Research on the Metabolites of Cladosporium tenuissimum MT-35, an Endophytic Fungus of Cryptomeria sinensis
Huperzia serrata (Thunb. ex Murray) Trev It is a plant of the genus Taxodium in the family Taxaceae, also known as the Thousand Layer Pagoda. It is used as a whole herb in medicine and has the effects of clearing heat and detoxifying, promoting muscle growth and stopping bleeding, dispersing blood stasis and reducing swelling. It can be used to treat injuries caused by falls, snake bites, blood stasis and swelling. According to literature reports, there are abundant endophytic bacteria in the roots, stems, and leaves of the Chinese fir, which can produce structurally diverse metabolites when cultured in vitro; Some endophytic fungi can also produce huperzine A during in vitro fermentation and culture. The preliminary research of the research group found that multiple endophytic fungi were isolated and identified from Cryptomeria lanceolata. Further studies were conducted on their fermentation products, and a series of structurally novel terpenoid and polyketide metabolites were isolated and identified. Some compounds exhibited significant anti-inflammatory and acetylcholinesterase inhibitory activities in vitro. C. Tenuissimum MT-35 is an endophytic fungus isolated and purified by our research group from Cryptomeria acutissima in the early stage. Its fermentation product has certain acetylcholinesterase inhibitory activity. Therefore, the research team isolated and purified the metabolites of this endophytic fungus, combined with in vitro activity screening, hoping to obtain metabolites with acetylcholinesterase inhibitory activity.

 

Microorganisms can produce novel and diverse metabolites during in vitro fermentation and cultivation. Through the isolation and identification of microbial metabolites, combined with activity screening, it is expected to discover active molecules with development potential. C. Tenuissimum is an endophytic fungus isolated by our research group from Cryptomeria lanceolata in the early stage. It has been reported in literature that this fungus has also been isolated in plants such as Pinus wallichiana and Maytenus hookeri. Naseer, Dai, and others studied its metabolites fermented in potato glucose agar medium and isolated multiple macrolide polyketones, some of which have antibacterial activity. In this study, from C Ten metabolites were isolated and identified from the fermented products of Tenuissimum’s brown rice, including six nitrogen-containing compounds, two steroidal compounds, and two polyketide compounds. Some of the compounds exhibited biological activities against acetylcholinesterase and anti-inflammatory. Although the structure of compound 1 has been reported, there is no literature reference for its nuclear magnetic resonance data. In this paper, two-dimensional nuclear magnetic resonance (2DNMR) and other methods were used to accurately assign its carbon hydrogen data. The above research results are helpful for further understanding of Bacillus subtilis C The discovery of the structural types and active natural products of tenuissimum metabolites has certain reference significance. However, in the systematic isolation study of this strain, it was found that the endophytic fungi were cultured under the conditions reported in this article, and their metabolites were very limited. The macrolide components reported in the literature were not isolated, which may be due to different cultivation conditions or different plant hosts of the endophytic fungi, resulting in different metabolites. In subsequent studies, it is possible to try changing the fermentation culture conditions or exploring different fungal co culture methods. Combined with liquid chromatography-mass spectrometry (LC-MS) analysis guidance, suitable culture conditions can be screened before LC-MS guided separation can be carried out to avoid low-level repetitive separation as much as possible. On the other hand, with the rapid development of genome sequencing technology, the discovery strategy of novel structurally active natural products based on gene mining technology has become a cutting-edge research hotspot. By activating the expression of specific gene clusters or expressing related gene clusters in other heterologous systems, it is expected to discover a large number of novel products that cannot be obtained under conventional conditions.