LAUSR

We conducted an investigation to search for the possibility of phytotoxic compounds and then identify them in C. aciculatus. The aqueous methanol extracts of C. aciculatus imposed a strong suppressive effect on the shoots and roots growth of Medicago sativa and Echinochloa crus-galli. The C. aciculatus extracts were subsequently purified through chromatography and three growth-inhibitory compounds were identified by spectral data as methyl cis-p-coumarate, methyl trans-p-coumarate, and trans-ferulaldehyde. The seedlings growth of Lepidium sativum was suppressed by methyl cis-p-coumarate, methyl trans-p-coumarate, and trans-ferulaldehyde. The I50 values (concentration required for 50% growth inhibition) for the seedling growth of L. sativum ranged from 1.25 to 1.73 mM for methyl cis-p-coumarate, 0.74 to 1.23 mM for methyl trans-p-coumarate, and 1.05 to 1.84 mM for trans-ferulaldehyde. Our finding indicates that methyl cis-p-coumarate, methyl trans-p-coumarate, and trans-ferulaldehyde may contribute to the phytotoxic effects of C. aciculatus.