Page 117 - Pharmacognosy 2 PG303

Pharmacognosy-2 (PG303) Level 2 Clinical Pharmacy-Pharm D

Powder

It is green to olive- green in color with refreshing aromatic odor and
aromatic taste followed by a cooling sensation in mouth. It is characterized microscopically by the
presence of the following:

1- Fragments of both the upper and lower epidermis with wavy anticlinal walls and diacytic
stomata.

2- Non- glandular trichomes covered with fine warty cuticle.
3- Glandular labiaceous trichomes.
4- Fragments of neural epidermal cells with capitate trichomes.
5- Fragments of vein islet show no crystals of calcium oxalate.
6- Fragments of collenchyma.
7- Fragments of spiral, reticulate and pitted vessels.
8- Spherical pollen grains with smooth surface.

Constituents

volatile oil (0.7- 1.5%) containing menthol (50%), menthyl isovalerianate, menthyl acetate,
menthone and cineol. Menthol is deposited as crystals by cooling the oil. It contains also
catechol tannins (6- 12%).

Uses

o Carminative and aromatic stimulant.
o Flavoring agent.
o Relieves rheumatic pain in combination with thymol and other substances.

Adulterants and substituents

1- Spearmint oil: obtained from Mentha spicata (family: Labiatae) and contains mainly
carvone in addition to some unsaturated monoterpene e.g., limonene.

2- Japanese peppermint oil: contains up to 85% menthol and obtained from Mentha arvensis
var. piperascens Holmes (fam. Labiatae) and it is considered the commercial source of
menthol.

3- Menthene: dementholised oil of peppermint.

Chemical tests: Test for Menthol

Peppermint oil (3 drops) + glacial acetic acid containing 0.3% HNO3 (5 mL), heat 5 min.
blue fades to golden yellow

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