A study on the allelopathic activity and quantitative determination of total phenolic and flavonoid of six plants in the Asteraceae family.

Abstract

This study aims to determine the allelopathic activities of six plants that belong to Asteraceae family such as China wedelia (Wedelia chinensis), sunflower (Helianthus annuus), cosmos (Cosmos bipinnatus), marigolds (Tagetes erecta), Mexico sunflower (Tithonia diversifolia), and zinnia (Zinnia elegans) by applying their methanolic extracts on barnyardgrass (Echinochloa crus-galli L.) and mustard green (Brassica juncea) with different concentrations (0.03, 0.1, 0.3, 1 g/ml). Results conducted from the study showed that the aqueous solutions extracted from the above-mentioned plants inhibited shoot and root length of barnyardgrass, mustard green at different intensity ranges in which cosmos aqueous extract gave the strongest impact, says, 23.01 and 97.54% of shoot length inhibition; 56.45 and 93.52% of root length inhibition at 0.3 and 1.0 g/ml respectively for mustard green. In case of barnyradgrass, the same results were also reported, says, 8.5 and 88.15% of shoot length inhibition; 36.35 and 99.99% of root length inhibition at 0.3 and 1.0 g/ml respectively. Total phenolic contents of the fresh plants of cosmos, China wedelia, sunflower, Mexico sunflower, marigolds and zinia were 4.51, 3.96, 1.05, 1.45, 3.61, and 0.99 mg/g, respectively; their total flavonoid contents were 1.58, 0.76, 0.29, 0.39, 0.65, and 0.45 mg/g, respectively. It is obvious that cosmos aqueous extract can be effectively and safely used for biological control of barnyardgrass.