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ETHNOBOTANICAL AND PHYTOCHEMICAL STUDIES ON SOME MEDICINAL
ARID ZONE PLANTS OF NAGAUR DISTRICT
INTRODUCTION
The North-Western part of the state Rajasthan is a part of Thar Desert and it lies between
2303' to 30012' North latitudes and 6903' to 78017' East longitudes. It covers an area of about
3,42,239 sq km, representing nearly 11% of total area of Indian sub continent. About 61% of the
total hot arid zone of country lies in Western Rajasthan (Singh and Shankarnarayan, 1986). It
spreads over 12 out of 33 districts namely Barmer, Bikaner, Churu, SriGanganagar,
Hanumangarh, Jalore, Jaisalmer, Jhunjhunu, Jodhpur, Nagaur, Pali and Sikar.
Physiographically, it is the eastern extension of Sahara-Thar desert covered by shifting
and fixed sand deposits.
This region of Rajasthan suffers periodic droughts and comprised of isolate and dreary
regions which are occupied by fixed or mobile dunes. The vegetation consists of xerophytes
which are stunted or prickly shrubs and perennial herbs capable of drought resistance. Many
artiodactyls, insects pests and rodents are the main groups of those animals who are responsible
for the destruction of plants diversity and identification of desertic conditions. In the Thar desert
around 10% of the existing plant diversity is endangered. Among the flora the medicinal plants
like Tumba (Citrullus colocynthis), Rohida (Tecomella undulata), Khejri (Prosopis cineraria),
Babool (Acacia senegal), Kankero (Maytenus emarginata), Bordi (Ziziphus glabarata), Jal
(Salvadora oleoides), Kair (Capparis decidua), Nagauri Ashwagandha (Withania somnifera),
Guggal (Commiphora wightii), Bhur hingani (Solanum surattense), Andho khimp (Ephedra
foliata), Urginea indica etc. are depleting and becoming endangered (Sinha, 1997). In these
regions the plant diversity is subjected to intense population pressure. Trees, shrubs and even
their roots are mercilessly exploited by human beings for fuel fodder, fencing, construction and
medicinal use.
In arid region plants are adapted to soil moisture stress, dryness of air and high
atmospheric temperature. Arid zone plants show morphological adaptation that enables them to
survive under lack of moisture and prolonged periods of drought.
Physiography of Study Area
Nagaur District is situated between 260.25” & 270.40” North Latitude & 730.10” &
750.15” East Longitude. It is situated amidst seven districts namely Bikaner, Churu, Sikar,
Jaipur, Ajmer, Pali, Jodhpur. Nagaur is the fifth largest district in Rajasthan with a vast terrain
spreading over 17,718 sq. K.M. Its geographical spread is a good combine of plain, hills, sand
mounds & as such it is a part of the great Indian Thar Desert.
Nagaur has a dry climate with a hot summer. Sand storms are common in summer.
The climate of the district is conspicuous by extreme dryness, large variations of
temperature & highly variable rainfall. The mercury keeps on rising intensely from
March till June. These are the hottest months. The maximum temperature recorded in
district is 470 C with 00 C as the lowest recorded temperature. The average temperature of
the district is 23.50 C. The winter season in the extends from mid November till the
beginning of March. Rainy season is of a short during from July to mid September. There
are ten raingage stations, namely - Nagaur, Khinvsar, Didwana, Merta, Parbatsar,
Makarana, Nawa, Jayal, Degana & Ladnun in the district. The average rainfall in the
district is 36.16 cm & 51.5 percentage humidity.
The district of Nagaur is poor in forest resources. The total area under including
hills, is reported to be 240.92 Sq.kms., which is 1.3 percent of total geographical area of
the district. Scanty rainfall & other geographical constraints account for this. The western
part of the district is divided of natural vegetation cover except for low hurbs & grass
which grows on low sand dunes. However, the south-eastern part of the district & part of
the northern tehsil of Ladnun & Didwana have much greater greenery as compared to
north-west part of the district. Khejri trees are commonly found in the district. It's leaves
are used as fodder. It also gives gum. Apart from commercial value, this this tree is
considered holy. The tree also plays an important role in checking soil crosion.
