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    CURCUMIN

    First draft prepared by
    Dr. C.B. Johnson and Dr. A.N. Mattia
    Division of Health Effects Evaluation
    Office of Premarket Approval
    Center for Food Safety and Applied Nutrition
    Food and Drug Administration
    Washington, DC, USA

    Explanation
    Biological data
         Biochemical aspects
    Toxicological studies
         Acute toxicity studies
         Short-term toxicity studies
         Long-term toxicity/carcinogenicity studies
         Reproductive toxicity studies
         Special studies on teratogenicity
         Special studies on genotoxicity
         Special studies on anti-mutagenicity
         Special studies on pharmacology
         Observations in humans
    Comments
    Evaluation
    References

    1.  EXPLANATION

         Turmeric and curcumin (the main colouring component of turmeric)
    were considered at the thirteenth, eighteenth, twenty-second,
    twenty-fourth, twenty-sixth, thirtieth, and thirty-fifth meetings of
    the Committee (Annex 1, references 19, 35, 47, 53, 59, 73, and 88).

         At the eighteenth meeting, a temporary ADI of 0-0.1 mg/kg bw was
    established for curcumin based on the ADI for turmeric and an assumed
    average level of 3% curcumin in turmeric (Annex 1, reference 35). The
    temporary ADI for curcumin was extended after the twenty-second,
    twenty-fourth, twenty-sixth, and thirtieth meetings following the
    evaluation of new data (Annex 1, references 47, 53, 59, and 73).

         The temporary ADI of 0-0.1 mg/kg bw for curcumin was again
    extended at the thirty-fifth and thirty-ninth meetings (Annex 1,
    references 88 and 101). At the latter meeting the Committee requested
    the results of carcinogenicity studies in mice and rats given tumeric
    oleoresin (which were known to have been completed) and the results of
    a reproductive toxicity/teratogenicity study with curcumin.

         The results of the carcinogenicity studies, together with new
    biochemical and genotoxicity data, were available to the Committee
    for evaluation. Information previously requested on the reproductive
    effects of curcumin was not provided, although a published
    reproductive toxicity study on turmeric was available.

         Relevant information from the previous monographs and information
    received since the previous evaluation are summarized and discussed in
    the following monograph addendum.

    2.  BIOLOGICAL DATA

    2.1  Biochemical aspects

         Male Swiss mice were initially treated with carbon tetrachloride,
    paraquat or cyclophosphamide (compounds known to induce free radicals)
    and then given daily gavage doses of 250 mg/kg bw curcumin (98% pure)
    suspended in 1% gum acacia for 14 days. Mice fed curcumin showed
    significant decreases in lipid peroxidation in liver, lung, kidney and
    brain in comparison to control mice that did not receive curcumin,
    regardless of the nature of the free radical inducer (Soudamini
     et al., 1992).

         Curcumin at a level of 0.1% in the diet was reported to lower
    serum and liver cholesterol in rats fed 1% cholesterol-containing
    diets for 7 weeks (Rao  et al., 1970).

         Triton-induced hyperlipidemic rats (inbred colony, strain not
    identified) were fed 3000 mg/kg bw of an ethanolic extract (50% v/v)
    of defatted  Curcuma longa and the serum lipid profile was determined
    from tail vein blood taken every 6 h for 48 h after feeding. Rats fed
    the  Curcuma extract had lower levels of serum cholesterol and
    triglycerides and elevated high density lipoprotein (HDL)-cholesterol
    compared to controls (n=10 rats/group). It appeared that the  Curcuma
    extract was fed repeatedly every 6 h; however, methodological details
    were not clearly presented (Dixit  et al., 1988).

         A series of experiments were conducted to determine the effect of
    powdered  Curcuma xanthorrhiza Roxb.(a plant from the same genus as
     Curcuma longa L.) and curcuminoids from  Curcuma xanthorrhiza
    (consisting mainly of curcumin and desmethoxycurcumin) on lipid
    metabolism in normal male Sprague-Dawley rats and in a special strain
    of exogenous hyper-cholesterolemic (ExHC) rats.

         In the first experiment, 4% powdered  Curcuma xanthorrhiza was
    fed to normal rats in a cholesterol-free diet for 34 days. In treated
    rats, the serum lipid profile was affected in the following manner
    compared to controls: levels of triglycerides and phospholipids were
    decreased and HDL cholesterol and apolipoprotein A-I (Apo A-I)
    increased. In the liver, the lipid profile was affected as follows
    compared to controls: levels of cholesterol and triglycerides were
    decreased and phospholipids increased. Additionally, the activity of
    liver fatty acid synthase, but not glycerophosphate dehydrogenase, was
    decreased.

