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.
The pepper vine, Piper nigrum, Linne (N.O. Piperaceoe), is a perennial climbing plant indigenous to southern India, but spread by cultivation over the islands of the Malay Archipelago and to the West Indies and South America. It is now cultivated chiefly in Sumatra, Singapore, Johore, the islands of the Rioux-Lingga Archipelago, Penang and Siam. Probably no drug or spice has been so sought after, or has played so important a part, as pepper. It was apparently brought to Europe soon after the expedition of Alexander the Great to India. During the Middle Ages the trade in it was concentrated in Venice, and the desire to divert so profitable a commerce acted as a direct inducement to the Genoese and Portuguese to seek a sea route to India, which resulted in the discovery by Vasco da Gama in 1498 of the route round the Cape of Good Hope to India. At the present moment the centre of the pepper trade is Singapore, whence about one-half of the world's supply is exported (Tschirch, 1892).
The pepper vines are cultivated in gardens as hops are in England, but instead of poles being used, trees are planted to afford the necessary shade and support. The plant bears a pendulous spike of sessile flowers (fig. 73 G), which are succeeded by small drupaceous fruits; these do not become raised upon stalks as the cubebs do, but remain sessile. As soon as the lower berries on the spike begin to ripen, which is shown by their colour changing from green to red, the whole spike is picked and dried in the sun, during which the fruits turn black. Separated from the rachis and sorted they constitute the black pepper of commerce.
For the production of white pepper the fruits are allowed to become nearly ripe; they assume a crimson colour, and the mesocarp acquires a pulpy consistence. They are then either heaped and allowed to ferment, or soaked in water, until the outer part of the pericarp is loosened; from this they are separated by rubbing between the hands or treading under the feet, after which they are washed free from the pulp and dried. White pepper is therefore the nearly ripe fruit from which the outer part of the pericarp has been removed. A similar separation is easily effected from the black pepper of commerce after soaking in water.
Black pepper consists of small dark brown or nearly black spherical fruits, measuring about 5 mm. in diameter, with a more or less regularly and deeply reticulate, wrinkled surface. At the apex the remains of the sessile stigmas can be traced; the base bears a scar indicating the point of attachment to the rachis, but, the fruits being sessile, there is no stalk.
If a fruit be cut in halves and examined with a lens, the pericarp will be seen to be thin and dark and completely filled with a seed to which it is closely adherent. The seed is globular and covered with a brown seed-coat. It contains a small endosperm, near the apex of the fruit, in which the minute embryo is situated; but the major part of the seed is composed of perisperm, which is yellowish and horny near the periphery, whitish, mealy, and frequently hollow in the centre.
Both pericarp and seed have an aromatic odour and pungent taste; they both contain oil-cells, visible under the microscope.
The student should observe
(a) The absence of stalk,
(b) The seed completely filling the pericarp and adherent to it.
(c) The characteristic odour and taste,
(d) In white pepper the adherent inner part of the pericarp, with its fibro-vascular bundles.
Fig. 75. - Black Pepper. A, transverse section. B, longitudinal section, showing pericarp, sch; perisperm, p; endosperm, en; and embryo, e. Magnified. (Tschirch).
Both the seed and the pericarp contain numerous oil-cells in which a volatile oil (1.0 to 2.3 per cent.), a resin, and a crystalline alkaloid, piperine (50 to 8.25 per cent.), are contained. The volatile oil consists almost entirely of terpenes. The resin, which has been termed chavicin, and to which the pungency of pepper is chiefly due, has not been sufficiently examined. The alkaloid piperine, C17H19N03, forms colourless and odourless crystals, which are at first tasteless, but subsequently pungent; heated with alcoholic solution of potassium hydroxide it is split up into piperic acid and piperidine. The seeds contain, further, a large quantity of starch in minute angular grains united into polygonal masses. Black pepper yields from 4.0 to 7 0 per cent, of ash.
White Pepper is of about the same size and shape as black. The surface is greyish white in colour, and nearly smooth. From the base to the apex there run about sixteen light lines; these are the fibro-vascular bundles that traverse the pericarp; they are left, together with the inner part of the pericarp, attached to the seed when the outer part of the fruit is removed. By gently scraping white pepper the adherent part of the pericarp can be removed and the dark brown seed disclosed; the latter possesses the characters above described. It contains from 4 to 6.5 per cent, of piperine.
Long pepper is the dried unripe fruit of Piper officindrum, Casimir de Candolle, and is exported chiefly from Java. It consists of a large number of minute sessile fruits which, together with the bracts that support them, are crowded together on and partially embedded in an elongated axis so as to form a dense spike. Each spike is about 40 mm. long and 6 mm. thick; it is nearly cylindrical, tapering to a rounded apex, and often covered with a greyish powder. When washed free from this the spikes are seen to be reddish brown in colour, and the minute fruits are then more easily visible; they are arranged in a close spiral, and each bears the remains of the stigma at its apex. Cut transversely, the section of the spike shows eight or ten fruits with starchy perisperm arranged around a central axis.
The taste and odour resemble those of black pepper, but are not so strong. The active constituents are the same, but they are present in smaller proportion (volatile oil 1.0 per cent., piperine 6.2 per cent.).
The student should cut long pepper transversely and observe the minute fruits, which appear white and starchy in section.
Fig. 76. - Long Pepper. (Planchon and Collin).
Applied externally pepper acts as a rubefacient, anodyne, and counter-irritant. It is given internally as a local stimulant, and as a stimulant to the urethra and rectum; it increases gastric secretion and improves the appetite; it is also occasionally used for haemorrhoids and other diseases of the rectum.