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Juglone: A Natural Herbicide ( Allelopath )

Juglone: A Natural Herbicide ( Allelopath ). Historical Profile/Toxicity? Isolation Synthesis Mechanism Characterization Recent Studies Future plans Acknowledgement. JUGLONE C 10 H 6 O 3. 1,4-Naphthalenedione, 5-hydroxy- Formula: C10H6O3 Molecular Weight: 174.15

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Juglone: A Natural Herbicide ( Allelopath )

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

  2. JUGLONEC10H6O3

  3. 1,4-Naphthalenedione, 5-hydroxy- Formula: C10H6O3 Molecular Weight: 174.15 CAS Registry Number: 481-39-0 Chemical Structure:

  4. Other Names: 1,4-Naphthoquinone, 5-hydroxy-; Akhnot; C.I. Natural Brown 7; C.I. 75500; Iuglon; Juglane; Juglon; Juglone; Nucin; Regianin; Walnut Extract; Yuglon; 5-Hydroxy-1,4-naphthoquinone; 5-Hydroxy-1,4-naphthosemiquinone; 5-Hydroxynaphthoquinone; 8-Hydroxy-1,4-naphthoquinone; Jugnlon; NCI 2323; Oil Red BS; 1,4-Naphthoquinone, 8-hydroxy-; 5-Hydroxy-1,4-naftochinon; Lawsone

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

  6. 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.

  7. 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!

  8. 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.

  9. 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.

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

  11. 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.

  12. Juglone

  13. Molecular Mass Fragments

  14. 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

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

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

  17. 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.

  18. Future Plans • To setup an experiment to test and compare the allelopathic activity of both the isolated and synthesized Juglone on earth and space tomatoes.

  19. Acknowledgements • Kelly Wentz-Hunter • Sherry Litko • __________________________ • University of St. Francis • NASA Tomato Space Program

  20. Thank you Professor Salim M. Diab Department of Natural Sciences University of St. Francis Joliet, Illinois 60435 sdiab@stfrancis.edu 2000

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