Toxicity of some cinnamic acid derivatives to common bean (Phaseolus vulgaris).

Cinnamic acid derivatives are an important class of biologically active compounds, playing an important role in the plants’ development, but may also present a wide range of actions: antimicrobial, antioxidant, antiinflamatory, antitumoral. The present study investigated the toxicity of ten cinnamic acid derivatives on Phaseolus vulgaris, this being the first step in evaluating their pharmacotoxicological potential (usually, plant toxicity tests are used for ecotoxicity assessment, but they can also provide some useful general information about the toxic potential of a pharmaceutical substance to living organisms). The bean seeds were exposed to three different concentrations of each substance (28.6 I¼g/cm2, 57.3 I¼g/cm2, 114.6 I¼g/cm2). All the tests were conducted in Petri dishes, using an artificial substrate (Whatman filter paper) impregnated with the investigated compounds. The analyzed elements were seedling length, root length, percentage of seeds that developed into seedlings, fresh seedling weight and the total polyphenols content. The tested compounds showed phytotoxic effects, inhibiting the growth of the plants and the biosynthesis of polyphenols as compared to the control. The substances with high logP values showed greater phytotoxic potential, but to establish an exact correlation between hydrophobicity and toxicity of the molecules a QSAR analysis must be further done.