compound which is being illustrated.

HYDROLYSIS OF THE NATURAL GLUCOSIDES

All natural glucosides are hydrolyzed into a sugar and another organic
residue by boiling with mineral acids; although they vary widely in the
ease with which this hydrolysis is brought about.

In most cases, the glucoside is easily hydrolyzed by an enzyme which occurs
in the same plant tissue, but in different cells than those which contain
the glucoside. Injury to the tissues, germination processes, and perhaps
other physiological activities of the cells, result in bringing the enzyme
in contact with the glucoside and the hydrolysis of the latter takes place.
A large number of such enzymes have been found in plants, many of which
hydrolyze only a single glucoside. However, two enzymes, namely, the
emulsin of almond kernels, and _myrosin_ of black mustard seeds, each
hydrolyze a considerable number of glucosides. In general, _emulsin_ will
aid in the hydrolysis of any glucoside which is a derivative of
[beta]-glucose, and myrosin will help to split up any sulfur-containing
glucoside. Glucosides which are derivatives of rhamnose require a special
enzyme, known as _rhamnase_, for their hydrolysis.

The following reactions for the hydrolysis of arbutin and of amygdalin are
typical of this action, and will serve to illustrate the general structure
of these compounds:

------O-------
| |
CH_{2}OH.CHOH.CH.CHOH.CHOH.CH.O.C_{6}H_{4}OH + H_{2}O
Arbutin
= C_{6}H_{12}O_{6} + HOC_{6}H_{4}OH
Glucose Hydroquinone

C_{6}H_{5}
|
(_a_) C_{6}H_{11}O_{5}.O.C_{6}H_{10}O_{4}.O.CH + H_{2}O
Amygdalin |
CN
C_{6}H_{5}
|
= C_{6}H_{11}O_{5}.O.CH + C_{6}H_{12}O_{6}
Mandelo-nitrile | Glucose
glucoside CN

C_{6}H_{5}
|
(_b_) C_{6}H_{11}O_{5}.O.CH+H_{2}O = C_{6}H_{5}.CHOH.CN+C_{6}H_{12}O_{6}
Mandelo-nitrile |