Identification and Characterization of Herbicide from Pileostegia viburnoides var.glabrescens

Increasing resistance to agrochemicals by insects and plant pathogens and the loss of weed and disease control agents are factors that drive the need to search for new natural product derived plant protestants and agrochemicals. Bio-prospecting natural products allows discovery of new agrochemicals for pest management and chemistry found from plants used worldwide in traditional medicines have not been evaluated as potential bio-pesticides or new plant growth regulators. Pileostegia viburnoides var. glabrescens is a traditional Chinese medicine plant used for treating traumatic injury and fractures. Preliminary evaluations of P. viburnoides var. glabrescens was completed in 2012 for antifungal and herbicidal activity. N-Butanol extract from P. viburnoides var. glabrescens was shown to be active at higher concentrations to Agrostis (monocot) and less active against lettuce (dicots). Several pure compounds were separated by chromatography from n-butanol extract of P. viburnoides var. glabrescens. The pure compound skimmin in the active fractions obtained from n-butanol extract was identified. These fractions and skimmin showed phytotoxic activity against Iceberg lettuce and Agrostis seeds in primary research. Skimmin possessed high seed germination inhibition of monocot species and moderate seed germination inhibition against the dicot species. Therefore, we began a more in-depth evaluation of 8 pure compounds obtained from the active n-butanol extract of P. viburnoides and skimmin. Following natural product leads offers an efficient approach to discovering and optimizing new herbicides for weed management. Due to the continuing development of chemical resistance in agriculture, discovery of new herbicides is an important research objective. Natural product based herbicides with low mammalian and environmental toxicity will help guarantee food safety and sustainability of U.S. and Chinese agriculture.