         In the second experiment, 4% powdered  Curcuma xanthorrhiza was
    fed to ExHC rats in a diet with 10% olive oil and 1% cholesterol for
    21 days. Analysis of serum lipids showed that the test material
    elevated cholesterol level, HDL-cholesterol, triglycerides and Apo A-I
    compared to controls, while in the liver, it decreased cholesterol and
    triglycerides but elevated phospholipids levels.

         In the third experiment, 0.2% curcuminoid extract was fed to ExHC
    rats in a cholesterol-free diet for 28 days and in a cholesterol-
    containing diet (both with 10% olive oil) for 14 days. The curcuminoid
    extract did not influence lipid parameters in this experiment
    (Yasni  et al., 1993).

         Long-term studies in rats reported discoloration of the fur in
    curcumin-exposed rats and mice and discolored faeces in rats receiving
    50 000 mg/kg curcumin (equal to 2 g/kg bw/day) indicating that
    significant absorption and bioaccumulation of curcumin occurs at the
    high doses employed in the studies (NTP, 1993). This is in agreement
    with absorption studies previously reviewed by JECFA (Annex 1,
    reference 60) which indicated that after a single high oral dose of
    400 mg/rat (equal to 2 g/kg bw) of [3H]-labeled curcumin
    administered to rats, only 60% of the dose was excreted by 12 days.
    However, at the lower doses of 10 and 80 mg/rat (equal to 0.05 and
    0.4 g/kg bw), most of the label was excreted within 72 h. The
    percentage of dose absorbed (60-66%) was constant regardless of the
    dose administered (Ravindranath & Chandrasekhara, 1982). In rats
    receiving a single oral dose of 0.6 mg curcumin, 89% of the dose was
    excreted in the faeces and 6% in the urine within 72 h
    (Holder,  et al., 1978).

          In vitro studies indicated that curcumin was rapidly
    metabolized when incubated with hepatocytes or microsomal suspensions
    (Wahlstrom & Blennow, 1978). Metabolism also appeared to be rapid
     in vivo. When labelled curcumin was administered to cannulated rats
    by i.v. injection, 85% of the dose was recovered in the bile by 6 h.
    Major metabolites included the glucuronides of tetrahydrocurcumin and
    hexahydrocurcumin, with dihydroferulic acid and ferulic acid present
    as minor metabolites (Holder  et al., 1978).

    2.2  Toxicological studies

    2.2.1  Acute toxicity studies

         No new information.

    2.2.2  Short-term toxicity studies

         No new information.

    2.2.3  Long-term toxicity/carcinogenicity studies

    2.2.3.1  Mice

         Groups of 60 male and 60 female B6C3F1 mice were fed  ad libitum
    diets containing 0, 2000, 10 000 or 50 000 mg/kg turmeric oleoresin
    (79% 85% curcumin) for 103 weeks, equal in males/females to daily
    doses of 0, 220/320, 1520/1620 or 6000/8400 mg turmeric oleoresin/kg
    bw/day. Dose levels were based on the results of a 13-week study.

    Mice were housed one per cage and observed twice daily, 7
    days/week. Individual animal weights were recorded weekly for the
    first 13 weeks, then once every 4 weeks thereafter; food consumption
    was monitored once every 4 weeks. An interim sacrifice of 9 or 10
    randomly selected mice/group was conducted at 15 months, which
    included complete gross and microscopic evaluations, assay of a
    standard set of haematology and clinical chemistry parameters and
    weights of 7 selected organs. At termination, a complete necropsy was
    done on all animals, including both gross and microscopic evaluations.

         Survival rates were unaffected by dietary turmeric. For male
    mice, the survival ranged from 74%-86% and for female mice, from
    68%-84%. At dietary levels of turmeric oleoresin of 10 000 mg/kg
    (females only) and 50 000 mg/kg (males and females), final group mean
    body weights were significantly lower than controls: however, food
    consumption in these groups of mice was the same relative to controls.
    At 15 months, absolute and relative liver weights were elevated in
    mice of both sexes fed 10 000 and 50 000 mg/kg but returned to
    control levels at terminal sacrifice. No significant differences in
    haematological and clinical chemistry parameters were reported,
    although at 15 months alkaline phosphatase levels were elevated in
    males and females at the mid and high doses. In female mice, turmeric
    oleoresin was also associated with thyroid gland follicular cell
    hyperplasia. Table 1 summarizes significant results from the
    statistical analyses of primary tumour data which were presented in
    the original report. Under the conditions of the study these data
    showed a marginal increase of neoplasms in mice which were not
    considered to be treatment-related (NTP, 1993).

