Study On Isolation, Identification And Fermentation Of A DMC-producing Endophytic Fungus, Ceriporia Lacerata DMC1106, From Cleistocalyx Operculatus

2’,4’-Dihydroxy-6’-methoxy-3’,5’-dimethylchalcone (DMC), an interesting flavonoid, is mainly produced by Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae) that is a well-known medicinal plant distributed and propagated widely in Southern China, Vietnam and some other tropical countries. DMC is regarded as a promising anti-cancer candidate based on encouraging in vitro and in vivo pharmacological studies. Moreover, our very recent report demonstrated that DMC can effectively reverse multi drug resistance of cancer cells. In another aspect, DMC also exerted other important bioactivities, including anti-inflammatio, hepatoprotection, antioxidant, antimicrobial, antithypergcaemic, spasmolytic and immunomdulatory effect. Currently, the most common source of DMC is the buds of C. operculatus. However, C. operculatus are rare, slow growing and a large amount of buds are needed to obtain a small amount of DMC. Without doubt, a new approach for the DMC production is urgently required.Endophytes are the micro-organisms that colonize the interior parts of the plant, typically causing no apparent symptoms of diseases and well recognized as a promising source of bioactive secondary metabolites. In this study,69endophytic fungi are screened from the stem, leaf, fruit, root from a traditional Chinese medicine C. operculatus and ten strains may produce DMC, one of strains had a higher capacity of producing DMC. This strain was finally selected and coded as DMC1106. Strain DMC1106was identified as Ceriporia lacerata DMC1106based on rDNA internal transcribed spacer (ITS) sequences and phylogenetic analysis for the first time. The identity of the fungal DMC was confirmed by LC-HRMS/MS through comparison with the authentic DMC. Then, fermentation medium and fermentation conditions of strain DMC1106were optimized. The optimized fermentation medium is:10g/L peptone,20g/L sucrose,0.72g/L MgSO47H2O,4g/L KH2PO4,0.34g/L oxalic acid,0.78g/L L-phenylalanine, pH4.8-5.0, and strains were cultured with150rpm shaking and20%inoculum size at28±2℃for6days in a rotary shaker. Under the optimized conditions, the production of DMC amounted to100.24±1.60μg/L.