Mastic is a resinous exudation from Pistacia Lentiscus, Linn. (N.O. Anacardiaceae), a small tree indigenous to the Mediterranean countries. It is official in the U.S.P. Mastic is collected on the island of Scio (Chios), in the Grecian Archipelago, by puncturing the bark of the trees, and allowing the oleoresin, which is contained in schizogenous ducts in the bast, to exude and harden. It occurs in small, hard, pyriform or nearly globular tears about 5 millimetres long. When fresh, they are pale yellow in colour, clear, and glassy; but on keeping, the surface becomes dull and dusty. It has a somewhat aromatic odour, and agreeable taste, breaking up when chewed into sandy fragments which agglomerate into a plastic mass. The acid number of mastic varies from 45 to 67, according to the method adopted in its determination; specific gravity, 1.074; melting-point, about 106°. East Indian or Bombay mastic is obtained from P. khinjuk, Stokes (and possibly other species); it somewhat resembles genuine mastic, but the tears are darker, less vitreous, and not so clean. It is also more soluble in alcohol, less soluble in oil of turpentine, and less disposed to agglomerate when chewed; the acid number varies from 103 to 109.
Insoluble in water, partially soluble in alcohol or oil of turpentine, very soluble in chloroform (2 in 1), and in ether (2 in 1).
Constituents.—The chief constituent of mastic is resin, which is associated with about 2 per cent. of volatile oil. The resin has been separated into the following constituents: α- and β-masticinic acids (together about 4 per cent. of the drug), masticolic acid (crystalline, traces), α- and β-masticonic acids (amorphous, about 38 per cent.), α-masticoresene (soluble in alcohol, about 30 per cent.), β-masticoresene (also called masticin, insoluble in alcohol, about 20 per cent.). The volatile oil consists chiefly of d-pinene.
Action and Uses.—Mastic is used in Eastern countries as a masticatory to sweeten the breath and preserve the teeth and gums. It was formerly much employed internally, as a stimulant to the mucous membranes in place of other terebinthinate resins, but is now rarely used. Solutions of mastic in alcohol, ether, or chloroform are used, applied on cotton wool, as temporary stoppings for carious teeth (see Mastiche et Chloroformum).
Dose.—1 to 3 grammes (15 to 45 grains).
- Mastiche et Chloroformum, B.P.C.—MASTIC AND CHLOROFORM. Syn.—Mastiche cum Chloroformo; Chloroformum Mastichis.
- Mastic, 65; chloroform, to 100. Applied on cotton wool as a temporary stopping for decayed teeth the cavity should be previously cleansed, and well dried. Mastic Dentaire is a preparation similar to the above, but made with ether in place of chloroform. Alcohol Mastichi (Harvardid Varnish) is prepared by digesting 2 of mastic with 1 of alcohol; it is used in dental operations for coating temporary coverings of cotton wool.