民族药马利筋内生真菌生物活性研究.

Endophytic fungi in medicinal plants have the capacity to produce bioactive compounds whose features have great identity or similarity with the phytohosts. Since Asclepias curassavica has been known to possess a broad range of biological activities, we sought to obtain the active endophytic fungi from this plant. We performed the study followed the idea of “ethnic drug-endophytic fungi-active ingredients”, and thereafter we examined the bioactivities of fungal metabolites from 168 strains of endophytic fungi isolated from A. curassavica. To evaluate the biological activities of anti-tumor, anti-inflammatory, anti-α-glucosidase and anti-oxidant in these fungi, the ethyl acetate extracts from fermentation broth of endophytic fungi were first determined using the methods of SRB, Griess, PNPG and DPPH, respectively. Furthermore, we identified the bioactive fungal strains with conserved ITS sequencing. The results were as follows:(1) A total of 22 in 168 isolated strains had variable biological activities. Nine strains had obvious anti-tumor effect with the IC50 values of 0.1-40 μg·mL-1. Further, the strain MJF-53 displayed prominent inhibitory effects on the release of both NO and IL-1β in Raw264.7 cell line by LPS- induction under the concentration of 2.5 μg·mL-1. There were seven strains showing α-glucosidase inhibitory activity with the IC50 values ranging from 1.0 to 4.0 mg·mL-1, especially, the inhibitory activities of MYF-16 and MYF-55 were close to acarbose; 19 endophytic fungi had different degrees of DPPH free radical scavenging activities, among which MYF-9, MYF-19 and MJF-84 showed moderate anti-oxidant activities with IC50 values of 13.562, 17.776 and 12.395 μg·mL-1 respectively.(2)The ITS identification showed that the 22 active strains were mainly distribute in six genera: Alternaria sp., Colletotrichum sp., Fusarium sp., Diaporthe sp., Talaromyces sp. and Neofusicoccum sp. This study indicates that the bioactivities of the endophytic fungi from A. curassavica are diverse, which lays a foundation for exploring new potential natural anti-tumor, anti-inflammatory, hypoglycemic and anti-oxidant compounds from the endophytic fungi of A. curassavica. [ABSTRACT FROM AUTHOR]