This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Betel leaves are obtained from Piper Betle, Linne (N.O. Piperaceœ), a shrub indigenous to and cultivated in India and the Malay Archipelago. The leaves are collected, put into baskets, and pressed under heavy weights, after which they are dried. They occur in commerce either loose or tied into small packets.
Betel leaves are brownish, broadly ovate, about 15 cm. long and 10 cm. broad, thin and brittle; they are acuminate at the apex, unequally cordate at the base; lateral veins well marked, 5 to 7 in number, curving from base to apex. Under the microscope abundant, rounded oil cells filled with a brownish secretion are conspicuous. Taste warm, aromatic.
The drug yields from 0.2 to 1 per cent, of volatile oil, the principal constituent of which is betel-phenol (about 70 per cent.), a substance isomeric with eugenol. Chavicol and cadinene have also been found in the oil.
Fresh betel leaves are very extensively used in India and the Malay Archipelago as a masticatory and slight stimulant, commonly in conjunction with areca nut, lime, catechu, and cloves or other spice; they are said to lose much of their volatile oil (and activity) by drying.