Medicinal Plants
Plants are important source of medicines. These are used by the human beings for the
treatment of many diseases from ancient time. There are so many references about natural
vegetation, those are used as medicines in the ‘Rigveda’ which is the India’s ancient Religious
Grantha.
The Indian traditional clinical method ‘Ayurveda’ is based on Chrak- Sanhita and
Susruta- Sanhita that include description of about 700 medicinal plants.
Medicinal plants were known to the early civilizations. As a matter of fact the history of
the drug plants is as the history of these civilizations. The Chinese reported to have use of drugplants, as early as 5000 to 4000 B.C. The Assyrians, Babylonians and Egyptians knew many
drug plants in about 1600 B.C. The work of Greeks viz. Aristotle (384-322 B.C.), Hippocrates
(460-370 B.C.), Pythagaras and Theophratus (370-287 B.C.) have numerous references of many
of the present day drugs.
In 77 B.C., a Roman physician Dioscorides wrote “De Materia Medica” which described
the nature and properties of all the 500 medicinal plants known at that time. His book was
considered to be the most authentic work on medicinal plants for the next 16 centuries or so.
There was no advancement in the knowledge of drug plants during the dark ages. After
the introduction of printing in Europe in the 15th century many persons published ‘Herbals’
which contained many true and false information.
Some people advanced the ‘Doctrine of Signs or Signatures’ which meant that the
appearance of a plants or its organs indicated its utility, the sign being placed there by the
creator.
Mandrake (Mandragora officinarum) was one such plant, the human body like
appearance of which led to the superstition that it was useful in the treatment of human diseases.
Medicinal importance of any plant depends on some specific substances found from the
plant as alkaloids, steroids, resins, glycosides, volatile oils, gums, tannins etc. These active
substances are present in storage organs of plants as roots, leaves, bark, seeds etc.
In the present time medicinal science has paid great attention to the study of drug plants.
The branch of medicinal science which deals with the drug plants is called Pharmacognosy,
where as the study of the action of the drug plants is called Pharmacology.
Phytochemical Aspects
At first International congress on ‘Medicinal Plant Research’ held at the University of
Munich, Germany, during September, 1976, it was estimated that 6,00,000 plant species existed
on the earth, and only some 5 per cent of them had been specifically investigated chemically and
pharmacologically.
This indicates the immense scope of research work in the field of
phytochemistry. The knowledge of the chemical composition of foods is the first essential in the
dietary treatment of disease or in any quantitative study of human nutrition. Both of these have
become important in recent years and consequently there has been a demand for better and
more up to date information about the chemistry of food.
Plant body is composed primarily of carbohydrate proteins, amino acids, nucleotides,
lipids and porphyrins. The plant parts used by desert dwellers has not been analysed fully from
nutritive value point of view. Life can not be sustained without adequate nourishment. Man
needs adequate food for growth, development and to lead an active and healthy life. Plant can
manufacture the food they need from simple chemicals derived from the soil, water and carbon
dioxide of the air.
Higher organisms on the other hand do not possess this capacity to
manufacture food from simple chemicals and hence they depend on plants or other animals for
obtaining the food they need. Procuring enough food for its survival is the main aim of life’s
struggle in all the higher organisms.
Dietary habits of populations in different regions of the world have been determined
mainly by the availability of foods locally and local practices. Man has evolved his habitual
dietary pattern to maintain good health, perhaps after a good deal of trial and error. Satisfaction
of hunger is usually the primary criteria for adequate food intake. But satisfaction of hunger
itself is not a safe guide for the selection of proper foods. For sustaining healthy and active life,
diet should be planned on sound nutritional principles.
With the increasing demand for the natural drug and to fill the void in our knowledge
regarding the chemistry of famine foods and plants of desert origin, there is urgent need to
undertake a full scale phytochemical survey of our indigenous plant to locate the potential
sources of pharmacologically active chemical compounds of alkaloid nature like tannin etc.
