Chemical Properties
alpha-Terpinene is a clear colorless to light yellow liquid with a woody, terpene, lemon odor with a lemony flavor, becoming bitter at high levels. It dissolves in ethanol and most non-volatile oils but does not dissolve in water. It is found naturally in oils such as cardamom, sweet oregano, and coriander seed oil.
Occurrence
Reported found in roots, stems, leaves and flowers of Echinacea species. Also reported found in in tea tree oil,
papaya fruit, grapefruit, lemon, lime, mandarin, oranage, spearmint, citrus peel oils, cranberry, currants, guava, grapes, raspberry,
peach, carrot, celery, cinnamon, clove, cumin seed, ginger, peppermint and corn mint oils, other mentha oils, nutmeg, pepper, mace,
parsley, thymus, rum, tea, filberts, pecans, soybeans, passion fruit, beans, sweet marjoram, starfruit, mango, cardamom, coriander
seed, origanum, prickly pear, litchi, calamus, dill herb, lovage seed and leaf, juniper berries, laurel, fennel, rosemary, buchu oil, tur meric, sage, nectarines and many other sources.
Uses
α-Terpinene is suitable for use in a study to evaluate the antimycotic properties of Melaleuca alternifolia essential oil (tea tree oil, TTO). 1 It is suitable for use to investigate the in vitro antibacterial activity of the essential oils extracted from the fruits of Coriandrum sativum L. and Foeniculum vulgare Miller var. vulgare (Miller).
Uses
It can be used as a chemical fragrance essential oil and spices. It is used as a flavoring and fragrance chemical used in the personal care and cosmetic and food industries. Also used in the pharmaceutical, electronics, food processing, semi-conductor manufacturing industries.
Production Methods
alpha-Terpinene can be produced
1) by isolation from the Terpene fraction of
sweet Orange oil or "Orange terpenes".
The title material may constitute as much
as 8 to 10% of the total Monoterpenes.
2) by isolation from fractions of American
Turpentine oil.
3) from 1-Methyl-4-iso-propylcyclohexadien-1,3-one-2.
4) from Terpinene dihydrochloride with
Aniline.
Definition
ChEBI: Alpha-terpinene is one of three isomeric monoterpenes differing in the positions of their two double bonds (beta- and gamma-terpinene being the others). In alpha-terpinene the double bonds are at the 1- and 3-positions of the p-menthane skeleton. It has a role as a volatile oil component and a plant metabolite. It is a monoterpene and a cyclohexadiene.
Preparation
May be obtained by isolation from the terpene fraction of sweet orange oil or orange terpenes (8 to 10% of the total
monoterpenes); by isolation from fractions of American turpentine oil; from 1-methyl-4-isopropylcyclohexadien-1,3-one-2; also from
terpinene dihydrochloride with aniline.
Aroma threshold values
Aroma characteristics at 10%: citrusy, woody, terpy with camphoraceous and thymol notes; it has spicy
and juicy citrus nuances.
Taste threshold values
Taste characteristics at 5 to 100 ppm: terpy, woody, piney, citrus lemon and lime with spice and mint
nuances.
General Description
α-Terpinene, a volatile essential oil derived from
Melaleuca alternifolia, shows antimicrobial properties against various human pathogens.
Flammability and Explosibility
Flammable
Biochem/physiol Actions
Odor at 10%
Pharmacology
Combinations of terpenes, such as terpinene, with nonionic surfactants and stabilizers
have been patented for use as gallstone solvents. Artificial or human cholesterol calculi placed
in terpinene with or without human bile at 37°C were dissolved within 1-2 hr (Hisamitsu Pharmaceutical
Co., Inc., 1973).
Safety Profile
Moderately toxic by
ingestion. When heated to decomposition it
emits acrid smoke and irritating fumes.
