GAMMA-TERPINENE

Description

γ-Terpinene is a monoterpene that has been found in various plants, including C. sativa, with diverse biological activities. It scavenges 2,2''-diphenyl-1-picrylhydrazyl (DPPH; ) and 2,2''-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS⁺) free radicals (IC₅₀s = 2.8 and 30 mM, respectively) and reduces hemolysis induced by AAPH in isolated human erythrocytes. γ-Terpinene reduces the growth of T. evansi in a concentration-dependent manner. It increases membrane permeability and decreases growth of X. oryzae bacteria. In vivo, γ-terpinene (100 mg/kg) reduces Triton WR1339-induced increases in serum cholesterol and triglyceride levels in rats. It reduces paw edema induced by histamine, bradykinin (Item No. 15539), carrageenan, and prostaglandin E₂ (PGE₂; ) in mice. It also inhibits fluid extravasation in a mouse model of acetic acid microvascular permeability and reduces neutrophil migration in lung in a mouse model of acute lung injury.

Chemical properties

clear liquid

Chemical properties

γ-Terpinene is a colorless liquid with an herbaceous citrus odor and can be prepared by isomerization of limonene.

Chemical properties

p-Mentha-1,4-diene has a characteristic lemon odor (not as lemony as the alpha-isomer, but warmer). It has a slightly bitter, herbaceous, citrus-like flavor; woody, terpene, tropical lemon odor.

Occurrence

Reported found in papaya fruit, tea tree oil, tangerine, citrus, mandarins, Finocchoi fennel oil, papaya fruit, citrus peel oils, etc.

The Uses of GAMMA-TERPINENE

γ-Terpinene can be used as:

• Hydrogen precursor in the catalytic transfer hydrogenation of silyl enol ethers.
• A reference compound in the kinetic study of ozonolysis of (E)-β-farnesene.
• A hydrogen atom donor in the Cr-catalyzed radical cyclization of halo acetals.

The Uses of GAMMA-TERPINENE

γ–terpinene has been used as a standard in the determination of γ–terpinene, present in tea tree oil extracted from various parts of Melaleuca alternifolia tree and analyzed using gas chromatography coupled with mass spectrometry(GC-MS).

Preparation

From geranyl pyrophosphate by migration of a positive-charge, hydrid shift from the isopropyl side chain into the cyclohexenoid ring; from the essential oil of Lantana camara; also from p-cymene by the action of sodium and alcohol in liquid ammonia.

Definition

ChEBI: Gamma-terpinene is one of three isomeric monoterpenes differing in the positions of their two double bonds (alpha- and beta-terpinene being the others). In gamma-terpinene the double bonds are at the 1- and 4-positions of the p-menthane skeleton. It has a role as an antioxidant, a plant metabolite, a volatile oil component and a human xenobiotic metabolite. It is a monoterpene and a cyclohexadiene.

Taste threshold values

Taste characteristics at 40 ppm: terpy, citrus, limelike, oily, green with a tropical fruity nuance.

General Description

γ-Terpinene, volatile essential oil derived from Melaleuca alternifolia, shows antimicrobial properties against various human pathogens. It is also extracted from Lippia multiflora. The antioxidant, anti-inflammatory and anti-proliferative activities of γ-terpinene is studied.

Flammability and Explosibility

Flammable

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. A skin irritant. When heated to decomposition it emits acrid smoke and irritating fumes.