The present project was undertaken with the analysis of the
antimicrobial activity of the some aromatic plants or herbs.
The science of ayurveda is a unique holistic system, based
on the interaction of body mind and spirit in ayurveda, the origin of all
aspects of existence is pure intellect or consciousness. The treatment
of Ayurveda is based on Indian herbs, which has a healing energy.
Ayurveda has focused on the various aspects of herbs and there
practice in our day to day life. Ayurveda is prevalent in India since
2000 B.C.and it means the science of life and drives the medicine form
nature. Ayurveda is a Sanskrit word. Ayur mean “life” and Veda mean
Herbs are a plant or plant extract including leaves, stem,
seed, and flower, bark, which are bestowed with nourishing and
healing elements. In herbal medication herbs are used for their
therapeutic and medicinal value.
Higher and aromatic plants have traditionally been used in folk
medicines as well as to extend the self life of foods showing inhibition
against bacteria, fungi and yeast. Most of there properties are due to
essential oils produced by their secondary metabolism. Essential oils
are extracted from several plant species and able to control
microorganism related to skin, dental cares, and food spoilage,
including Gram-negative and Gram-positive bacteria.
Many countries have maintained research programs to
screen traditional medicines for antimicrobial activity, as is the case of
the Indian, Africa and Italy etc.
Plants from India biomes have also been used as natural
medicines by local population in the treatment of several tropical
diseases, including malaria, leishmaniasis, fungal and bacterial
infections. Extracts, fractions and compounds isolated from some
aromatic plants were able to control one or more microorganisms.
Aromatic plants and spices have great importance for food, cosmetics,
and pharmaceutical industries.
Their use has taken place since ancient time, and despite
many of them were substituted by synthetic ones, the demand for
natural products is increasing. Leaves from Mentha and Lemon Grass
have been used as spices and teas after drying. While the essential oil
is utilized in cosmetics pharmaceuticals. The essential oils contents in
different species is influenced by genetic material, culture conditions
environment and finally, by crop and post crop processes.
Objective: The object of the present investigation was to study
invitro antimicrobial activity of the extracts from two aromatic
plants viz. Mentha and Lemon Grass.
REVIEW OF LITRATURE
An herb is a plant with no woody stem above ground distinguished
from a tree or a shrub. However, that is meaning as per botany. In
general, any part of the vegetable species that can be used for
medicine, cosmetic culinary or such purposes are known as herbs. The
roots, leaves, bark, fruits, flowers, stem or any part of the plant can
be used for such purposes.
Also an herb is valued for flavor, scent or other qualities.
Herbs are used in cooking and for spiritual purpose. Herbs are the
highest quality food known to man containing vitamin, mineral and
trace element in natural balance and harmony (Ratnakar, 1997).
HISTORY OF HERBS
The use of plant for medicinal purpose is as old as our civilization. The
first known written record of creative plants was of Sumerian herbal of
2200 B.C. In the fifth century B.C, the Greek doctor Hippocrates, list
out some 400 herbs in common use. Dioscorides in the first century
A.D wrote an herbal plant by using 600 plants which ultimately
become the base for many later works.
Herbs have been used for uncounted time for various
purposes like healing the sick. Most of the people still continue to use
herbs to benefit their bodies. Many scientific studies are still continued
with modern research following the lead of old folklore and herbal uses
to help finding new western medicine. Man has also been aware of the
effect of herbs on the body; mind and emotion for e.g. flower were
utilized to attract love. Fragrant plants were work to heal the body and
give a sense of well being (Kapoor, L.D., 1990).
Herbalists today believe to help people to build their good
health with the help of natural resources. Herbs are considered to be
food rather than medicine because they are complete all natural and
pure as nature intended. When herbs are cleansed, it gets purified
itself (Bisset N.G., 1994).
For thousand of years, human have been used the herbs as following -
In cooking for flavorings foods.
To protect us against germs.
As medicine to heal when we are sick.
The ancient history of Indian herbs depict that the Rig Veda, the oldest
document of human knowledge carries the evidence of the use of
medicinal plants in the treatment of various diseases. The tradition of
Ayurveda originated around 5000 years ago. The basic concept of
Ayurveda is to maintain the balance of life with the environment along
with the usage of some herbs that are widely cultivated in India for its
medicinal usages. The ancient book of Charka, which was written
around 1000 B.C., concentrates on medicine and depicts that in
ancient times the practitioners used to treat diseases with the help of
the decoctions from different herbs.
