Morphological and microscopic identification of three major medicinal Dendrobium species in Ta-pieh Mountains area

Integrated metabolomic and transcriptomic analysis reveals variation in the metabolites of Dendrobium officinale, Dendrobium huoshanense, Dendrobium nobile

INTRODUCTION

Dendrobium is a perennial herb of the genus Dendrobium in the orchid family. Generally, Dendrobium officinale (TP) and Dendrobium huoshanense (HS) are both considered to have the function of yin-nourishing, while Dendrobium nobile (JC) has better efficacy of heat-clearing. However, because of the wide variety of Dendrobium species, the classification and clinical application of Dendrobium are often confused clearly distinguished in different medicinal uses.

OBJECTIVE

In order to compare the differentially accumulated metabolites (DAMs) and differentially expressed genes (DEGs) of the three Dendrobium.

METHODS

We selected TP, HS, and JC cultivated on stone for metabolomic and transcriptomic analyses between 2 and 3 years.

RESULTS

The results showed that a total of 489 metabolites were obtained, including 72 were DAMs. The 72 DAMs were mainly enriched in metabolic pathways and biosynthesis of secondary metabolites. Transcriptome analysis results showed that 1,038 annotated DEGs were identified among the three Dendrobium species. The comprehensive analysis showed that the three Dendrobium differed in the distribution of the content of four major active components: flavonoids, amino acids, alkaloids, and sugars and alcohols, among which the DAMs and DEGs were mainly enriched in metabolic pathways and secondary metabolite biosynthesis.

CONCLUSION

In this study, metabolomics and transcriptomics were utilized to compare the differences among the three species of Dendrobium, to provide theoretical references for future research and selection of different species of Dendrobium based on different medicinal uses, and to lay the foundation for further research on the biosynthesis of flavonoids in Dendrobium.

An improved deep learning network for image detection and its application in Dendrobii caulis decoction piece

In recent years, with the increasing demand for high-quality Dendrobii caulis decoction piece, the identification of D. caulis decoction piece species has become an urgent issue. However, the current methods are primarily designed for professional quality control and supervision. Therefore, ordinary consumers should not rely on these methods to assess the quality of products when making purchases. This research proposes a deep learning network called improved YOLOv5 for detecting different types of D. caulis decoction piece from images. In the main architecture of improved YOLOv5, we have designed the C2S module to replace the C3 module in YOLOv5, thereby enhancing the network's feature extraction capability for dense and small targets. Additionally, we have introduced the Reparameterized Generalized Feature Pyramid Network (RepGFPN) module and Optimal Transport Assignment (OTA) operator to more effectively integrate the high-dimensional and low-dimensional features of the network. Furthermore, a new large-scale dataset of Dendrobium images has been established. Compared to other models with similar computational complexity, improved YOLOv5 achieves the highest detection accuracy, with an average mAP@.05 of 96.5%. It is computationally equivalent to YOLOv5 but surpasses YOLOv5 by 2 percentage points in terms of accuracy.

Identification of toxic Gelsemium elegans in processed food and honey based on real-time PCR analysis

Gelsemium elegans (GE) is a widely distributed hypertoxic plant that has caused many food poisoning incidents. Its pollen can also be collected by bees to produce toxic honey, posing a great threat to the health and safety of consumers. However, for the complex matrices such as cooked food and honey, it is challenging to perform composition analysis. It is necessary to establish more effective strategies for investigating GE contamination. In this study, the real-time PCR (qPCR) analysis combined with DNA barcode matK was proposed for the identification and detection of GE. Fifteen honey samples along with twenty-eight individuals of GE and the common confusable objects Lonicera japonica, Ficus hirta, Stellera chamaejasme and Chelidonium majus were gathered. Additionally, the food mixtures treated with 20-min boiling and 30-min digestion were prepared. Specific primers were designed, and the detection capability and sensitivity of qPCR in honey and boiled and digested food matrices were tested. The results demonstrated that the matK sequence with sufficient mutation sites was an effective molecular marker for species differentiation. GE and the confusable species could be clearly classified by the fluorescence signal of qPCR assay with a high sensitivity of 0.001 ng/μl. In addition, this method was successfully employed for the detection of deeply processed food materials and honey containing GE plants which even accounted for only 0.1 %. The sequencing-free qPCR approach undoubtedly can serve as a robust support for the quality supervision of honey industry and the prevention and diagnosis of food poisoning.

