Hydrolytic maceration

• Certain plant materials require maceration in warm water before they release their essential oils, as their volatile components are glycosidically bound.
• For example, leaves of wintergreen (Gaultheria procumbens) contain the precursor gaultherin and the enzyme primeverosidase; when the leaves are macerated in warm water, the enzyme acts on the gaultherin and liberates free methyl salicylate and primeverose.
• Other similar examples include brown mustard (sinigrin), bitter almonds (amygdalin) and garlic (alliin).