Coumestrol- and 4',7-Dihydroxyflavone Content in four Alfalfa Cultivars after Ozone Exposure

Fertility in live-stock is sometimes known to be disturbed by the plant estrogen coumesterol, an isofalvonoid, which can accumulate in plant foliage due to biotic stresses. Leaves of soybeean have been reported to produce coumestrol after ozone exposure, an abiotic stress. Seven-week alfalafa plants of four differen cultivars were exposed to 773 ug/m3 (0.40 ppm) ozone for three hours to investigate whether coumestrol is also produced in other legumes after ozone exposure. 48 h after exposure, the most severely injured leaves have harvested for analysis. Leaves were extracted in methanol and samples were subjected to thin layer chromatography with subsequent fluorometer readings. Coumestrol was never detected in any crude extract of control or experimental sampels. However, all crude extracts from plants expsoed to ozone contained high amount of the favonoid compound, 4',7-Dihydroxyflavone. This compound was not detected in any crude extracts from the control plants