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Indian Journal of Natural Products and Resources
Vol. 3(1), March 2012, pp. 123-127
Short Communications
Efficacy of some medicinal plants against
human dental pathogens
Anupama Pathak*, Aparna Sardar, Vynkatesh Kadam,
Bhagwan Rekadwad and S Mohan Karuppayil
School of Life Sciences
SRTM University, Nanded- 431 606, Maharashtra, India
Received 2 June 2011; Accepted 2 November 2011
Dental caries is one of the most prevalent diseases having
multifactorial etiology. Most of the treatments in dental caries is
aimed at either elimination or suppression of bacteria by
antibiotics. Increased resistance of oral bacteria to antibiotics
however, has developed keen interest of researcher in herbal
treatment. In our investigation we have screened nine medicinal
plants from Marathwada region. We have proved effective
inhibition of dental pathogens by aqueous extract of plants.
Amongst selected plants leaves of Emblica officinalis Gaertn. syn.
Phyllanthus emblica Linn. and Terminalia bellirica Roxb. and
flowers of Syzygium aromaticum (Linn.) Merrill & Perry showed
three to four times more inhibition in comparison with effective
antibiotics like Carbenicillin, Tetracycline, Nalidixic acid and
Nitrofurantoin of four dental pathogens, viz. Streptococcus
mutans, Streptococcus mitis, Streptococcus sanguis and
Actinobacillus actinomycetemcomitans isolated by us.
Keywords: Dental pathogen, Dental caries, Medicinal plants,
Emblica officinalis, Terminalia bellirica, Syzygium
aromaticum
IPC code; Int. cl. (2011.01)—A61K 36/00, A61P 31/04
Introduction
Dental caries is a very common problem in
humans1. It is very prevalent in Asian and Latin
countries and least prevalent in African countries. In
India, nearly 60-70% of the child population is
affected by dental caries2. The main etiological agents
of dental caries are Streptococcus mutans, S. mitis, S.
sanguis, S. salivarius, and S. sobrinus. Fermentation
of carbohydrate by acidogenic oral bacteria is the key
factor in the development of dental caries. The acid
released through microbial action leads to
demineralization and cavitations of tooth3. S. mutans
can colonize the tooth surface and initiate plaque
formation by synthesizing extracellular polysaccharide
_____________
*Correspondent author: E-mail: [email protected]; Phone:
02462 229242; Fax: 02462-229245
from sucrose. Accumulation of plaque around the
gingival margin and subgingival region may lead to
shifts in the population of the microflora from Gram
positive to Gram negative bacteria1. These Gram
negative plaque forming bacteria may cause
periodontal disease in periodontal tissues and alveolar
bone surrounding the teeth. Several potential
periodontal pathogens have been studied and Gram
negative anaerobic bacteria such as Porphyromonas
gingivalis, Prevotella intermedia, Actinobacillus
actinomycetemcomitans and Camphylobacter rectus
are considered to represent a significant portion of
pathogenic bacteria1. Dental caries are generally
treated with effective antibiotics like Chlorohexidine
digluconate, Penicillin, Methicillin, Ampicillin,
Erythromycin and Cephalothin. However, it was
observed that herbal products used against oral
infection have more inhibitory effect on dental
pathogen. Various plants and extracts are used
traditionally for dental care. Twigs of plants like
Babul, Neem, clove oil and many others are used for
brushing teeth in India3-4. In this study, we are
reporting the efficacy of aqueous extracts of nine
medicinal plants against four pathogens causing
dental caries.
Materials and Methods
Preparation of aqueous extract
Plants were collected from Nanded, District of
Maharashtra, and identified with the help of regional
flora; powdered and stored at 4°C throughout
investigation. Few plants were purchased in powder
form from the local market. Dried leaves of
Azadirachta indica A. Juss., Acacia nilotica (Linn.)
Delile subsp. indica (Benth.) Brenan, Ocimum
basilicum Linn., Emblica officinalis Gaertn.,
Hemidesmus indicus R. Br., Terminalia bellirica
Roxb., Syzygium cuminii (Linn.) Skeels and flowers
of Spilanthes calva DC. and Syzygium aromaticum
(Linn.) Merrill & Perry were used to prepare aqueous
extract. Botanical and common names along with
their family and parts used are given in Table 1. The
aqueous extract of plant material was prepared by
using a Soxhlet apparatus. The extracts were filtered
through a musclin cloth. Filtrate was then
INDIAN J NAT PROD RESOUR, MARCH 2012
124
Table 1Plants used in this study
Sample No. Scientific name
1
2
5
3
4
6
7
8
9
Acacia nilotica (Linn.) Delile subsp. indica (Benth.)
