Three-Dimensional Evaluation on Ecotypic Diversity of Traditional Chinese Medicine: A Case Study of Artemisia annua L

Three-tiered authentication of herbal traditional Chinese medicine ingredients used in women's health provides progressive qualitative and quantitative insight

Traditional Chinese Medicine (TCM) herbal products are increasingly used in Europe, but prevalent authentication methods have significant gaps in detection. In this study, three authentication methods were tested in a tiered approach to improve accuracy on a collection of 51 TCM plant ingredients obtained on the European market. We show the relative performance of conventional barcoding, metabarcoding and standardized chromatographic profiling for TCM ingredients used in one of the most diagnosed disease patterns in women, endometriosis. DNA barcoding using marker ITS2 and chromatographic profiling are methods of choice reported by regulatory authorities and relevant national pharmacopeias. HPTLC was shown to be a valuable authentication tool, combined with metabarcoding, which gives an increased resolution on species diversity, despite dealing with highly processed herbal ingredients. Conventional DNA barcoding as a recommended method was shown to be an insufficient tool for authentication of these samples, while DNA metabarcoding yields an insight into biological contaminants. We conclude that a tiered identification strategy can provide progressive qualitative and quantitative insight in an integrative approach for quality control of processed herbal ingredients.

Chemical composition, antioxidative and antimicrobial activities of essential oil of wild Artemisia annua from Ningxia, China

Artemisia annua is an essential aromatic medicinal plant endemic to China. Here, essential oil was extracted from wild A. annua from Ningxia, China. GC-MS analysis showed that A. annua essential oil was dominated by artemisia ketone, a characteristic compound accounting for 31.26%, followed by eucalyptol (14.89%), camphor (8.69%), myrcene (8.25%) and α-pinene (6.65%). The overall antioxidative potential represented by DPPH and ATBS free radical scavenging rates was weak. The essential oil exhibited good bactericidal activities against Escherichia coli and Staphylococcus aureus and fungicidal activities against Trichophyton rubrum and Epidermophyton floccosum. The minimum inhibitory and microbicidal concentrations were 0.02 mg/mL and 5.12 mg/mL for both bacteria, 0.315% and 2.5% for E. floccosum, and 0.625% and 5% for T. rubrum. The results suggest that A. annua essential oil may be an antimicrobial adjuvant to be applied in pharmaceutical and cosmetic industries.

Genome-wide characterization of regulator of chromosome condensation 1 (RCC1) gene family in Artemisia annua L. revealed a conservation evolutionary pattern

BACKGROUND

Artemisia annua is the major source for artemisinin production. The artemisinin content in A. annua is affected by different types of light especially the UV light. UVR8, a member of RCC1 gene family was found to be the UV-B receptor in plants. The gene structures, evolutionary history and expression profile of UVR8 or RCC1 genes remain undiscovered in A. annua.

RESULTS

Twenty-two RCC1 genes (AaRCC1) were identified in each haplotype genome of two diploid strains of A. annua, LQ-9 and HAN1. Varied gene structures and sequences among paralogs were observed. The divergence of most RCC1 genes occurred at 46.7 - 51 MYA which overlapped with species divergence of core Asteraceae during the Eocene, while no recent novel RCC1 members were found in A. annua genome. The number of RCC1 genes remained stable among eudicots and RCC1 genes underwent purifying selection. The expression profile of AaRCC1 is analogous to that of Arabidopsis thaliana (AtRCC1) when responding to environmental stress.

CONCLUSIONS

This study provided a comprehensive characterization of the AaRCC1 gene family and suggested that RCC1 genes were conserved in gene number, structures, constitution of amino acids and expression profiles among eudicots.

