Studies On The Chemical Constituents From Three Plants Rich In Terpenoids

Three plants, which are rich in terpenoids, have been systematically investigated from phytochemical viewpoint, including Lindera aggregata (Lauraceae), Rhododendron rufum Batalin (Ericaceae), and Wedelia trilobata (Compositae). Lindera aggregata is an important medical plant and its root tubers are used as traditional Chinese herbs for the treatment of renal, cystic, and rheumatic diseases. Rhododendron rufum Batalin is a well-known ornamental plant in central and western China. Wedelia trilobata is an invasive plant and has been mainly used for the treatment of snakebite, fish injury, diarrhea, kidney stones, colds and other diseases.There have been 62 compounds, including 8 new compounds, isolated from the three plants by means of silica gel column chromatography (CC), preparative thin layer chromatography (PTLC), and recrystallization etc. There are 21 compounds of these secondary metabolites obtained from Lindera aggregata,27 compounds from Rhododendron rufum Batalin, and 14 compounds from Wedelia trilobata. The structures of these compounds were elucidated by extensive spectroscopic methods, including IR, UV, CD, EIMS, HRESIMS,1H NMR,13C NMR, DEPT-135, NOEDS,1H-1H COSY, HSQC, HMBC, and X-ray single-crystal crystallography. In addition, the absolute configuration of compounds La3, La4, and La5 have been determined based on CD spectra analysis.The ecological significance of phytochemical study on Wedelia trilobata was discussed. A detailed literature research, together with our experiment results, indicated that the kaurane diterpenoids may be an important factor contributing to its strong invasiveness. We hope this conclusion can provide references for the ecological blance and the development of botanical pesticides.We summarized the secondary metabolites from the genus Lindera reported during the period of 1920-2011 as well as the biological activities assigned to this genus during the same period, which indicated the genus Lindera may be a rich source of substances with structral and biological diversity.Finally, we summarized the distribution of terpenoids in the family Lauraceae, Ericaceae, and Compositae, which will be useful for the further study on terpenoids and development of chemotaxonomy of these families.