S1 L2 Evaluation of plant drugs

1. BotanicalA. Macroscopy

Anna Drew

Evaluation of plant materials

• Eg for pharmacopoeial purposes

• 1. Botanically• 2. Chemically• 3. Biologically

• Often need the combination of all 3

1. Botanically• Authentication of material• Genus – species – botanist – family• Eg Cinnamomum verum J.S.Presl.• (Vernacular name: ‘kurundu’ etc)• (Common name: Cinnamon)• (Latin name: Cortex Cinnamomi Ceylanici)• Part of the plant -• Dried inner bark of the shoots grown on cut

stock or trunk bark

Description

• Sensory characters• Colour, odour, taste

• Macroscopical• Fibrous etc• Rarely get whole plant to identify• Organ may be fragmented• Only part of plant may be sent

• Microscopical• Sections (transverse, longitudinal etc)• Soften – maceration – 5%KOH first• Depigmentation to see – chloral hydrate etc

2. Chemically• Quantitative

• Need to develop assay» Titration» Coloured derivative spectroscopy» Chromatography – more specific

• Ash value• H2O content

• Qualitative• Extractive value – certain weight plant material• Volatile oil – steam distillation• Tannins – complex with skin – heat with hide powder• Saponins – froth with beer – haemolyses red blood cells

• 3. Biological• Assay to measure active ingredient• Ethical?

• 1. BOTANICAL aspects• Identification of plant material

» Essential to recognise diagnostic structures• Quality assurance

• A. Macroscopy• Naked eye• Hand lens

Diagnostic structures

• Living plant may include one or more:• Leaf• Flower• Fruit• Seed• Stem• Bark• Root• Rhizome (underground stem)

The "Typical" Plant Body The Root System

• The "Typical" Plant Body The Root System • Underground (usually) • Anchor the plant in the soil • Absorb water and nutrients • Conduct water and nutrients • Food Storage • The Shoot System • Above ground (usually) • Elevates the plant above the soil • Many functions including:

– photosynthesis – reproduction & dispersal– food and water conduction

• Note: the shoot system includes the leaves & reproductive organs

Leaves• Appendages to stem

• blade / lamina• petiole (stalk)

• Wide variety of external features• leaf or leaflet• simple or compound• shape• apex• margin• base• petiole• venation• vein angle• texture• size

[i] Composition

[ii] Size

Measure length and breadth of several leaves, leaflets and record a range of sizes

[iv] Apex

[vi] Base: sessile (no stalk) or petiolate (stalk)lamina equal or unequal at base

[vii] Surface• Adaxial (upper) and abaxial (lower) leaf surfaces

may vary and differ from each other• Pubescent – leaf hairs and trichomes• Glaborous – smooth• Other specialised features - oil ducts• Venation parallel, pinnate, reticulate• Midrib / veins prominent , depressed• Number and angle of lateral veins• If lateral veins run straight to margin, divide or

anastomose

Flowers

• Indeterminate or racemose• Central axis from which pedicels arise

» Raceme» Corymb» Spike» Umbel» Head» Panicle

• Determinate or cymose• Central bud becomes flower, no further growth possible

» Diachasium» Sympodial cyme

Barks• Shape in commerce

• Flats, curved, channel, • quill, double quill, compound quill

• Epiphyte tissue on outer surface• Lichen, moss, liverwort

• Outer surface• Colour, texture, lenticels, cracks

• Inner surface• Colour markings

• Fracture• Fibrous, starchy

Roots & Rhizomes

• Shape, size, colour• Surface markings• Transverse surface markings

• Roots have rootlet scars• Solid xylem core

• Rhizomes have central pith, scale leaves, buds

Seeds• Shape• Size• Colour• Surface markings• Micropyle (hole in seed coat)• Hilum (funicular scar on seed coat)• Raphe (ridge formed from fused funiculas)• Aril (outgrowth from hilum)• Caruncle (outgrowth from micropyle)• Strophiole (outgrowth from raphe)• Wings• Plumes

Fruits

• Wide variety• Dry fruits

» Eg cremocarps (Umbelliferae)» Eg legumes (Senna)» Eg capsules (Poppy)

• Succulent fruits» Eg drupes (Olive)» Eg berries (orange, Solanaceae fruits)» Etc

• 2 mericarps each with seed = 1 cremocarp» Eg coriander

Pericarp - development of ovary wall3 layers - epicarp (outer epidermis)

- endocarp (inner with modified layers)- mesocarp , succulent, pithy, spongy

parenchyma

• Separate mericarps or entire cremocarps• Shape from lateral and dorsal views• Stylopod• Number of primary ridges• Any secondary ridges• Colour• Size