Structure Identification of an Acaricidal Active Ingredient From Green Walnuts Husks (Juglans regia)
Most plants could produce bioactive substances including alkaloids, flavonoids, terpenes and relative materials, which are poisonous or have antifeedant effect to herbivorous animals, including some insects. Some well-known pesticides originated from plant bioactive substances have been successfully identified and used, for example, the azadirachtin from neem, nicotine from tobacco, rotenone and deguelin from derris, and pyrethrin from pyrethrum. Its necessary to extract, separate and identify single compounds from plants with biological activity in order to use them directly on crop protection, or to use them as model to synthesize new pesticides without pollution. The green walnut husks contain many kinds of bioactive compounds. By now more than 16 kinds of important components have been found, including tannin, walnuts quinone (juglone), nuts Glycoside (juglanin), α-hydride quinone walnuts (α-Hydrojuglone) and β-hydride quinone walnuts (β-Hydrojuglone), naphthalene Qian (naphthazarin), gallic acid, walnuts drunk alkaloids (C10H8O3), 1, 4-naphthoquinone and some pigments. We have found that the petroleum-ether extracts of walnut have strong acaricidal activity, but the major compounds of the extracts and the structures of the compounds are unclear. Here we isolated one bioactive fraction G7 from the green walnut husks which have better acaricidal activity and identified the structure of the compound. The fraction was found to be a signal compound by two-dimensional thin-layer chromatography and High Performance Liquid Chromatography (HPLC), and the HPLC analysis also showed the absorbance peak at 222nm wavelength of G7 was the same as that of methyl palmitate reported by Moshitzky and the molecular weight of G7 was identified by mass spectrometry, and the result showed the G7 have the same MW as methyl palmitate. Furthermore the molecular structure was analyzed with the nuclear magnetic resonance spectroscopy and the infrared spectrum. It was found that G7 had the same molecular formula as methyl palmitate C17H34O2. Then, G7 was compared with methyl palmitate through thin-layer chromatography and HPLC, and it was found that G7 had the same Rf value 0.6 on TLC and the same absorbance peak at 222nm wavelength in HPLC as methyl palmitate. So the G7 fraction was confirmed to be the methyl palmitate.
green walnuts husks acaricidal active methyl palmitate structure identification
WANG You-Nian SHI Guang-Lu REN Jian-Jun ZHAO Lei DU Juan LIU Yu-Bo ZHAO LI-Lin
Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture P.R.China Beijing University Department of Biotechnology Beijing University of Agriculture Beijing,China State Key Laboratory of Integrated Maagement of Pest Insects & RodentsInstitute of Zoology,Chinese A
国际会议
北京
英文
1-4
2009-06-11（万方平台首次上网日期，不代表论文的发表时间）