The Indian herbs are considered helpful in building good health with
the help of natural sources (Thakur and Mandal, 1992).
The Indian herbs are used as culinary herbs, Aromatic herbs ,
ornamental herbs and medicinal herbs or in some cases even spiritual
usage .In medicinal and spiritual use any of the parts of the plant
might be considered herb including leaves, roots, flowers, seeds, resin,
root bark, inner bark, barries, and sometimes the pericarp or other
portions of the plant . Culinary herbs are distinguished from
vegetables even spices; they are used in small amounts and provide
flavor rather than substance to food.
The other usage of Indian herbs is as the Aromatic herbs
which are pleasant smelling flowers or foliage. Oils from these
aromatic herbs can be used to produce perfumes, toilet cologne, oils
and are some times used as essential oils (Basu, 1971).
Types of Ayurvedic Herbs
Ayurveda is the ancient science of life, which aims to promote the
healthy lifestyle, free of diseases. The herbs have been in used
since the ancient times, when people were not familiar with allopath
and other form of treatments. The Ayurvedic herbs can be classified
into five types: according to origin, according to habitat, according
to various actions, according to actions on doshas and according to
there uses (Chunekar, 1997).
Classification of Herbs
According to Rastogi et al, (1995) Herbs are classified in many
ways. Some of them are: ----
According to the usage.
According to the active constituents.
According to the period of life.
1) According to the Usage, the herbs are classified into four
parts: Medicinal herbs, Culinary herbs, Aromatic herbs,
a) Medicinal herbs:
Medicinal herbs have curative powers and are
used in making medicines because of their healing properties.
b) Culinary herbs:
Culinary herbs are probably the mostly used as
cooking herbs because of their strong flavors like mint, parsley,
c) Aromatic herbs:
Aromatic herbs have some common uses
because of their pleasant smelling flowers or foliage. Oils from
aromatic herbs can be used to produce perfumes, toilet water and
various scents. For e.g. mint, rosemary, basil etc.
d) Ornamental herbs:
Ornamental herbs are used for decoration because
they have brightly colored flowers and foliage like lavender, chives.
2) According to the active constituents present in them, the
herbs are divided into five major categories: Aromatic (volatile oils)
Astringents (tannins), Bitter (phenolic compounds, saponins, and
alkaloids), Mucilaginous (polysaccharides) and Nutritive (food
a) Aromatic herbs:
Aromatic herbs, the name are a reflection of
the pleasant odor. They are used extensively both therapeutically
and as flavorings and perfumes. Aromatic herbs are divided into
two subcategories: stimulants and nervines.
Stimulant herbs: increase energy and activities of the body or
organs, and most often affect the respiratory, digestive, and
circulatory systems. E.g. fennel, ginger, garlic, lemon grass.
Nervine herbs: are often used to heal and soothe the nervous
system, and often affect the respiratory, digestive, and circulatory
systems. E.g. ginger, catnip.
b) Astringent herbs:
Astringent herbs have tannins, which have the
ability to precipitate proteins, and this tightens, contracts or tones
living tissue, and helps to halt discharges. They affect the digestive,
urinary, and circulatory systems, and large doses are toxic to the
liver. They are analgesic, antiseptic, antiabortive, astringent,
homostatic, and styptic. For e.g. peppermint, red raspberry.
c) Bitter herbs:
Bitter herbs are named because of the presence of
the phenols and phenolic glycosides, alkaloids or saponins and are
divided into four subcategories: laxative herbs, diuretic herbs,
saponin-contaning herbs and aloaloid-contaning herbs.
Laxative bitter herbs: Include alterative, antipyretic, purgative,
hepatonic, vermifuge and blood purifier. For e.g. aloe, cascara,
licorice, pumpkin, senna, yellow dock, barberry, safflowers and
Diuretic herbs: Induce loss of fluid from the body through the
urinary system. The fluids released help cleanse the vascular
system, kidneys, and liver. They are alterative, antibiotic,
antipyretic, antiseptic and blood purifier in nature. For e.g.
asparagus, blessed, burdock, butcher’s broom, corn silk, dandelion,
dog grass, grapevine and parsley.
Saponin-containing herbs: Are known for their ability to produce
frothing or foaming in solution with water. The name saponin comes
from the Latin word for soap. They emulsify fat soluble molecules in
the digestive tract, and their most important property is to enhance
the body’s ability to absorb other active compounds. Saponins have
the ability to effectively dissolve the cell membranes or red blood
cells and disrupt them.
d) Mucilaginous herbs:
Mucilaginous herbs derive their properties from
the polysaccharides they contain, which give these herbs a slippery,
mild taste that is sweet in water. These herbs are most effective
topically as knitting agents, and are also used topically in the
digestive tract. They eliminate the toxins from the intestinal
system, help in regulating it and reduce the bowel transit time.
