Chemistry of Essential Oils

PIPEKACEJE 115

to 75 per cent, of betel-phenol, which was found to be a methoxy-

ohaviool. They identified the sesquiterpene as cadinene. Schimmel

states that the oil distilled from leaves from all sources contained this

betel-phenol, and in addition the oil from Java leaves contained several

terpenes and chavicol, that from dried Siam leaves contained a sesqui-

terpene, and that from Manila contained betel-phenol, but no chavicol.

Bykman l has found a body of peppermint odour in the Java oil

.(menthone or menthol?).

OIL OF PBPPEK.

This oil is distilled from the unripe berries of Piper nigrum. The

yield of oil is from 1 to 2*5 per cent. The oil is often of a greenish

-colour, somewhat resembling oil of cubebs, but with a much more pun-

gent odour. The green colour is due to a high boiling constituent,

possibly identical with that in oil of cubebs.

Pepper oil has the following characters :—

Specific gravity 0-870 to 0-915

Optical rotation - 10° „ + 4°

Refractive index. 1*4875 „ 1-500

The oil consists largely of phellandrene, principally the laevo-modi-

fication. Dipentene is also present, and a small quantity of a sesquiter-

pene which is probably caryophyllene. Haensel

2

has isolated from the

.high boiling fractions a body melting at 138°.

Other " pepper oils " of interest are as follows :—

The so-called " long pepper," a mixture of Piper longum and Piper

•officinarumj yields about 1 per cent, of an oil of specific gravity 0*861,

distilling mainly between 250° and 260°.

Piper Lowong, known as a kind of "false cubebs," yields about 12

per cent, of oil having a specific gravity about 0

*

865. It contains a
     •crystalline substance of the formula C 10 H 16 , 2H 2 O, melting at 164°.

OIL OF ASHANTI PEPPER.

According to Schimmel & Co. the fruit of Piper yuineense, or
Ashanti pepper, yields an essential oil which has not previously been ex-
amined. The yields in two cases were 115 per cent, and 1096 per
•cent. The oil was colourless or pale yellow, and had a peppery odour.
The two samples gave the following figures on analysis:—

Specific gravity0*873

Optical rotation

Refractive index .....

Acid value ......

Ester „

„ „ (after acetylation).

Solubility in 90 per cent, alcohol.

f-i

0*8733

. -3° 43'
. 1-48905
0-6
5-5
—
1 in 8

2.

0*8788

- 5° 34'

1-48847

0-9

4-2

22-1

1in9

OIL OF PIPER ADUNCUM.

The fruits of Piper Aduncum, known in Java as Daon Sisirihan, yield

essential oil having the following characters :—

(^1) Bericht, 22 (1899), 2736. (^2) Pharm. Zeit., 50 (1905), 412.
(^3) Arch. Pharm., 234 (1896), 238.