    2.2.3.2  Rats

         Groups of 60 male and 60 female F344/N rats were fed  ad libitum
    diets containing 0, 2000, 10 000 or 50 000 mg/kg turmeric oleoresin
    (79% -85% curcumin) for 103 weeks, equal in males/females to daily
    doses of 0, 80/90, 460/440 or 2000/2400 turmeric oleoresin/kg bw/day.
    The rats were housed 5/cage and observed twice daily 7 days/week.
    Individual animal weights were recorded weekly for the first 13 weeks,
    then once every 4 weeks thereafter; food consumption was monitored by
    cage once every 4 weeks. An interim sacrifice of 10 randomly selected
    rats/group was conducted at 65 weeks, which included complete gross
    and microscopic evaluations, assay of a standard set of haematology
    and clinical chemistry parameters and weights of 7 selected organs. At
    termination, a complete necropsy was done on all animals, including
    both gross and microscopic evaluations.

         No differences in survival rates between treated and control rats
    were observed. Survival rates ranged from 30%-36% for males and
    54%-68% for females. No explanation for the lower survival rate in
    males compared to females was given; survival rates in treated males
    were similar to the survival rate in male controls. Hyperactivity was
    observed at the highest dose of curcumin during some observation

    periods. The final mean group body weights of the high-dose males and
    females were slightly less than the controls despite similar food
    intake. At 15 months, relative liver weights were significantly
    elevated in females fed 10 000 and 50 000 mg/kg. At 15 months for the
    50 000 mg/kg groups, haematocrit, haemoglobin and red cells were
    significantly lower while platelet and reticulocytes (males only) were
    significantly higher.

    Table 1.  Incidence of primary tumours in individual organs in
              male and female B6C3F1 mice after dietary exposure to
              turmeric oleoresin for 103 weeks (NTP, 1993).
                                                                         

    Sex    Site           Tumour              mg/kg of feed   Incidencea
                          morphology
                                                                         

    M      Liver          Hepatocellular      0                 25/50
                          adenoma             2000              28/50
                                              10 000            35/50*
                                              50 000            30/50

    M      Liver          Hepatocellular      0                 30/50
                          carcinoma           2000              38/50
                          or adenoma          10 000            41/50*
                          (combined)          50 000            37/50

    M      Small          Adenoma or          0                 0/50
           Intestine      carcinoma           2000              3/50
                                              10 000            3/50
                                              50 000            0/50

    F      Liver          Hepatocellular      0                 7/50
                          Adenoma             2000              8/50
                                              10 000            19/51*
                                              50 000            14/50

    F      Liver          Hepatocellular      0                 13/50
                          carcinoma           2000              12/50
                          or adenoma          10 000            25/51*
                          (combined)          50000             19/50

    F      Pituitary      Adenoma             0                 0/46
           Gland (Pars                        2000              2/49
           Distalis)                          10 000            4/50
           Adenoma                            50 000            5/50*
                                                                         

    a    Incidence was adjusted for mortality
    *    Asterisks indicate significant p values (p<0.05 or 0.01) for
         paired comparisons between the control and the dosed groups.

         In the GI tract of high-dose male rats, the following
    non-neoplastic effects were reported: ulcers, hyperplasia and
    hyperkeratosis of the forestomach; ulcers, hyperplasia and
    inflammation of the caecum and colon; and sinus ectasia of the
    mesenteric lymph node. These lesions were considered likely to be
    regenerative and not neoplastic in nature. Non-neoplastic GI effects
    reported in high-dose female rats included ulcers, hyperplasia and
    inflammation of the caecum and sinus ectasia of the mesenteric lymph
    node. Neoplasms were not reported in males. In females, however,
    clitoral gland adenoma and carcinoma were reported (Table 2); however,
    the incidence of hyperplasia of the clitoral gland was similar in all
    groups of female rats. The marginal increase of clitoral gland adenoma
    was neither dose-related nor associated with a corresponding increase
    in hyperplasia (NTP, 1993).