They are antibiotic, demulcent and detoxifier in nature. For e.g.
althea, aloe, burdock, comfrey, kelp, slippery elm, Irish moss.
e) Nutritive herbs:
These herbs derive both their name and their
classification from the nutritive value they provide to the diet. They
are true foods and provide some medicinal effects as fiber,
mucilage, and diuretic action. But most importantly they provide
the nutrition of protein, carbohydrates, and fats, plus the vitamins
and minerals that are necessary for adequate nutrition. For e.g.
rosehips, acerola, apple, asparagus, banana, barley grass, bee
f) According to the period of life:
Herbs also can be classified as annuals,
biennials, and perennials. Annuals bloom one season and then die.
Biennials live for two seasons, blooming the second season only.
Ones established, perennials live over winter and each season.
Annual herbs complete their life cycle in one year; start them from
seed. Annual herbs include: anise, basil, borage, calendula, and
Perennial herbs grow for more then one season and include sweet
marjoram, parsley, mint, thyme and chives.
Biennial herbs are plants which live two season and bloom in the
second season only. E.g. caraway, prime rose.
HERBAL EXTRACTS AND OIL
ESSENTIAL OILS –
Essential or aromatic oil is a concentrated, hydrophobic liquid
containing odoriferous, volatile aroma compounds from plants which
are called aromatic plant. Oil is essential in the sense that it carries a
distinctive scent of the plant. It is free from enzyme and also
Essential or aromatic oils are generally extracted by
distillation. They are used in perfumes, cosmetic and bath product for
flavoring food and drinks for medicinal purpose and household cleaning
products (Banerjee and Nigam., 1977).
Some oils are –
ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL PLANTS
Nature has been a source of medicinal agent for thousand of years and
an impressive number of modern drugs have been isolated from
natural source. Various medicinal plants have been used for years in
daily life to treat disease all over the world. Plants produce a diverse
range of bioactive molecule making them a rich source of different
types of medicine. Plants with possible antimicrobial activity should be
tested against an appropriate microbial model to confirm the activity
and to ascertain the parameter associated with it. The effect of plant
extracts on bacteria has been studied by a large number of
researchers in different part of the world (Ahmed et al., 2001).
In the present work a few selected medicinal flora were
screened for potential antimicrobial activity.
PUDINA (Mentha arvensis)
s an herbaceous perennial plant growing to 10-60cm (rarely to 100cm)
tall. The leaves are in opposite pairs, simple 2-6.5cm long and 1-2cm
broad, hairy and with a coarsely serrated margin. The flowers are pale
purple (occasionally white or pink) in clusters on the stem, each flower
is 3-4mm long (Gupta et al., 1997).
Field mint, wild mint or corn mint is a species of mint native to
the temperate region of Europe, western and central Asia, east to the
Himalaya and eastern Siberia. It is in flower from May to October and
the seeds ripen from July to October.
Part used - whole plant, oil
It has characteristically pure and refreshing odor, pungent
and burning taste. Menthol and methyl acetate are responsible for the
pungent and refreshing odor; they are mostly found in older leaves
and are preferentially formed during long daily sunlight periods.
The entire plant is antibacterial, antifebrile, it yield an
essential oil and menthol which exert through their rapid evaporation,
a slightly anesthetics and has some local effect. It is effective in
headache, rhinitis, cough and sore throat.
TAXONOMY OF PUDINA -
Kingdom - Plantae
Division - Angiosperm
Class - Eudicots
Order - Lamiale
Family - Lamiaceae
Genus - Mentha
Species - arvensis
Leaves raw or cooked. A reasonably strong mint flavor with
a slight bitterness. It is used as a flavoring in salad or cooked foods. A
herb tea is made from the fresh or dried leaves. An essential oil from
the plant is used as a flavoring in sweets and beverages. The leaves
contained about 0.2% essential oil.
Corn mint like many other members of this genus is often
used as domestic herbal remedy; it is used for antiseptic properties
and its beneficial effect on the digestion. The whole plant is
anesthetics, antiseptic, antiphagistic, antispasmodic, aromatic,
stimulant and stomachic. The tea made from the leaves has
traditionally been used in the treatment of fever, headaches, digestive
disorder and various minor ailments. The leaves are harvested as the
plant comes into flower and can be dried for later use. The plant is
used as an insect repellent. Also used to form menthol crystals, in
flavoring toothpaste, mouthwashes and pharmaceuticals.
