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the chemistry of juglone: a detective story

2. 3. 4. Juglone: A Natural Herbicide (Allelopath). Historical Profile/Toxicity?IsolationSynthesisMechanismCharacterizationRecent Studies Future plansAcknowledgement. 5. 6. 7. JUGLONE C10H6O3. 8. 1,4-Naphthalenedione, 5-hydroxy- Formula: C10H6O3 Molecular Weight: 174.15 CAS Registry Number: 481-39-0 Chemical Structure: .

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the chemistry of juglone: a detective story

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    1. 1 THE CHEMISTRY OF JUGLONE: A DETECTIVE STORY

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    4. 4 Juglone: A Natural Herbicide(Allelopath) Historical Profile/Toxicity? Isolation Synthesis Mechanism Characterization Recent Studies Future plans Acknowledgement

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    7. 7 JUGLONEC10H6O3

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    10. 10 Historical Profile of JugloneThe Birth of Allelopathy (1950) Toxicity of Juglone has been and continues to be an unsolved Problem!

    11. 11 1925 - Massey reported experiments showing a toxic effect of walnut bark on tomato plants. 1927 - Schneiderhan reported killing of apple trees near walnuts. 1950 - Davis reported that isolated Juglone was highly toxic when injected into alfalfa and tomato plants.

    12. 12 1940 - MacDaniels and Muenscher reported a 3-year greenhouse study showing no toxicity by Juglone on tomato plants, alfalfa, and apple trees. 1950 - USDA published a press release under the title “Test Clears Walnut Reputation.” claiming no evidence of any toxic effect by Juglone on Tomatoes. Birth of Allelopathy!

    13. 13 1951 - Brooks studied the controversy for 12 years on 218 species. He confirmed Massey’s earlier work suggesting that the toxicity appeared only when the roots were in contact with each other. Dow Chemical reported that UV light was essential for the secretion of Juglone, which explained the negative toxicity reported by MacDaniels and Muenscher in 1940.

    14. 14 1975 - An extensive study at Ithaca, New York confirmed the toxicity of Juglone with the following assertions: Antagonism between walnut and other plants has been observed. The substance responsible for this antagonism is Juglone. Root to root contact must exist for toxicity to occur.

    15. 15 Isolation of Juglone Isolation was done by extracting crushed hull with petroleum ether. Recrystallization produced orange needles with MP of 153-159 C

    16. 16 Synthesis of Juglone Sodium dichromate in water is carefully added to conc. sulfuric acid. To this slurry, add 1,5-dihydroxynaphthalene. The mixture is then heated to no more than 50C for thirty min. Crude product is recrystallized from hexane. Yellow-orange needles were produced with MP 148-153C.

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    29. 29 Juglone

    30. 30 Molecular Mass Fragments

    31. 31 Recent Studies Krajci, W. M., and Lynch, D. L. (1978). The inhibition of various micro-organisms by crude walnut hull extracts and Juglone. Microbios Letters. 4, 175-181

    32. 32 Craton, D. W., and Williams, R. D. (1980). Juglone Dermatitis: Allergy or Irritant? Indiana Academy of Science. 90: 98-102

    33. 33 Clark, A. M., Jurgens, T. A., and Hufford, C. D. (1990). Antimicrobial Activity of Juglone. Phytotherapy Research. 4, 11-14.

    34. 34 Galey, F. D., Whiteley, H. E., Goetz, T. E., Kuenstler, A. R. Davis, C. A., and Beasley V. R. (1991). Black walnut (Juglans nigra) Toxicosis: A Model for Equine Laminitis. J. Comp. Path. 104, 313-326.

    35. 35 Future Plans Test and compare the allelopathic activity of both the isolated and synthesized Juglone on Earth and Space Tomatoes.

    36. 36 Acknowledgements Kelly Wentz-Hunter Sherry Litko Kerri Banser Kristina Taylor University of St. Francis NASA Tomato Space Program

    37. 37 Thank you Professor Salim M. Diab Department of Natural Sciences University of St. Francis Joliet, Illinois 60435 sdiab@stfrancis.edu 2001

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