Bioactive Flavonoids from Endophyte-Infected Blue Grass (Poa ampla)

Abstract

Ethanol extract of leaves of Poa ampla, either infected or uninfected with the symbiotic fungus Neotyphodium typhnium, were tested for bioactivity against the mosquito larvae. Results of these tests indicated that only the extracts obtained from endophyte-infected grass are active against mosquito larvae. Relatively high activity was detected in stromata, seeds, spikelets, and leaves of plants, while only weak or no activity was found in extracts of the isolated fungus. The ethyl acetate fraction had approximately the same activity as that of the crude extract, while the activities from 1-butanol and hexane were intermediate and low, respectively. Bioassay-guided fractionation of the ethyl acetate fraction yielded tricin (1), 7-O-(β-d-glucopyranosyl)tricin (2), and isoorientin (3) as the bioactive constitutents. A fourth compound, 7-O-[α-l-rhamnopyranosyl(1−6)−β-d-glucopyranosyl]tricin (4), was also isolated from the active fraction but showed little activity in this assay. Keywords: Poa ampla; turf; endophyte; Neotyphodium typhnium; insecticidal properties; bioactivity; flavonoid; flavonoid−glycoside

Influence of Fungal Endophyte Infection on Phenolic Content and Antioxidant Activity in Grasses: Interaction between Lolium perenne and Different Strains of Neotyphodium lolii

“…Hence, N. lolii infection affects only the level of polyphenol expression rather than changing the number or type of polyphenols in L. perenne. Our results contradict with the earlier findings of Ju et al 18 and Ponce et al, 17 who reported significant qualitative along with quantitative changes in the phenolic composition of P. ampla and L. multif lorum infected with their respective Neotyphodium spp. Knowing that not only were different plants used by Ju et al and Ponce et al but different species of Neotyphodium were used as well, we conclude that the influence of endophyte infection on polyphenol composition of grasses is case specific and depends on several factors including, but not restricted to, plant type, endophyte species, and endophyte strain.…”

Positive association between mycorrhiza and foliar endophytes in Poa bonariensis, a native grass

“…This hypothesis is supported by the observation that endophyteinfected plants of Poa ampla produce this type of compounds (Ju et al 1998). No specific phytochemical information is available to date for Poa bonariensis.…”

Effect of Neotyphodium endophyte-tall fescue symbiosis on mineralogical changes in clay-sized phlogopite and muscovite

“…Finally, entophytes have been known to enhance biomass, tiller numbers, seed production, and root growth (Clay 1987;Cheplick et al 1989;Belesky and Fedders 1995) via plant hormone production, increased photosynthetic performance, and reduced transpiration rate (Belesky et al 1987;Clay 1990;Bacon 1993). Some of these benefits to plants due to fungal endophytes are attributed to the production of a diverse range of secondary metabolites such as alkaloids and phenolic-like compounds (Bush et al 1997;Ju et al 1998).…”