Oil is good for the nervous system acting as a regulator and sedative.
Menthol is well known as a cardiac tonic in pharmaceutical
preparation. It is a good blood cleanser because it is antiseptic and
anti bacterial it can be used in swollen gums, mouth wash and mouth
ulcer. Philips and Foy.N.
The essential oil of peppermint (up to 2.5% in the dried
leaves) is mostly made up from menthol (50%), menthone (10 to
30%), menthyl Easters (up to 10%) and further monoterpene
derivative (pulegone, piperitone, menthofurane) Traces of
jasmine(0.1%) improves the oil quality remarkably(Vyas et al.,1979).
Antimicrobial activity of Mentha:
Several studies indicate that the essential oils of the Mentha possess
biological activity against several bacteria.
According to Ohno et al., (1995), there are differences in the
activity of oil to other subproducts, due to the structure activity
relationship. Many of the oil components may possess the ability to
break or to penetrate the lipid structure present in the Gram-negative
Trabulsi et al., (1992) studied that the essential oil of Mentha
showed the least susceptibility against E.coli ATCC 25922 and have the
minimum zone of inhibition.
Regarding the strains of Staphylococcus aureus, it was
observed that all of the tested substances presented antimicrobial
activity, characterized by the presence of zone of inhibition with
diameters that varied from 9mm to 16mm for the strain S.aureus
Lemon Grass (Cymbopogon flexusosus) -
TAXONOMY OF LEMON GRASS-
Kingdom - Plantae
Division - Angiosperm
Class - Monocots
Order - Poales
Genus - Cymbopogon
Species - flexusosus
Lemon Grass is an aromatic, perennial, tall grass with
rhizomes and densely tufted fibrous roots. It has short underground
stems with ringed segment, coarse, green, slightly leathery leaves in
dense cluster terminating in a long bristly point. The blades of the
grass are about 90cm long and 0.5cm wide.
Lemon grass contains an essential oil. This oil is sherry colored
with a pungent taste and lemon like odor with citral as the principal
Lemon grass is native to India. It is widely used as a herb in
Asian cuisine. It has a citrus flavor and can be dried and powdered or
used fresh. Cymbopogum is a genus of about 55 species of grasses
native to warm temperate and tropical region. Lemon grass is
commonly used in teas, soups and curries. It is also suitable for
poultry, fish and seafood.
Research also shows that lemongrass oil has antifungal and pesticide
properties. Lemon grass is also known as Gavati chaha. Lemon grass
oil is applied on the ancient manuscript found in India in oriental
research institute Mysore for preservation, which acts as a pesticide. It
is supposed to help in relieving cough and nasal congestion.
Lemon grass oil revitalizing the body and relieves the symptoms
of headache and helps to combat nervous exhaustion and stress
related condition. It is useful in respiratory infection such as sore
throats, laryngitis and fever and helps to prevent spreading of
infectious disease. It helps to tone the muscles and tissues, relives
muscle pain by making the muscle suppler.
Lemon grass is beneficial in strengthening the function of
stomach and promoting its action. It is beneficial in the treatment of
indigestion. Lemon grass oil also treats spasmodic, affection of the
bowels, gastric irritability and cholera(Hugo & Russell).
Lemon grass oil has a lemony, sweet smell and is dark yellow to
amber and reddish in color with a watery viscosity. The principle
chemical constituent are citronella, geranial and citronellal, they have
antiseptic action, hence their use in household disinfectant and soaps.
It is fresh smelling oil that can be used with success for revitalizing a
tired body and mind as well as keeping the family pet free of flies and
Fresh lemongrass contains an essential oil which has substantial
amount of citral. Dry herbs yield 0.4% essential oil containing 72.3%
Lemon grass is commonly used in teas, soups and curries. It is also
suitable for poultry fish and seafood (Hugo and Russell., 1995).
