Absorption, Distribution and Excretion
Following intravenous injection of 0.1 mL/kg, the animals died within minutes due to severe pulmonary edema. Concentrations of α-terpineol in the blood and tissues of these animals ranged from 150 to 300 ppm. Horses surviving for 48 hours after injection of a smaller dose of pine oil (0.033 mL/kg) were euthanized. In one animal, the concentration of α-terpineol in the blood became undetectable after 2 hours, and no α-terpineol was detected in the tissues upon necropsy. … Metabolism/Metabolites The metabolic pathway of oral α-terpineol in male albino rats was investigated, as well as its effects on the hepatic microsomal cytochrome P-450 system. In the metabolic studies, α-terpineol was administered once daily at a dose of 600 mg/kg body weight for 20 days; the longest administration period in the cytochrome P-450 studies was 9 days. The isolated neutral fraction revealed the presence of one major compound (α-terpineol) and two minor compounds. One of the minor compounds was identified as p-menthane-1,2,8-triol. Further investigation revealed the presence of methyl esters of oleuropenicillic acid and dihydrooleuropenicillic acid. The allyl oxidation of the C-1 methyl ester appears to be the major metabolic pathway. It is speculated that the allyl methyl group at the C-7 position may be oxidized before the reduction of the 1,2-double bond. Following administration of α-terpineol, hepatic microsomal cytochrome P-450 levels increased by 72%, 104%, 90%, 54%, and 52% on days 1, 2, 3, 6, and 9, respectively. During the first 3 days of repeated administration, hepatic microsomal NADPH-cytochrome c reductase levels showed a moderate increase. No significant changes were observed in cytochrome b5 and NADH-cytochrome c reductase. The authors conclude that the allyl methyl oxidation of α-terpineol is the major metabolic pathway for its metabolism in rats. The reduction of the inner ring double bond was specifically observed during the conversion of oleuropeinic acid to dihydrooleuropeinic acid. The biotransformation of α-terpineol by Spodoptera litura larvae was investigated. α-terpineol was mixed into an artificial diet, and Spodoptera litura larvae (fourth to fifth instars) were fed this diet. Metabolites were isolated from feces and subjected to spectroscopic analysis. The main metabolites were 7-hydroxy-α-terpineol (p-menth-1-en-7,8-diol) and oleuropeinic acid (8-hydroxy-p-menth-1-en-7-acid). Enteric bacteria in larval feces did not participate in the metabolism of α-terpineol. Spodoptera litura larvae preferentially oxidized α-terpineol at the C-7 position (allyl methyl). This paper details the metabolism of α-terpineol by Pseudomonas incognita. The degradation of α-terpineol by this bacterium produces a series of acidic and neutral metabolites. Among the acidic metabolites, β-isopropylheptanic acid, 1-hydroxy-4-isopropenylcyclohexane-1-carboxylic acid, 8-hydroxycumyl acid, oleuropeinic acid, cumyl acid, and p-isopropenylbenzoic acid have been identified. Neutral metabolites identified include limonene, p-cymene-8-ol, 2-hydroxyeudesmol, and uraterol. …The southern root-knot nematode (P. incognita) appears to degrade α-terpineol via at least three distinct pathways. One pathway appears to occur via oleuropeinic acid, while another may begin with the aromatization of α-terpineol. A third pathway may involve the formation of limonene from α-terpineol and its further metabolism. In a minor pathway, the inner-ring olefin of α-terpineol undergoes epoxidation followed by hydrolysis to the triol metabolite 1,2,8-trihydroxyp-menthane. This metabolite has also been reported in humans after accidental ingestion of pine oil disinfectants containing α-terpineol. This metabolite is primarily metabolized through conjugation with glucuronic acid and excreted in urine. Oxidation and hydrogenation of the allyl methyl group may also occur, producing the corresponding saturated acid.

