[Biosynthetic pathways of triterpenes in medicinal plants and key enzyme genes: a review].

Triterpenes, with high diversity and a wide range of sources, can be found in many medicinal plants. They have been found free or as glycosides/esters by combining with sugars. Most of them act as signaling molecules and function in stress response. They are also the material basis for the therapeutic effect of various medicinal plants. Modern pharmacological research has shown that they have the anti-inflammatory, antibacterial, antiviral, anti-tumor, fertility-regulating, and immunomodulatory effects. They top plant natural products in both quantity and diversity, and among them, tetrachyclic triterpenes and pentachyclic triterpenes are most abundant. The first step of the structural diversification is the cyclization 2,3-oxidosqualene, which is catalyzed by oxidosqualene cyclases(OSCs). Numerous OSCs exist, each with a specific cyclization mechanism, and thus over 100 different cyclic triterpene skeletons have been found in nature. This study reviewed the research on the biosynthetic pathways of triterpenes in medicinal plants, regulatory mechanisms of the pathways, and the key enzymes, and analyzed the expression regulation and structural characteristics of key enzyme genes involved in the synthetic pathways. This study is expected to serve as a reference for further research on triterpenes, such as the directional regulation of metabolic flow and heterologous biosynthesis and lay a basis for the regulation of triterpene synthesis and the selection of high-quality germplasm. This study also provides basic materials for further research and development of triterpenes from medicinal plants.

Systematic elucidation of the mechanism of Jingyin granule in the treatment of Novel Coronavirus (COVID-19) Pneumonia via Network Pharmacology.

Background: Jingyin granule is one of the widely used traditional Chinese medicine mixture composed of multiple herbs in the treatment of respiratory system diseases. The mechanism of its therapeutic effects has still been obscure. The aim of this study is to use the network pharmacology approach for identification of the main active ingredients of Jingyin granule against COVID-19 targets and to explore their therapeutic mechanism. Material and Method: In this study, the ingredients of Jingyin granule were evaluated by the usage of Traditional Chinese Medicine Systems Pharmacology Database and Traditional Chinese Medicine Integrated Database, and the interactions between potential gene targets and ingredients were identified using the SwissTargetPrediction database. Meanwhile the possible efficient targets COVID-19 acts on were identified via Online Mendelian Inheritance in Man database, DisGeNET database and GeneCards database. In addition, functions, components and pathways were identified by Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis. Protein interaction, ingredients-targets network was established. Results: Our findings showed that numerous ingredients of Jingyin granule could act on COVID-19 with 88 target genes. GO enrichment analysis, KEGG pathway analysis, and protein-protein interaction network revealed that these targets were interrelated with regulation of immune function, directly targeting disease genes. Conclusions: Jingyin granule could be utilized to exert systematic pharmacological effects. Jingyin granule could directly target the major genes, and also regulate the immune system, acting as oblique disease treatment.