Antimicrobial activity of Lemon Grass:
Baratta et al., (1998) studied that the zone of inhibition exhibited by
the essential oil of Lemongrass was 33mm against S.aureus MTCC
3160 whereas the zone of inhibition yielded against E.coli MTCC 1089
Lemongrass (Cymbopogon flexosus L.) oil (ranging between 25 and
500 ppm) was tested for antifungal activity against Colletotrichum
coccodes, Botrytis cinerea, Cladosporium herbarum, Rhizopus
stolonifer and Aspergillus niger in vitro. Oil-enrichment resulted in
significant (P < 0.05) reduction on subsequent colony development for
the examined pathogens. Fungal spore production inhibited up to 70%
at 25 ppm of lemongrass oil concentration when compared with
equivalent plates stored in ambient air. In the highest oil concentration
(500 ppm) employed, fungal sporulation was completely retarded.
Lemongrass oil reduced spore germination and germ tube length in C.
coccodes, B. cinerea, C. herbarum and R. stolonifer with the effects
dependent on oil concentration. However, lemongrass oil
(up to 100 ppm) accelerated spore germination for A.niger. Work is
currently focusing on the mechanisms underlying the impacts of
essential oil volatiles on disease development with a major
contribution to limiting the spread of the pathogen by lowering the
spore load in the storage/transit atmospheres as well as the use of
essential oil as an alternative food preservative.
MATERIALS AND METHODS –
MATERIAL REQUIRED FOR PREPARATION OF PLANT EXTRACT
Plant parts (powdered form)
Sterilized glass wares (iodine flask, test tube, funnels, test
Tube stand, thermometer)
Whatmans filter paper (no.1)
Instruments (oven, water bath, chemical balance,
Chemical (methanol, distilled water, hexane, RO water)
METHODS FOR PREPARATION OF PLANT EXTRACT -
Solvent extraction -
Hydrocarbon solvents (hexane or methanol) were generally
Plants material was dissolved in these solvent and filtration
was done after 24 hours.
The filtrate was concentrated by distillation.
Protocol for solvent extraction –
Weighed the total quantity of powdered plant parts
using digital weight balance.
Divided each plant powder into two equal fractions for
dilution in – hexane and methanol.
Equal quantities were dissolved in the above two
solvents and kept them overnight.
On the next day filtered out the extracts.
The filtered extracts were kept for distillation in a water
bath heated at 95oC for aqueous extracts and at 70oC
for hexane and methanol extract.
The concentrated extract were kept in separate test
tube and covered with aluminum foils and stored in
refrigerator for further use.
The table no 1. Given below, list the range of bacterial organisms used
through out the study. These organisms were used for the
investigation of antibacterial activity of extracts of Pudina and Lemon
grass. The bacteria were propagated using the conditions described in
table 1 according to the recommendations of the supplier.
Bacteria used in this study
S.No. Bacterial Liquid Solid Temp.(CO) Strain
Species Medium Medium No.
1) S.aureus NB NA 37OC MTCC – 737
2) E.coli NB NA 37OC MTCC - 452
NA – Nutrient Agar
NB – Nutrient Broth
MTCC – Microbial Type Culture Collection
METHODS FOR ANTIMICROBIAL ACTIVITY TESTING –
Well diffusion method –
This method is used in case of low concentration
extracts suspected to show some antimicrobial activity.
Comparatively require more quantity unlike antibiotics, thus
wells are needed to be bored in the culture plates. It is a
1. Media preparation:
Dissolved 18.5gms. Of Nutrient Agar in 500 ml of distilled water. The
composition of Nutrient Agar was peptone=10 gm/lt, beef extract
=10gm/lt, NaCl =5gm/lt and agar =12gm/lt.
After dissolution the media was kept for sterilization in
autoclave at 15lb/inch pressure and 121 C temperatures for 15
minutes, ph. was checked and set at 7.
2. Culture preparation:
The surface of the laminar air flow was sterilized with UV for 15
minutes. After switching off UV. The freshly prepared media were
inoculated with 100µl of E.coli and S.aureus cultures separa .Media
was cooled to at least 45oC before inoculation with bacteria.
Fifteen ml of inoculated media was poured into each petri-plate for
each bacterial culture. One replica for each test was made for better
result. After setting of culture plates, wells were bored. The wells were
filled up with 50 µl of concentrated extract with the help of
micropipette. The petri-plates were covered and incubated for 24
hours. After 24 hours the petri-plates was examined.
Methodology of testing:
SELECTION OF PLANTS
POWDERING OF THE PLANT PARTS TO
PREPRATION OF PLANT EXTRACTS IN:
FILTRATON OF EXTRACTS
WELL- DIFFUSING METHOD
Antimicrobial activity of Mentha arvensis:
Zone of inhibition in methanol extract of Mentha arvensis against
S.aureus was 22mm as shown in Fig 1.whereas its hexane extract
yielded a zone of 15mm (Fig 2) against S.aureus.