    Table 2.  Incidence of primary tumours in individual organs (excluding
              mammary gland tumours) in female F344/N rats after dietary
              exposure to turmeric oleoresin for 104 weeksb (NTP, 1993)
                                                                        

    Site         Tumour morphology         mg/kg of feed      Incidencea
                                                                        

    Clitoral     Adenoma                   0                  5/50
    Gland                                  2000               12/48*
                                           10 000             15/47*
                                           50 000             16/49*

    Clitoral     Carcinoma                 0                  1/50
    Gland                                  2000               4/48
                                           10 000             0/47
                                           50 000             0/49

    Clitoral     Adenoma or                0                  6/50
    Gland        carcinoma (combined)      2000               16/48*
                                           10 000             15/47*
                                           50 000             16/49*
                                                                        

    a    Incidence was adjusted for mortality
    *    Asterisks indicate significant p values (p<0.05 or 0.01) for
         paired comparisons between the control and the dosed groups.
    b    No neoplasms were found in male rats.

    2.2.4  Reproductive toxicity studies

         Groups of 10 male and 20 female weaned Wistar rats were
    maintained throughout the experimental period on diets containing
    either (a) turmeric (2.5% curcumin) at 500 mg/kg bw/day or (b) an
    alcoholic extract of turmeric fed at 60 mg/kg bw/day (equivalent in
    curcumin content to a dose of 500 mg turmeric/kg bw/day). Matings were
    initiated after 12 weeks on the two test diets using 1 male per 2
    females. Lactation was permitted for 3 weeks. The first litters were
    discarded and the females were re-mated after a 2-week post-weaning
    rest. From the second litters, 10 male and 20 female rats were
    selected from each group after weaning (F1 generation), they were
    raised to maturity and then mated like the F0 parent generation; the
    matings continued until the first litters from the F2 generation
    were weaned at which time the F0 generation rats were two years old.
    Pups were weighed at birth and at 4, 12 and 21 days.

         The following indices were calculated from observations and
    records of performance: fertility index (FI), the percentage of
    matings resulting in pregnancy; gestation index (GI), the percentage
    of pregnancies resulting in the birth of live litters; viability index
    (VI), the percentage of pups born that survived for 4 days or longer;
    and the lactation index (LI), the percentage of pups alive at 4 days
    that survived the 21-day lactation period. Liver, kidney, heart,
    brain, spleen, gonads, pituitary, adrenals and thyroid were examined
    histologically.

         No differences in the FI, GI, average number of pups born alive,
    or VI were reported. In the 2nd litter of the F1 generation, LI was
    higher than control for rats fed the alcohol extract. This difference
    was statistically significant but is not likely to be of biological
    importance; no other differences in treated versus control rats were
    reported for LI. The following differences in average weight of pups
    were reported for rats fed the alcohol extract versus controls:
    decreased weight at 12 days in the 2nd litter of the F0 generation;
    and increased weight at birth in the 2nd litter of the F1 generation
    and in the 1st litter of the F2 generation. These changes in pup
    weights are not likely to be of biologically importance. No
    histological abnormalities were reported. The authors concluded that
    the consumption of turmeric and its alcoholic extract appeared safe at
    the doses tested (Bhavanishankar & Murthy, 1987).

    2.2.5  Special studies on teratogenicity

         No new information.

    2.2.6  Special studies on genotoxicity

         The results of genotoxicity studies on turmeric or curcumin are
    summarized in Tables 3 and 4.

         No mutagenic activity was demonstrated in bacteria treated with
    curcumin preparations of purity up to 85%, or of unknown purity. A
    79-85% purity preparation induced chromosomal aberrations and SCEs
     in vitro. In vivo, a curcumin preparation of unknown purity
    administered to mice by intraperitoneal injection did not induce
    micronuclei in bone marrow cells, whereas a low level of chromosomal
    aberrations was reported in the same cell population (Jain  et al.,
    1987). In another  in vivo study in mice injected J.p. with curcumin
    of unknown purity there was some evidence of SCE induction at low
    frequency above 25 mg/kg bw, while in rats fed curcumin of unknown
    purity there was equivocal evidence for the induction of chromosomal
    aberrations (Giri  et al., 1990). It was concluded that there was no
    adequate evidence for the genotoxicity of curcumin. In reaching this
    conclusion, the SCE data in particular was considered to be of little
    relevance in the evaluation, while other studies could not be reliably
    interpreted because of the impurities in the curcumin preparations
    used.

    2.2.7  Special studies on anti-mutagenicity

         In contrast to some results presented in Tables 3 and 4,
    several studies have indicated that curcumin possesses  in vitro
    anti-mutagenic activity. Using the Ames test, curcumin itself a
    non-mutagen, inhibited the mutagenic effects of chili extract and
    capsaicin (Nagabhushan & Bhide, 1986). Similarly, curcumin was
    reported to inhibit the activity of known environmental mutagens which
    require metabolic activation, although it was reported to be
    ineffective against mutagens which do not require metabolic activation
    (Nagabhushan  et al., 1987; Nagabhushan & Bhide, 1987).

