OCTANAL

    Explanation

         The biological data on octanal were 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 bw was established (FAO/WHO, 1967;
    FAO/WHO, 1968).

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

    BIOCHEMICAL DATA

    BIOCHEMICAL ASPECTS

         The unsubstituted aliphatic aldehydes are readily oxidized in the
    body to the corresponding fatty acids (Williams, 1959; F.E.M.A.,
    1974). Short and medium chain length fatty acids, including octanoic
    acid, are oxidized primarily to CO2 and water (Scheig & Klatskin,
    1968). Such oxidation takes place rapidly both in the liver and other
    tissues (Geyer et al., 1951; Valdivieso & Schwabe, 1964). The series
    of reactions involved in the degradation of the fatty acid chain have
    been fully described (Deuel, 1957; F.E.M.A., 1974).

    TOXICOLOGICAL STUDIES

    Acute toxicity

                                                               

                                 LD50
    Animal         Route         ml/kg bw       References
                                                               

    Rat            oral          5.63           Opdyke, 1973

    Rabbit         dermal        6.35           Opdyke, 1973
                                                               

    Short-term studies

         In a 12-week feeding study on groups of 12 male and 12 female
    weanling rats using a blend of six aliphatic aldehydes, providing an
    estimated daily intake for octanal of 13 mg/kg bw (with a total intake
    for the blend of 112 mg/kg), no adverse effects were observed in
    appearance, behaviour, growth, food intake, efficiency of food
    utilization, presence of sugar or albumin in the urine, blood
    haemoglobin, liver and kidney weights, or gross pathology (Oser,
    1967).

    Long-term studies

    None available.

    Comments

         Octanal showed no adverse effects in the one available subchronic
    study.

         The evaluation of octanal is based on the presumed in vivo
    oxidation to the corresponding acid.

         The evaluation of octanal is based on a short-term study, assumed
    metabolic fate, and analogy with several structurally related esters,
    alcohols, aldehydes and acids, which display consistent biological
    properties over a wide range in the homologous series.

         The previous conditional ADI was changed into a temporary ADI.

    EVALUATION

    Level causing no toxicological effect

    Rat: 13 mg/kg bw.

    Estimate of temporary acceptable daily intake for man (ADI)

    0-0.06 mg/kg bw.

    FURTHER WORK OR INFORMATION

    Required by 1981.

         Adequate metabolic studies in several species.

    REFERENCES

    Aurousseau, B. et al. (1972) Energy and nitrogen utilization of diets
         containing caprylic, lauric, and myristic acids by growing rats,
         Effect of intake level, Ann. Biol. anim., 12(2), 263-280

    Deuel, H. J. jr (1957) The lipids, their chemistry and biochemistry.
         Chapter III in Biochemistry, Biosynthesis, Oxidation, Metabolism
         and Nutritional Value, New York, Interscience Publishers Inc.

    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. (1974) Scientific literature review of aliphatic primary
         alcohols, aldehydes, esters, and acids in flavor usage.
         Published by the National Information Services under contract
         with the Food and Drug Administration

    Geyer, R. P. et al. (1951a) Extrahepatic lipid oxidation by the rat,
         Fed. Proc., 10(1), 188-189

    Opdyke, D. L. J. (1973) Fragrance raw materials monographs, Food
         Cosmet. Toxicol., 11, 113-114

    Oser, B. L. (1967) Unpublished report

    Scheig, R. & Klatskin, G. (1968a) Hepatic metabolism of 2-Cl4 octanoic
         and 1-Cl4 Palmitic acids. In: 40th fall meeting program of the
         American Oil Chemists' Society: Symposium on medium chain
         triglycerides, 2-5 October 1966, J. Am. Oil Chem. Soc.,
         45(1), 31-33

    Valdivieso, V. D. & Schwabe, A. D. (1964) Effect of exclusion of
         hepatic circulation on oxidation of octanoic acid in the rat,
         Proc. Soc. Exptl. Biol. Med., 116(2), 290-292

    Williams, R. T. (1959) Detoxication mechanisms, The metabolism and
         detoxication of drugs, toxic substances and other compounds,
         London, Chapman & Hall Ltd, 2nd ed.
    

    See Also:
       Toxicological Abbreviations
       Octanal (FAO Nutrition Meetings Report Series 44a)
       OCTANAL (JECFA Evaluation)