Need to Classify Drugs
Classification is a prerequisite to study the various aspects of the plant diversity. The main aim of classification is to study the origin of plants and their evolution from a simpler to advanced form over a period of time, in other words to investigate the phylogenetic relationships of plants.
An attempt to classify the plants has led to the development of
various fields like Taxonomy and Systematics. The terms such as classification,
taxonomy and systematics are inter-related. G Simpson (1961) relates
classification as arranging of organisms into groups, and taxonomy as the study
of principles and procedures of classification. He explains systematics as the
study of comparative and evolutionary relationships of plants, based on their
comparative anatomy, physiology, and biochemistry.
Systematics is an important tool in Pharmacognostical practice and research. This is due to the fact that related families often contain similar type of compounds. The systematic position of a particular plant helps to have an idea about the probable presence of secondary metabolites in it. For example, many members of Family Umbellifereae contain volatile oils.
Units of Classification
Taxonomy is the science of naming the organisms. This is based on
the study of morphological variation of organisms, and to investigate the cause
of this variation. That is to integrate a particular organism into the current
system of nomenclature by manipulating the data so obtained.
A taxon (pl. taxa), stands for any named taxonomic unit such as a
phylum, a family or a species. It is used to indicate the rank of a group as
well as the organisms contained within that group.
A series of hierarchical categories are structured to understand
the diversity of plants.
The categories which represent the natural relationship between
all the taxa are: Species, Genus, Family, Order, Class, Phylum, Subphylum,
Division and Kingdom.
Species: A species is a group of individuals, characterized by: morphologically and functionally similar members; able to inbreed freely and true to type; have 2n chromosomes in somatic cells and n chromosomes in reproductive cells.
Varieties: Sometimes, individuals of a species show variation in form, size, shape and color under the influence of environmental factors. These individuals are said to form varieties.
Genus: A genus is a collection of species bearing a close resemblance to each other in terms of morphological and reproductive characters.
Family: A family is a group of genera have general structural resemblance in their floral organs.
Nomenclature
The system of designating a plant with a name consisting of two
parts is known as binomial nomenclature. Carl von Linnaeus (Linne), Swedish
Botanist (1707-1778) developed the binomial nomenclature. It was accepted by
the International Botanical Congress held in Amsterdam in 1935.
Significance of Taxonomy : The naming of plants and understanding of the species’ relationship to other species is essential for biologists, and people working in the field of agriculture, forestry, pharmacognosy, phytochemistry and industry. This forms the basis of correct identification and authentication of the crude drug. Correctly identified drug will lead to phytopharmacological studies and development of novel drugs.
Example of Botanical Classification: Cuminum cyminum Linn. (L.)
The above name indicates the genus (Cuminum) and species (cyminum)
followed by the authority- Linn. represents the botanist who provided the first
scientific description of the species and assigned the botanical name. In this
case it is Carl von Linnaeus (Linne).
Species: cyminum
Genus:
Cuminum
Family:
Umbelliferae
Class:
Magnoliopsida
Subphylum: Magnoliphytina (seed bearing plants with covered seeds)
Division (Phylum): Spermatophyta (seed bearing plants)
Kingdom:
Plantae (plants)
Special Case: Aloe vera (L.) Burm. f.
The name in parentheses indicates the botanist Linnaeus. He first
described the species but assigned it to a different genus. The second name,
Burm. f., stands for botanist Nicolaas Laurens Burman; f. stands for filius
(son), he is the son of another well known botanist.
Classification of the Plant Kingdom
The basic classification of the plant kingdom includes the
following main groups:
1. Thallophytes include: Bacteria, Algae, Fungi and
Lichens.
2. Bryophytes
3. Pteridophytes
4. Gymnosperms
5. Angiosperms
The present chapter will focus on the following families of
pharmaceutical interest.
Thallophyta: the body is undifferentiated into root, stem or leaf. This group is nearest to beginning of the plant kingdom.
Algae
Algae are green thallophytes that contain chlorophyll. In many Algae, other pigments like, brown, red, blue-green are also present besides chlorophyll. The body of algae is composed of true parenchymatous tissue and the cell wall is composed of true cellulose. Reserve carbohydrate in algae is present in the form of starch. Reproduction takes place vegetatively by cell division.
The commercially important algae are limited to the diatoms and
marine forms of brown and red algae. The Kelps and Rockweeds (brown algae) are
the most important source of iodine and are also harvested for their potash
content as a fertilizer.
Agar and Alginic acid (red algae) because of their abundant
mucilage content are used as demulcents and nutritives.
Rhodophyceae
The group is represented largely by marine algae and few fresh
water forms. Marine red algae are beautiful plants and are found at great
depths. The plant body is unicellular, filamentous and membranous. Their
plastids contain chlorophyll a along with phycoerythrin, a red pigment, present
in large amounts and phycocyanin, and the blue pigment of Cyanophyceae. The
storage product Floridean starch, an amylopectin stains red with iodine.
Gelatinous material is abundant in red algae, present within the
thallus or forms a sheath in the filamentous form. Few forms are incrusted with
lime. Rhodophyceae is the most highly specialized group of Algae.
Agar and Alginic acid, two important members of the family are
discussed below:
(i)Agar
Synonyms: Agar-agar, Vegetable Gelatin, Japanese or Chinese Gelatin, Japanese Isinglass.
Biological Source: It is the dried colloidal concentrate prepared from the decoction of various species of the genus Gelidium, family Gelidaceae. The genus Gelidium provides about 35% of the total raw material. Japanese agar is obtained from Gelidium amansii.
It is also obtained from genus Gracilaria, family Gracilariaceae.
Other Geographical Sources include Korea, South Africa, Atlantic and Pacific
Coasts of the USA, Chile, Spain and Portugal. More than 6500 tonnes of agar is
produced annually.