Zone of inhibition in methanol extract of Mentha against E.coli was
12mm as shown in Fig 3 and its hexane extract yielded a zone of
13mm against E.coli (Fig 4).
Antimicrobial activity of Lemongrass:
Zone of inhibition in methanol extract of Lemon grass against S.aureus
was 23mm that shown in Fig 5 whereas its hexane extract yielded a
zone of 17mm against S.aureus.(Fig 6) .
No activity was detected in both methanol and hexane extract of
Lemon grass against E.coli as shown in Fig 7 and 8 respectively.
No activity was detected in negative control in both methanol and
hexane against E.coli that shown in Fig 9 and 10 respectively.
Zone of inhibition in case of Ciprofloxacin was 36mm against S.aureus
that shown in Fig 11.
The observations are shown in table 2. Later
Fig 1:- Zone of inhibition in methanol extract of Mentha arvensis (Pudina)
Fig 2:-Zone of inhibition in hexane extract of Mentha arvensis (Pudina)
Fig 3:-Zone of inhibition in methanol extract of M.arvensis
(Pudina) using E.coli.
Fig4:-Zone of inhibition in hexane extract of M.arvensis (Pudina)
Fig 5:-Zone of inhibition in methanol extract of C.flexusosus
(Lemon grass) using S.aureus
Fig 6:-Zone of inhibition in hexane extract of C.flexusosus
(Lemongrass) using S.aureus.
Fig 7:- N.A.D. in methanol extract of C.flexusosus (Lemongrass) is
Fig 8:-N.A.D.in hexane extract of C.flexusosus using E.coli.
Fig. 9:- Negative control in methanol using E.coli.
Fig. 10:- Negative control in hexane using E.coli.
Fig. 11:- Positive control was using S.aureus.
Table 2:-Antimicrobial activity of plant extract
TEST DIAMETER OF
S.No PLANT USED EXTRACT TYPE MICROBE ZONE OF
(LEMONGRASS) E.coli NAD
METHANOL E.coli NAD
3. Negative control
HEXANE E.coli NAD
CIPLOX S.aureus 36mm
4. Positive control (CIPLOFLOXACIN)
No Activity Detected*
NOTE: The diameter of well was 6mm, so the zone of inhibition has
Positive control showed a large diameter of 36mm while negative
controls didn’t showed any zone of inhibition. Refer to photographs
displayed under result.
In this study the antimicrobial activity of Mentha and Lemongrass was
studied against E.coli and S.aureus. First we powdered the plant parts
to be used, then plant extracts were prepared in hexane and
methanol, we used the well-diffusion method for antimicrobial activity
From the observations made it is inferred that out of the two plants
selected both of them showed antimicrobial activity while Lemongrass
showed activity against S.aureus but not against E.coli in the both
methanol and hexane extract.
Moreover we can clearly observe that the maximum antimicrobial
activity was shown by methanol extract of Lemongrass followed by
methanol extract of Mentha against S.aureus.
It was also seen that these plant extracts were found to be more
effective against S.aureus which is Gram-positive bacteria.
On comparing the type of extracts, it is clear that methanol and
hexane extracts of Lemongrass show no activity against E.coli but
Mentha showed activity against both S.aureus and E.coli.
If on the other hand comparison is done on the basis of plants
selected, Mentha have good antimicrobial activity.
According to Trabulsi et al.,(1995) the Mentha shows antimicrobial
activity against both S.aureus (9-16mm) and E.coli (minimum i.e.6-
7mm), In this study, the zone of inhibition of menthe extract was
about 22mm and 15mm against S.aureus , 12mm and13mm against
E.coli in methanolic and hexane extracts respectively .
According to Baratta et al.,(1998), the zone of
inhibition/mm of Lemongrass against S.aureus was 33mm and against
E.coli was22.3 mm. Whereas in this study, the zone of inhibition was
23mm and 17mm against S.aureus in both methanol and hexane
extracts respectively. No activity was detected against E.coli.
This discrepancy in the results may be due to the use of
different strains and different method for the study of antimicrobial
activity of plant extracts, as they used S.aureus ATCC 25923 and
MTCC 3160 and E.coli ATCC 25922 and MTCC1089 for Mentha and
Lemongrass respectively. Besides, they used disc-diffusion method for
their study on the other hand we used S.aureus MTCC 737 and E.coli
MTCC 452 and well diffusion method for our study.
