Screening The Biological Compounds By Secondary Metabolites Of Endophytes

OBJECTIVE To sceen the antitumor, antibiosis and the antioxidant activity of secondary metabolites produced by endophytes which contain PKS or NRPS biosynthesis genes and looking for pharmaceutical lead compounds.METHODS Based on preliminary screening and identification of containing PKS or NRPS endophytes were revitalized, purificated, fermentated and sterilized, then the vitro screening of antitumor activity was determined by MTT assay; The antibiosis activity was detected by Kirby-Bauer filter paper diffusion method; The antioxidant activity was measured by the Total Antioxidant Capacity Assay Kit with FRAP method. We fementated and extracted the metabolic product of active strains, then screened the in vitro antitumor activity repeatedly by MTT assay. RESULTS The recovery of28endophytes are in good conditions and no miscellaneous bacteria pollution. We can fenmentate for extracteing the metabolic products because the recovery results are same as the previous results. We fermentated the well growth endophytes, then got the fermentation broth, at the same time, we sceened the biological activity of fermentation broth after the sterilization. The antitumor activity screening results showed that there are4inhibition ratios of endophytes’ fermentation broth>50%. Among them,3endophytes have effect to QBC, the inhibtion ratios are62%,51.8%and60.9%, the other one have effect to K562, the inhibtion ratio is52.5%. The antibiosis activity screening results showed that there is1endophyte has good effect to Escherichia coli, and the diameter of inhibition zone is22mm.5endophytes’ diameters of inhibition zone are between10and20mm,3endophytes’ diameters of inhibition zone are between6and10mm, the rest of the19cases without effect. The results of effect to staphylococcus aureus showed,3endophytes’ diameters of inhibition zone are>30mm,11endophytes’ diameters of inhibition zone are between20and30mm,8endophytes’ diameter of inhibition zone are between10and20mm, the rest of the6cases without effect. In addition,28endophytes’ fermentation brothes have no effect to Anti-Ampicillin Escherichia coli, Enterococcus faecalis, Candida mycoderma and Pseudomonas aeruginosa. The antioxidant activity screening results showed,4endophytes have better antioxidant activity, the FRAP are>0.1mM, but are weak relatively comparing with positive control (Trolox). The results of screening the antitumor activity repeatedly of endophytes’ secondary metabolites showed, the27#2and46#9have effect to SPC-A-1, but not obvious. At the same time, there is no difference between48hours and72hours. The others should do a further research. CONCLUSION It is feasible that screening the bioactive compounds by secondary metabolism of endophytes, and can provid reference for the research of endophytes and the development of medicine.