| Rheum L. is a genus of about 60 perennial plants in the family Polygonaceae and the subfamily Rumicoideae. It is mainly distributed throughout the high and cold mountain areas in temperate and subtropical Asia.Thirty-nine species including 2 mutations are native to China, which make up three quarters of the total and are especially abundant in the Qinghai-Tibet plateau and its vicinity. Most of them are high altitude plants. And china is the origin and differentiation centre of Rheum L. Rheum L. is famous for the herbal medicine "Rhubarb", which is listed in both ancient and modern medical books. In the Pharmacopeia of the People’s Republic of China (Vo.1,2010 edition), Rheum tanguticum Maxim, R.palmatum L. and R.officinale Baill. are the original plants of Rhubarb.In order to further study the Pharmacophylogenetic relation among rheum plants, to explain its taxonomic status and relationships among species, to provide the basis for resource utilization and protection, and to address the problems in the use of rhubarb, the research focuses on the system evolution of the rheum plants at first. Guided by the ethnopharmacology, then investigation is conducted on the application of this genus. By analyzing the components of rhubarbs from different sources with chromatography, the differences in component between wild samples and cultivated samples and the differences between the genuine and the fake are discussed. The anti-HIV activity of the extracts from this genus is observed. Based on these researches, a hypothesis of rhubarb’s nature is proposed with the guidance of pharmacophylogeny. And the power elements of life are used to verify the hypothesis.With cladistics taxonomy, researches on system evolution are conducted to study the 39 species of rheum plants in china. The phylogenetic analysis is carried out on Twenty-nine morphological characters from 29 species. It is the first time to discus the phylogenetic relation among species of domestic rhubarbs. With the compatible analysis/ (harmonious analysis), most of the morphologic features are in concord with system evolution. System evolution has studied the evolutionary sequences among Rheum L, which indicates that 3 branches emerged during the Rheum plant’s evolution. During the study on the classification of several species of plants, the classification of the Rheum subacaule Sam. and Rheum inopinatum Prain. are clarified. At the same time, the relation between morphologic change and system evolution is discussed.In the research, Ethnopharmacological research of Rheum L is carried out to know how this genus of plants is medically applied by the natives. And the result shows that 26 species of Rheum plants can be used as folk medicine. They all have the effects of "clearing heat" and "purging fire" and can be used to treat the heat-constipation. It is clear that all the plants in the genus rheum L. are cold in nature.On-the-spot-investigation, it is revealed that the quality control of Rhubarb is unreasonable. Compared to the wild samples, the efficacy of the cultivated samples is poorer, and this could be due to planting patterns, such as reaction time or altitude. At the same time, current determination methods aren’t specific and reasonable enough. To solve these problems, analytical methods by applying HPLC-PDA have been established for simultaneously determining 5 anthraquinones and 2 sennosides. Collected constituents of 44 batches of Rhubarb samples (27 batches of 3speicies of official Rhubarbs,17 batches of 13 species of inofficial Rhubarbs), are analyzed. The result shows that the chemical compositions in cultivated samples are much less than that in the wild sample. In the wild samples, the total anthraquinones contents are 2 times as much as that in the cultivated samples, when total sennosides is nearly 4 to 7 times more than that. In some cultivated rhubarb samples, no sennoside or only one kind of sennoside can be detected. Rather than the sennoside and rhein, free anthraquinone is common in inofficial rhubarb. Meanwhile, the anthraquinones content is in a high level in a few inofficial samples, such as R.inopinatum Prain, R.likiangense Sam., R.wittrockii Lundstr., R.tibeticcum Maxim. and R.alexandrae Batal..In the research, it is the first time to study the effect of Rheum plants on anti-HIV activity. By screening and comparing the anti-HIV activities of Rheum plants from a number of sources, it is showed that the effect of wild Rhuabrb is better than that of the cultivated Rhuabrb. By selecting rheum plants from various sources, three species (Rheum australe, Rheum hotaoense and Rheum alexandrae) with a higher rate of HIV-1 RT inhibition are detected. And with analyzing different receptors,2 functions of those 3 kinds of plants on HIV-1 RT enzymes are clarified. However, it doesn’t affect the mutation and HIV-2 RT.Rhubarb is a commonly-used herbal drug, but there is no reasonable explanation for the causes of its cold nature. In this research, the nature of rhubarb is studied with the main thought of "pharmacophylogeny-chemical compositions- effectiveness" and the theory of "effectiveness -drug property", and a hypothesis of rhubarb’s nature is proposed.In the hypothesis, the "cold" nature is correlated with the main chemical compositions (sennosides and anthraquinones) and with the bioactivity (antibacterial and purgative activities). The "cold" nature is also influenced by the environmental factors (growth pattern). The hypothesis explains the nature of Rhubarb in pharmacophylogenetic point of view, according with the ethnopharmacological investigation and the analysis of chemical contents.To verify the hypothesis, analysis of the power elements of life in 14 batches of Rheum samples are carried out. The researches indicate that the Yin property in all official Rhubarbs is much stronger than that of the unofficial Rhubarbs except the R.officinale Baill. There is significant difference between them. The research confirm the accuracy of the hypothesis. |
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