Betel consists of the fresh or dried leaves of Piper Betle, Linn. (N.O. Piperaceae), a shrub indigenous to and cultivated in India, Ceylon, and Malay Islands. The leaves are picked while green, pressed together by means of stones, and dried, when they become brown in colour and brittle. They generally occur in commerce tied up in small packets. The leaves are broadly ovate in shape, about 16 centimetres long and 10; centimetres broad; they are unequally cordate at the base and acuminate at the apex. They have five to seven well-marked lateral veins which curve round to the apex. They are of a dull brown colour, and brittle, thin, not coriaceous in texture, and glossy; they have a slight and warm aromatic taste. Examined under the microscope they exhibit a multitude of rounded oil cells filled with a dark brown secretion. Certain of the epidermal and hypodermal cells contain colourless siliceous deposits, while the walls of many epidermal and other cells are impregnated with silica.
Constituents.—The chief constituent of the leaves is the volatile oil, of which they contain between 0.2 and 1.0 per cent. Specific gravity, 0.958 to 1.044. This oil varies in the leaves from different countries. Two phenols, betel-phenol (chavibetol) and chavicol, have been isolated, the former of which has been found in all betel oils, and may therefore be taken as characteristic. Betel phenol is isomeric, but not identical, with eugenol. Cadinene has also been found in betel oil.
Action and Uses.—Fresh betel leaves are used in India as a masticatory for their antiseptic, stimulant, and carminative properties; the juice obtained from them has similar properties. Betel is sanctioned for use in India and the Eastern Colonies.
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.