oral practice quiz

 

1.      Mention six advantages of Asexual propagation

1. There is no variation between the plant grown and

plant from which it is grown. As such, the plants are

uniform in growth and yielding capacity. In case of

fruit trees, uniformity in fruit quality makes harvesting

and marketing easy.

2. Seedless varieties of fruits can only be propagated

vegetatively e.g. grapes, pomegranates and lemon.

3. Plants start bearing earlier as compared to seedling

trees.

4. Budding or grafting encourages disease-resistant varieties

of plants.

5. Modifying influence of root-stocks on scion can be

availed of.

6. Inferior or unsuitable varieties can be over-looked.

2.      Outline ten General factors to consider when harvesting/collecting drugs from medicinal plants

a.      Underground organs are collected when aerial parts die down

b.      Leaves are collected when flowers are beginning to open

c.       Flowers are collected in dry weather and just before they fully expand e.g. cloves

d.      Fruits and seeds are collected when fully mature but unripe

e.      Barks are collected in damp weather

f.        Unorganized drugs are collected in dry weather

g.      Leaves, flowers and fruits should not be collected when covered with dew or rain

h.      Discolored or parts attacked by insects should not be collected

i.        Large organs should be sliced soon after collection to facilitate drying

j.        Limits of unwanted parts in desired parts must be considered when collecting medicinal plants e.g. aerial stems in rhizomes

 

3.      Explain storage of crude drugs

a.      During storage, drugs are affected by physicochemical and biological factors

b.      Physicochemical factors include light, moisture, temperature and air oxygen while biological factors include fungi, bacteria, worms, insects and mites

c.       Long storage is not recommended, due to deterioration except in cascara bark. Active constituents decrease massively

d.      Drugs should be stored in sealed containers in cool dark places

e.      Generally, the permissible moisture content is 8% or below.

f.        Air dried drugs are always liable and are easily attacked by insects and other pests, so they should be frequently examined during storage or may require sterilization by ethylene oxide or methyl chloride before storage

 

4.      Outline general conditions and techniques when drying medicinal plants as follows

a.      For Leaves/Herbs: ( four points)

                                                              i.      Temperature should be between 40-50º C to maintain good colour

                                                             ii.      Leaves or herbs should normally be destalked first

                                                           iii.      They are best dried for short periods of time only to prevent shrivelling and discoloration

                                                           iv.      They may be bleached through the drying process

b.      For Roots/Rhizomes:( five points)

                                                              i.      They should be washed

                                                             ii.      They should be sliced

                                                           iii.      They should be dried between at temperatures between 30-65ºC

                                                           iv.      Too high temperature may prevent further drying in deeper parts of the drug

                                                             v.      Thick organs may require long periods of drying (10days-3weeks) to avoid mould growth

c.       For Flowers;(two points)

                                                              i.      Flowers are normally destalked before drying

                                                             ii.      Flowers may also be bleached when dried 

d.      Volatile oil-containing drugs;(two points)

                                                              i.      Are air-dried at very low temperature to avoid volatilization of oil contents

                                                             ii.      They should be dried separately from other herbs

e.      Fruits and Seeds;(five points)

                                                              i.      They are normally partially dry before harvesting

                                                             ii.      They may be air-dried afterwards

                                                           iii.      Seeds are normally separated from the fruits before drying

                                                           iv.      Fruits are normally left whole

                                                             v.      Some fruits (cardamom) rupture due to excessive heat.

 

5.      Explain four process of drying

                                                              i.      Air Drying

1.      Sun Drying

a.      Is done when drugs are not adversely affected by excessive sunlight.

b.      Drugs are dried in thin layers and tuned over occasionally

c.       Drugs dried in this way include clove and cardamom

2.      Shade Drying

a.      Done when sunlight causes discoloration and warping/shrivelling of the drugs e.g. cinnamon

                                                             ii.      Artificial Drying

1.      Artificial source of heat is used in the drying process

2.      Drying in the oven (oven drying) is the commonest methods used in artificial drying

3.      Artificial drying is more accepted and more rapid than air-drying

4.      Artificial drying is more suitable for use in the wet weather

5.      Drying temperature is governed by constituents

a.      Generally, leaves, herbs and flowers are dried between 20-40^oC, barks and roots: 40-65^oC