Plants have met various human needs from earliest times. Their
medicinal uses similarly date back to the beginning of human
civilization. The Indian systems of Medicines, Ayurveda, Siddha, Unani
and even Homeopathy are largely plant based. The emphases for
development of new biologically active molecule have been gradually
replaced by use of the plants as medicine and food supplements.
This project work involves the assessment of the antimicrobial activity
of two plants.
The antimicrobial activity in plants may be contributed by
phytochemicals. For this two common and traditional plants were
selected processing antimicrobial properties which were Pudina and
For the work, the plant parts were taken in powdered form.
After the selection process, the extracts were prepared. Although there
are different methods of extract preparation but solvent extraction
method was chosen because of the simplicity and high yield, Extracts
were prepared in two solvents – Methanol and Hexane. The extracts
were prepared by soaking the plant parts in the solvents overnight
followed by filtration with Whatman paper and boiling the filtrate in
waterbath until an oily and viscous extract is obtained. After the
extract preparation, comes the antimicrobial testing process. For this
Agar well diffusion method was used. The media was inoculated with
the selected bacterial strain. After inoculation media was poured into
the petri plates and was allowed to set. After the media was solidified,
wells were bored into the plates and the extracts were poured into the
labeled wells, All this work was carried out in laminar air flow under
aseptic conditions and autoclaved glasswares. After which the petri
plates were incubated under optimum conditions in bacteriological
incubator at 40oC.for 24hours. After 24 hours the plants are examined
for results i.e. Zone of inhibition. If the zones were observed their
diameter was noted. The zones indicate the extent to which the growth
of bacteria is inhibited.
All the inoculation work was carried out with precautions like use
of shoe cover, face mask, head cap and constant sterilization with
The antimicrobial activity of the selected plants can be concluded as
On the basis of plants used : PUDINA >LEMON GRASS
On the basis of extracts used : METHANOL > HEXANE
Hence we can concluded on the basis of the results that these
plants extracts which are used and known to treat fungal and
bacterial diseases like Typhoid,Gonorrhoea ,
Tetanus, Syphilis, Disentery, Influenza etc.have shown their
medicinal importance as quoted in the ancient literature books.
SCOPE AND APPLICATIONS
Not only in India, but in many other countries plant have played
significant and prominent role as medicine. At one time it was felt that
the chemical synthesis would completely replace the drugs of natural
origin. In spite of the emergence of many wonder drugs from the
synthetic field, the problem of senescence and so called civilization
disease e.g. immuno deficiency, arthritis and cancer. They cannot be
tackled and therefore there is a greater demand for natural medicine
and health food, today then ever before in the world.
A large number of aromatic plants containing essential oils are
also important from the utilization point of view. Natural perfume is
one of the most remarkable phenomenons of plant utilization. The
essential oils are used in every day human life in various ways and
their consumption is rapidly increasing. A few of the common uses to
which essential oils and their derivative are put to are in the
manufacture of soaps, cosmetics, pharmaceutical preparation,
disinfectant, detergent etc.
There is ample scope for setting up of small scale extraction and
manufacturing units for indigenous medicine, pharmaceutical products
and the food processing unit at central and salient places. In the
medicinal plant sector, the world health organization (WHO) has
estimated that about 80% of the population of developing countries
rely on the modern medicine that also contain 25% drugs derived from
The derivatives of medicinal and aromatic plant are non-narcotic
having no side effect even if used for the prolonged time in permissible
doses. The aromatic plants provide the raw material for the production
of flavors, condiments, herbal cosmetic, perfumery, scented soaps,
and hair oils. Demand for these herbs is increasingly progressively
with increase in number of star hotels and multinational establishing
consumer oriented cosmetics and pharmaceutical units.
Why global resurgence in the use of green medicine?
Comparatively more safe.
Only cure where modern drugs are either unavailable or
Preventive, promotive and curative.
Beside health benefit medicinal and aromatic plant provide
crucial livelihood option for millions of rural people,
particularly women, tribal and the poorest of the poor.
In India 35 million workdays of employment per year are
contributed by collection and processing of medicinal plant.
95% of medicinal and aromatic plant are harvested and
collected from the wild.
25% modern medicine derived from the plant.
CLEANING & SANITATION OF MICROBIOLOGY LAB
Cleaning and Sanitation is major part of lab It is done to insure that
testing of material hading of sample instruments lab work place is
clean and sanitary conditions. Also to insure that bourdon in
microbiology lab remains under control. Housekeeper engaged in
cleaning and sanitation should be adequately trained in this programe.
