Study On Antioxidant Activity Of Endophytic Fungal Metabolites

Nowadays, a huge of endophytic fungi can be described as the world is a waiting for mining rich resources and its metabolites is an untapped natural product libraries,endophytic fungal antibiotics, immunosuppressants, anti cholesterol drugs(statins)have been available and some have antitumor, anti depression, antibacterial active substances have become the focus of modern medical research, plant endophytic fungal metabolites for the development of new drugs and lead compounds and utilized to open the door. The recent studies’ results show that oxidative stress is the important cause of cancer, diabetes, heart disease, cerebrovascular disease and so on.Due to the limitations such as the side effects of synthetic antioxidants on the use, development and utilization of natural antioxidants is particularly important, and the extraction of natural compounds from plants, by region, season, weather, yield and other factors,and some precious and endangered plant resources is so rare, therefore, it has a broad prospect to search for natural antioxidants from the metabolites of endophytic fungi.In this study, 356 strains of endophytic fungi were isolated from 27 plant samples which,and belonging to 12 genera, the fermentation broth of 356 strains of endophytic fungi detected by DPPH free radical scavenging antioxidant model 5 strains which reflects the different degree,and the ability of scavenging DPPH free radical.Using the plasmid antioxidant model experiment, the metabolites of strain CBB055-1 also has the ability to protect the plasmid from oxidative damage, by morphological and molecular biological identification, strain CBB055-1 is Aspergillus sydowi. Using single factor method to optimize the fermentation conditions of the strain CBB055-1concluded: when the medium with 0.05% Magnesium Sulfate and 0.1% potassium dihydrogen phosphate as the inorganic nutrients, carbon source is 2% potato extract powder, 2% yeast extract as nitrogen source, initial p H was 5, 2% inoculation amount was 1×107CFU/ml spore suspension. The liquid volume is 200 ml, 28 ℃, 120 rpmshake flask culture of 7d was the best fermentation conditions, the fermentation product of the dry weight of 305 mg, free radical scavenging rate of 96.77%. The antioxidant activity of strain CBB055-1 metabolites by silica gel column chromatography, HPLC, reversed-phase ODS column purification, to obtain the effective component S4-1, the DPPH radical scavenging rate of 80.52%. after a preliminary analysis of the LC-MS spectrometer against oxidative metabolites of component S4-1, the molecular weight of 611.1604. By comparison of chemical components in natural products database, deduce the structure for anthocyanin compounds.