Studies On Chemical Constituents Of Three Medicinal Plants

The discovery of bioactivity compounds from herbs which have well antitumor, antivirus, and chemical defence activity is always the important direction of our research. This thesis elaborated the studies on the chemical constituents of the medicinal herb of Euphorbia kansui L. (Euphorbiaceae) which was documented in China Pharmacopoeia, together with another two natural resource Stemona tuberosa L. (Stemonaceae) and Trichilia connaroides (Wight et Am.) Bentv. (Meliaceae) which were reported to have well effects on chemical defence. By means of different kinds of chromatographies over various materials, eighty-two compounds, including ten new ones were isolated, which covered macrocyclic diterpenoids, tetracyclic triterpenoids, Stemona alkaloids, limonoids, flavonoids and phenylpropanoids. Their structures were elucidated mainly on the basis of spectroscopic studies.Chapter 1:Deal with study on the chemical constituents of Euphorbia kansui. Twenty-eight macrocyclic diterpenoids, seven tetracyclic triterpenoids, together with seven other constituents were isolated from the roots of Euphorbia kansui. Among them, compound 1, named kansuinine J, is a new jatrophane-type diterpenoid with an isopentanoate substituted group, being the first example for the macrocyclic ditepenoids. Compound 2, named kansuinone possessed an unprecedented rearranged skeleton involving spiro [5,6] rings system which might be derived from euphane-type triterpenoids.Chapter 2:Reports study on the bioactivities of Euphorbia kansui. The antitumor and antiviral activities of 10 compounds were tested using MTT or SRB method. Several compounds showed significant activities. The inhibitory activity against the human and mouse 11β-HSD1 and 11β-HSD2 also was tested. For the first time, the tetracyclic triterpenoids showed the potent treatment of diabetes. Chapter 3:Presents study on the chemical constituents of Stemona tuberose L. Sixteen Stemona alkaloids, together with two stilbene constituents were isolated from the roots of Stemona tuberosa. Among them, compounds 1～3 are new alkaloids, named dehydroisostemotinine (1), isoxotuberostemonine (2) and 11α-tuberospiro-nine (3). The anti-TMV activities of 7 compounds were tested. Two compounds showed the significant activities.Chapter 4:Deal with study on the chemical constituents of Trichilia connaroides. Eleven limonoids, together with eleven other constituents were isolated from the roots of Trichilia connaroides. Among them, compounds 1～5 are new compounds, named trichilitons C (1), (2), (3), (4), and△8,14-11-hydroxy-6-deoxyswietenine (5). Compounds 1～3 formed a new six-members lactone ring based on the skeleton of trichiliton-type, and compound 5 has a hydroxyl group sited on the C-11 which has never been reported.