Studies On The Chemical Constituents Of Ligularia Hodgsonii

There are about 130 species in the genus Ligularia widely distributed throughout the world, with more than 110 species being distributed in China, about 30 of which have long been used as folk medicines. Their roots, stems, leaves and flowers possess the efficacy of relieving internal heat or fever, reducing phlegm and relieving a cough, invigorating the circulation of blood and stopping pain, as well as antibiotic and anti-inflammation effect. Their main bioactive components are eremophilane sesquiterpenes and pyrrolizidine alkaloids (PAs). The genus Ligularia is diversified particularly in the Hengduan Mountains in mainland China, where is considered to be the main center of the on-going evolution of the genus and provide a good set of subject for the study of plant evolution.There are many evidences to show that the components from the different species of same genus, even from the same species, displayed differences because of the differences of ecological environments, which inspired the interest of the planttaxonomists to study the inter- and intra- specific diversity of Ligularia. The primitive species Ligularia hodgsonii Hook is distributed from E. Sichuan to Japan via Hubei, Hunan, Anhui, Fujian, which are defined as the authentic herbal plants for "Chuanziwan" in Sichuan and Guizhou provinces, clinically utilized as a replacement for Ziwan with similar antitussive and expectorant actions to those of Ziwan. With the interest of continuing studies of the influence of different ecological environments on the chemical constituents of this plant, we studied the constituents of L. hodgsonii collected in Enshi of Hubei in China, where this plant was collected for the first time. More than 40 constituents have been isolated by means of silica gel column chromatography (CC), prearative thin layer chromatography (PTLC) and recrystallization etc. The structures of 36 compounds have been elucidated on the basis of spectroscopic methods (UV, IR, EI-MS, HR-ESI-MS, ¹H- and ¹³C-NMR, ¹H-¹H COSY, HMBC, NOED), in combination with the data from literatures, 8 of which are new compounds.The results in this thesis offer phytochemical proofs to plant chemotaxonomy and provide chemical evidences for exploiting and utilizing the natural resources.In the end one review of the bioactivities of Liguralia has been made.