DNA barcoding: an efficient technology to authenticate plant species of traditional Chinese medicine and recent advances

Traditional Chinese medicine (TCM) plays an important role in the global traditional health systems. However, adulterated and counterfeit TCM is on the rise. DNA barcoding is an effective, rapid, and accurate technique for identifying plant species. In this study, we collected manuscripts on DNA barcoding published in the last decade and summarized the use of this technique in identifying 50 common Chinese herbs listed in the Chinese pharmacopoeia. Based on the dataset of the major seven DNA barcodes of plants in the NCBI database, the strengths and limitations of the barcodes and their derivative barcoding technology, including single-locus barcode, multi-locus barcoding, super-barcoding, meta-barcoding, and mini-barcoding, were illustrated. In addition, the advances in DNA barcoding, particularly identifying plant species for TCM using machine learning technology, are also reviewed. Finally, the selection process of an ideal DNA barcoding technique for accurate identification of a given TCM plant species was also outlined.

A Chromosome-Level Genome of the Camphor Tree and the Underlying Genetic and Climatic Factors for Its Top-Geoherbalism

Camphor tree [Cinnamomum camphora (L.) J. Presl], a species in the magnoliid family Lauraceae, is known for its rich volatile oils and is used as a medical cardiotonic and as a scent in many perfumed hygiene products. Here, we present a high-quality chromosome-scale genome of C. camphora with a scaffold N50 of 64.34 Mb and an assembled genome size of 755.41 Mb. Phylogenetic inference revealed that the magnoliids are a sister group to the clade of eudicots and monocots. Comparative genomic analyses identified two rounds of ancient whole-genome duplication (WGD). Tandem duplicated genes exhibited a higher evolutionary rate, a more recent evolutionary history and a more clustered distribution on chromosomes, contributing to the production of secondary metabolites, especially monoterpenes and sesquiterpenes, which are the principal essential oil components. Three-dimensional analyses of the volatile metabolites, gene expression and climate data of samples with the same genotype grown in different locations showed that low temperature and low precipitation during the cold season modulate the expression of genes in the terpenoid biosynthesis pathways, especially TPS genes, which facilitates the accumulation of volatile compounds. Our study lays a theoretical foundation for policy-making regarding the agroforestry applications of camphor tree.

Distribution Analysis of Salvianolic Acids in Myocardial Ischemic Pig Tissues by Automated Liquid Extraction Surface Analysis Coupled with Tandem Mass Spectrometry

The distribution of active compounds of traditional Chinese medicine Salvia miltiorrhiza Bunge (Chinese name: Danshen) in vivo was determined by establishing a liquid extraction surface analysis coupled with the tandem mass spectrometry (LESA-MS/MS) method. Stability analysis and distribution analysis were designed in the present study using normal animals or a myocardial ischemia model. The model assessment was performed four weeks after surgery, and then three groups were created: a normal-dose group, a model-blank group, and a model-dose group. Meanwhile, Danshen decoction administration began in dose groups and lasted for four weeks. In stability analysis, four salvianolic acids—Danshensu (DSS), caffeic acid (CAA), rosmarinic acid (RA), and salvianolic acid A (SAA)—in kidney tissues from the normal-dose group were detected by LESA-MS/MS under four conditions, and then distribution analysis was conducted in different tissues using the same method. Ejection fraction (EF) and fractional shortening (FS) in animals from two model groups decreased significantly four weeks after surgery (P < 0.01) and were improved after four weeks of Danshen decoction administration (P < 0.01). Results of stability analysis demonstrated that this method was basically stable since there were no significant differences in signal intensities of DSS, CAA, and SAA under four conditions (P > 0.05). Distribution analysis showed the signal intensities of DSS in the liver and kidney and SAA in the heart were higher in the model-dose group than in the normal-dose group (P < 0.05 or P < 0.01). Signal intensities of RA in the liver and kidney, and SAA in the liver were lower in the model-dose group compared with the normal-dose group (P < 0.05 or P < 0.01). In conclusion, Danshen decoction has the effect of improving the ischemic condition in a chronic myocardial ischemia model, and the content of two active compounds increased in the targets. These findings contribute to an understanding of the therapeutic role of Danshen in cardiovascular disease.

