Determination of multiple elements in samples of the medicinal plant Marsdenia tenacissima and estimation of geographic origin via pattern recognition techniques

Marsdenia tenacissima genome reveals calcium adaptation and tenacissoside biosynthesis

Marsdenia tenacissima is a medicinal plant widely distributed in the calcium-rich karst regions of southwest China. However, the lack of a reference genome has hampered the implementation of molecular techniques in its breeding, pharmacology and domestication. We generated the chromosome-level genome assembly in Apocynaceae using combined SMRT sequencing and Hi-C. The genome length was 381.76 Mb, with 98.9% of it found on 11 chromosomes. The genome contained 222.63 Mb of repetitive sequences and 21 899 predicted gene models, with a contig N50 of 6.57 Mb. Phylogenetic analysis revealed that M. tenacissima diverged from Calotropis gigantea at least 13.43 million years ago. Comparative genomics showed that M. tenacissima underwent ancient shared whole-genome duplication. This event, together with tandem duplication, contributed to 70.71% of gene-family expansion. Both pseudogene analysis and selective pressure calculations suggested calcium-related adaptive evolution in the M. tenacissima genome. Calcium-induced differentially expressed genes (DEGs) were mainly enriched in cell-wall-related processes. Domains (e.g. Fasciclin and Amb_all) and cis-elements (e.g. MYB and MYC) frequently occurred in the coding and promoter regions of cell-wall DEGs, respectively, and the expression levels of these genes correlated significantly with those of calcium-signal-related transcription factors. Moreover, calcium addition increased tenacissoside I, G and H contents. The availability of this high-quality genome provides valuable genomic information for genetic breeding and molecular design, and lends insights into the calcium adaptation of M. tenacissima in karst areas.

Trends and Application of Chemometric Pattern Recognition Techniques in Medicinal Plants Analysis

Medicinal plants have been used and studied for ages, from very old registers to modern ethnopharmacology, which encompasses analytical chemistry, foods, and pharmacy. Based on international norms and governmental organizations of health, phytomedicine-for example, herbal drugs-needs to guarantee the quality control of products and identify contaminants, biomarkers, and chemical profiles, among other issues. In this sense, is necessary to develop advanced analytical methods that show interesting possibilities and obtain a great amount of data. In order to treat the data, a set of mathematical and statistical procedures named chemometrics is necessary. In terms of herbal drugs, chemometric tools may be used to identify the following in plants: parts, development stages, processing, geographic origin, authentication, and chemical markers. This review describes applications of chemometric pattern recognition tools to analyze herbal drugs in different conditions associated with analytical methods in the last six years (2015-2020).

Concentration of fifteen elements in herbaceous stems of Ephedra intermedia and influence of its growing soil

Mineral nutrients play important roles in the growth and metabolism of Ephedra intermedia, and are affected by soil factors. Fifteen elements were measured from wild E. intermedia as well as their growing soils using inductively coupled plasma mass spectroscopy to investigate the influences and characteristics of herb elements. The pH, cation exchange capacity, humus and soil mechanical composition were also determined in rhizosphere soils. Results showed that E. intermedia stems contained high N, low P concentrations in macronutrients and high Fe in micronutrients, and enriched N, S, Cl, P and Sr from soils. The 15 herb elements were affected by one or more soil factors, and K, P, Zn, Fe and Mn were important soil elements that influenced the mineral accumulation of E. intermedia. This study was useful for the artificial cultivation of wild E. intermedia.

Geographic authentication of the traditional Chinese medicine Atractylodes macrocephala Koidz. (Baizhu) using stable isotope and multielement analyses

RATIONALE

Atractylodes macrocephala Koidz (Baizhu) is a valuable traditional Chinese medicine, and medicines of that type originating from Zhejiang province are the most famous and much more expensive than those from other regions. Driven by the great difference in prices, fraudulent labeling often occurs. In order to protect the interests of consumers, producers and honest traders, reliable techniques for the geographic authentication of Baizhu are needed urgently.

METHODS

The stable isotope ratios of five light elements (C, N, H, O and S) in Baizhu samples originating from four provinces of China were determined with an elemental analyzer coupled to isotope ratio mass spectrometry, and the concentrations of 45 elements in these samples were measured using inductively coupled plasma mass spectrometry. Chemometric approaches including principal component analysis (PCA) and orthodox partial least squares discriminant analysis (OPLS-DA) were applied to the obtained data.

RESULTS

The PCA results showed that the techniques enabled clear classification of the Baizhu samples into three clusters: A (Zhejiang province), B (Shaanxi province) and C (Hebei and Ahui provinces). Furthermore, OPLS-DA using 27 key variables provided 100% correct discrimination between samples originating from Zhejiang province and those from the other three provinces.

CONCLUSIONS

Stable isotope ratio and multielement analyses in combination with chemometric approaches showed great potential for the geographic authentication of Baizhu, providing a promising method for the control of fraudulent labeling that frequently occurs with traditional herbal medicines in China.