6.      When done rapidly, the drugs retain colour and aroma

 

                                                           iii.      Vacuum Drying

1.      It is also done in oven, but at low temperature

2.      Low pressure ensures rapid and complete drying

3.      It is an expensive method and thus reserved for expensive drugs or drugs which cannot be sufficiently dried by other methods

                                                           iv.      Lyophilisation

1.      Involves freezing of the drug and then evaporation under low pressure

2.      Very suitable method for drugs that are very sensitive to heat

3.      The resulting product is a fine powder

4.      This method is used for drying biological fluids, enzymes, proteins and royal jelly

 

6.      a. mention three medicinal plants which require slowly drying at moderate temperature due to enzymatic desired after collection

vanilla pods, gentian roots and cocoa seeds

 

b. list five reasons for drying drugs obtained from medicinal plants

§  To decrease size and weight i.e. to facilitate packing, transport and storage

§  To facilitate powdering

§  To prevent enzyme action

§  To prevent microbial growth

§  To prevent degradation of active constituents

7.      Enlist four disadvantages of Wild Plant collection

a.      Sparse distribution e.g. Sceletium tortuosum. Potentially difficult to transport plant to area of processing

b.      Difficult access (e.g. forests, mountains etch)

c.       Collector ignorance leads to  admixture of other plants, collection of undesired plant parts or stage of development or during an incorrect season à  loss of medicinal activity.

d.      Damage to natural environment which leads to extinction of a species

8.      Give the differences between monocot and dicot roots

9.      Explain the following methods of adulteration

Spoilage, Admixture, Sophistication with inferior varieties

·         Spoilage of Drug

§  When the quality or medicinal value/ usefulness of herb is impaired or destroyed by bacterial/ fungal action, insects, rodents or other pests

§  Normally results from incorrect storage (effects of water/temperature)

§  Avoided by careful attention to the drying and storage conditions

·         Admixture

§  Admixture occurs when another species is added to the medicinally valuable drug; intentional or accidentally

§  This may result from;

·         Poor collection due to unskilled labour

·         Presence of plant parts other than those allowed by the definition

·         Collection of foreign material (stones, dirt)

·         Sophistication with inferior varieties

§  This is the deliberate addition of inferior material with the intention of decreasing medicinal action of the desired drug e.g.

·         Candle wax coloured yellow and being offered as Beeswax

·         Addition of flour to powdered ginger with chillies for potency

 

10.  With examples of medicinal plant explain Allelopathy

a.      Allelopathy

                                                              i.      Allelopathy is the constant effect which living organisms exert on each other, which may be either beneficial or harmful

                                                             ii.      Different plants growing together affect each other in terms of:

1.      Germination rate

2.      Leaf development

3.      Fruit maturation

4.      Chemical constituents produced

                                                           iii.      It is transmitted between plants in a number of ways

1.      Exhalation of leaves

2.      Root secretions

3.      Extractions from fallen leaves into the soil

                                                           iv.      Mutual dependant organisms (beneficial) symbiosis e.g.  Urtica dioica

                                                             v.      Destructive allelopathy antibiosis e.g.  Belladonna growth is inhibited when cultivated next to mustard

11.  With  at least five examples,  explain how Day-length (sunlight)  , Latitude and Altitude affecting cultivation of medicinal plants

a.      Day-length (sunlight)

                                                              i.      Amount and intensity of light needed differs from plant to plant

                                                             ii.      Amount of glycosides, alkaloids and volatile oils produced are greatly affected by amount of sunlight

1.      Long day:  menthone, menthol and menthofuran traces

2.      Short day:  menthofuran is a main component

                                                           iii.      Belladonna, Stramonium and Cinchona ledgeriana full sunshine gives high content of alkaloids than does shade

                                                           iv.      Other species:  produce more active constituents at night e.g. Nicotiana

b.      Latitude and Altitude

                                                              i.      Gentian produce bitter constituents when grown in higher altitude

                                                             ii.      Thyme and Peppermint produce less constituents when grown in higher altitude

                                                           iii.      Coconut needs a maritime climate

                                                           iv.      Sugar cane is lowland plant

                                                             v.      Tragacanth, Cinchona succirubra require elevation

                                                           vi.      Tea requires (1000-2000 M), coffee (800 – 1800 M), and cocoa (100 – 200 M)

