Study On Secondary Metabolites Of Two Symbiotic

During the long-term process of coevolution between symbionts and the host, symbionts had formed a particular metabolic pathways and could produce secondary metabolites which possess a variety of bioactivities and structures. In addition, symbionts are characterized by possessing the regeneration ability, short vegetative cycle and their metabolism and breeding are easy to control. Therefore, research on nature products from symbionts had been attracted more and more attention.Endophytic fungus IFB-WQ was separated from Imperata cylindrical by Institute of Functional Biomolecules, Nanjing University. It was identified as Chaetomiun globosum. based on its morphologic characters. Chemical constituent of crude extract of solid fermentation of the strain was studied in this dissertation. The solid biomass was extracted with CHCl3-CH3OH (v/v1:1) several times and then evaporated in vacuo to afford the crude extract (26g). After fractionation on silica gel column chromatography, guided by1H-NMR spectrum and TLC, further separation and purification was performed using several methods such as silica gel column chromatography, Sephadex LH-20gel column chromatography, HPLC and so on. Finally, six compounds had been obtained. Structures of these compouds were determined through modern spectrum technology such as HR-ESI-MS,1D and2D NMR etc. Compounds1-6were identified as Chaetoglobosin F (1), Chaetoglobosin Fex (2), Chaetoglobosin E (3), Cytoglobosin A (4), Penochalasin C (5) and isochaetoglobosin D (6)respectively, which are all cytochalasin compounds.Actinomycete IFB-WQ2was separated from Busycon canaliculatu by Institute of Functional Biomolecules, Nanjing University. It was identified as Streptomyces sp. according to its morphologic characters. Chemical constituent of crude extract of solid fermentation of the strain was studied in this dissertation. The solid biomass was extracted with CHCl3-CH3OH (v/v1:1) several times and then evaporated in vacuo to afford the crude extract (35g). After fractionation on silica gel column chromatography, guided by’H-NMR spectrum and TLC, further separation and purification was performed by silica gel column chromatography, Sephadex LH-20gel column chromatography, HPLC and so on. Finally, four compounds had been obtained. Structures of these compouds were determined through modern spectrum technology such as HR-ESI-MS,1D and2D NMR and so on. Compounds7-10were determined as hexanehexol (7), daucosterol (8),2-oxo-3-Pyrrolidinecarboxylic acid (9) and ergosterol (10) respectively.In vitro cytotoxicity of compounds1,3and5to human liver cell lines SMMC-7721and human cervical cancer cell lines HeLa were evaluated by MTT method. The result showed that compounds1,3and5inhibited the growth of SMMC-7721cells to some certain extent with IC50 value of49.2μg/ml (0.092μmol/ml),51.7μg/ml (0.097μmol/ml) and35.4μg/ml (0.069μmol/ml) respectively. Compounds1,3and5also showed cytotoxic activity to HeLa cells to some certain extent with IC5o value of52.7μg/ml (0.099μmol/ml),12.6μg/ml (0.024μmol/ml) and43.9μg/ml(0.086μmol/ml), respectively. In addition, Activity of anti-oxidative stress of DPPH of compounds1-6were tested. The result indicated that compound1and6had strong anti-oxidative activity with IC50value of0.002μmol/ml and0.002μmol/ml,respectively. Compounds2-4showed week anti-oxidative effects, compound5showed no effects.Natural product is a rich source of lead compounds. In this dissertation, several cytochalasin compounds obtained from endophytic fungi IFB-WQ solid fermentation product possess both anti-oxidative activity and anti-tumor activity to human liver cell lines SMMC-7721and human cervical cancer cell lines HeLa, which were worthy of further study.