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Effect of Gallotannins Derived from Sedum takesimense on Tomato Bacterial Wilt

December 2013 , Volume 97 , Number  12
Pages  1,593 - 1,598

Thuy Thu Vu and Jin-Cheol Kim, University of Science and Technology, Biobased Chemistry Research Center, Convergence Chemistry Division, and Yong Ho Choi, Gyung Ja Choi, and Kyoung Soo Jang, Biobased Chemistry Research Center, Convergence Chemistry Division, Korea Research Institute of Chemical Technology, Daejeon 305-600, Republic of Korea; Tae Ho Choi and Tae Mi Yoon, SNTech Co., Bundang-Technopark, Bundang-gu, Seongnam 463-816, Republic of Korea; and Seon-Woo Lee, Department of Applied Biology, Dong-A University, Busan 604-714, Republic of Korea

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Accepted for publication 20 June 2013.

In the process of searching antibacterial agents from plants, we discovered that the methanol extract of Sedum takesimense showed potent antibacterial activity against Ralstonia solanacearum in vitro and in vivo. Eight antibacterial gallotannins were isolated from the aerial parts of S. takesimense and identified as gallic acid, methyl gallate, 4,6-di-O-galloylarbutin, 2,6-di-O-galloylarbutin, 2,4,6-tri-O-galloyl-glucose, 1,3,4,6-tetra-O-galloyl-β-glucose, 1,2,4,6-tetra-O-galloyl-β-glucose, and 1,2,3,6-tetra-O-galloyl-β-glucose based on electrospray ionization mass spectrometry and proton nuclear magnetic resonance spectroscopy. These gallotannins displayed broad-spectrum activity against various plant-pathogenic bacteria, and the strongest in vitro antibacterial activities of these gallotannins were against R. solanacearum minimum inhibitory concentration = 0.02 to 0.10 g/liter). Among these gallotannins, methyl gallate and 1,2,3,6-tetra-O-galloyl-β-glucose showed the strongest activities. In addition, synergistic or partial synergistic effects were observed in most combinations between major antibacterial compounds. The wettable powder formulation of the S. takesimense crude extract effectively reduced the development of tomato bacterial wilt caused by R. solanacearum under greenhouse conditions for 14 days after infection. This is the first report on the isolation of antibacterial compounds from S. takesimense. These results suggest that the extract from S. takesimense or the isolated gallotannins could be used as natural bactericides for the control of tomato bacterial wilt.

© 2013 The American Phytopathological Society