                                                         vii.      Peanut & olive grown in the subtropics produce a higher unsaturated fat

Content

 

12.  What is the difference between monocot and dicot stem

13.  Outline three (3) types of fruits

a.      Simple fruits

                                                              i.      Fruits formed from one ovary in one flower

b.      Aggregate fruits

                                                              i.      Fruits formed from more than one ovary of one flower

c.       Multiple fruits

                                                              i.      Fruits formed from an inflorescence and include accessory structures

14.  Outline six simple succulent Fruits

a.      Berries

                                                              i.      Have soft epicarp and fleshy mesocarp and endocarp

b.      Hesperidiums

                                                              i.      Berries with a thicker skin containing oils

c.       Pepos

                                                              i.      Berries with a comparatively thick exocarp or rind

d.      Drupes/stones

                                                              i.      Have edible exocarp and fleshy mesocarp and inedible, hard stone-like endocarp

e.      Pome

                                                              i.      A fleshy fruit with mature ovary and accessory structures e.g. petals, sepals and receptacle

f.        Polydrupes

                                                              i.      Are soft aggregate fruits (fusion of several drupes) e.g. strawberries, blackberries etc.

15.  Outline four Simple dry indehiscent fruits and two simple dehiscent fruits

a.      Simple dry indehiscent fruits

                                                              i.      Samara

1.      A winged fruit

                                                             ii.      Achene

1.      A hard dry fruit with one seed which almost feels the pericarp but attached loosely

                                                           iii.      Nuts

1.      Simple dry fruit similar to achenes, but formed from two or three carpels. Pericarp is relatively hard and heavy

                                                           iv.      Caryopsis

1.      It is a simple, dry fruit in which the testa and pericarp are fused

b.      Simple dry dehiscent fruits

                                                              i.      Legumes

1.      Are dry fruits which split along both dorsal and ventral sutures to release their seeds e.g. Cassia angustifolia 

                                                             ii.      Follicles

1.      Dry fruits which splits along inner suture only e.g. strophanthus

 

16.  Outline seven External structures of a seed

a.      Seed coat

                                                              i.      Most seeds have two seed coats

                                                             ii.      Testa (the outer seed coat)

1.      Outer most protective layer of the seed –form the seed coat

2.      Protects the seed

3.      Thickness varies with type of seed

                                                           iii.      Tegmen

1.      The inner seed coat

b.      Funicle or stalk

                                                              i.      A structure that attaches the seed to the placenta

c.       Micropyle

                                                              i.       An opening that marks position of the radicle

d.      Hilum

                                                              i.      Scar left by the funiculus (attachment to the embryo)

e.      Raphe

                                                              i.      Fibrovascular tissue formed by adhesion of funicle and testa

f.        Aril

                                                              i.      Expansion of placenta or funicle over the surface of the seed

                                                             ii.      Formed in some seeds

g.      Elaiosome

                                                              i.      Fleshy structures rich in lipids and proteins attached to the seed

h.      Caruncle or Strophiole

                                                              i.      A structure that arises from the testa near the hilum

 

17.  With examples outline eight methods of vegetative propagation

By the development of bulbs (e.g. squill); corms (e.g. colchicum); tubers (e.g. jalap and aconite); or rhizomes (e.g. ginger).

 

 By division, a term usually applied to the separation of a plant which has a number of aerial stems or buds, into separate parts each having roots and a growing point. This method may be used for althaea, rhubarb, gentian and male fern.

 

 By runners or offsets (e.g. chamomile and the mints).

 

 By suckers or stolons (e.g. liquorice and valerian).

 

By cuttings or portions of the plant severed from the plant and capable of developing roots. Success by this method has been extended to a large number of plants by the use of rooting hormones  and by the employment of mist propagation.

By layers. A layer is a branch or shoot which is induced to develop roots before it is completely severed from the parent plant. This is done by partly interrupting the food supply by means of a cut or ligature and embedding the part. Alternatively the slit portion of the branch is enclosed in moist peat, surrounded by moss, and the whole enclosed in polythene. This method has been used successfully for the propagation of cascara.