Collection and Preparation: In the coastal area of Japan, the algae are cultivated in special areas. The poles are planted in the sea to form supports for the development of algae. The poles are withdrawn from time to time and the algae are stripped off in the months from May to October. The algae are dried, beaten and shaken to remove any earthy material adhering to it. It is then bleached by watering and drying in the sun. The algae are then boiled with acidulated water for several hours. A mucilaginous decoction is formed, which is filtered while hot through a linen cloth. On cooling, a jelly is produced which is cut into bars and subsequently strips are produced.
The manufacturing of agar takes place only in winter season. The
moisture is removed by freezing, thawing and drying at about 35 ° C.
Morphological Characters:
Form: occurs in two forms: 1) Coarse powder or
flakes 2) bundles of translucent, and crumpled, strips, 2-5mm wide.
Color:
colorless to pale yellow.
Fracture: Tough when damp and brittle when dry.
Odor:
not distinct
Taste:
mucilaginous
Chemical Constituents: It is a heterogeneous polysaccharide composed of two
principal constituents: agarose and agaropectin. Agarose represents the gel
strength and agaropectin is responsible for the viscosity of the agar
solutions.
Uses:
.. The gels of pure agarose are used for the electrophoresis of
proteins.
.. Agar is used for the preparation of culture media
.. It is used as an emulsifying agent
.. In the treatment of constipation
.. Used in affinity chromatography
Physical Characteristics:
Solubility:
Cold water: does not dissolve but swells to a gelatinous mass
Boiling water: dissolves and 1% solution gives a stiff jelly on
cooling
Chemical Tests:
1. Warm a small quantity of drug with caustic potash solution, a
canary-yellow color is produced.
2. To 5ml of 0.5% solution of drug in water, add 0.5ml of HCl and
heat on a water bath for about 30 min. neutralize the solution and divide it
into two portions. To one portion, add Fehling’s solution and heat on a water
bath, a red precipitate is formed. To other portion, add solution of BaCl2. A
slight, white precipitate is formed (tragacanth gives no precipitate) (on
hydrolyzing, galactose and sulphate ions are produced, former reducing
Fehling’s solution and the latter precipitating with BaCl2)
3. Moisten the drug with N/50 iodine solution, a deep crimson
color is produced
(distinction from Acacia and Tragacanth)
4 Moisten the drug with a solution of Ruthenium red, a pink color
is produced.
5 Heat a little drug in a test tube with soda-lime. Test the
vapours with litmus paper, no alkaline reaction (since no ammonia is produced)
6 Warm a little drug with acetic acid, solution occurs on
prolonged heating.
7 Dissolve 0.2 g of the drug in 40ml of hot water. Divide the
solution in three parts and treat it as follows:
a. Add a few drops of 10% solution of tannic acid. A white
precipitate in the cold and on boiling, an opalescence is produced.
b. Add a few drops of Millon’s reagent. No white precipitate is
produced.
c. Add excess of saturated solution of trinitrophenol. No yellow
precipitate is formed.
Note:
Tests 4-6 differentiate it from gelatin
Adulterants:
.. The powdered drug is adulterated with starch.
.. Mount the drug in chloral-iodine solution and observe the
starch grains.
Note:
Agar BP is required to comply for the absence of Escherichia coli and
Salmonella.
The general microbial contamination should not exceed a level of
103microorganisms/ gram by a plate count.
(ii)Alginic Acid
Biological Source: It is prepared from large quantities of brown seaweeds (Phaeophyceae). Species of Laminaria and Fucus are commonly used for the preparation of alginic acid. The main producers of alginic acid are: USA, Chile, China, Canada, Irish Republic, Australia, Iceland, UK and South Africa.
Method of Preparation: Large quantities of seaweed are collected
from colder waters of the world. They are dried and washed with faintly
acidulated water to remove the salt content. They are then chopped and bruised in
a hammer mill. The dried milled seaweed is macerated with dilute sodium
carbonate solution and diluted with sufficient soft water to separate the
insoluble material. Soft water is added to avoid the precipitation of insoluble
alginates. The resulting clear liquid is poured into dilute sulphuric acid as a
result the insoluble alginic acid is precipitated as a bulky, heavily hydrated
gel. The liquid is removed from the gel by expeller presses.
Chemical Constituents: It is composed of residues of D-mannuronic and
L-galuronic acids.
Physical Characteristics:
Solubility: cold water: insoluble but swells and absorbs many times its own
water.
Hot water: slightly soluble
Organic Solvents: insoluble
Uses:
Used as a tablet disintegrating agent
In the textile industry
Fungi
Fungi are thallophytes, lacking in chlorophyll. They have infinite
variety of shapes and sizes. The carbohydrate food is stored in the form of
glycogen and not starch. They closely resemble the algae (not blue-green algae)
and other green plants in their nuclear organization. The plant bodies of fungi
are the simplest in the plant kingdom, being either unicellular or filamentous.
In the latter case, the plant body is called mycelium and the individual
filaments are called hyphae. The cell walls of most fungi contain chitin,
others contain cellulose and polysaccharides.
Some fungi develop absorptive branches, called rhizoids in
saprophytic species and haustoria in parasitic species.
In some species like mushrooms (toadstools), puffballs and shelf
fungi, the vegetative mycelium is the ‘fruiting body’, which arises in some of
the sac and club fungi. The fruiting 6
body of a fungus has been preceded by an extensive vegetative
mycelium that has grown for months or years.
Fungi are classified in five major classes:
.. Myxomycetes or slime fungi
.. Phycomycetes or alga-like fungi
.. Ascomycetes or sac fungi
.. Basidomycetes or club fungi
.. Deuteromycetes or imperfect fungi
The following drugs are of pharmaceutical interest:
Ergot
It is an important member of the class Ascomycetes.
Synonyms: Ergota, Ergot of Rye
Biological Source: It is the dried sclerotium of a fungus, Claviceps purpurea
Tulasne, Family Hypocreaceae (Clavicipitaceae), arising in the ovary of the rye
plant, Secale cereale Linn., Family Gramineae.
The main source of the crude drug is the controlled field
cultivation of rye plant. The chief producers are: Czechoslovakia, Hungary,
Switzerland and Yugoslavia. Commercially, ergot of wheat is becoming more
important (90% in UK).