Toxicity Summary
Identification and Uses: α-Terpineol is a colorless solid. It is used in perfumery; for the denaturation of fats in soap making; as a solvent for hydrocarbons; a solvent for resins, cellulose esters, and ethers; a disinfectant; an antioxidant; a pharmaceutical ingredient; and a flavoring agent. Currently, α-terpineol is not registered as a pesticide in the United States, but approved pesticide uses may change periodically, so it is essential to consult federal, state, and local authorities for currently approved uses. Human Exposure and Toxicity: In human subjects, α-terpineol exhibits low irritation but a strong odor. Two patients with dermatitis have been reported to be allergic to α-terpineol, but attempts to induce skin allergies in volunteers using diluted α-terpineol solutions have been unsuccessful. Two deaths described in the literature were caused by accidental ingestion of products containing pine oil and were attributed to the combined toxicity of isopropanol and 1-α-terpineol. This study evaluated the regulatory effect of Melaleuca alternifolia oil (tea tree oil) on the production of oxygen free radicals by activated human peripheral blood leukocytes in vitro. It found that α-terpineol significantly inhibited superoxide production stimulated by fMLP, LPS, and PMA, suggesting that these components may selectively regulate specific cell types during inflammation. Animal experiments: In rabbits, pure α-terpineol exhibited moderate skin irritation. Low toxicity was generally reported after acute oral exposure in rodents. Acute toxicity following intravenous injection of pine oil (a commercially available disinfectant) in horses was investigated. α-terpineol was identified as the major component of pine oil. Following intravenous injection of 0.1 mL/kg α-terpineol, the substance was recovered from horse tissues, and the horse died within minutes due to severe pulmonary edema. In rats, indirect evidence of liver effects was observed after repeated oral administration. In limited studies in mice (injection), no signs of lung cancer carcinogenicity were found. Terpineol caused a slight, dose-dependent increase in the number of his+ reversion mutants in the Salmonella TA102 test strain, regardless of activation. The effects of terpineol on the complex action potential (CAP) of the sciatic nerve in rats were investigated. Terpineol blocked CAP in a dose-dependent manner.

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Toxicity Data
LC50 (Rat)> 4,760 mg/m3/4hr

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Non-human Toxicity Values
LD50 Rats: Oral 5170 mg/kg
LD50 Mice: Oral 12,080 ug/kg
LD50 Mice: Intramuscular injection 2000 mg/kg
LD50 Mice (CD-1, male): Oral 2830 mg/kg (95% CI, 2290-3497 mg/kg)

[1]. Antimicrobial effect of linalool and α-terpineol against periodontopathic and cariogenic bacteria. Anaerobe. 2012 Jun;18(3):369-72.

[2]. Effect of citral, eugenol, nerolidol and alpha-terpineol on the ultrastructural changes of Trichophyton mentagrophytes. Fitoterapia. 2009 Jul;80(5):290-6.

α-Terpineol is a terpineol with the structure propan-2-ol substituted at the 2-position with a 4-methylcyclohexyl-3-en-1-yl group. It is a plant metabolite. α-Terpineol has been reported in tea (Camellia sinensis), callistemon citrinus, and other organisms with relevant data. 2-(4-methyl-3-cyclohexen-1-yl)-2-propanol is a metabolite found or produced in Saccharomyces cerevisiae. See also: coriander oil (partial); European coriander leaf (partial); aerial parts of hemp (Cannabis sativa subsp. indica (partial).

C10H18O

154.2493

154.135

98-55-5

68540-43-2 (hydrochloride salt)

17100

White to off-white solid powder

0.9±0.1 g/cm3

217.5±0.0 °C at 760 mmHg

31-34ºC

89.4±0.0 °C

0.0±0.9 mmHg at 25°C

1.483

2.79

1

1

1

11

168

0

WUOACPNHFRMFPN-UHFFFAOYSA-N

InChI=1S/C10H18O/c1-8-4-6-9(7-5-8)10(2,3)11/h4,9,11H,5-7H2,1-3H3

2-(4-methylcyclohex-3-en-1-yl)propan-2-ol

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 250 mg/mL (~1620.75 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (13.48 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (13.48 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (13.48 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)