These nutritive contents are found in all green plants. The primary productivity of the
green autotrophic plants is the main base for the present existence of entire biosphere. It
determines the carry capacity of earth for human beings. Great importance is being laid on the
rate of energy storage in diverse ecosystem by green plants. The standing crop can be expressed
in terms of biomass i.e. organism mass and it can be measured as living weight, dry weight, ash
free weight and in calories etc. Primary productivity is the gain in the weight of organic matter
generated by photosynthesis in a given period of time. Net production is that part of gross
photosynthetic production, which is accumulated in plant after metabolic activities and hence
becomes available for utilization as food.
Amino acids in plants are found in the free and bound state. All amino acids are made up
of C, H, O and N. However, few posses sulfur also (cystein and methionine). The general
formula for amino acids is R.CH. (NH2) COOH. The group R being either a simplest hydrogen
atom (as in glycine) or a complex organic group. The group R may also show neutral basic or
acidic character and include a hydroxyl, aromatic or sulfur containing substituents. An amino
acids may be cyclic (aromatic) non cyclic (aliphatic) or heterocyclic. Due to the presence of at
least one acid or carboxylic group (-COOH) and one or more basic or amino (-NH2) group, these
acids can behave as acids towards bases and a basic towards acids, thereby they are amphoteric
compounds. The compounds are generally exists in two stereo isomeric form, L-forms and Dforms. The asymmetry exists at -carbon atom (except in glycine where R=H) only L-forms of
amino acids are encountered in plant protein. However, the D-forms of many amino acids are
found in cell wall, antibiotic peptide of many micro organism seaweeds.
Ascorbic acid is a good electron donor in photosynthetic phosphorylation acid as an
important regulator of oxidation-reduction state of protoplasm. All these properties shows that
various metabolic compounds are useful to cattle as well as human being so we investigate the
five plant species on the basis of various aspects.
Chlorophylls are the most important leaf pigments capable of photosynthesis.
pigment complex is also responsible for the green colouration of leaves.
The
Nine types of
chlorophylls i.e. chlorophyll a, b, c, d, e, bacteriochlorophyll ‘a’, and ‘b’ and chlorobium
chlorophylls 650 nm and 660 nm (Allen,1966) have been distinguished. Chlorophyll ‘a’ is
universal since it is found in all the autotrophic organisms excepting the photosynthetic bacteria;
chlorphyll ‘b’ is another important chlorophyll present in association with chlorophyll ‘a’ in all
the autotrophic higher plants and algal members of chlorophyta. The chlorophyll ‘c’, ‘d’ and ‘e’
are restricted in distribution to certain divisions of algae. Bacterio chlorophyll and chlorobium
chlorophylls have been isolated from photosynthetic bacteria.
In the leaves of green plants, the ratio of chlorophyll ‘a’ and ‘b’ is usually (but not
invariably) near about 2:1. Chlorophyll ‘a’ is normally blue green while chlorophyll ‘b’ is yellow
green. Besides, there are also other light absorbing pigments associated with chlorophyll ‘a’ and
‘b’. These are often called accessory photosynthetic pigments and are not green in colour.
Carotenoids are such pigments.
chlorophylls.
Quantitatively they are usually one third as compared to
Two groups of carotenoids are known in plants.
Hydrogen carotenoids or
carotenes and oxygen carotenoids or xanthophylls. They range in colour from purple to yellow.
Both chlorophyll ‘a’ and ‘b’ are optically active and laevorotatory but show differences
in molecular structure, absorption spectra and solubility. Chlorophyll ‘a’ is highly soluble in
petroleum ether while chlorophyll ‘b’ in methyl alcohol. Both shows an absorption maximum in
the blue violet region with peaks at about 429 and 453 nm and with minor peaks at 410 and 430
nm, respectively for ‘a’ and ‘b’. In addition they have a secondary absorption maximum in the
red region with peaks at about 600 nm and 642 nm.
In addition to primary metabolites (amino acid, sugar) common to all life forms, some
reactions lead to the formation of compounds unique to a few species as even to a single cultivar.
These reactions are classified under the “Secondary Metabolites” and their products so produced
are called secondary metabolites.
Secondary metabolites are those substances whose structure and metabolic interactions
within the cell are apparently different from those involved with the primary growth metabolism.
