Objective: To study the cyclic dipeptides secondary metabolites from endophytic AR-15-1 in Astragali Radix. Method: AR-15-1 was isolated from the roots of Astragali Radix by the method of histology. The fungus was identified by morphological method combined with molecular biology method

and solid culture method was used for large-scale fermentation of endophytic fungi. Cyclic dipeptides were isolated by column chromatography

Sephadex LH-20

and HPLC

and their chemical structures were elucidated by the spectral analysis. Result: Endophytic fungi AR-15-1 isolated from roots of Astragali Radix were identified as Aspergillus sp. Eight cyclic dipeptides were obtained and elucidated as cyclo-(Pro-Gly) (1)

cyclo-(Pro-Leu) (2)

cyclo-(Pro-Ile) (3)

cyclo-(Pro-Vla) (4)

cyclo-(Phe-Gly) (5)

cyclo-(Phe-Ala) (6)

cyclo-(Phe-Tyr) (7) and cyclo-(Phe-Pro) (8). Conclusion: All cyclic dipeptides were isolated from the endophytic fungi of Astragali Radix for the first time

and most of the cyclic dipeptides of Aspergillus sp. showed good biological activity.