Eltayeb, Elsadig , Al Barwani, Fatma , Al Sabri, Iman , Khan, Tabisam .
Analysis of Phytoalexins by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) following Induction in Nerium oleander.
Some plants are able to defend themselves by accumulating newly synthesized antifungal compounds called phytoalexins. As part of a larger project, screening Omani plants for phytoalexin induction, we have looked at phytoalexin induction in Nerium oleander, of the family apocynaceae. Parts of this plant have been used as therapeutic agents against leprosy, eye and skin diseases. N. oleander leaves play a role as anticancer and antibacterial. In vitro antimicrobial activity of N. oleander roots' bark and leaf extracts was studied against bacteria e.g., Bacillus subtilis. Chemical induction of phytoalexins was achieved using CuCl2 solution, and UV induction with wavelength 254 nm. Extracted phytoalexins were detected using (TLC)-Cladosporium bioassay followed by large scale preparative TLC. Eluted antifungal compounds were purified by TLC and identified by HPLC-MS. We have identified phytoalexins as well as other constitutive antifungal compounds in Nerium oleander. Treated N. oleander leaves and solutions accumulated both Pisatin and Genistin which were not detected in control leaves and solutions but not in controls, this indicates that these two isoflavonoids are phytoalexins; induced antifungal compound in N. oleander. Another isoflavonoid, Pentamethoxyflavone was found as constitutive antifungal compound, detected in control solution and in treated leaves. The terpenoids Amyrin and Ursolic acid or Oleanolic acid were detected in treated as well control leaves and solutions as constitutive antifungal compounds. Genistein is a common phytoalexin in legumes but this is the first report of this compound in apocynaceae. In plants, genistein exhibits antifungal activity while in human, genistein has been reported to acts as phytoestrogen, cancer chemo-preventive agent.
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1 - Sultan Qaboos University, Department of Biology, College of Science, P.O.Box 36, Muscat, PC 123, Oman
2 - Sultan Qaboos University, Department of Biology
3 - Sultan Qaboos University, Central Analytical and Applied Research Facility
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM