ORGANOLEPTIC EVALUATION OF CRUDE DRUGS

ORGANOLEPTIC EVALUATIONOrganoleptic (lit. impression on the organs) refers to evaluation by means of the organs of sense and includes the macroscopic appearance of the drug, its odour and taste, occasionally the sound or snap of its fracture and the feel of the drug to touch.

For convenience of description the macroscopic characteristics of a drug maybe divided into following headings.

Shape and sizeColourFractureExternal markingsOdour and taste

SHAPE AND SIZE OF CRUDE DRUGSCrude drugs can be of different shapes

etc.

Cylindrical (Sarsaparilla)

Sub cylindrical (Podophyllum)

Conical (Aconite)

Fusiform (Sweet potato)

Ovoid (Cactus)

Pyriform (Jalap)

Terrete (Orchid)

Disc shape (Calumba)

SIZE OF CRUDE DRUGSSize of crude drugs may vary because their

length, diameter and width is different. Size of crude drugs can be measured by vernier callipers in cm & mm.

COLOURExternal colour of crude drugs is mostly

greyish brown and internal colour is whitish yellow, external colour maybe yellowish grey, yellowish brown, reddish orange to brown black. It is often more or less grey from clay dust.

FRACTUREThere are three types of fracture.Complete fracture : the drug breaks completely when pressure is applied.Incomplete fracture: the drug does not break completely when fracture is applied.Short fracture: the drug breaks with a snap sound when pressure is applied.

Nature of fractureNature of fractured surface is as important as fracture. Even: smooth surfaceUneven: irregularly broken surfaceGranular : grain like appearanceHard: a compact surfaceHorny: Horn like surfacePowdered: powdery surface Resinous: smooth glossy surfaceConchodial : a resinous surface having the

surfaces curved in convex and concave form.

External markings:How the drug looks externally. They may be classified as

Furrows: alternate ridges and valleys due to shrinkage of internal parts caused by drying

Wrinkles: fine or delicate furrows

Annulations: transverse ring like markings on exterior

Fissures: splits extending into tissues

Nodule: rounded outgrowth on surface

Scars: produced due to injury or cut

ODORIt is a very sensitive criteria based on individual perception. Odor may be divided into two main classes Distinct odor e.g. camphor and cloveIndistinct odordepending upon the amount of volatile constituents the drug possesses.The different odors may include1. Aromatic odor2. Alliaceous3. Camphoraceous4. Spicy etc.

Taste

Usually crude drugs cannot be tasted because some may be poisonous or may cause allergic reactions. But some tastes which are known are:Sweet taste e.g. liquorice, honeyAcidic/sour taste e.g. lemonSaline/salty taste e.g. kasharAcrid taste : unpleasant and irritating e.g.

Jalap

A handbook of pharmacognosy by V.E, TylerEvaluation of crude drugs, mono or polyherbal

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