Page 51 - phytochemistry I - PharmD Clinical

Used for volatile oils:
 Containing thermo-labile constituents (sensitive to heat). The
relatively long action of boiling water or steam on the plant material
affects some of the more delicate constituents of the oil (hydrolysis,
polymerization and resinification).
 Present in extremely small quantities the minute quantities of oil
actually distilling over are "lost" in the large volume of distillate from
which the oil cannot be recovered. ex. in the flowers of jasmine,
violet, roses (Perfumes).

a) Using volatile solvent:
Usually light petroleum is used by percolation.
The material containing the volatile oil (fresh flowers) is extracted with
volatile solvent usually light petroleum by percolation or by continuous
extraction. The solvent penetrates the flowers and dissolves the natural
flower perfume together with some waxes and albuminous and coloring
matter, then concentrated at low temperature.

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