xperiments were conducted to examine the allelopathic effect of chamomile (Matricaria chamomilla L. Rydb.) flowers on germination and early growth of some weeds (Lolium multiflorum Lam., Avena fatua L. and Phalaris paradoxa L. associated to wheat (Triticum aestivum L.) crops with various concentrations (10, 20, 30, 40, and 50 g l -1 ) of aqueous extracts. Aqueous effect caused pronounced pre and post emergence inhibitory potential on A. fatua, L. multiflorum than T. aestivum that was

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... l to the concentration of the extract. Via activity, acetylated flavonoids isolated from chloroform extracts were apigenin-7-O-(4", 6"-diacetyl glycoside) and apigenin 7-O-(4-acetyl glycoside), which caused reduction in the total weed fresh weights by 77.0 and 65.4% for A. fatua and 79.3 and 67.0% for L. multiflorum, respectively. The purified apigenin, matricolone, herniarin and coumarin reduced total biomass by 53.1, 59.1, 56.0 and 51.4% for A. fatua and 54.86, 58.61, 56.1 and 52.0% for L. multiflorum, respectively, compared to its control. The discovery of acetylated flavonoids allelopathic properties from chamomile flowers may contribute to effective and environmental friendly weeds control approaches in wheat crops.