Caffeic Acid Identified as an Inhibitory Compound in Asparagus Root Filtrate

Abstract

A potential allelochemical was isolated and identified from methanol extracts of asparagus (Asparagus officinalis L.) fresh root tissue. Fractions were collected by cellulose column chromatography and tested for inhibition by an asparagus seed germination bioassay. The fraction showing the greatest inhibition contained caffeic acid, as identified by melting point, thin-layer chromatography, and infrared spectrum analysis. Seed germination bioassays and greenhouse pot tests showed depression of seedling emergence when asparagus seeds were exposed to various dosages of crude filtrate, a methanol extract from crude filtrate, and caffeic acid.