By grafting and budding. Grafting is an operation in which two cut surfaces, usually of different but closely related plants, are placed so as to unite and grow together. The rooted plant is called the stock and the portion cut off the scion or graft. In Guatemala young Cinchona ledgeriana scions are grafted on Cinchona succirubra root-stocks, eventually giving a tree which produces bark rich in the alkaloid quinidine. Grafting of female scions of Myristica fragrans on male stocks may be used to increase the proportion of fruit-bearing trees in the plantation. The method has been used considerably in phytochemical research to study sites of synthesis of metabolites etc. Budding consists of the introduction of a piece of bark bearing a bud into a suitable cavity or T-shaped slit made in the bark of the stock. Budding is largely used for Citrus species, selected strains of sweet orange, for example, being budded on sour stocks. 8. By fermentation. This process applies particularly to the production of moulds and bacteria, and is extensively used in the manufacture of antibiotics, lysergic acid derivatives and some vitamins.

 By inoculation. Specific to ergot whereby the spores of the fungus are artificially cultured and injected into the rye heads by special machines,

 

 

18.  Factors affecting storage of the crude drug

Moisture leading to decomposition of constituents of some crude drugs if not stored properly, example digitalis leaf absorb moisture which may be sufficient to activate enzymes present in the leaves and bring about decomposition of the glycosides

Other drugs, such as powdered squill, which contain mucilage quickly absorb moisture and become a sticky mass

An increase in temperature, in combination with moisture, may accelerate enzyme activity; a large temperature rise will obviously lead to a loss of volatile constituents (e.g. essential oils from dried plant material)

 

Direct sunlight can cause decomposition of certain constituents (e.g. vitamins in cod-liver oil) as well as producing a bleaching of leaves and flowers.

Oxygen assists in the resinification of volatile oils and in the rancidification of fixed oils hence these crude drugs should be stored in airtight container

19.  Importance of processing medicinal plants

To improve the purity of the plant part being employed

Reduce drying time

Prevent damage from mould,other microorganisms and insects

Detoxify indigenous toxic ingredients; and

Enhance therapeutics efficacy

20.  Classification of the leaf

Based on arrangement on the stem

ü  Alternate – is characterized by the presence of one leaf at each node and all leaves together make a spiral path on the axis

ü  Opposite – When two leaves are placed at the same node and are opposite to one another

ü  Whorled - When more than two leaves are present in a single node and are arranged in a circle

ü  Rosulate –the leaves arrange themselves in a ring-like pattern around the stem

  Divisions of the lamina

ü  Simple leaves: A leaf which has only one leaf blade or lamina is called a simple leaf. It may be stipulate or exstipulate, petiolate or sessile, but always possess axillary bud in its axil. It may have an undivided lamina or may be lobed, e.g. vasaka, digitalis, eucalyptus, datura, carica, castor and argemone.

ü  Compound leaves: A compound leaf consists of more than one leaf blade or the lamina, the compound leaf is divided into several segments called leaflets or pinnae, e.g. senna, tamarind, acacia

The apex of the leaf may be one of the following kinds:

ü  Obtuse: Rounded tip, i.e. banyan.

ü   Acute: When it is pointed to form acute angle, but not stiff, i.e. hibiscus.

ü  Acuminate: Pointed tip with much elongation,peepal.

ü   Recurved: When the apex is curved backward.

ü  Cuspidate: With spiny tip like date palm.

ü   Mucronate: Rounded apex ending abruptly in a short point i.e vinca, ixora.

ü   Retuse: Broad tip with slight notch, i.e. pistia.

ü   Emarginate: When tip is deeply notched as in bambinia.

Leaf margin

ü  Entire-smooth margin

ü   Ciliate-with fine hairs

ü  Crenate-with rounded teeth

ü  Dentate-have large pointed teeth like margin

ü  Denticulate-with fine dentition

ü  Doubly toothed- serrate with sub-teeth

ü   Lobate-indented, but not to midline

ü  Serrate-have saw like margin

ü  Serrulate- with fine serration

Surface of the leaf

ü  Farinose-covered with a meal-like powder or minute particles

ü  Glabrouse- free from hairs

ü  Verucose-

ü  viscid- covered with sticky or resinous secretion

ü  punctate -dotted with oil glands

ü  pubescent-with hairs

ü  hirsute- with long distinct hairs

ü  hispid - with rough hairs

ü   glandular-