Alpha-Ionone was reviewed at the eleventh meeting of the Joint
    FAO/WHO Expert Committee on Food Additives, specifications were
    prepared, and a conditional acceptable daily intake for man (ADI) of
    0-0.1 mg/kg body weight was established (FAO/WHO, 1967; FAO/WHO,

         Since this previous review, new data have become available and
    are included in this monograph.



         Following oral administration, alpha-ionone undergoes biochemical
    oxidation in the rabbit and is excreted in the urine, principally, as
    5-oxo-cis-tetrahydro-ionone, indicating in vivo oxidation of carbon
    atom 5 in the ionone structure (Prelog & Wursch, 1951).


    Acute toxicity


                             LD50               References
    Animal     Route    mg/kg body weight

    Mouse      i.p.           2 277           (Sporn et al., 1963)
    Mouse      s.c.           2 605           (Wenzel & Ross, 1957)
    Rat        Oral           4 590a          (Jenner et al., 1964)

    a  Test material identified as 60% alpha-ionone and 40% -ionone.

    Short-term studies


         Groups of 10 male and 10 female rats were maintained for 17 weeks
    on diets containing "Ionone Standard" (60% alpha-ionone and 40%
    -ionone) at levels of 0, 1000, 2500, and 10 000 ppm (approximately
    equivalent to 50, 125, and 500 mg/kg body weight). No adverse effects
    were observed on growth, appearance, food intake, haematology, final
    body weight, organ weights or macroscopic appearance of organs of rats
    on all levels of "Ionone Standard" in the diet. However, microscopic
    examination revealed swelling of the hepatic parenchymal cells at all
    dietary levels. This "swelling of parenchymal cells" was dose-

    dependent, being "slight to moderate" at the highest dietary level
    (10 000 ppm), "slight" at the intermediate level (2500 ppm), and "very
    slight" at the lowest level (1000 ppm) (Hagan et al., 1967).


         The evaluation of alpha-ionone is based on the previous
    evaluation of the eleventh Expert Committee. The previous conditional
    ADI was converted to a temporary ADI.


    Estimate of temporary acceptable daily intake for man

    0-0.05 mg/kg bw.


    Required by 1980.

         (1) An additional short-term toxicity study (90 days) on a well-
    characterized sample of alpha-ionone with one dietary level comparable
    to those at which minimal effects were previously observed.

         (2) Metabolic studies.


    FAO/WHO (1967) Toxicological evaluation of some flavouring substances
         and non-nutritive sweetening agents, FAO Nutrition Meetings
         Report, Series No. 44a; WHO/Food Add./68.33

    FAO/WHO (1968) Specifications for the identity and purity of food
         additives and their toxicological evaluation: some flavouring
         substances and non-nutritive sweetening agents, Eleventh Report
         of the Joint FAO/WHO Expert Committee on Food Additives, FAO
         Nutrition Meetings Report Series No. 44, Wld Hlth Org. techn.
         Rep. Ser. No. 383

    F.E.M.A. (1976) Scientific literature review of alicyclic compounds
         of carbon, hydrogen and oxygen in flavour usage, published by the
         National Information Services under contract with the Food and
         Drug Administration

    Hagan, E. C. et al. (1967) Food flavourings and compounds of related
         structure: II. Subacute and chronic toxicity, Food Cosmet.
         Toxicol., 5, 141-157

    Jenner, P.M. et al. (1964) Food flavourings and compounds of related
         structure. I. Acute oral toxicity, Food Cosmet. Toxicol., 2,

    Prelog, V. & Wuersch, J. (1951) Organ extracts and urine. 21. The
         biochemical oxidation of alpha-ionone in the animal body. Helv.
         Chim. Acta, 34(3), 859-861 (in German)

    Sporn, A. et al. (1963) The toxicity of butyl acetate, methyl naphthyl
         ketone, and ionone, Igiena (Bucharest), 12(5), 437-446

    Wenzel, D. G. & Ross, C. R. (1957) Central stimulating properties of
         some terpenones, J. Am. Pharm. Assoc., 46, 77-82

    See Also:
       Toxicological Abbreviations
       Ionone, alpha- (FAO Nutrition Meetings Report Series 44a)