Botany secondary metabolism Kossel first put forward the concept of "" in 1891. The active ingredient of many plant drugs is the secondary metabolites contained in them. When planted artificially, their yield depends on the accumulation of primary products, and their quality depends on the accumulation of secondary products. The quality and effectiveness of medicinal materials are based on the secondary metabolism of plants. The production of secondary metabolites is based on the degree of development Tissue differentiation and external stimuli are controlled by influencing the expression of biosynthetic genes [1] 。 Plant secondary metabolites are a kind of adaptation of plants to the environment Abiotic factor Results of interaction. On Environmental stress Adaptation, competition between plants and Coevolution , plant damage to insects Herbivorous It plays an important role in the defense of animal feeding and the invasion of pathogenic microorganisms. The process of secondary metabolism is considered to be the key to the long-term evolution of plants ecological environment As a result of adaptation, it plays an important role in dealing with the relationship between plants and the ecological environment. Many plants produce and accumulate a lot of secondary metabolites after being infected by pathogenic microorganisms to enhance their own immunity and resistance. Plant secondary Metabolic pathway They are highly branched pathways. These pathways are not all open in plants or cells, but located in a certain organ, tissue, cell or organelle and are independently regulated. They are small molecule compounds that are not necessary for the normal operation of cell life activities or plant growth and development. Their production and distribution usually have the specificity of species, organs, tissues and growth and development stages.
There are few examples of microbial and mammalian genetic information transmission, and an interesting discovery is human Chorionic gonadotropin Can enter from Malignant tumor The protein was detected in some bacteria isolated from non malignant tissues, while bacteria isolated from non malignant tissues did not produce this protein. The gene encoding this protein is only expressed in bacteria associated with tumor cells, and its DNA may be obtained from host cells. Secondary metabolites produced by microorganisms, and some specializations Animal cell There are also interesting similarities between the "luxury molecules" that are not important for their own survival. Many of these secondary metabolites are proteins formed in large quantities in specialized cells. Surprisingly, there are insertion sequences in the genes that can encode these substances [2] 。 It can be believed that the biochemical regulation mechanism of some fungi has existed in higher organisms, and the regulatory substances produced by them have various functions in mammals by interfering with receptor ligand interaction and extracellular signal generation. For example, ergot alkaloids produced by Clavi ceps pur throw tea acts as an activator or inhibitor to mammalian cell receptors and dopamine. The continuous evolution of biochemical pathways in the secondary metabolism process will lead to the entry of beneficial substances into symbionts, and the basic biochemical process information will sometimes be transferred to other organisms. In the early phylogenetic process of organisms, some other whole organisms (such as bacteria or cyanobacteria) that have completely complementary genetic characteristics or participate in the metabolic process are considered to be able to combine Eukaryotic cell And develop into mitochondria and chloroplasts. These secondary metabolites can be divided into Phenylpropanoids , quinones, flavonoids, tannins Terpenoid 、 Steroid And its glycosides alkaloid Seven categories. Others can be divided into Phenolic compounds There are thousands or even tens of thousands of known compounds in each category. Secondary metabolites may become Gratitude bank The main components of, such as Rubber tree A large amount of rubber and Stevia in Stevia rebaudiana The content of glycosides can reach more than 10% of dry weight. There is a contradiction between the accumulation of secondary metabolites and the demand for growth environment conditions, which is a difficult problem for the cultivation of medicinal plants [1] .。