         There was a significant time-dependent reduction in the number of
    radiation-induced micronucleated polychromatic erythrocytes in mice
    given single gavage doses of 5, 10 or 20 mg/kg bw curcumin in peanut
    oil (Abraham  et al., 1993).

         In another  in vivo study to determine the anti-mutagenic
    effects of turmeric, rats were fed turmeric for up to 3 months at
    dietary levels of 0.1, 0.5, 1, 5, or 10%, then given single
    intraperitoneal injections of 5 mg benzo[a]pyrene (BP) or 1 mg of
    3-methylcholanthrene (3-MC). After injecting BP or 3-MC, 24-h urine
    samples were collected and assayed for mutagenic activity by
    determining the frequency of histidine revertants with  Salmonella
     typhimurium strains TA98 and TA100, with and without S-9 metabolic
    activation. The number of revertants was reduced in urine samples from
    rats fed turmeric at dietary levels of 0.5% and higher. Feeding
    turmeric for one month appeared as effective as feeding for longer
    time periods (Polasa  et al., 1991).

        Table 3.  Summary of recently published data on the mutagenic potential of turmeric or
              curcumin in several strains of Salmonella typhimurium (i.e., the Ames assay).
                                                                                              

    Test       Test       Test Material     Dose                 Result     Reference
    System     Strain                       (g/plate)
                                                                                              

    Amesa      TA100      3 TLC curcumin    60.2                 -/-        Nagabhushan &
               TA98       components        125                  -/-        Bhide, 1986
                                            250                  -/-
                                            500                  -/-

    Amesa      TA100      turmeric          (fresh)                         Nagabhushan &
               TA98       extract           360                  -/-        Bhide, 1986
               TA1535     with 40%          (dried)
               TA1538     curcumin          250                  -/-
                                            (pyrolyzed) 200
                                                                 -/-

    Amesa,b    TA100      turmeric          50                   -/-        Shah & Netrawali,
               TA98       extract           100                  -/-        1988
               TA97a      with 33-35%       200                  -/-
                          curcumin

    Ames       TA1535     turmericc         50                   +weak      Sivaswamy et al.,
               TA1537                       100                  -          1991
               TA1538                       100                  -

    Amesa      TA100      turmeric          5 doses up to        -/-        NTP, 1993
               TA1535     ole-oresin        333 g/plate         -/-
               TA1537     containing        (higher doses        -/-
               TA98       79%-85%           were toxic)          -/-
                          curcumin
                                                                                              

    a     activation with and without rat liver S9
    b     activation with rat caecal microorganisms
    c     estimated curcumin content of 3% (actual not specified)
        2.2.8  Special studies on pharmacology

         Recent reviews indicate that curcumin has a broad spectrum of
    pharmacological activity (Ammon & Wahl, 1991; Srimal, 1987). Some
    studies which appeared in the literature following the 1986 JECFA
    evaluation (Annex 1, reference 73) are briefly summarized below to
    indicate the range of activities reported, however, a comprehensive
    review of all of the published literature was not undertaken.

        Table 4.  Summary of recently published non-microbial genetic toxicological
              studies with curcumin or turmeric
                                                                                              

    Test System         Test Object     Test          Dose         Result     Reference
                                        Material
                                                                                              

    Micronucleus        mouse           turmeric      100, iph     -          Jain et al.,
                        bone marrow     extracta      200          -          1987
                                                      500          -

    Chromosome          mouse           turmeric      100, iph     2.00b      Jain et al.,
    aberration          bone marrow     extracta      200          1.73       1987
                                                      500          6.22

    Sister chromatid    mouse           curcumin,     5, iph       -          Giri et al.,
    exchange            bone marrow     at 24h        10           -          1990
                                                      25           +
                                                      50           +
                                                      100          +
                                                      200          +

    Chromosome          rat             curcumin                   months     Giri et al.,
    aberrationc         bone marrow     chronic                    3 6 9      1990
                                        dietary       100i         - - -
                                        exposure      200          - - -
                                                      500          - - +
                                                      1000         - - +

    Sister chromatid    CHO cells       turmeric      0.16 g/ml    +, -      NTP, 1993
    exchanged,e                         oleoresin     0.50          -, -
                                        with          1.60          -, +
                                        79%-85%       5.00          -, +
                                        curcumin
                                                                                              

