Studies On The Chemical Constituents And Biological Activity Of The Aerial Parts Of Rheum Officinale Baill.

"Da-huang",is the roots and rhizomes of Rheum palmatum L.,Rheum tanguticum Maxim.ex Balf.or Rheum officinale Baill.,was first recorded in Sheng Nong's herbal classic.The plants are mainly distributed in Qinghai,Gansu,Sichuan,Yunnan province and so on."Da-huang" was also called as "general" because of the acute effect and was widely used clinically.In traditional Chinese medicine,"Da-huang"has been used to dredge intestine for purgation,clear heat and drain fire.Modern pharmacological research showed that it had many activities such as cathartic,diuretic,liver-protection,anti-inflammatory,anticancer,analgesic and antioxidant effects.The traditional medicinal parts of "Da-huang" are roots and rhizomes.However,the aerial parts of the plant are generally disregarded as having no value,although these parts of the plant are abundant in resources.Compared with the intensive investigations of the underground parts of R.officinale Baill.,few chemical studies have been conducted on the leaves and stems of the plant.From the starting point of medicinal resource utilization and environmental protection,we researched the chemical constituents from the aerial parts extract and performed inhibitory activity experiments on some known anthraquinones against HepG2 cell.In this dissertation,36 compounds were separated and purified by many chromatographic methods such as RP-18 Flash MPLC column chromatography,silica column chromatography,ODS column chromatography,Sephadex LH-20,prep-HPLC and recrystallization.The structure of these compounds were elucidated based on their physical and chemical properties,as well as MS and NMR analyses.The structure of 30 compounds were finally identified,including 11 anthraquinones,11 flavonoids,two indole compounds,one nucleoside compounds,one chromone compound,one alkane compound and three glucosides.The structure were identified as follows:emodin(S1),chrysophanol(S2),physcion(S3),questin(S4),aloe-emodin(S5),citreorosein(S6),kaempferol(S7),quercetin(S8),kaempferol-3-O-[6"-O-(3-hydroxy-3-methylglutaroyl)glucoside](S9),kaempferol-3-O-a-L-rhamnopyranosyl-(1?6)-?-D-glucopyranoside(S10),1-methyl-1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid(S11),n-heptacosane(S12),isovitexin(S13),quercetin-3-O-robinobioside(S14),2-methyl-5-methoxycarbonylmethyl-7-hydroxychromone(S15),emodin-8-O-?-D-glucoside(S16),chrysophanol-8-O-?-D-glucoside(S17),physcion-8-O-?-D-glucoside(S18),catechin(S19),tryptophan(S20),(-)-catechin 7-O-?-D-glucopyranoside(S21),quercetin-3-O-?-D-glucopyranoside(S22),emodin-1-O-?-D-glucoside(S23),rutin(S24),hyperin(S25),3-[1-(?-D-glucopyranosyloxy)ethyl]-1H-Pyrrole-2,5-dione(S26),8-[(2-O-a-L-glucopyranosyl-?-D-glucopyranosyl)oxy]-3-hydroxy-9,10-Anthracenedione(S27),2-O-?-D-fructofuranosyl-a-D-allopyranose(S28),2-methylphenyl-1-O-?-D-glucopyranoside(S29),p-methylphenyl-1-O-?-D-glucopyranoside(S30).Among these compounds,compounds S26 and S27 are new compounds,compounds S9,S10,Sll,S14,S20,S21,S28,S29,S30 were isolated from the genus Rheum for the first time.The inhibition rate was evaluated by MTT assay and the experimental results indicated that emodin,physcion,physcion-8-O-?-D-(6'-O-acetyl)glucoside,chrysophanol-8-O-?-D-(6'-O-acetyl)glucoside,emodin-8-O-?-D-glucoside showed significant cytotoxic effects against HepG2 cell.