Wild imitating vs greenhouse cultivated Dendrobium huoshanense: Chemical quality differences

Dendrobium huoshanense (D. huoshanense) has been used as functional food supplements and herbal medicines for preventing and managing diseases with a long history in China. Due to its endangered natural resources and huge demand, people tend to cultivate D. huoshanense to protect this species. However, the quality of wild and cultivated herbs of the same species may change. This work quantified and compared the main quality traits and chemical components of wild imitating and greenhouse cultivated D. huoshanense with different growth years. As a result, wild and cultivated D. huoshanense had similar chemical composition, but there are significant differences in the content of many ingredients (polysaccharides, flavonoids, nucleosides, bibenzyls, lignans and volatile compounds). And the contents of many of these components increased with growing years. In addition, multivariate statistical analyses have been applied to classify and evaluate samples from different cultivation modes according to these components. In conclusion, our results demonstrated that the overall quality of greenhouse cultivated D. huoshanense was not as good as wild-grown, but this mode can be a promising and sustainable way of producing D. huoshanense.

Comparison of the Metabolomics of Different Dendrobium Species by UPLC-QTOF-MS

Dendrobium Sw. (family Orchidaceae) is a renowned edible and medicinal plant in China. Although widely cultivated and used, less research has been conducted on differential Dendrobium species. In this study, stems from seven distinct Dendrobium species were subjected to UPLC-QTOF-MS/MS analysis. A total of 242 metabolites were annotated, and multivariate statistical analysis was employed to explore the variance in the extracted metabolites across the various groups. The analysis demonstrated that D. nobile displays conspicuous differences from other species of Dendrobium. Specifically, D. nobile stands out from the remaining six taxa of Dendrobium based on 170 distinct metabolites, mainly terpene and flavonoid components, associated with cysteine and methionine metabolism, flavonoid biosynthesis, and galactose metabolism. It is believed that the variations between D. nobile and other Dendrobium species are mainly attributed to three metabolite synthesis pathways. By comparing the chemical composition of seven species of Dendrobium, this study identified the qualitative components of each species. D. nobile was found to differ significantly from other species, with higher levels of terpenoids, flavonoids, and other compounds that are for the cardiovascular field. By comparing the chemical composition of seven species of Dendrobium, these qualitative components have relevance for establishing quality standards for Dendrobium.

Comparative authentication of Semiliquidambar cathayensis and its substituted species via macroscopic and microscopic features

Objective

Ban Fenghe recorded in the Quality Standard of Yao Medicine of Guangxi Zhuang Autonomous Region (Volume 1) is derived from the dried stems and leaves of Semiliquidambar cathayensis. It is usually confused with medicinal herbs from Pterospermum heterophyllum and Dendropanax dentiger. However, they are very different in chemical composition, and should not be used as the same drug. To ensure their safety and efficacy, a method based on macroscopic and microscopic characteristics was developed to distinguish them.

Methods

A total of 14 batches of Ban Fenghe samples from three species were collected from different producing areas in China. The macroscopic characteristics were examined by observing external traits. The tissue structures of transverse sections of stems and leaves, the leaf epidermis, and the powder were observed microscopically.

Results

The branchlets and leaf surfaces of S. cathayensis and P. heterophyllum were hairy, especially the lower leaf surfaces of P. heterophyllum were densely covered with hairs, but those of D. dentiger were hairless. The pericyclic fibers of S. cathayensis stems were intermittently distributed in a circular shape and accompanied by stone cells, whereas those of P. heterophyllum and D. dentiger were bundled without stone cells. So stone cells and hairs were present in S. cathayensis powder, stone cells were not found in P. heterophyllum and D. dentiger powder, and hairs were not present in D. dentiger powder. The distribution sites, sizes and types of secretory tissues of these three species were also different in transverse sections of stems and leaves. Stomata on the lower epidermis of S. cathayensis leaves were paracytic, whereas those of P. heterophyllum and D. dentiger were anomocytic.

Conclusion

Ban Fenghe drugs derived from S. cathayensis could readily be distinguished from those of P. heterophyllum and D. dentiger by macroscopic and microscopic features.

