Secondary Metabolites Of 6 Endophytic Fungi Inhabiting In Desert Plants

Endophytic fungi are a member of unique fungi that live in different tissues or organs of a host plant.With the continuously chemical investigation on the secondary metabolites of endophytic fungi,it becomes more and more difficult to find novel and active compounds from endophytic fungi inhabiting common habitats.Endophytic fungi of unique niches evolve different gene clusters with the potentials to produce secondary metabolites with vitally chemical ecological roles to adapte to their biological and abiotic factors.Therefore,six endophytic fungi isolated from desert plants were selected to obtain novel bioactive secondary metabolites as the lead compounds for drug or agricultural chemicals discovery.The EtOAc extract of six endophytic fungi Rhinocladiella similis(TL-1-3),Paraphoma sp.(HR-12-1),Embellisia chlamydospora(TR-6-2),Embellisia chlamydospora(AR-14-22),Paraphoma chrysanthemicola(TR-2-3),Phoma betae(TS-10-1)were chemically investigated,and 32 compounds(1-32)were isolated.Based on chromatographic approaches,11 compounds(1-11)were isolated from the EtOAc extract of R.similis.These compounds were elucidated by different spectroscopic analysis(IR,UV,1H-NMR,13C-NMR,HSQC,HMBC,ROESY,ESI-MS,CD,and XRD),among which compounds 1,2,5-9 were new compounds.12 compounds(12-23)including three new compounds 12-14 were isolated and identified from the EtOAc extract of Paraphoma sp..Compounds 24-32 were isolated from other 4 endophytic fungi.Biological evaluation showed that compounds 1,4,6 and 10 displayed low cytotoxic activities against U937 cancer cell lines,and 26 and 27 have the bioactivity of inhibiting root growth of Arabidopsis seedlings.In addition,the structures and bioactivities of secondary metabolites from endophytic fungi inhabting in grassland and desert plants were also reviewed in this paper,which provides foundation for further research.