Life history of the Fungus: In the spring or early summer
(flowering stage), the ovary of rye plants get infected by the ascospores of
the fungus. During damp weather, the spores germinate at the base of the ovary,
forming filamentous hyphae which enter the wall of the ovary by an enzymatic
action and form a soft, white mass over its surface. This stage is called
‘sphacelia’, it produces a yellowish, reducing saccharine secretion, ‘honey
dew’. Insects are attracted by the secretion and carry away the spores to other
rye plants which become infected with the disease. As the development of the
hyphae proceeds, they penetrate deeper and deeper, feeding on the ovarian
tissue and finally replacing it by a compact tissue called as pseudoparenchyma.
This forms the sclerotium or the resting stage of the fungus. In the summer, as
the rye ripens, a dense core of compact hyphae develops in the diseased ovary
and projects from the ear of the rye, bearing at its apex the pale coloured
remains of the sphacelia. This compact, hard structure is dark purplish-brown
in colour and is known as the sclerotium. The sclerotia falls along with the
ripened rye grains falls on the ground and remain in the ground through out
winter. In the following spring, the sclerotium germinates and forms several
cylindrical stalks or stromata (10-20mm long). The apex of each stroma swells
into a spherical head (2mm in diameter), in which are embedded numerous flask
shaped cavities, perithecia. Each perithecium contains numerous elongated asci
(sporangia), each contains eight filiform ascospores. The ascospores escape
from the pore in the apex of the ascus, fall on the ground and develop into
small branching threads, which in turn abstricts small spores. These small
pores are carried by the wind to the ovaries of new crop of rye, at their
flowering stage.
Cultivation and collection: The number and size of the sclerotia varies on each spike of rye. The number of sclerotia produced on rye is usually more than that produced on wheat. Ergots are cultivated successfully by spraying the culture of spores on the rye crops during their flowering season. ]
The ergots are picked by hand or separating from the rye after
threshing the crop. This separation is effected by use of special machines.
Sometimes the grain is thrown into a 20-30% solution of common salt, whereby
the ergots float and the rye sinks.
Macroscopical characters:
Form: thick, fusiform or sub-cylindrical with tapering ends, three
sided with a shallow groove along each face.
Color: externally dark-purple to nearly black
Fracture: short and the exposed surface is white or
pinkish, showing few darker lines radiating from the centre, the outer margin
is purplish-violet.
Taste:
unpleasant
Odor:
disagreeable and faint.
Microscopical Characters: The pseudoparenchyma consists of oval or rounded cells containing fixed oil and protein. It is marked by an outer zone of obliterated purplish-brown rectangular cells. Cellulose and lignin are absent.
Chemical Constituents: The ergotalkaloids (ergolines) the percentage (.01-0.25%)
varies according to the geographical source. These are of two types: the
clavine-type and the lysergic acid derivatives. The lysergic acid derivatives
are pharmacologically active alkaloids. Each active alkaloid is associated with
an inactive isomer involving isolysergic acid.
Six pairs of alkaloids predominate in the sclerotium and are
classified as water soluble (ergometrine or ergonovine) and water insoluble
(ergotamine or ergotoxine).
Uses:
Ergot has been replaced by the isolated alkaloids. Ergometrine produces
oxytocic effect; Ergotamine and the semisynthetic dihydroergotamine salts are
used as analgesics for the treatment of migraine; Lysergic acid diethylamide
(LSD-25), prepared from lysergic acid is used as a psychotomimetic.
Storage:
Ergot should be dried after collection, kept entire and stored in a cool, dry
place, as it is liable to be attacked by insects, moulds and bacteria. If
required in a powdered form, it should be immediately defatted; else it will
lose its activity.
Yeast
Biological Source: It consists of unicellular fungi, genus Saccharomyces, family Saccharomycetaceae. The species used in industry are: S. cerevisae, S. carlsbergensis and S. monacensis.
Cultivation and Preparation: It is grown in brewers’ medium at 20-25
degree centigrade. It multiplies rapidly by germination or budding. The yeast
is skimmed off from the surface, washed in water and the liquor is passed
through sieves, after several washings the yeast is allowed to settle and
removed by filter presses.
Morphological Characters: consists of rounded or ovoid cells, occurring singly or
in short straight or branched chains; the cells are colourless (4-7-9 microns
in diameter).
Chemical Constituents: contains about 73% of moisture, 13% proteins (partly free
and partly combined with nucleic acid) and 0.27% of oil. It contains enzymes
like invertase, maltase, diastase and zymase. It also contains vitamins of the
Vitamin B complex.
Uses: It is a chief source of Vitamin B complex.
Mushrooms
Mushrooms, the edible and poisonous species are saprophytes,
generally called as ‘toadstools’, as they depend on wood and soils rich in
organic matter. The mushroom is a basidiocarp (fruiting body) of the organism.
It is built up by complicated interwoven hyphae of the filamentous mycelium.
The mushroom cap bears gills on its lower surface. The gills produce the
basidia and basidiospores and are also composed of interwoven hyphae. Mushrooms
have two additional features of special interest:
Bioluminescence and hallucinogenic properties of some species:.
The mycelium of some species is luminescent, mediated by the enzyme luciferase
in the presence of luciferin as substrate.
Types of mushrooms:
Edible Mushrooms: There are about 200 species of edible mushrooms available. Agaricus bisporus is the common edible mushroom. It is grown commercially from spawn, a mass of soil, manure and rotting leaves that contains the mycelium of the fungus. Other common edible species are: Agaricus campestris, Morchella esculenta ,and Volvaria terastria.
Poisonous Mushrooms: It is very difficult to distinguish
between edible and poisonous mushrooms. On the basis of experience, there are
some observations, which may help to identify the poisonous mushrooms: bright
color, pink spores, a hot burning taste or acidic flavor, growing on wooden
pieces in hidden places, difficult to break and bear a cup like structure
(volva) at the base.
Some of the poisonous mushrooms when taken orally produce
hallucinations. These include toadstools of the genera Amanita, Psilocybe and
Conocybe.
