Identification of Herbicidal Compound Glycine Betaine from Tree of Heaven (Ailantus altissima Swingle)

Misun  Yun1   Jung Sup  Choi2   NamKyu  Cho 3   Sang-sub  Han4   Songmun  Kim1,*   

1School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon 24341, Korea
2Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
3Moghu Reaserch Center Ltd., Daejeon 34115, Korea
4Department of Forest Environment Science, College of Agriculture and Life Science, Jeonbuk National University, Jeonju 54896, Korea

Abstract

Objective of this study is to discover new herbicide parent mother compound(s) from native plants in Korea. The leaves of Ailanthus altissima Swingle were collected in Jeonju, Jeollabuk-do in 1995. The shade dried and powdered plant samples were extracted with methanol (MeOH). The methanol extract of A. altissima was subjected to in vitro seed bioassay on rapeseed (Brassica napus L.). The results indicated that the methanol extract significantly inhibited the germination of rapeseed with the GR50 (growth retardation 50%) value of 739 μg g-1. In order to isolate the bioactive substances that inhibit plant growth, the MeOH extract was sequentially fractionated with hexane, dichloromethane, ethyl acetate, butanol, and H2O. Among them, the EtOAc fraction showed the lowest GR50 value (561 μg g-1) than other fractions. The EtOAc fraction was further fractionated on column chromatography, which showed 5 fractions (EAA-EAE) with good plant growth inhibitory effect. In these, the EAC fraction showed the highest inhibitory effect (GR50 at 50 μg g-1). The gas chromatography and mass spectrometry analysis of EAC fraction revealed that molecular ion (M+) was m/z 117 and fragment ions were m/z 116, 100, 72, and 58. Based on the results obtained from GC-MS, 1H-NMR, and 13C-NMR analyses, the EAC fraction was identified as 1-carboxy-N,N,N-trimethyl, and its common name was glycine betaine. The seed bioassay of glycine betain results revealed that the GR50 value was 91 μg g-1, which was comparable with the GR50 value of the EAC fraction of A. altissima.

Figures & Tables

Fig. 1. Grwoth retardation curve of L. seedlings by treatment of the MeOH extract of Swinggle experiment. The regression formula based on the experimental data is y=2E-06x-0.0226x+89.099 and the calculated growth retardation 50% (GR) value of MeOH extracts of Swinggle to L. is 2,132 μg g-1. Date, means and Swinggle.