Identification and poisoning diagnosis of Aconitum materials using a genus-specific nucleotide signature

Aconitum genus generally contains hypertoxic alkaloids. Poisoning incidents due to the improper ingestion of Aconitum materials frequently occur around the world. DNA barcoding is considered as a powerful tool for species identification, but complete sequences of conventional DNA barcodes are sometimes unattainable from food and highly processed products due to severe DNA degradation. Therefore, a shorter molecular marker will be more profitable for the authentication and poisoning diagnosis of Aconitum materials. In this study, 1246 psbA-trnH sequences and chloroplast genomes representing 183 taxa of Aconitum were collected, and a 23-bp nucleotide signature unique to Aconitum genus (5'-TATATGAGTCATTGAAGTTGCAG-3') was developed. The nucleotide signature was conserved and universal within Aconitum while divergent among other genera. The specific molecular signature was then successfully applied to the detection of processed Aconitum ingredients. To further evaluate the application potential of nucleotide signature in completely unknown mixture samples, boiled food mixtures, containing different ratios of Aconitum materials, were sequenced by high-throughput sequencing technology. The results showed that the nucleotide signature sequence could be directly extracted from raw sequencing data, even at a low DNA concentration of 0.2 ng/µl. Consequently, the 23-bp genus-specific nucleotide signature represents a significant step forward in the use of DNA barcoding to identify processed samples and food mixtures with degraded DNA. This study undoubtedly provides a new perspective and strong support for the identification and detection of Aconitum-containing products, which can be further introduced to the diagnosis of food poisoning.

Natural Composition and Biosynthetic Pathways of Alkaloids in Medicinal Dendrobium Species

Dendrobium is the second biggest genus in the Orchidaceae family, some of which have both ornamental and therapeutic values. Alkaloids are a group of active chemicals found in Dendrobium plants. Dendrobine has emerged specific pharmacological and therapeutic properties. Although Dendrobium alkaloids have been isolated and identified since the 1930s, the composition of alkaloids and their biosynthesis pathways, including metabolic intermediates, alkaloid transporters, concrete genes involved in downstream pathways, and associated gene clusters, have remained unresolved scientific issues. This paper comprehensively reviews currently identified and tentative alkaloids from the aspect of biogenic pathways or metabolic genes uncovered based on the genome annotations. The biosynthesis pathways of each class of alkaloids are highlighted. Moreover, advances of the high-throughput sequencing technologies in the discovery of Dendrobium alkaloid pathways have been addressed. Applications of synthetic biology in large-scale production of alkaloids are also described. This would serve as the basis for further investigation into Dendrobium alkaloids.

Comparative nutritional characteristics of the three major Chinese Dendrobium species with different growth years

Dendrobium, an important medicinal plant, is a source of widely used herbal medicine to nourish the stomach and treat throat inflammation. The present study is aimed at distinguishing and evaluating three major Dendrobium species by comparing physiochemical characteristics and understanding differences between different growth years in the Ta-pieh Mountains. Polysaccharides and total alkaloids of Dendrobium were determined, and the amino acids and trace elements were determined by UPLC (Ultra High-Performance Liquid Chromatography) and ICP-MS (Inductively coupled plasma mass spectrometry). It can be seen from the results that the polysaccharide content of these three kinds of Dendrobium in different growth years ranges from 249.31 mg·g^-1 to 547.66 mg·g^-1, and the highest content is in the 3-year-old Dendrobium huoshanense. The total alkaloid content ranges from 0.21 mg·g^-1 to 0.54 mg·g^-1, and the highest content is also the 3-year-old Dendrobium huoshanense. We determined the amino acid content of these three Dendrobium in different growth years, and we can see that each of the three kinds of Dendrobium contain seven kinds of amino acids required by the human body. We conducted a safety evaluation of the essential trace elements of Dendrobium, and the results showed that the dosage of 12g·d^-1Dendrobium prescribed in China Pharmacopoeia is in accordance with the recommended daily intake of trace elements recommended by the Food and Drug Administration of the United States, and will not cause trace element poisoning. Linear discriminant analysis was carried out on the basis of amino acids and trace elements and confirmed the applicability of multi-elemental analysis for identifying different Dendrobium species.