Since it is difficult to distinguish poisonous mushrooms on the
basis of morphological characters, they are classified on a physiologic basis
that is according to the symptoms produced by them following ingestion:
Protoplasmic poisons:
Amanita Toxins: It is a mixture of peptide toxins and was first detected in
Amanita species. Genus Amanita is characterized by: white spores, presence of
both annulus and volva and free gills.
Some species of genus Galerina also contain peptide toxins. These
are characterized by small non – descript carpophores with yellowish brown
spores. They often occur in lawns and grassy areas.
Poisoning of amanita toxins is characterized by a long latent
period between ingestion and onset of symptoms; asymptomatic latent period
lasting up to 24 hours precedes violent diarrhea and vomiting which may cause
death. If the patient survives this initial period, the 9
progressive injury to the liver, kidneys, heart and skeletal
muscles continues and death results in 50% of the cases within 2-5 days.
The treatment includes: removal of the toxic material from the
GIT, followed by symptomatic and supportive therapy. No antidote is
sufficiently established till date.
Gyromitrin: The toxic principle is N-methyl-N-formylhydrazone of
acetaldehyde. Helvella esculenta (Gyromitra esculenta Fries), Helvella gigas
Krombholz and Helvella underwoodii Seaver are some of the species representing
this class. This genus is characterized by pileus surface ( nearly smooth to
strongly convoluted).
Poisoning of gyromitrin is characterized by its toxic effect on
liver. The hematopoietic and the central nervous system is also effected. A
minimum latent period of 6-10 hours is observed between onset of symptoms and
ingestion of the drug. The treatment is similar to that given in poisoning
caused by Amanita toxins. The mortality rate ranges between 2-4%.
Orellanine: Orellanine is the toxic principle and species of Cortinarius (C
orellanus Fries) represents this class. This genus is characterized by brownish
to reddish brown spores. Orellanine poisoning is characterized by an extremely
long latent period (3-14 days). An intense burning thirst is followed by GIT
disturbances, headache, pain in the limbs, spasms and loss of consciousness.
Severe poisoning may lead to kidney damage and death after several weeks. About
15% of the cases have proved fatal. Symptomatic and supportive treatment with
specific maintenance of kidney function is recommended.
Compounds exerting Neurologic effects:
Muscarine: Muscarine is the toxic principle and species of genus Amanita
muscaria (Fries) Hooker and A. pantherina (Fries) represents this class.
Muscarine is also found in species of Boletus, Clitocybe, Lepiota, Hebeloma,
Inocybe and Russula. Clitocybe and Inocybe contain high concentration of
muscarine (3% of dry weight). Clitocybe is recognized by white spores, fleshy
central stripes, broadly adnate to decurrent gills. Inocybe is recognized by its
subconic to campanulate pileus and brownish spores. Muscarine poisoning is
characterised by increased salivation, perspiration and lacrimation within
15-30 minutes. These symptoms are followed by abdominal pain, severe nausea and
diarrhea. Though the patient’s mental condition is stable, his pulse is slowed
down, heavy breathing and the pupil is constricted. The cardiac and respiratory
failure leads to death, which is rare. Treatment involves gastric lavage and
administration of a specific antidote atropine.
Ibotenic acid-Muscimol: Muscimol and ibotenic acid are the toxic principles.
Muscimol is five times as active as ibotenic acid. Amanita muscaria (fly
agaric) and A pantherina represents this class. The poisoning is characterized
by an initial state of excitement, followed by muscular twitching, depression
and loss of consciousness within 1-2 hours. Death is rare and treatment
involves mild depressants followed by stimulants and the recovery is rapid.
Psilocybin: The toxic principle is 2 tryptamine derivatives, psilocybin and
psilocin. Species of Psilocybe and Conocybe represents this class. The genus is
characterized by the presence of bluish stains near the base of stipe, when the
tissue is damaged or becomes aged. Psilocybin poisoning develops rapidly and
leads to anxiety and difficulty in concentration and comprehension. It lasts
for several hours and true hallucinations may be experienced. Recovery is
spontaneous and complete after 5-10 hours.
Gastrointestinal irritants: Toxic principles are resin like
substances. Boletus satanas Lenz. Lactarius torminosus (Fries) Gray, Russula
emetica (Fries) SF Gray are some of the species representing this class.
Symptoms of the poisoning are quick and include nausea, vomiting and diarrhoea.
It is fatal among children. Treatment includes symptomatic care, bed rest and
light diet. Generally, recovery is spontaneous and complete.
Disulfiramlike Constituents: Toxic principles are the constituents
resembling disulfiram like or cyanamide. Coprinus atramentarius (Fries) and the
subsequent ingestion of alcohol represent this class. This species is
recognized by black spores, smooth or minutely scaly grayish pileus and free
gills that deliquesce into a dark colored fluid as the spores are discharged.
Poisoning symptoms include: flushing, palpitations, dysopnea, hyperventilation
and tachycardia. Treatment includes gastric lavage and symptomatic care.
Recovery is spontaneous and complete.
Gymnosperms
The phanerogams, seed producing plants are of two types:
angiosperms, or flowering plants and Gymnosperms. The family consists of 750
species, out of which more than 50 species occur in India. In gymnosperms, the
seeds develop on the surface or at the tip of an appendage- ovuliferous scale
or peduncle. The seed bearing structures of gymnosperms may occur in cones or
strobuli. These structures hide the seeds from the view by the grouping and
overlapping of these structures. They do not enclose the seeds.
Gymnosperms may be woody trees, shrubs, or vines, for example,
pine, hemlock, fir, Ginkgo biloba. In woody plants, the vascular cambium adds
annual increments of secondary xylem or wood. Stems of herbaceous plants are green
and soft because very little secondary xylem is added by the vascular cambium.
Gymnosperms include divisions: Cycadophyta, Ginkgophyta,
Coniferophyta and Gnetophyta.