In Daffohils laboratories plant cleaning program should be done
To clean the area suitable disinfectant with there appropriate
dilution can be used.
The disinfectant and there dilution should be made just before
The person who is carrying out cleaning should where proper
clothes, apron, gloves, masks, goggles to protect his eyes and
They should first sweep the followed by mopping with freshly
Prepared disinfectant solution.
Doors windows, ventilation duct, grills and outer area of lab
should be cleaned by same disinfectant.
It should be keep for 10 to 15 minutes and after that it should
be cleaned with pure milli Q water to remove the traces of
disinfectant. Quality control supervisor of the lab shall insure
that work place is clean and all the things are kept in proper
CLEANING AND DISINFECTION OF INSTRUMENTS
Cleaning and disinfection of instruments like oven, refrigerator,
incubator is done monthly to insure that these instruments itself does
not add any contamination to the article stored.
Incubator in the microbiology lab is instruments which are operated to
allow the microbial growth on suitable medium under appropriate
temperature. It is double walled steel chamber which is adjusted to
desired temperature by using external knob controlling the thermostat
system. As the temperature influence the microbial growth therefore
instruments is generally designed that can allow the desired
microorganism to grow at particular temperature. Variation in
temperature should not more than one degree.
Similarly refrigerator shall be used for storage, preservation of
microbial cultures, test samples, particular count TOC of standard.
Temperature of refrigerator near about 8 C .
The entire article kept inside the refrigerator or incubator shall
be properly labeled. To clean and disinfect follow the following
Power supply to the refrigerator or incubator shall be switched
off before starting the cleaning operator.
Remove all the particles from refrigerator and incubator.
Defrost the refrigerator to remove ice formation.
70% of IPA, dettol or savlon use to disinfect the area outside
and inside of refrigerator and incubator.
Carryout the moping with the swab of disinfectant.
After 10 minutes carryout moping with DI water in order to
remove the residues of disinfectant.
Microbiologist shall insure that the entire articles are put back
in the refrigerator or incubator in orderly manner.
All these activities control by microbiologist and quality control
STERILITY MONITORING OF AUTOCLAVE
Autoclave or steam sterilizer is a device like a pressure cooker in which
the killing action of heat on organism can be done by using increase in
steam. Hot saturated steam continues to enter until the chamber
reaches the desired temperature pressure (121 C and 15 pound) at
this temperature and pressure steam destroys all vegetative cells and
In Daffohils Laboratories, there is a modern automatically
controlled autoclave or steam sterilizer which is having different
chambers. Temperature and pressure of each point is maintained
automatically to load the material. Autoclave have one none sterile
side and to unload the contents there is a sterile door which is opened
inside the sterile lab. This autoclave operates under two cycles.
Cleaning and performance check of autoclave is done to ensure that
autoclave is functioning satisfactory and completing the sterilization
cycle the functioning of autoclave:
Water Pressure is above 1.2 kg on gauge off water line.
Compressed air pressure is 7.0+0.5 kg.
Door gasket pressure on sterile and non sterile door is
maintained at 3.0+0.5 kg.
Door pre condition light on control panel glows during the
process is on.
Chamber pressure in sterilization cycle is between 1.1 to 1.2kg.
Display on panel of recorded as well as pressure gauge on the
panel of autoclave.
Place one strip of autoclave places other strip along with the
material to be sterilized inside the autoclave chamber.
At the completion of cycle check the color change if there is
color change of strip autoclave is certified to the in proper
All these activities are under the control of Microbiologist and
are supervised by Quality Control Manager.
STERILITY MONITORING OF LAF (LAMINAR AIR FLOW)
Laminar air flow is an apparatus consist of an air blower in the
rear side of chamber which can produce air flow with the uniform
velocity along parallel flow lines. This cabinet employs a high
efficiency particles air (HEPA) filter which fro microorganism being
handled with the cabinet and prevent room contamination.
Cleaning and sterilized monitoring is done to ensure that:-
LAF is functioning satisfactory or not.
Air provided by filter is microbe free.
Before using the LAF. UV light for a period of 30 min is
switched on so to kill the germs if present.
A suitable disinfectant is used to clean inside and outside of
To ensure that there is proper cleaning sterilized SCDA
PLATES are exposed inside the chamber and allow it for
30-35 C for 48 hours.
If there is no growth occurs on this plate that means it is
Any leakage is HEPA filter is checked by instrument section.
Laminar Air Flow Hood