BIOACTIVE FLAVONOIDS FROM ENDOPHYTE-INFECTED BLUE GRASS (POA AMPLA)

Ethanol extract of leaves of Poa ampla, either infected or uninfected with the symbiotic fungus Neotyphodium typhnium, were tested for bioac tivity against the mosquito larvae. Results of these tests indicated t hat only the extracts obtained from endophyte-infected grass are activ e against mosquito larvae. Relatively high activity was detected in st romata, seeds, spikelets, and leaves of plants, while only weak or no activity was found in extracts of the isolated fungus. The ethyl aceta te fraction had approximately the same activity as that of the crude e xtract, while the activities from 1-butanol and hexane were intermedia te and low, respectively. Bioassay-guided fractionation of the ethyl a cetate fraction yielded tricin (1), 7-O-(beta-D-glucopyranosyl)tricin (2), and isoorientin (3) as the bioactive constitutents. A fourth comp ound, -rhamnopyranosyl(1-6)-beta-D-glucopyranosyl]tricin (4), was also isolated from the active fraction but showed little activity in this assay.