Coniferophyta: Extensive forests are formed by Pines and
associated conifers. They are the rich source of wood pulp for the manufacture
of paper and coniferous gums and resins. There are numerous canals within the
leaves and throughout the plant, filled with resin. Pine leaves are known as
needles and have little surface area. The stems and roots of pine contain
active, vascular cambial layers that add secondary xylem, increasing the
woodiness and diameter of the axis. The wood largely consists of conducting
cells, tracheids and associated living parenchyma cells. Internally, the leaves
are covered by a heavily cutinized epidermis with sunken stomata and a
hypodermis. Resin canals occur in the mesophyll. A prominent endodermis
surrounds the vascular tissue, may be in one or two groups, depending on the
species.
Genetophyta: This division includes three genera: Ephedra, Gnetum and
Welwitschia. These are restricted in distribution and not widely cultivated.
1. Pinaceae
Distribution: The family consists of 9 genera and 230 species. It is widely distributed in north temperate regions of the world. They are frost and drought resistant plants which form large tree or shrub dominated zones of vegetation. It is also called pine family or coniferae.
Identifying Morphological Characters of the family: Leaves are needle shaped and linear
(pine needles), usually evergreen. Flowers are separate and monoecious. The
cones are small and herbaceous. They produce large amount of pollen, carried
away by wind. The female cones are woody with spirally arranged scales, two
winged wind-distributed seeds per scale are present.
Chemical Constituents of the family: Essential oils and balsams are the main
constituents of pharmaceutical interest. Monoterpenoids (alpha pinene and
borneol) are the main constituents of essential oils and balsams. Flavonoids,
condensed tannins and lignans are widely present in the members of this family.
Important Medicinal Plants of the family:
Turpentine: manufacture of fragrances, flavours and insecticides
Colophony: residue left after the distillation of the oil of turpentine from
the crude oleo resin of various species of Pinus; stimulant and diuretic.
2. Genetaceae
Genetaceae is an important family of the order Gnetales. The
Gnetales have reached the highest degree of evolution among the Gymnosperms.
They bear a close resemblance to Angiosperms. Gnetaceae is represented by a
single genus Gnetum.
Angiosperms
Angiosperms (Magnoliphyta): The angiosperms include more than
250,000 species. These are the fruit bearing plants ( seed is covered by closed
carpels) and include herbs, shrubs and trees. The phylum is divided into
monocotyledons and dicotyledons.
This section of the chapter will highlight the pharmaceutically
important families. In other words, the families producing medicinally
important crude drugs.
1. Apocynaceae
Distribution: A family of about 250 genera and 2000 species, out of which 67
species are available in India. Most of the members are woody climbers and are
natives of tropical and sub-tropical region.
Identifying Morphological Characters of the family: These are mostly twining or erect shrubs, a few herbs and trees with latex; leaves are simple, opposite or whorled, rarely alternate; flowers are regular, bisexual and hypogynous, in cymes, funnel shaped, often with corolla; sepals are 5, rarely 4, gamosepalous and often united only at the base; 5 petals, rarely 4), gamopetalous and twisted; 5 stamens, rarely 4, epipetalous, alternating with the petals, included within the corolla tube; carpels are 2 or (2), apocarpous or syncarpous, superior; Fruits are a pair of follicles, berries or drupes; seeds are flattened and often have a crown of long silky hairs.
It is closely related to Asclepiadaceae
Floral Formula: . K (5) C (5) A(5) G 2 or (2)
Main Chemical Constituents of the family: The family is a rich source of indoline
alkaloids; steroidal alkaloids and cardioactive glycosides. The other
constituents are cyanogenetic glycosides, saponins, tannins, coumarins,
phenolic acids and triterpenoids.
Important Medicinal Plants of the family:
Alstonia scholarasis: cardioactive
Catharanthus roseus: anticancer
Holarrhena antidysenterica: bitter and antidysenteric
Nerium (Olender): cardioactive
Rauwolfia serpentina: management of essential hypertension
Strophanthus kombe: diuretic
Thevetia nererifolia (yellow oleander): cardioactive
2. Cruciferae
Distribution: A family of about 375 genera and about 3200 species out of which
174 species are available in India. Distributed in temperate regions
Identifying Morphological Characters of the family: Commonly known as Mustard family; annual
herbs; leaves are alternate, simple, rarely compound, exstipulate, entire, or
toothed, often more or less hairy; inflorescence at first is a corymbs or
shortened raceme, later elongating into a loose raceme; flowers are
regular-rarely irregular (candytuft), and tetramerous; sepals 4, green, equal
or the 2 laterals may be pouched as nectar receptacles; petals 4, yellow to
white, pink or purple and arranged in the form of a cross; stamens
tetradynamous, hypogymous; pistil, syncarpous, bicarpellate; superior; carpels
lateral; fruit is a capsule (silique) that bursts lengthwise by two valves;
seeds remain attached to a wiry frame work, called the replum which surrounds
the fruit.
Floral formula: ♂ K 2+2 C 4 A2+4 G (2))
Chemical Constituents of the family: Many members contain mustard-oil
glycosides. Cardiac glycosides are present in some genera. Seeds usually
contain mucilage and fixed oil.
Important Medicinal Plants of the family: The members of this family are rich
source of fixed oils and condiments; rubefacient and counter-irritant. e.g.
Brassica campestris (mustard), B alba (white mustard), B nigra (black mustard),
B napus (Indian rape)
3. Compositae
Distribution: The family contains about 900 genera and more than 21000
species, out of which 674 species are available in India. It is also known as
Asteraceae or Daisy family. It is distributed in all parts of the world, except
Antartica. It is widely distributed in Central America and Mexico.