    Table 4. (cont'd).
                                                                                              

    Test System         Test Object     Test          Dose          Result    Reference
                                        Material
                                                                                              

    Chromosome          CHO cells       turmeric      5 g/ml       -, -      NTP, 1993
    aberrationd,g                       oleoresin     10            -, -
                                        with          15            +, +
                                        79%-85%
                                        curcumin
                                                                                              

    a     actual curcumin content not specified: typically, the curcumin content of
          turmeric is approximately 3%
    b     of aberrant cells (negative and positive controls produced 0.5 and 12.8%
          responses, respectively)
    c     gaps not included
    d     two trials
    e     with S9 metabolic activation
    f     negative results were obtained in a single trial with S9 metabolic
          activation up to 10/g/ml
    g     estimated curcumin content of 3% (actual not specified)
    h     doses in mg/kg bw
    i     doses in mg/kg of feed
    
    2.2.8.1  Anti-tumour effects

         Topical application of curcumin inhibited 12- O-tetradecanoyl-
    phorbol-13-acetate (TPA)-induced epidermal ornithine decarboxylase
    activity, epidermal DNA synthesis, and skin tumour promotion in female
    mice initiated with 7,12-dimethyl-benz[a]anthracene (DMBA)
    (Huang  et al., 1988).

         In another similar study, mice were treated with 3 dose levels of
    topical curcumin and with TPA (5 nmol) twice weekly for 19 weeks
    following tumour initiation with DMBA. At 1, 3, and 10/mol, curcumin
    inhibited the number of tumours by 39, 77 and 98%, respectively,
    indicating a marked inhibitory effect on tumour promotion (Conney
     et al., 1991). This anti-tumour effect of curcumin is supported in
    another study of skin carcinogenesis in mice by Soudamini & Kuttan
    (1989).

         A DMBA-initiation/TPA-promotion organ culture model was used to
    demonstrate an anti-initiator effect of 10-6 M curcumin on mammary
    lesions induced in cultured mouse mammary glands. Under the conditions
    of the model, areas of alveolar growth that develop during incubation
    with the carcinogen and certain growth promoting hormones are termed
    mammary lesions if the growths do not regress after withdrawal of the
    hormones (except insulin) (Mehta & Moon, 1991).

         The anticarcinogenic effects of oral and topically applied
    curcuminoids (i.e. curcumin I and curcumin III prepared via
    chromatographic separation of an alcoholic extract of powdered
    turmeric) on different stages in the development of cancer in mice and
    rats was discussed and it was concluded that curcuminoids inhibit
    cancer at various stages including initiation, promotion and
    progression (Nagabhushan & Bhide, 1992).

         Commercial grade curcumin (77% curcumin, 17% demethoxycurcumin
    and 3% bisdemethoxycurcumin) was fed to different strains of 6-week
    old mice (14-46/group) for variable time periods (up to 24-27 weeks)
    to determine its effects on BP-induced forestomach tumorigenesis,
    N-ethyl-N'-nitro-N-nitroso-guanidine-induced duodenal tumorigenesis
    and azoxymethane-induced colon tumorigenesis. In addition, a single
    group of azoxymethane-treated mice was fed 2% pure curcumin (> 98%
    pure). Mice were fed curcumin at levels up to 4% during one of the
    following periods of the study: (a) during the initiation phase of
    tumorigenesis (i.e. 2 weeks before and 1 week after the carcinogen was
    given); (b) during the post-initiation phase (i.e. beginning 1 week
    after the carcinogen was given and continuing until the study was
    terminated); and (c) during both the initiation and post-initiation
    phases of tumorigenesis.

         In female A/J mice receiving dietary curcumin (0.5-2%), the
    incidence of tumours (papillomas and squamous cell carcinomas) of the
    forestomach were significantly decreased (51%-67%) during the
    initiation or post-initiation phases and tumour size was reduced. In
    male C57BL/6 mice, curcumin at a level of 0.5% in the diet
    significantly reduced the number of adenomas and the total number of
    duodenal tumours per mouse (44-77%) during the post-initiation phase;
    however, the inhibition of tumorigenesis was not statistically
    significant at dietary levels of 1% and 2%. A non dose-related
    reduction in the size of duodenal adenomas and a trend toward
    increased duodenal adenocarcinoma size was observed.

