yesterday test with answer

1.       With seven (7) examples describe how Latitude and Altitude affecting cultivation of medicinal plants

a.       Gentian produce bitter constituents when grown in higher altitude

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

c.       Coconut needs a maritime climate

d.      Sugar cane is lowland plant

e.       Tragacanth, Cinchona succirubra require elevation

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

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

2.       Define the following terms; Stomatal number, Stomatal index, Vein-islet number, Veinlet termination number, Palisade ratio

Stomatal number is average number of stomata per sq. mm of epidermis of the leaf

Stomatal index: It is the percentage which the numbers of stomata form to the total number of epidermal cells, each stoma being counted as one cell.

Vein-islet number: It is defined as the number of vein islets per sq. mm of the leaf surface midway between the midrib and the margin

Veinlet termination number: It is defined as the number of veinlet termination per sq. mm of the leaf surface midway between midrib and margin

Palisade ratio: It is defined as the average number of palisade cells beneath each epidermal cell

3.       Describe the following ways in which adulteration can occur

Fault of collection

Collection of the drug from the correct identified plant but done during improper time of collection

That is the drug might not be collected during the right season, proper age, and correct stage of development

Collection of the drug together with allied species of inferior quality

 

Improper preparation

Non-removal of associated structures

Eg. Aconite and pyrethrum limit of stem is 5%, hyocyamus stem over 5mm diameter should not exeed 3%

Non-removal of the inner part of the drug

Eg in ginger

Negligence in drying procedure

 

Poor storage

Lead to a substandard drug

Opium if kept in the open loss of morphine

Digitalis should be stored with a dehydrating agent to prevent enzymic reactions

Biological preparations need to be stored at low temperature so as to preserve their activities

Squill should be stored in a tightly closed container so as to prevent the mucilage contain in the drug to absorb moisture from the air which could lead to activation of enzymic actions

 

Deliberate practice

Sometimes the drug is substituted with the exhausted drugs. This is applicable increase volatile containing drugs

This is only possible where exhaustion does not alter the appearance of the drug

The drug can be subjected to steam distillation then dried up ready for the market.

Sometimes colour can be slightly dark, common for drugs from umbelliferous, ginger, cardamom, cloves

Gentian its bitter restored by using aloes

Drug is weighed with inert materials

Large mass of stones (volcanic lava), were added to liquorice

Sophistication methods

 

4.       Describe the following factors which affecting storage of crude drugs

Moisture- in digitalis it may 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

 Temperature- 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.

5.       With examples describe six ways on how Inferior medicinal plant quality occur

Ignorance/carelessness e.g. collection of genuine material regardless of the time factor –collecting herbs prior/after ideal time

Collection at incorrect stage of development e.g. coriander – fully ripe fruits (should be nearly ripe), clove (flowers in bud stage)

Collection of parts which are not medicinally valuable e.g.  Chamomile leaves

Collection of incorrect herb (close resemblance to intended herb)

Imperfect preparation e.g. not removing undesired parts e.g. cork from ginger rhizome/incorrect drying conditions

Incorrect storage: e.g. volatile oils: cool, dry place in air tight containers

 

6.       With at least three point, give short explanation on spoilage of drugs

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

 

7.       With four examples describe Sub-aerial modification stem

Runner: These creep on the ground and root at the node

Stolon: These are lateral branches arising from the base of the stems which grow horizontally

Offsets: These originate from the axil of the leaf as short, thick horizontal branches and also characterized by the presence of rosette type leaves and a cluster of roots at their bottom

Sucker: These are lateral branches developed from underground stems. Suckers grow obliquely upwards, give rise to a shoot which develop further into a new plant

8.       With examples describes at least five methods of cultivation by vegetative means

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

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 e.g cascara.

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

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.

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

9.       What is the differences between Gum and Mucilage?

Gums are considered to be pathological products formed upon injury of the plant or owing to unfavourable conditions such as draught, by a breakdown of cell walls while mucilage are generally normal products of metabolism formed within the cell (intracellular formation) and may represent storage material, a water storage reservoir or a protection for germinating seeds

List two uses of Sterculia Gum

§  Granular grades are used as a bulk laxative (second only to psyllium seed in use as a bulk laxative).

§  Powdered gum is used in lozenges, pastes and denture fixture powders.

  

11.   Explain the following Essay questions;

1.       Explain eight advantages of a sexual 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.

7.       vegetative propagation helps to alter the size of the plant. i.e. dwarfing effect

8.        by means of bridge grafting a repairing of injured plants can be done

 

2.       Explain eight methods of extraction of crude drugs

                      Infusion

                                                                                                  i.      Infusion: Fresh infusions are prepared by macerating the crude drug for a short period of time with cold or boiling water. These are dilute solutions of the readily soluble constituents of crude drugs.

                                                                                                 ii.      Types of Infusion:

1.       Fresh Infusion: e.g. Infusion of orange }

2.       Concentrated Infusion: e.g. concentrated infusion of Quassia

Decoction

b.      Decoction: In this process, the crude drug is boiled in a specified volume of water for a defined time; it is then cooled and strained or filtered. This procedure is suitable for extracting water-soluble, heat stable constituents. e.g. Tea , Coffee

Digestion

c.       This is a form of maceration in which gentle heat is used during the process of extraction. It is used when moderately elevated temperature is not objectionable. The solvent efficiency of the menstruum is thereby increased. e.g. Extraction of Morphine

Maceration

d.      Maceration: In this process solid ingredients are placed in a stoppered container with the whole of the solvent and allowed to stand for a period of at least 3 days (3 - 7 days) with frequent agitation, until soluble matter is dissolved. The mixture is then strained (through sieves / nets), the marc pressed and the combined liquids clarified (cleaned by filtration) or by decantation, after standing.

ü  Soxhlet (hot continuous) extraction

In this method; the fine ground crude drug is placed in a porous bag (Thimble), which is placed in the chamber of the soxhlet extractor.

The extracting solvent in the flask is heated and its vapors condense in condenser.

The condensed drops of solvent fall in the porous bag (thimble), dissolving out the desired component from a solid mixture.

When the siphon tube fills to overflowing, it initiates a siphoning action into the flask. This process is continuous/repeated and is carried out until a drop of solvent from the siphon tube does not leave residue when evaporated.

 

ü  Supercritical fluid extraction

•       It is the process of separating one component (the extractant) from another (matrix) using supercritical fluids as the extracting solvents

•       The system must contain a pump for CO2, a pressure cell that contains the sample, a mean of maintaining pressure in the system and a collecting vessel

Ø  The liquid is pumped to heated zone, where it is heated to supercritical conditions

Ø  It then passed into extraction vessel. Here it diffuses in the solid matrix and dissolves the material to be extracted

Ø  The dissolved material is taken out from extraction vessel into a separator at low pressure

ü  Counter –current extraction

A liquid-liquid extraction process in which the solvent and the process steam in contact with each other flow in opposite directions

Process

In counter current extraction, wet raw material is pulverized toothed disc disintegrators to produce fine slurry.

The material to be extracted is moved in one direction (generally in the form of fine slurry) within a cylindrical extractor where it comes in contact with extraction solvent

The further the starting material moves, the more concentrated the extract becomes

Finally, sufficiently concentrated extract comes out at one end of the extractor while the marc falls out from the other end