Identifying Morphological Characters of the family: All the members of the family have a
complex inflorescence (the capitula) gave rise to the older name of the family
compositae (inflorescence composed of many flowers). Herbs, rarely shrubs or
trees of annual or perennial habit, and with watery or milky juice; Leaves
alternate, rarely opposite, simple to compound, estipulate; Inflorescence a
capitulum or a raceme of capitula, each capitulum surrounded by an involucres
or protective whorl of bracts, and composed of numerous florets that may be:
(a) wholly regular tubular and hermaphrodite (thistle) or (b) central florets
as in (a) but marginals strap-shaped or ligulate and usually pistillate (Daisy,
Dahlia); or (c) florets all ligulate and hermaphrodite (chicory); or (d) florets
in part or in whole bilabiate (Mutisia). Flowers small (florets), closely
crowded, pentamerous shaped as above, with ovary inferior and other floral
parts superior. Sepals rudimentary, tooth like (sunflower), or reduced to a
papose or hairy rudiment above ovary that is functionless during flowering, but
that expands in fruit as a hairy fruit disseminator (thistle); or sepals wholly
absorbed (Daisy). Petals synpetalous, tubular, ligulate or rarely bilabiate,
greenish-yellow to white, or through pink-crimson and purple to blue (chicory).
Stamens five, epipetalous; Carples two, syncarppous; Fruit an indehiscent
achene, often (thistle) crowned by the papose, calyx rudiment (pappus) seed
single. The ray florets are zygomorphic, ligulate, unisexual (female), or
sometimes neuter, as in sunflower, and epigynous, each usually in the axil of a
bracteole calyx is usually modified into pappus; corolla has (5) petals,
gamopetalous and lingulate (strap-shaped); gynoecium and fruit are similar to
disc floret.
Floral Formula:% ♂ K pappus or O C (5) G (2) )
Chemical Constituents of the family: A characteristic feature of the family
is the storage of carbohydrate in the form of inulin; sesquiterpene lactones;
polyacetylenic compounds and essential oils; alkaloids of pyridine, quinoline ,
diterpenoid and pyrrolizidine group in small amounts; diterpene glycoside.
Important Medicinal Plants of the family: It includes plants having antitumour or
antibacterial activity.Some members are also commercial sources of rubber latex.
Chrysanthemum cinerarifolium: insecticide
Artemisia cina: anthelmintic
Artemisia annua: antimalarial
Artemisia absinthium: bitter tonic and choleretic
Calendula officinalis: topical use for skin infections
Arnica montana: externally in hair preparations and for bruises
Echinacea angustifolia: immunostimulant
Stevia rebaudiana: stevioside; sweetener for soft drinks.
Chicory intybus: hepatoprotective
4. Convolvulaceae
Distribution: A family of about 55 genera and 1650 species, out of which 157
species occur in India. Also called as Morning Glory family.
Identifying Morphological Characters of the family: Herbaceous more rarely sub woody to
woody, perennial climbing plants with underground parts sometimes swollen into
tuberous roots (Jalap, sweet potato); stems rarely short, upright or tufted,
usually elongate and circumnutating in action; leaves alternate, simple,
extipulate, varying from cordate to cordate-sagittal, to broad reniform to
reniform, palmately – lobed to palmatifid to palmately –compound (Ipomoea);
stems and leaves frequently contain a dull, viscous, watery to milky-white
juice; inflorescence is cymose; flowers are regular, bisexual,hypogynous, often
large and showy; flowers pentamerous; sepals five, green, gamosepalous; corolla
varying in shape from rotate to funnel-like with expanded mouth, in color from
greenish-yellow to white or through yellowish-pink to scarlet, crimson, purple
or blue, stamens five; Fruit usually a capsule, rarely a berry.
It is related to Solanaceae by virtue of its persistent calyx,
regular gamopetalous corolla, 5 epipetalous stamens, often false septum in the
ovary, bicollateral vascular bundles. But it is distinguished from Solanaceae
by the fact that it has a definite number (1or 2) of ovules in each chamber of
the ovary, the micropyle points downwards, median carples.
Floral Formula: ♂ K (5) C (5) A (5) G (2)
Chemical Constituents of the family: It includes indole, isoquinoline,
pyrrolidine and tropane and pyrrolizidine alkaloids. Purgative resins, phenolic
acids and triterpenoid saponins are also reported in some species.
Important Medicinal Plants of the family:
Ipomoea hederacea: purgative
Cuscata reflexa: as hypotensive and have bradycardiac effects
Ipomoea purga: strong purgative
Argyreia speciosa: roots in rheumatic afflications and leaves in
skin diseases and wounds
5. Labiatae
Distribution: A family of about 200 genera and 3300
species, out of which 391 species are available in India. It is also known as
Laminaceae or Mint family. It is widely distributed in Mediterranean region to
Central Asia.
Identifying Morphological Characters of the family: Herbs producing creeping runners that
spread out and root at the nodes. Square Stems, rarely cylindrical in outline
leaves opposite, decussate, mainly petiolate; leaf margin nearly always
serrate, dentate or crenate. Stems and leaves further characterized by the
presence of glandular hairs containing aromatic volatile oil. These hairs
consist of a short one-celled stalk and a head (gland) of six or eight cells.
Inflorescence a raceme or spike of verticillaster. Flowers typically
pentamerous; five fused sepals, five zygomorphic petals, four or two stamens
and two characteristic fused gynaecia. Fruit consisting of four nutlets, each
with one seed.
Floral Formula: ƒs ¡ñ K (5) C (5) A4 G (2ƒw)
Chemical Constituents of the family: Volatile oils; menthol and thymol; other
constituents include: diterpenoids and triterpenoids, saponins, polyphenols,
tannins,iridoids and their glycosides and coumarins. Pyridine and pyrrolidine
alkaloids are also present.
Important Medicinal plants of the family:
Ocmium sanctum: antipyretic, respiratory problems
Mentha arvensis: for respiratory problems
Mentha piperita: source of menthol; Flavouring, carminative
Thymus vulgaris: antispasmodic
Rosemarinus officinalis: carminative and spasmolytic
Salvia officinalis; topical antiseptic and orally as a carminative
and spasmolytic
Lavendula angustifolia: carminative and spasmolytic
6. Leguminosae
Distribution:
The family contains 600 genera and 12000 species, out of which 951
are available in India. It is divided into three sub families: papilionaceae,
mimosoideae, caesalpinoideae. Also called as pea or bean family
Identifying Morphological characters of the family: Herbs, shrub, trees, twiners or
climbers; the roots of papilionaceae have tubercles; many contain nitrogen
fixing bacteria in root nodules, which enables the availability of
physiologically usable nitrogen. Leaves alternate, and pinnately compound, two,
usually free, stipules. Flowers are bisexual and complete; Sepals 5 united,
green, petals 5, with the odd one anterior.stamens, 10 or more, free or united;
one carpel; Fruit a legume or a pod.
