Evaluation of Crude Drugs and Pharmacognostic Standards

Comprehensive flashcards covering the evaluation of crude drugs, including histological staining, leaf constants, quantitative microscopy, and physicochemical standards like ash and extractive values.

Crude Drug

Any naturally occurring, unrefined substance derived from organic sources (plants, animals, minerals, or marine sources) used for its therapeutic effect.

Adulteration

The intentional substitution of a drug with inferior substances.

Substitution

The intentional addition of spurious materials to a drug.

Evaluation

The process of confirming the identity of a drug, determining its quality and purity, and detecting the presence of adulterants.

Microscopic Evaluation

The study of organized crude drugs using a microscope to identify unique tissue features, especially useful for whole and powdered plant parts.

Senna vs. Digitalis (Microscopic differentiation)

Senna has isobilateral leaf structure, unicellular warty trichomes, and crystals; Digitalis has dorsiventral leaf structure, multicellular collapsed trichomes, and no crystals.

Quantitative Microscopy

The use of microscopic linear measurements (micrometry), leaf constants, and specific cell counts to identify or standardize drugs.

Stomatal Number

The average count of stomata per $\text{sq.\thinspace mm}$ of leaf epidermis.

Stomatal Index (S.I.)

The percentage of stomata relative to the total number of epidermal cells, calculated as $\text{S.I.} = \frac{S}{E + S} \times 100$, where $S$ is the number of stomata and $E$ is the number of epidermal cells.

Vein Islet Number

The number of vein islets per $\text{sq.\thinspace mm}$ of leaf surface midway between the midrib and the margin.

Veinlet Termination Number

The number of veinlet terminations per $\text{sq.\thinspace mm}$ of the leaf surface midway between the midrib and the margin.

Palisade Ratio

The average number of palisade cells beneath each epidermal cell; it can be determined using the powdered drug.

Lycopodium Spore Method

An analytical technique used to determine the proportions of substances in a powder by counting defined particles relative to a known constant of spores.

Purity Calculation Formula (Lycopodium)

$\frac{N \times W \times 94,000 \times 100}{S \times M \times P} = \text{\% purity}$, where $N$ is structures in 25 fields, $W$ is Lycopodium weight, $S$ is spore count, $M$ is sample weight, and $P$ is a specific constant (e.g., $286,000$ for ginger).

Chemo-microscopy

The study of cellular constituents and diagnostic structures by applying chemical reagents to histology sections or powdered drugs.

Test for Lignified Cell Walls

Reaction with Phloroglucinol and Hydrochloric acid ($1:1$) produces a brilliant pink or deep red color.

Test for Mucilage and Pectin

Reaction with Ruthenium Red produces a pink or light red color.

Test for Fixed/Volatile Oils, Suberin, and Cutin

Reaction with Sudan III or Sudan Red produces a bright orange to red color.

Diffentiating Calcium Oxalate from Calcium Carbonate

Acetic acid and Hydrochloric acid cause Carbonate to dissolve with effervescence, while Oxalate crystals do not.

Moisture Content Determination

Calculated as the loss of weight after heating a drug at $105^\text{\thinspace o}C$ to constant weight; prevents deterioration by enzymes or microbes.

Total Ash Value

The sum of physiological ash (natural minerals) and non-physiological ash (sand/soil), determined by incineration at $450^\text{\thinspace o}C$ - $600^\text{\thinspace o}C$.

Acid-Insoluble Ash

The amount of silica, sand, and earthy matter remaining after total ash is boiled with dilute Hydrochloric acid ($HCl$).

Water-Soluble Ash

Used to detect if material has been exhausted (extracted) by water; calculated by subtracting the water-insoluble residue from the total ash.

Sulphated Ash

An inorganic residue tracked gravimetrically after treating a sample with concentrated $H_2SO_4$ prior to incineration.

Extractive Values

Physicochemical parameters used to estimate active constituents (water, alcohol, or ether soluble) that cannot be easily measured by other means.

Extractive Value Formula

$\text{Extractive Value (\% w/w)} = \frac{W_\text{residue} \times V_\text{total}}{V_\text{aliquot} \times W_\text{drug}} \times 100$.

Swelling Factor (Index)

The volume occupied by $1\text{\thinspace g}$ of a drug after standing in water for $24\text{\thinspace hours}$; used to evaluate drugs containing mucilage.

Dragendorff’s Test

A chemical test for alkaloids using Dragendorff’s reagent that produces an orange or reddish brown precipitate.

Mayer’s Test

A chemical test for alkaloids that results in a white or creamy precipitate.

Shinoda Test

A chemical test for flavonoids using magnesium turning and concentrated Hydrochloric acid to produce pink, scarlet, crimson red, green, or blue colors.

Molisch’s Test

A test for carbohydrates using $\text{alpha-naphthol}$ and concentrated sulfuric acid, producing a reddish violet or purple ring at the junction.

Keller-Killiani Test

A test for cardiac glycosides involving glacial acetic acid, ferric chloride, and sulfuric acid to form a brownish-green color.

Biuret Test

A test for proteins using copper sulphate and $\text{NaOH}$ which results in a purple or violet color.