Ultraviolet-induced amides and casbene diterpenoids from rice leaves

作者：Horie Kiyotaka; Sakai Kengo; Okugi Misaki; Toshima Hiroaki; Hasegawa Morifumi^*

来源：Phytochemistry Letters, 2016, 15: 57-62.

DOI：10.1016/j.phytol.2015.11.009

• Mass spectrometry
• Phytoalexin
• Rice

To discover new phytoalexins, an 80% MeOH extract of UV-irradiated rice leaves was analyzed using LC-MS, resulting in the detection of three unidentified compounds. We isolated the compounds from the UV-irradiated rice leaves using chromatographic methods and identified the compounds as N-benzoyltyramine (1), and two casbene-type diterpenes, 5-dihydro-ent-10-oxodepresssin (2) and 5-deoxo-ent-10-oxodepressin (3), using spectroscopic methods. Additionally, we compared the accumulation levels of major UV-inducible compounds in response to Magnaporthe oryzae inoculation and the antifungal activities of the compounds against M. oryzae colony growth. Although 1-3 showed negligible antifungal activity against M. oryzae, the compounds significantly accumulated in M. oryzaeinoculated rice leaves. Furthermore, we confirmed that N-benzoyltryptamine and N-cinnamoyltryptamine also accumulated after M. oryzae inoculation and have relatively high antifungal activity against M. oryzae to the same extent as phytocassanes. These results strongly support the hypothesis that the two amides are rice phytoalexins.

• 出版日期2016-3