NEW C-4''-HYDROXY DERIVATIVES OF MAYSIN AND 3'-METHOXYMAYSIN ISOLATEDFROM CORN SILKS (ZEA-MAYS)

Reduced derivatives of maysin [2 amnosyl-6-C-(6-deoxy-xylo-hexos-4-ulo syl)luteolin] and 3'-methoxymaysin have been isolated and identified f rom several corn (Zea mays L.) inbreds. These include 2 ''-O-alpha-L-r hamnasyl-6-C-quinovosylluteolin (equatorial 4 ''-OH-maysin, eq-4 ''-OH -maysin), 2 ''-O-alpha-L-rhamnosyl-6-C-fucosylluteolin (axial 4 ''-OH- maysin, ax-4 ''-OH-maysin), and 2 O-alpha-L-rhamnosyl-6-C-fucosyl-3'-m ethoxyluteolin (ax-4 ''-OH-3'-methoxymaysin). In addition to maysin an d 3'-methoxymaysin, inbred Tx501 contains minor amounts of ax-4 ''-OH- maysin and ax-4 ''-OH-3'methoxymaysin. Corn Lines A103, GE275, ESDJ1, and CML131 contained relatively large levels of both ax-4 ''-OH-maysin and eq-4 ''-OH-maysin. Synthetic 4 ''-OH-maysin (obtained by NaBH4 re duction of maysin) was tested for growth inhibition of corn earworm (H elicoverpa tea Boddie) larvae in a laboratory bioassay and found to be almost as active as maysin, suggesting that incorporation by breeders of these compounds into silks could enhance the resistance of corn to corn earworm larvae.