(i)Papilionaceae (Fabaceae):
A subfamily with 11000 species of which 754 species are available
in India. Distributed in tropical and temperate regions; herbs, shrubs or
rarely trees trees. Leaves are pinnate and sometimes the terminal leaf is
modified to form a tendril; Flowers papilionaceous (butterfly like shape);
Inflorescence is racemose; five sepals united at the base; five petals with two
lower petals fused and forming a keel-shaped structure, the two lateral ones
protruding on both sides of flower and the largest petal extending above the
flower; stamens ten, (9+1), forming a tubular structure. Fruit is a legume.
Floral Formula: ƒsƒn¡ñ K(5) C(5) A (9) + 1 G1
Chemical Constituents of the family: Flavonoids and tannins are common.
Quinolizidine and pyrrolizidine alkaloids are specific to certain genera; Isoflavonoids,
coumarins and saponins are other important phytoconstituents repoted in many
species. Lectins, high molecular weight sugar-binding proteins are present in
the seeds of many speies. Phasin from Phaseolus species is toxic to mammals.
Important Medicinal Plants of the family:
Psoralea corylifolia: various skin infections
Glycine hispida: source of proteins
Mucuna pruriens:Parkinsonism
Arachis hypogea: Fixed oil
Astragalus gummifer :demulscent, suspending and emulsifying agent
Trigonella foengraceum: source of steroids
Tolu balsam: cough mixtures and antiseptic
Peru balsam: antiseptic and expectorant
Tragacanth:
Indigofera tinctoria:
Glycyrrhiza glabra: expectorant
(ii)Caesalpiniaceae
Distribution: Formerly part of Leguminosae (Fabaceae), about 110 species are
available in India. Distributed in tropical region.
Identifying Morphological Characters of the family: Shrubs and trees, rarely climbers or
herbs; leaves pinnate or bipinnate; inflorescence, raceme; flowers zygomorphic,
resembles a shallow cup when seen from above; sepals 5, polysepalous,
imbricate; petals 5, free. The odd one always innermost, aestivation imbricate;
ten stamens, free, many taxa showing reduction in stamens (5) or development of
staminodes instead of stamens.
Floral Formula: ƒsƒn¡ñ K 5 C5 A10 G1
Chemical constituents of the family: Major ones are anthraquinones; diterpene
alkaloids are also reported in some taxa.
Important medicinal plants of the family:
Cassia acutifolia:Laxative
Cassia angustifolia: Laxative
Caesalpinia sappan: red dye
Cassia tora: Laxative
Cassia occidentalis:Laxative
Cassia fistula:Laxative
(iii)Mimoseae
Distribution: The larger genera are: Acacia (800
species) and Mimosa (500 species). Distributed in the tropical region.
Identifying Morphological characters of the family: Most members are trees or shrubs; leaves
usually bipinnate; Inflorescence head or a spike; Flowers regular, often small
and aggregated in spherical heads; 5 or 4 sepals, generally gamosepalous,
valvate, 5 or 4 petals, mostly gamopetalous, valvate; Stamens equal in number
to the petals or twice as numerous; fruit legume.
Floral Formula: ƒn¡ñ K(5-4) C(5-4) A ƒnor 10 G1
Chemical constituents of the family: Tannins and polysaccharides are common constituents of the
family
Important Medicinal Plants of the family:
Acacia senegal: gums
Acacia catechu: astringent, tanning and dyeing industry
Acacia farnesiana: perfumery
Albizzia lebbek: timber tree
7. Rubiaceae
Distribution: A family of about 500 genera and 6000 species, out of which 489
species are available in India. It is called as Madder family; widely
distributed in tropical and warmer regions.
Identifying Morphological Characters of the family: Herbs, shrubs, or trees with fibrous
roots, sometimes annually enlarged (Ipecac). Leaves simple, opposite
(decussate), entire and stipulate. Inflorescence cymose.;flowers bisexual and
epigynous; sepals four to five gamosepalus. The calyx-tube adnates to the
ovary; petals five to four, varying from shallow-rotate to elongate-tubular or
funnel-shaped with stellate limbs; stamens five to four, epipetalous; two
gynaecia; Fruit capsule , berry or drupe.
Rubiaceae is distantly related to compositae by virtue of the head
or capitulum.
Floral Formula: ¡ñK (4-5) C (4-5) A (4-5) G (2ƒw)
Chemical constituents of the family: A large diversity in constituents;
alkaloids indole, oxindole, quinoline and purine type are common; catechins;
anthraquinones, di and triterpenoids; irridoid glycosides.
Important Medicinal Plants of the family:
Cinchona ledregiana, C calisaya, C officinalis, C succirubra:
antimalarial, bitter tonic and febrifuge
Cephaelis ipecacuanha: expectorant and emetic
Uncaria gambier: astringent, tanning and dyeing industry
Coffea arabica: stimulant
Morinda citrifolia: traditional drug, anthraquinones
8. Rutaceae
Distribution: The family consists of 150 genera and 1700 species, out of which
66 species are available in India. It is widely distributed all over the world,
particularly tropical regions are rich sources of these plants.
Identifying Morphological characters of the family: It is also
called as Rue and Citrus family; shrubs and trees. Stems upright, often wiry
xerophytic, leaves are simple or compound, alternate or rarely opposite and
gland-dotted. Flowers are regular, bisexual and hypogynous, varying in colour
from yellow, white, pink to pink crimson. The disc below the ovary is prominent
and ring or cap-like; 4 or 5 sepals free or connate below and imbricate. Petals
4 or 5, free, imbricate; stamens are twice as many as the petals or numerous,
free or united in irregular bundles and inserted on the disc.
