Hydroxychalcones as Herbicides

Abstract

Efforts to develop weed management alternatives are urgently required due to various challenges, such as declining crop yields, rising production costs, and the growing prevalence of herbicide-resistant weed species. Chalcones occur in nature and have phytotoxic potential and concise synthesis; additionally, they are multifunctional, with diverse biomolecular targets and a broad spectrum of biological activities. This study sought to assess the herbicidal potential of 3′-hydroxychalcones against weed species under laboratory conditions. Their effects were investigated using germination bioassays, early growth measurements, and the seedling vigor index, all prepared with a concentration of 1 × 10−3 mol L−1 3′-hydroxychalcones. 3′-Hydroxy-4-pyridyl-chalcone caused the greatest inhibition (81%) of the seedling length in Urochloa decumbens. Other 3′-hydroxychalcones also caused large initial growth reductions, such as 3′-hydroxy-4-pyridyl-chalcone (75%) and 3′-hydroxy-4-nitrochalcone (68%) in Digitaria insularis and 3′-hydroxy-4-bromochalcone (73%) in Raphanus raphanistrum. The greatest reduction in the seedling vigor index was 81% in D. insularis treated with the 3′-hydroxy-4-bromochalcone. The same 3′-hydroxychalcone caused an 80% reduction in Amaranthus viridis. In conclusion, 3′-hydroxychalcones exhibit herbicidal activity, suggesting they could serve as a solution for future weed management strategies.