Camptotheca Acuminata Endophytic Fungi And Their Secondary Metabolites

Camptothecin (CPT), specifically inhibits DNA topoisomeraseⅠ, is a potent antineoplastic agent. However, it's difficult to obtain CPT to meet the large need by extraction as well as chemical synthesis due to the low content in plants and complex structure. Thus, endophytic fungi have become important sources for CPT production.About 50 endophytic fungi were isolated from barks of C. acuminata. The metabolites were screened by TLC, UV and HPLC, EFC I-13 was considered to produce CPT. The fungus was identified as a Penicillium based on it's morphological features.Statistical experimental designs were used to optimize the fermentation medium for maximum camptothecin (CPT) production. Glucose, yeast extract and sulfate ammonium were selected as the suitable carbon sources and nitrogen sources via one-factor-at-a-time design. The most important factors influencing CPT production, as identified by Plackett-Burman design (PBD), were glucose, KH2PO4 and L-Trp. Steepest ascent method was used to determine the center point of these significant variables. Box-Behnken design (BBD) and response surface analysis predicted a maximum CPT yield of 80.41μg/L at glucose 10.48g/L, yeast extract 15 g/L, KH2PO42.91g/L, MgSO4 0.5 g/L, CaCl2 0.1 g/L, (NH4)2SO4 0.8 g/L and L-Trp 0.148g/L, which was in close agreement with the experimental result of 80.39μg/L,43.9% higher than the yield from initial medium.36 SRAP primer combinations were used to study the endophytic fungi. Six combinations amplified a total of 425 discrete bands of which 365 (85.9%) were polymorphic. These strains were grouped into 3 main clusters with a similarity index value of 0.54. The result revealed that SRAP could be used to discuss the genetic diversity of endophytic from C. acuminata.