NTP Carcinogenesis Studies of Food Grade Geranyl Acetate (71% Geranyl Acetate, 29% Citronellyl Acetate) (CAS No. 105-87-3) in F344/N Rats and B6C3F1 Mice (Gavage Study).
Geranyl acetate (3,7-dimethyl-2,6-octadiene-1-ol acetate) is a colorless liquid prepared by fractional distillation of selected essential oils or by acetylation of geraniol. It is a natural constituent of more than 60 essential oils, including Ceylon citronella, palmarosa, lemon grass, petit grain, neroli bigarade, geranium, coriander, carrot, and sassafras. Geranyl acetate is used primarily as a component of perfumes for creams and soaps and as a flavoring ingredient. On the U.S. Food and Drug Administration's list of substances "generally recognized as safe," the Food Chemicals Codex (1972) specifies that geranyl acetate must contain at least 90% total esters. Carcinogenesis studies of food-grade geranyl acetate (containing approximately 29% citronellyl acetate) were conducted by administering the test chemical in corn oil by gavage to groups of 50 male and 50 female F344/N rats at doses of 1,000 or 2,000 mg/kg body weight and to groups of 50 male and 50 female B6C3F1 mice at doses of 500 or 1,000 mg/kg. Doses were administered five times per week for 103 weeks. Groups of 50 rats and 50 mice of each sex received corn oil by gavage on the same dosing schedule and served as vehicle controls. The cumulative toxicity of geranyl acetate in the 2-year study was indicated by the significantly shorter survival of high dose male rats (control, 34/50; low dose, 29/50; high dose, 18/50) and of high dose male mice (control, 31/50; low dose, 32/50; high dose, 0/50) and of dosed female mice (38/50; 15/50; 0/50) when compared with controls. Throughout most of the 2-year study, mean body weights of high dose rats and mice of each sex were lower than those of the controls. The occurrence of retinopathy or cataracts in the high dose male rats and low dose female rats as compared with the controls does not appear to be related to the administration of geranyl acetate but rather the proximity of the rats to fluorescent light. The incidence of retinopathy or cataracts (combined) was: males: control, 0/50, 0%; low dose, 1/50, 2%; high dose, 11/50, 22%; females: control, 1/50, 2%; low dose, 13/50, 26%; high dose, 2/50, 4%. Kidney tubular cell adenomas, an uncommon tumor type, were found in 2/50 (4%) low dose male rats. The historical incidence of male corn oil gavage control F344/N rats with kidney tumors is 1/250 (0.4%) at this laboratory and 4/998 (0.4%) in the program. Squamous cell papillomas in the skin were increased marginally in low dose male rats (control, 0/50; low dose, 4/50, 8%; high dose, 1/50, 2%). In addition, one low dose male rat had a squamous cell carcinoma of the skin. The incidence of low dose male rats with either squamous cell papillomas or carcinomas was greater (P<0.05) in comparison with the controls. The historical incidence of squamous cell papillomas or carcinomas (combined) in gavage control male F344/N rats is 3.6% (9/250) at this laboratory and 2.5% (25/999) throughout the program. The incidence of all epidermal tumors was not significantly elevated in dosed male rats relative to controls (control, 3/50, 6%; low dose, 6/50, 12%; high dose, 1/50, 2%). All high dose (1,000 mg/kg) male and female mice were dead by week 91 as a result of accidentally being administered 2,800 mg/kg for 3 days during week 91; survival of low dose and control male mice was comparable. Survival of high dose male and dosed female mice may have been inadequate for the detection of late-appearing tumors. No evidence of any carcinogenic effect was found in either low or high dose mice of either sex. An infection of the genital tract was probably responsible for the deaths of 14/22 control and 8/32 low dose female mice before the end of the study. Cytoplasmic vacuolization was increased in the liver and in the kidney of male and female mice and was considered to be compound related (liver-- male: control, 1/50, 2%; low dose, 7/50, 14%; high dose, 47/50, 94%; female: 1/50, 2%; 27/50, 54%; 46/50, 92%; kidney or kidney tubule--male: 0/50; 0/50; 41/50, 82%; female: 0/50; 24/49, 49%; 37/50, 74%). Under the conditions of these studies, geranyl 4&percnt;; 46/50, 92&percnt;; kidney or kidney tubule--male: 0/50; 0/50; 41/50, 82&percnt;; female: 0/50; 24/49, 49&percnt;; 37/50, 74&percnt;). Under the conditions of these studies, geranyl acetate was not carcinogenic for F344/N rats or B6C3F1 mice of either sex; however, the reduced survival observed in high dose male rats, high dose male mice, and high and low dose female mice lowered the sensitivity of these studies for detecting neoplastic responses in these groups. In male rats the marginal increases of squamous cell papillomas of the skin and tubular cell adenomas of the kidney may have been related to administration of geranyl acetate. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative