4-Hydroxybenzyl alcohol from Sinapis alba mustard seed meal extract for control of liverwort (Marchantia polymorpha)

Abstract

Sinapis alba mustard seed meal extract is a by-product of mustard oil extraction, that is used for biodiesel and renewable jet fuel production. Recently, S. alba mustard seed meal has been shown to have herbicidal activity for a range of problematic weeds. The objectives of the present research were 1) to optimize the preparation of S. alba mustard seed meal extract; 2) to explore the applicability of S. alba mustard seed meal extract for control of liverwort, a common pest in ornamental plants greenhouses; and 3) to identify the major herbicidal compound(s) in these extracts. For extraction, methanol content in aqueous solution was optimized between 0% and 100%. Extracts prepared with 0–30% aqueous methanol provided 98–100% control of liverwort after single application and prevented liverwort plants from recovering. Extracts prepared using sequential extraction with 60% methanol provided an additional benefit of low particulate solutions. The efficiency of the produced S. alba mustard seed meal extract was comparable to two commercially available herbicides labeled for liverwort control under greenhouse conditions. Composition of S. alba mustard seed meal extracts was analyzed by high-performance liquid chromatography mass spectrometry and ion chromatography. 4-Hydroxybenzyl alcohol was identified as a main herbicidal compound based on the analysis and using commercially available reference solution. To the best of our knowledge, this is the first report of 4-hydroxybenzyl alcohol herbicidal activity toward nonvascular plants. The high concentrations of 4-hydroxybenzyl alcohol naturally produced from S. alba mustard seed meal, makes it a potential herbicide feedstock material.