Revealing the Impact of the Environment on Cistanche salsa: From Global Ecological Regionalization to Soil Microbial Community Characteristics

To understand the regulatory relationship between the environment and Cistanche salsa, here we integrated the macro- and microdimension methods. From a macroperspective, the MaxEnt model indicated that countries along the Belt and Road Initiative, such as China, Egypt, and Libya, were particularly suitable for growth of C. salsa from ancient times (Last Glacial Maximum and mid-Holocene) to the future (2050 and 2070). The Jackknife test revealed that precipitation is an important ecological factor that affects C. salsa's distribution. From a microperspective, 16S rRNA amplicon sequencing data showed that the soil microbial communities of three ecotypes (desert-steppe, grassland, and gravel-desert) were significantly different (p < 0.001). Core microbiome analysis demonstrated that the bacterial genera Arthrobacter, Sphingomonas, and Bacillus were enriched core taxa of C. salsa. LEfSe and random forest were used to excavate the Gillisia (desert-steppe), Flavisolibacter (grassland), and Variibacter (gravel-desert) as biomarkers that can distinguish among microbial communities from the three ecotypes. The prediction profile showed that the metabolic function of the microbial community was enriched in metabolic pathways and environmental information processing. Correlation analyses revealed that the altitude, precipitation of the warmest quarter (bio18), mean diurnal range (bio2), and mean temperature of the warmest quarter (bio10) were important ecological factors that affect the composition of soil microbial communities. This work provided new insights into the regulatory relationship among the suitable distribution of C. salsa, soil microbial communities, and ecological drivers. Moreover, it deepened the understanding of the interaction between desert plants and ecological factors in arid environments.

Seasonal and Differential Sesquiterpene Accumulation in Artemisia annua Suggest Selection Based on Both Artemisinin and Dihydroartemisinic Acid may Increase Artemisinin in planta

Commercial Artemisia annua crops are the sole source of artemisinin (ART) worldwide. Data on seasonal accumulation and peak of sesquiterpenes, especially ART in commercial A. annua, is lacking while current breeding programs focus only on ART and plant biomass, but ignores dihydroartemisinic acid (DHAA) and artemisinic acid (AA). Despite past breeding successes, plants richer in ART are needed to decrease prices of artemisinin-combination therapy (ACT). Our results show that sesquiterpene concentrations vary greatly along the growing season and that sesquiterpene profiles differ widely among chemotypes. Field studies with elite Brazilian, Chinese, and Swiss germplasms established that ART peaked in vegetative plants from late August to early September, suggesting that ART is related to the photoperiod, not flowering. DHAA peaks with ART in Chinese and Swiss plants, but decreases, as ART increases, in Brazilian plants, while AA remained stable through the season in these genotypes. Chinese plants peaked at 0.9% ART, 1.6% DHAA; Brazilian plants at 0.9% ART, with less than 0.4% DHAA; Swiss plants at 0.8% ART and 1% DHAA. At single-date harvests, seeded Swiss plants produced 0.55-1.2% ART, with plants being higher in DHAA than ART; Brazilian plants produced 0.33-1.5% ART, with most having higher ART than DHAA. Elite germplasms produced from 0.02-0.43% AA, except Sandeman-UK (0.4-1.1% AA). Our data suggest that different chemotypes, high in ART and DHAA, have complementary pathways, while competing with AA. Crossing plants high in ART and DHAA may generate hybrids with higher ART than currently available in commercial germplasms. Selecting for high ART and DHAA (and low AA) can be a valuable approach for future selection and breeding to produce plants more efficient in transforming DHAA into ART in planta and during post-harvest. This novel approach could change the breeding focus of A. annua and other pharmaceutical species that produce more than one desired metabolite in the same pathway. Obtaining natural variants with high ART content will empower countries and farmers who select, improve, and cultivate A. annua as a commercial pharmaceutical crop. This selection approach could enable ART to be produced locally where it is most needed to fight malaria and other parasitic neglected diseases.