Studies On The Chemical Constituents And Bioactivities Of Sonchus Arvensis And Ligularia Hodgsonii

The Sonchus genus is a genera of family Compositae tribe Lactuceae subtribe Lactucinae,and annual,biyearly or perennial herbs.There are about 50 species all over the world which are widely distributed in Europe,Africa and Asia.The genus Sonchus is composed of 8 species in China.They have long been used as folk medicines for the treatment of fever,stasis and inflammation.They also have effects on detoxification and mobilization of blood circulation.Flavonol,flavonol glycoside, steroid and terpenes were previously isolated from this genus.The Ligularia genus is a genera of family Compositate tribe Senecioneae subtribe Senecioninae and perennial herbs.There are about 150 species in the world which are widely distributed in Europe and Asia.More than 100 species are widely distributed in China from southeast to northeast,of which about 27 species(roots, stems,leaves,flowers)have long been used as folk medicines for the treatment of decoxication,fever and inflammation along with mobilization of blood circulation and soothing pain.Previous studies on this genus indicated that their main components were sesquiterpnes and pyrrolizidine alkaloids.In order to explore many more medical potential plants of Sonchus and Ligularia species,and to exploit new resources of Chinese traditional medicine,the chemical constituents of these two plants have been studied.The compounds were isolated by means of silica gel and Sephadex LH-20 gel columm chromatography, preparative thin layer chromatography and recrystallization etc.The structures of these compounds were elucidated by spectroscopic methods(IR,EI-MS,HR-ESI-MS, ¹H NMR,¹³C NMR,DEPT,¹H-¹H COSY,HMBC,HSQC etc.).From Sonchus arvensis,twenty-six compounds were isolated and elucidated,five of them are new. Three quinic acid derivatives(1.1-1.3),the rarely naturally occurring (p-hydroxyphenylacetyl)quinic acids,and two eudesmanolides(1.4 and 1.10)were newly found.Fourty compounds were isolated and elucidated from Ligularia hodgsonii.Nine of them were new eremophilanlides(2.1-2.9),and compound 2.1 was a novel dimeric sesquiterpene.Moreover,some compounds were tested for their 1,1-Diphenyl-2-picrylhydrazyl(DPPH·)-scavenging activity and anti-bacterial activity against Escherichia coli,Bacillus subtilis and Staphlococcus aureus.The result indicated that most of the compounds exihibited no antioxidant and anti-bacterial activity.Finally,the chemical constituents of quinic acid derivates and their bioactivities reports were reviewed in this thesis.