These substances includes Alkaloids, Antibiotics, Cardiac glycosides, Coumarins, Lignins,
Resins, Sterols, Sapogenins, Tannins, Volatile oil, Insecticidesetc.
Secondary products are produced from primary products and play an important role in
different metabolic activities of living organisms. In addition to their economic importance,
many secondary metabolites play ecological and physiological role in higher plants.
Investigations in the area of biochemical ecology indicate that some secondary
compounds produced by plants are important either to protect these plants against microorganisms and animals or to enhance to ability of one plant species to complete with other plants
in a particular habitat.
Higher plants produce a great variety of secondary products which play a minor role in
the basic life processes of the plant but often have an ecological role, such as attractant of
pollinators and chemical defense against micro-organisms, insects and higher predators. Many
of these natural products have been used as sources of large number of industrial products,
including agricultural chemicals, pharmaceuticals and food additives. Although, some of the
natural products have been replaced by synthetic substitutes because of cost considerations, a
number of commercially important high value chemicals are still being extracted from plants.
Many of the substances used in the pharmaceuticals, food, flavor and perfume industry
originate from plants and the trend over last fifty years have been towards chemical synthesis but
still the plants remain an important source of a lot of these compounds. Many compounds are
still difficult or costly to synthesize. Moreover, the increasing consumer preference for natural
food colours and flavours over their synthetic counter parts further increases our dependence on
plants.
Some of the plants are rich in secondary metabolites which are potential source of drug
and essential oils.
Biosynthesis of metabolites although controlled genetically is affected
strongly by environmental influence. As a result there are fluctuation in the concentration and
quantities of secondary metabolites such as flavonoids, phytosterols, steroidal sapogenins,
pyrethrins etc.
UNESCO (1960) has published a survey report with details of the old world medicinal
plants growing in different arid zones belonging to different families which are most adapted to
dry conditions for their growth and production of secondary metabolites in plants under limited
water supply points to the possibility of involvement of these compounds in the adaptability to
drought conditions. Much more research under controlled condition is required in this area. The
secondary metabolites have high economical and pharmaceutical importance and the industries
are deeply interested in large variety of chemical substances being produced by plants due to
their lesser toxicity. Though these substances are generally extracted from plant parts.
A number of plants have been screened for their antimicrobial activity. The antimicrobial
activity of leaves and flowers of Palicaria crispa, Sonchus asper and Xanthium strumarium
against selective micro organisms such as Staphylococcus aureus (Gram positive), Escherichia
coli (Gram negative) and a fungal pathogen Candida albicans.
Flavonoids are series of related water soluble phenolic glycosides having in common a
basic structural unit the C15 skelton of flavone or co-ester of 4- hydroxycinamic acid. They
occur universally in higher plants but are uncommon in cryptogams. They impart colour of
flowers and fruits and co-relation between flower colour and attraction of insects for pollination
is well known.
They also provide resistance to plants.
Some of the flavonoids are of
pathological significance whereas others are physiologically importance to animals.
Beside providing pigments and colour, these are also used for their therapeutic properties,
treating haemorrhagic conditions and protection against nuclear hazards.
Present study, thus aims to ethanobotanical and phytochemical studies of selected arid
zone plants from Nagour district.
IMPORTANCE OF PROPOSED RESEARCH INVESTIGATION
Plants are important source of medicines. These are used by human beings from ancient times.
Primitive people have always used many different kinds of plants as cure for various ailments.
Numerous drugs of plant origin have been found to be useful in the treatment of various
disorders. Their use has contributed greatly to a lengthening of the average human life span.
Plants, in the past, have played an important role in human nutrition and in providing other
necessities of life. Today, they are equally important and will, no doubt, remain intimately
connected with our life in the times to come. Keeping in view the importance of medicinal plants
of this semi arid region (Nagaur district) fifteen plants of high medicinal value have been
selected for ethnomedicinal studies. These plants not only have the great medicinal value but
also are very rich in nutritional value. Hence, the study of these plants regarding their
distribution, nutritive value and also the presence of some other economically important
metabolites is very essential