Research On The Endophytes In Ginkgo Biloba L. And Magnolia Officinalis Rehd. Et Wils

Endophytes are referred to fungi colonizing healthy plant tissues without causing overt symptoms in or apparent injury to the host. Research results in near years show that endophyte can produce some metabolites similar to those from the host plant. This feature could make endophyte became a new resource which can produce some compounds with novel structure and specific bioactivity. For above reasons we selected Ginkgo biloba L. and Magnolia officinalis Rehd. et Wils. as our original materials, to isolate and identify their endophytic fungi, and sift out the bioactive strains from them. Meanwhile, we studied the bioactivities of one bioactive strain in initial stage. According to our research findings, we concluded the above contents as following:Firstly, 178 strains endophytes were isolated from the roots and stems of Ginkgo biloba L. and they were morphologically identified belonging to 28 genera, 6 families, 4 orders and 1 class. Moniliales, which includes 96.6% of the whole strains, is believed the dominant order. While Fusarium, Aspergillus, Cladosporium are believed the dominant genera, which may include 36.5%, 19.7%, 10.1% of the whole strains in respective. It is shown that quantity, species and distributing of the endophytic fungi are varied in different organs of Ginkgo biloba L. Meanwhile, we used TLC method in order to compare the metabolites of 178 strains with terpenoids lactone and the result shows that the metabolites of 36 strains may include terpenoids lactone. On the other hand, the result of inhibition against platelet aggregating experiment proves that 7 strains may produce ginkgolide C or similar compounds.Secondly, 48 strains endophytes were isolated from the stems of Magnolia officinalis Rehd. et Wils. As a result, they were morphologically identified belonging to 16 genera, 6 families, 3 orders and 1 class. Moniliales, which includes 83.3% of the whole strains, is believed the dominant order. While Aspergillus, Penicillium, Fusarium are believed the dominant genera, which include 31.3%, 18.8%, 14.6% of the whole strains separately. It is also shown that quantity, species and distributing of the endophytic fungi are varied in different habitat of Magnolia officinalis Rehd. et Wils. The result of the HPLC experiment to metabolites of 27 strains indicates the mycelium or fermented liquid of 17 strains may include honokiol, magnolol or similar compounds. In addition, the result of antibacterial assay shows that 7 strains of the fungi have antagonism against one or more bacteria, such as Staphylococcus aureus, Escherichia coli, Pseudominas aeruginosa. After repeatedly sifted, we selected FM044, which had better antibacterial effect, to study antibacterial compounds. By this process, a crystal was isolated from the mycelium of FM044 and its structure was identified as D-mannitol by some structure analysis methods as IR, MS, ~1H-NMR. Further study on the antibacterial bioactivities is still in continuing.