         Curcumin during the initiation or post-initiation phase (0.5-2%
    dietary level), or during both phases (0.5-4% dietary level)
    significantly reduced the number and size of colon tumours in CF-1
    female mice. Similar to the effects of curcumin on tumour incidence
    and size, the percentage of mice with tumours was reduced in groups
    fed curcumin. Dietary commercial grade curcumin also decreased the
    acute lethal effects of azoxymethane, but pure curcumin did not

    (possibly due to reduced solubility and bioavailability of the pure
    compound). The authors noted that 0.5% curcumin was as effective as
    higher levels in inhibiting chemically-induced tumorigenesis in the
    gastrointestinal tract of mice (Huang  et al., 1994).

         Comparable anti-tumour effects were observed in animal studies
    with turmeric. A 1% dietary turmeric inhibited the formation of
    BP-induced forestomach tumours in female Swiss mice by 58% and lowered
    the incidence of spontaneous mammary tumours in C3H Jax mice by 60%
    (Nagabhushan & Bhide, 1987).

         In a 13-month oral study in hamsters, the inhibitory effects of
    betel-leaf ( Piper betel L.) extract, -carotene and alpha-tocopherol
    in drinking-water on methyl(acetoxy-methyl)-nitrosamine-induced oral
    carcinogenesis were enhanced when 5% turmeric was added to the diet
    (the antioxidants, -carotene and alpha-tocopherol, are components of
    betel-leaf extract). Curiously, the combination of betel-leaf extract
    with turmeric was apparently toxic and decreased survival in hamsters
    receiving the combination in this study (Azuine & Bhide, 1992).

         These data describing anti-tumour effects of curcumin and
    turmeric support previous results which indicated that turmeric
    extract and curcumin (which are cytotoxic to normal human lymphocytes,
    leukemic lymphocytes and Dalton's lymphoma cells  in vitro) reduced
    tumour formation in mice injected intraperitoneally with Dalton's
    lymphoma cells (Kuttan  et al., 1985). The precise mechanism by which
    curcumin exhibits its anti-tumour effect is unknown, although
    inhibition of arachidonic acid metabolism (Huang  et al., 1988)
    and/or an antioxidant effect (Kunchandy & Rao, 1990) may be involved.

    2.2.8.2  Anti-inflammatory effects

         Topical curcumin and related derivatives are reported to inhibit
    TPA-and arachidonic acid-induced inflammation in mouse epidermis using
    the ear edema test (Huang  et al., 1991b; Conney  et al., 1991).
    These effects parallel the ability of these compounds to inhibit
    lipoxygenase and cyclooxygenase; thus, Huang  et al. (1991b)
    suggested that inhibition of arachidonic acid metabolism is
    responsible for curcumin's ability to inhibit inflammation as well as
    tumour promotion in mouse skin (Huang  et al., 1988). However, the
    oxygen radical scavenging activity of curcumin has also been
    implicated in its anti-inflammatory effects (Kunchandy & Rao, 1990).
    These effects were investigated at the molecular level where curcumin
    has been shown to have an inhibitory effect on phorbol ester-induced
    protooncogene activity in mouse fibroblasts (Huang  et al, 1991a).

    2.2.8.3  Anti-ulcer effects

         An ethanolic extract of turmeric had significant anti-ulcer,
    anti-secretory and cytoprotective activity in rats subjected to a
    variety of ulcerogenic stresses and cytodestructive agents
    (Rafatullah  et al., 1990).

    2.2.8.4  Anti-hepatotoxic effects

         In hepatocytes from 3-methylcholanthrene-induced rats, curcumin
    was reported to be protective against paracetamol-induced lipid
    peroxidation, but not against cell death or glutathione depletion
    (Donatus  et al., 1990).

    2.2.8.5  Immunological effects

         Ukonan A, a polysaccharide from the rhizome of  Curcuma
     longa L., has been reported to have phagocytic, anti-complementary
    and mitogenic activities (Gonda  et al., 1992).

    2.2.8.6  Phototoxicity

         Phototoxicity resulted in bacterial test systems when curcumin
    was irradiated with visible light (Tonnesen  et al., 1987;
    Dahl  et al., 1989).

    2.3  Observations in humans

         The effects of 500 mg of curcumin (98% purity) administered
    orally via capsules on serum peroxides and cholesterol levels were
    compared in 10 human volunteers before and after administration for 7
    days. The volunteers were between 24 and 45 years of age and weighed
    46 to 70 kg; their sex was not reported. No adverse effects were
    reported. The data indicated significant decreases in serum lipid
    peroxides and in total cholesterol, a significant increase in
    HDL-cholesterol, and a non-significant decrease in serum triglycerides
    (Soni & Kuttan, 1992).

