Secondary Metabolites And Antifungal Activity Of Endophytic Fungus Chaetomium Globosum From Ginkgo Biloba

Endophytic fungi have many species that are widely distributed, they are rich resources of a variety of biologically active natural products. It has been reported that many secondary metabolites from endophytic fungi have anti-cancer, anti-inflammatory, antioxidant, cytotoxic and other activities.Fungi of the Chaetomium genus have been revealed to be a rich source of structurally diverse secondary metabolites.A variety of new and bioactive secondary metabolites associated with diverse structural types of chaetoglobosins, chromones and terpenoids have been discovered. Many of the compounds possess significant biological activities, such as antitumor, anti-inflammatory, cytotoxic, enzyme inhibitory, antibiotic and other activities.The secondary metabolites and antifungal activity of endophytic fungus Chaetomium globosum from Ginkgo biloba are studied. Twelve known metabolites are isolated from the mycelium and the filtrate,the structures of those compounds are identified respectively to be squalene (1), ergosterol peroxide (2), gliotoxin(3), chaetoglobosin G (4), (22E, 24R) - ergosta -7,22-diene-3β,5α,6β-three alcohol (5), fumitremorgin C (6), chaetoglobosin C (7), methylthiogliotoxin (8), 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (9), pseurotin A(10), amino acid(11) and 3,4-dihydroxyphenylacetic acid (12) by a combination of spectroscopic methods (MS, 1^H, (13)^C NMR and 2D NMR) and comparisons the data with those in the literature. Among them, compounds 1, 3, 6, 8-12 are first isolated from the fungus.The in vitro growth inhibition assay of compounds 1-12 against phytopathogenic fungi is carried out following mycelial growth inhibitory rate method. The result indicated that only compound gliotoxin (3) has good antifungal activity against all the fungi, of which it has significantly inhibitory activity towards Fusarium sulphureum, Alternaria alternata (Fries) Keissler and Cercospora sorghi with EC₅₀ values of 68.54,36.76 and 59.79μg/mL respectively; it has moderate inhibitory activity towards Fusarium oxysporum f.sp. vasinfectum, Fusarium graminearum and Botrytis cinerea.In summary, the secondary metabolites and antifungal activity of endophytic fungus Chaetomium globosum from Ginkgo biloba are studied.12 secondary metabolites are obtained from the fungus, including a compound gliotoxin (3) that has good antifungal activity. Studies mentioned above provide a theoretical principle for developing new drugs, also provide a theoretical basis for producing these active compounds.