Lauri Fructus. Laurel Berries.
Laurel berries are the ripe fruits of the bay laurel, Laurus nobilis, Linn. (N.O. Laurineae), a small evergreen tree universally cultivated in Europe. They are one-celled, one-seeded, ovoid, drupaceous fruits, about 12 millimetres in length, with a dark purple or nearly black, thin, brittle, wrinkled pericarp, which when broken discloses the kernel of the seed, the seed-coats adhering to the inner surface of the pericarp. The kernel is yellowish or brownish in colour, and lies loose in the cavity of the fruit; it is easily split into two large plano-convex cotyledons. The kernel has an aromatic bitter taste, the pericarp being less aromatic but more bitter. Expressed oil of bay (Oleum Lauri Expressum) is obtained in Greece and Northern Italy by steaming or boiling the fruits and expressing the oil; it solidifies when cold to a granular, green mass, with aromatic odour and taste. Lard, or other fatty basis, coloured green and made aromatic with the volatile oil, is sometimes substituted for the expressed oil, but is smoother.
Constituents.—Laurel berries contain about 30 per cent. of fat, 1 per cent. of volatile oil, together with starch and proteins. The bitter principle has not yet been isolated. The fat consists chiefly of laurostearin (glyceryl laurate); the volatile oil, which is more viscid and less aromatic than that from the leaves, contains cineol, together with a sesquiterpene and a little pinene, geraniol, and eugenol.
Action and Uses.—The volatile oil is used in preparations for external use on account of its pleasant odour. The fixed oil has been applied externally for rheumatism, but is now almost obsolete.