be performed for the routine quality-control of the KSK crude drugs for consumer reliance. According to chemical analysis, the results indicated BA, SA, and ZA have distinct chemical profiles, leading to differences in pharmacological activities. Consequently, further scientific investigations are required to ensure the quality and safety of Thai ethnobotanical medicine known as KSK.