Antifungal activity of the crude extraction of endophyte-infected and endophyte-free drunken horse grass

Antifungal activities of the alkaloid extraction from endophyte-infected (E+) and endophyte-free (E-) Achnatherum inebrians were tested against Claviceps purpurea, Drechslera erythrospila, Fusarium avenaceum, Bipolaris sorokiniana, Curvularia lunata, F. semitectum, F. solani and Alternaria alternata to definite the bacteriostatic activity of drunken horse grass (Achnatherum inebrians)alkaloid extract. The results of HPLC analysis found that ergot alkaloids, ergonovine and ergine were existed in the E+ drunken horse grass. The concentrations were 26.178 and 369.074 mg·kg-1, but these two alkaloids were not detected in the E- extraction. The alkaloid extraction from E+ and E- drunken horse grass inhibited the colony growth and spore germination of the 8 fungi differently, extraction from E+ had stronger inhibition to tested fungi than E-. The inhibition rate of E+ alkaloid extraction to the colony growth and spore germination of F. avenaceum was the highest with 63% and 57%, respectively. The concentration of alkaloid extraction and the spore germination inhibition rate of tested fungi was significantly positive correlation (P<0.05). Fungi of grass endophyte infection increased the antifungal activity of drunken horse grass extraction.The symbionts contained alkaloids ingredients, however .the specific chemical substances of the extractions and the mechanism of antifungal activity need further research.