          Azadirachta inica ADR (Neem) and  Curcuma longa (turmeric)
    ground into a paste in a proportion of 4:1 (Neem:turmeric) was
    reported to be effective in curing 97% of 824 cases of scabies within
    3-15 days of topical application (Charles & Charles, 1992).

         One case of allergic contact dermatitis to  Curcuma longa in a
    64-year old male Indian spice worker has been reported. Although no
    quantitative estimate of exposure was provided, the worker was
    reportedly exposed to 7 different spices and worked in a dusty place
    laden with spice powders. The authors concluded that turmeric is a
    weak sensitizer and that allergic contact dermatitis to it is uncommon
    (Gob & Ng, 1987).

    3.  COMMENTS

         In a study previously evaluated by the Committee, extracts of
    turmeric reportedly affected reproduction in rats when administered by
    gavage on days 1-7 of gestation at doses of 100 or 200 mg/kg bw/day
    (Annex 1, reference 60). However, no reproductive effects were
    reported in Wistar rats fed 500 mg/kg bw/day turmeric or 60 mg/kg
    bw/day of an alcoholic extract of turmeric (providing an equivalent
    dose of curcumin) in a multigeneration reproductive toxicity study.
    Data from multigeneration reproductive and/or teratogenicity studies
    with curcumin itself (rather than turmeric) were not available.

         Of a single oral dose of 400 mg [3H]curcumin (equivalent to
    2000 mg/kg bw) administered to rats, only 60% of the radioactivity was
    excreted by 12 days. At lower doses (equivalent to 50 or 400 mg/kg bw)
    most of the dose was excreted within 72 hours.

         No genotoxicity studies with high purity curcumin were available.
    In limited studies with curcumin preparations of up to 85% purity, or
    of unknown purity, no mutagenic activity was seen in bacteria and only
    equivocal activity in assays for the induction of chromosomal
    aberrations. The Committee concluded that there was no evidence to
    show that curcumin was genotoxic.

         Long-term studies on the carcinogenic potential of turmeric
    oleoresin containing a high percentage of curcumin (79-85%) have been
    completed in mice and rats at dose levels of 2000, 10 000 or
    50 000 mg/kg in the diet, equal to 220, 1520 or 6000 mg/kg bw/day
    in mice and 80, 440 or 2000 mg/kg bw/day in rats. The authors
    noted statistically significant increases in the incidences of
    hepatocellular adenomas (mid-dose males and females), small intestinal
    carcinomas (low- and mid-dose males) and pituitary gland adenomas
    (high-dose females) in mice and clitoral gland adenomas (females) in
    rats. On the basis of the results of these studies, the Committee
    concluded that the effects were not dose-related, and that curcumin
    was not a carcinogen.

         Gastrointestinal irritation (ulcers, hyperplasia and
    inflammation) was common in male and female rats in the high-dose
    group, but was not observed in mice. The NOEL for gastrointestinal
    effects in rats was 10 000 mg/kg in the diet, equal to 440 mg/kg
    bw/day.

         After 15 months of treatment, absolute and relative liver weights
    were increased in both male and female mice in the mid- and high-dose
    groups relative to control. The NOEL for liver enlargement was
    2000 mg/kg in the diet, equal to 220 mg/kg bw/day.

         Results from studies with curcumin indicated a wide and varied
    pharmacological activity, including anti-tumour, anti-inflammatory,
    anti-ulcer, and anti-hepatotoxic effects,  in vitro immunologic
    activity and phototoxicity.

         The Committee also considered a number of new studies with
    turmeric but concluded that the test ingredient in the studies was not
    comparable in composition to curcumin used as a colour additive in
    food. For this reason, these turmeric studies could not be used in the
    evaluation of curcumin.

    4.  EVALUATION

         On the basis of the NOEL of 220 mg/kg bw/day in the
    carcinogenicity study in mice and, using a safety factor of 200, the
    Committee increased the temporary ADI to 0-1 mg/kg bw and extended it,
    pending the submission of the results of a reproductive toxicity study
    with curcumin for review in 1998. The Committee has made repeated
    requests since the eighteenth meeting in 1974 for such a study. At its
    present meeting, it reconfirmed the need for the study and reiterated
    the view that previous studies with turmeric were not relevant to the
    evaluation of curcumin. If such studies are not submitted for review
    in 1998 it is unlikely that the temporary ADI can be further extended.

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    See Also:
       Toxicological Abbreviations
       Curcumin (WHO Food Additives Series 52)
       CURCUMIN (JECFA Evaluation)