| Morus species are of high economic and medicinal value. Previous studies on this genus have attracted a great deal of interest. Investigation on the plasm germ resources, genentic diversity, relationships between species, chemical constituents and pharmacological properties will have important theoretical and applicative significance. The researches in this thesis were mainly focused on the genetic diversity, chemical constituents and their bioactivities of Morus species from Xinjiang. The research aspects and conclusions were as follow:Genetic diversity of 11 cultivated populations of Morus alba L., M. alba var. tatarica and M. nigra L. from Xinjiang were determined for the first time by random amplified polymorphic DNA (RAPD) technique. 100 random primers were used for the test in which 10 were shown resultful. DNA of all populations were amplified by these 10 primers and the polymorphic bands of RAPD were counted. Clustering analysis was carried out by NTSYS software. A total of 108 bands were obtained, and 91 of total bands (84.26%) were polymorphic. The results indicated that there were apparent and abundant genetic variations in Morus genus of Xinjiang. Besides, 8 specific bands of M. nigra were obtained. The genetic relationships among medicinal mulberry resources plants in Xinjiang indicated by the RAPD analysis results are consistent with their traditional classifications in the main. 87.39% in total of the scorable markers were polymorphic and Shannon's Information index (I) was 0.3997 at genus level. However, the variations of within-population were considerably lower and different among populations, with PPB from 4.5% to 45.95% and / from 0.0312 to 0.2339. The variations of within-population were higher in M. alba than that in M. nigra. The way of vegetative reproduce may be responsible for the considerably lower within-population variation in cultivated populations of Xinjiang. The Gst showed 35.41% genetic variation between 11 populations of Morus cultivated in Xinjiang, 45.97% between 9 populations of M. alba and 47.28% between 2 populations of M. nigra. AMOVA showed 59.16% genetic variation between two species, 17.46% among different populations. Genetic distance indicated that the cultivatedpopulations of M. alba and that of M. nigra have large genetic difference.The antihypertensive effects of the fruits of Morus species in Xinjiang were screened for the first time. The results showed that the fruits of M. nigra were more effective than others. By the method of LC-MS and LC-DAD, the chemical fingerprints of four Morus samples were established, which indicated the obvious difference of chemical constituents, especially anthocyanins. The contents of anthocyanins in M. nigra collect in different place were higher than the other two Morus species, which possibly resulted in the difference of pharmacological effects. However, further phytochemical studies are necessary to clarify the bioactive constituents.An in-depth investigation on the chemical constituents and their antioxidant activities of the stem of Morus nigra L. was also carried out for the first time. Eight compounds were isolated from this plant by repeated column chromatography. Their structures were elucidated as oxyresveratrol, /?-sitosterol, dihydromorin, morin, sanggenols F and H, ursolic acid and 2, 4, 2', 4'-tetrahydroxy-3-(3-methyl-2-butenyl)-chalcone on the basis of the spectral evidence('H and 13C NMR, EIMS). Antioxidant bioassay showed that all these compounds exhibited hydroxyl radical, superoxide anion and lipid peroxidation scavenging effects, especially flavonoids. The lipid peroxidation scavenging effects of some flavonoids were more potent than the positive control, vitamin C.The research results of this thesis established a solid foundation for the genetic diversity preservation and the resource development of Morus species in Xinjiang, and demonstrate theoretical as well as practical values. |
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