Studies On The Chemical Constituents And Bioactivities Of Two Medicinal Plants

There are abundant plant resources in China, and ranks second in the world. A great number of drugs (ca.40%of drugs marketed) are directly or indirectly derived from natural products in the last several decades, indicating that natural products have played a significant role in modem drug researches. It is an important pathway to search for novel bioactive natural products from traditional Chinese medicine and folklore medicinal plants as new drug leading compounds, and it will provide scientific material basis of traditional Chinese medicine and folklore medicine.Elsholtiza bodinieri Vaniot (Lamiaceae) is an annual herbaceous plant distributed in the northwest and southwest district of China. It has been used as herbal tea or traditionnal folk medicine for the prophylaxis and treatment of cough, headache, pharyngitis, fever and hepatitis. The stems and leafs of Croton caudatus var. tomentosus (Euphorbiaceae) have been used as traditional medicines in Dai Nationality, which have been used in China as folk medicines for the treatment of cancer, wounds, pain, and digestive system disorders. Fifty compounds, including three new ones, were isolated from the above two specicies. The anti-HCV activities of the extract and isolated compounds from E.bodinieri were reported for the first time, and the cytotoxic activities of chemical constituents from C. caudatus var. tomentosus. were investigated.This thesis comprises of five chapters altogether. The first chapter presents a review on the chemical constituents and bioactivities of the plants of the genus Elsholtzia in the family Lamiaceae. The second chapter elaborates the studies on chemical constituents of E.bodinieri. Chapter3deals with the anti-HCV effects of E.bodinieri. In the fourth chapter, phytochemistry and biological activities of the compounds isolated from Croton caudatus var. tomentosus are reported. And in the last chapter, conclusion of this dissertation is made.The first chapter presents a review on the chemical constituents and bioactivities of the plants of Elsholtzia in the family Lamiaceae. Plants of the genus Elsholtzia have a long history of medicinal use in folk. Elsholtzia is a genus containing about40species in the family Lamiaceae. They have been widely distributed and applied in East Asia for centuries. As folk medicine, plants of this genus have been used for the treatment of colds, heatstroke, headaches, and fever in China. The phytochemical investigations revealed the presence of flavonoids, phenylpropanoids, terpenoids, and others compounds. Elsholtzia Plants have the effect of antibacterial, antiviral, antioxidant, anti-inflammatory, and can be used as a nectar plant, generation of tea and medicine.The second chapter elaborates the studies on chemical constituents of E.bodinieri Vaniot. Fourty-two compounds were isolated from the75%acetone-water extract of the E.bodinieri, including9new ones. These compounds isolated from E.bodinieri, containing flavonoids, triterpenoids, lignans, and iridoids, including11flavonoids (9-19),19triterpenoids (1-8,20-30),1monoterpene (31),2lignans (32、33),9iridoids (34-42). The new compounds was identified as bodinioside E (1),F (2),G (3),H (4),I (5),J (6), K (8),(2R)-eriodictyol7-0-(6"-3,4-dihydroxycinnamoyl)-β-D-glucopyranoside (9)和(2S)-eriodictyol7-0-(6"-3,4-dihydroxycinnamoyl)-β-D-glucopyranoside (10). Compounds7,11,23,27-33and35-42were isolated from E.bodinieri for the first time.The third chapter deals with the anti-HCV effects of E.bodinieri. Hepatitis C virus (HCV), a small and enveloped RNA virus, was classified to Hepacivirus genus of Flaviviridae family. It was estimated that170million people was infected with HCV worldwide. The increasing of infection case indicated the more severe prevalence. Once the occurrence of HCV infection, about80%infected individuals will progressed to chronic disease. Among them, about20%ended with liver failure and hepatocellular carcinoma. There is no drug and vaccine cured for HCV completely at present. Above all, it was urgent to develop anti-HCV drug screening system for the new treatment. In our study, based on the introduced HCV cell culture system, the anti-HCV drug screening system had been established with interferon and ribavirin as a positive control. By using this menthod, the anti-HCV effects of the extract and isolated compounds were tested. We found that the chloroform, ethyl acetate, and n-butanol extract from E. bodinieri have significant activity against HCV, which confirmed the effect of anti-HCV activity of E.bodinieri.4compounds showed obvious anti-HCV activities with SI>8. Among them, awn glycoside. showed the most potent anti-HCV activity with SI>500.The fourth chapter reported chemical constituents and biological activities of the compounds isolated from C.caudatus var. tomentosus. Seventeen compounds were isolated from the75%acetone-water extract of the stems of C.caudatus var. tomentosus, including6lignans (1-6),3sesquiterpenes (7-9),7iridoids (10-16), and1steroid (17). Compounds5-8,10-14were isolated from the genus Croton for the first time. In addition, the cytotoxic activities of the isolated compounds were investigated.3lignans (compounds1,2,3) showed obvious cytotoxic activities with IC50=101.9μg/ml,1.506μg/ml and21.24μg/ml, respectively.