Carples 4 or 5, syncarpous or free at the base and united above,
and either sessile or seated on the disc; Fruit capsule, hesperidium or berry.
Many of the plants contain volatile oils in their secretory cavities. Membrane
crystals and hespiridin are common.
Polyembryony is common in citrus fruits.
Floral Formula: ƒn¡ñ K 4-5 C 4-5 A8, 10 ƒnG (4,5)
Chemical Constituents of the family: Essential oil is the common constituent
of this family found in lysigenous secretory cavities in the parenchyma and
pericarp. Furano and pyranocoumarins are the typical constituents of this
family. Imidazole,acridone and benzyltetrahydroisoquinoline type of alkaloids
have been reported.Many of the fruits are rich source of Vitamin C and citric
acid.
Important Medicinal plants of the family:
Citrus aurantium: as food, flavouring agent
Citrus limonia: vitamin C
Aegle marmelos: immunomodulatory activity
Ruta graveolens : formerly used as emmenagogue and spasmolytic
Pilocarpus jaborandi : Pilocarpine, used in ophthalmology
Murraya paniculata: contraceptive
9 Scrophulariaceae
Distribution: a family of 220 genera and 3000 species, out of which 258
species are available in India. It is also called as Figwort family.
Identifying Morphological Characters of the family: : Herbs or undershrubs, stems, branches
and leaves usually green and independently vegetating, Stems cylindrical to
frequently guadrangular, especially when leaves are opposite. Leaves alternate
to opposite and decussate, simple, exstipulate, often hairy, reduced to scales
(because of draught). Inflorescence a raceme of cymes or a simple raceme or
spike or if leaves are opposite, often a whorl of axillary flowers or solitary
axillary flowers.
Flowers mostly irregular, five sepals condensed through absorption
of one sepal by fusion of two sepals; five to four petals, synpetalous, varying
from rotate, to irregular tubular to elongate, irregular bilabiate to
funnel-shaped; greenish to greenish yellow or white to pure white or from red
to purple to blue. Stamens,4, didynamous sometime 2, arching over in pairs. The
posterior stamen is absent or a staminode. The anthers are divaricate. The
carpels are 2 and syncarpous. Fruit capsule.
Floral Formula:ƒs ¡ñ K (5) C (5) A4 or 2 G (2ƒwƒ|)
Chemical Constituents of the family: Cardiac glycosides, bitter irridoid
glycosides, other constituents include: steroidal and triteroenoid saponins,
cyanogenetic glycosides and anthraquinones.
Important Medicinal Plants of the family:
Digitalis purpurea: cardioactive
Digitalis lanata: cardioactive
Picrorhiza kurroa: liver ailments
Verbascum thapsus: bronchial ailments
Baccopa monnieria: brain and nerve tonic
10 Solanaceae
Distribution: A family of about 90 genera and more than 2000 species, out of
which 58 species are available in India; also called as Nightshade family.
Distributed in tropical and temperate regions of the world.
Identifying Morphological characters of the family: Herbs, shrubs, or small trees; flowers
are regular, bisexual and hypogynous; Leaves are simple, alternate, sepals 5,
united and persistent; petals vary in color( greenish-yellow, greenish-white ,
white, pink, crimson, purple), The petals are (5) and united. It is usually
funnel or cup-shaped 5 lobed. The lobes are valvate or twisted in the bud;
stamens five, epipetalous, hypogynous, along with style usually forming nectar
glands; The carples are (2) and syncarpous. Fruit, a capsule or a berry.
Floral Formula: ¡ñ K (5) C (5) A (5) G (2)
Chemical Constituents of the family: : The family is known for the presence
of tropane, nicotine and steroidal type of alkaloids.
Important Medicinal plants of the family:
Atropa belladonna : pain relief, inflammatory conditions,
anti-emetic
Datura stramonium : spasmodic affections of the respiratory organs
D metel and D innoxia: hallucinogen, source of hyoscine,
preoperative medication
Hyoscyamus niger: spasmolytic and anticholinergic properties;
atropine is used in ophthalmology.
Withania somniferum:antioxidant, immunomodulatory
Duboisia species: source of tropane alkaloids
Solanum nigrm: source of steroids, hepatoprotective
Capsicum annum: counter irritant
Nicotiana tabacum: source of nicotine; insecticide
11 Umbelliferae
Distribution: The family consists of 275 genera and 3000 species, out of which
176 species are available in India. Members of the family are distributed to
temperate regions of the northern hemisphere. Presently called as Apiaceae.
Also known as Parsley family.
Identifying morphological characters of the family:
Generally as herbs. The stem is usually fistular (hollow at
internodes and solid at nodes); The leaves are alternate, simple, often much
divided, petiole usually sheathing at the base; Inflorescence: an umbel,
usually compound, surrounded by an involucre of bracts or bracteoles; The
flowers are regular, small, epigynous, bisexual or polygamous; 5sepals, free,
adnate to the ovary, often considerably reduced in size; the petals are 5,free,
adnate to the ovary. The margin is often curved inwards, valvate or imbricate;
5 stamens, free, alternating with the petals, epigynous; carpels are (2),
syncarpous; fruit is a cremocarp, consisting of two indehiscent carpels,
laterally or dorsally compressed, breaking up into two parts, called mericarps,
which are attached to a slender, often forked axis (carpophore). Each mericarp
usually shows five longitudinal ridges and oil canals (vittae).
Floral Formula:ƒn % ¡ñ K 5 C5 A5 G (2ƒw)
Chemical Constituents of the family: Rich source of essential oils; some
species accumulate alkaloids and furanocoumarins, coumarins, terpenes and
sesquiterpenes and triterpenoid saponins.
Important Medicinal Plants of the family:
Carum carvi: carminative and spice
Coriandrum sativum: carminative and spice
Cuminum cyminum: carminative and spice
Anethum graveolens: carminative and spice
Foeniculum vulgare: mild carminative and an excellent eye wash
Pimpinella anisum: expectorant, spasmolytic and carminative
Trachyspermum ammi: carminative, source of thymol