Brenan
Azadirachta indica A. Juss.
Emblica officinalis Gaertn.
Hemidesmus indicus R. Br.
Ocimum basilicum Linn.
Spilanthes calva DC.
Syzygium aromaticum (Linn.) Merrill & Perry
Syzygium cuminii (Linn.) Skeels
Terminalia bellirica Roxb.
concentrated using reflux method at 100°C for six
hours in Soxhlet apparatus to one fourth of the
original volume and used5- 11.
Isolation of bacteria
Ten samples were collected from a dental clinic
and civil hospital at Nanded. Isolation of bacteria was
carried out using blood agar and nutrient agar. Typical
colonies were selected after sufficient growth and
subcultured on nutrient agar. Various biochemical
tests were performed to identify clinical isolates.
Isolates were identified using Bergey’s manual of
Systematic Bacteriology112-13. The clinical isolates
were inoculated into nutrient broth (Hi-media Pvt
limited, Mumbai, India) and incubated at 37°C for 24
h and the suspension was checked to provide 105
CFU/ml by dilution plate count method4, 6.
Antibacterial assay
Antibacterial assay was performed using agar well
diffusion method4. Plates were prepared and 0.1ml of
culture broth was added and spread with a sterile
spreader. A well was made in the centre of plate with
the help of a cork borer (0.65 cm). 100µl test
compound was introduced into the well and the plates
were kept in a refrigerator for diffusion for 30 min
and then incubated overnight at 37°C. The
antimicrobial activity was interpreted by measuring
the diameter of zone of inhibition in mm. Sensitivity
of the clinical isolates to six commonly used standard
antibiotics, viz. Ampicillin 25mcg, Gentamycin 10
mcg, Carbenicillin 10 0 mcg, Nalidixic acid 30 mcg,
Nitrofurantoin 50 mcg, Tetracycline 200 mcg per disc
(Hi-media Pvt, Mumbai, India) was evaluated. All
experiments were performed in the triplicates.
Results and Discussion
Four different types of organisms were isolated
from ten different clinical samples. Morphological
Family
Common name
Part used
Fabaceae
Kikar
Foliage
Meliaceae
Euphorbiaceae
Asclepiadaceae
Lamiaceae
Asteraceae
Myrtaceae
Myrtaceae
Combretaceae
Neem
Awala
Anantmul
Tulsi
Akkal khara
Clove
Jambhul
Behada
Foliage
Foliage
Foliage
Foliage
Floral parts
Floral parts
Foliage
Foliage
and biochemical characters were studied performing
different tests (Table 2). Identification of the isolates
was carried out as per Bergey’s Manual of systematic
bacteriology the organisms were S. mitis, S. sanguis,
S. mutans and A. actinomycetemcomitans.
Out of nine, eight plants inhibited the growth of
S. mitis. The inhibitory activity was comparable to
that of standard antibiotics. Among these extracts
tested, E. officinalis was most effective followed by T.
bellirica. The activities of these extract were twofold
more than that of the standard antibiotics. The order
of inhibition was as follows: E. officinalis >
T. bellirica > S. cuminii > S. aromaticum > A. indica
> A. nilotica subsp. indica > O. basilicum > S. calva
(Table 3).
S. sanguis was inhibited by seven plant extracts in
above sequence except S. calva which showed no
activity against S. sanguis. The antimicrobial activity
was 2.5 times more than the standard antibiotics.
(Plate 1).
Eight plant extracts showed remarkable inhibition
of S. mutans. T. bellirica extract showed highest
inhibition and it was three times more as compared to
Carbenicillin, Nalidixic acid and Nitrofurantoin.
Other eight extracts mentioned above also inhibited S.
mutans effectively. All the nine plant extracts showed
inhibition of A. actinomycetemcomitans. T. bellirica
was more effective followed by S. cuminii and
E. officinalis. Overall three times more inhibition was
observed with plant extracts when compared with
standard antibiotics. The order of inhibition was as
follows T. bellirica > S. cuminii > E. officinalis > S.
aromaticum > A. nilotica subsp. indica > A. indica >
S. calva > H. indicus > O. basilicum (Plate 1).
It is very common practice to use antibiotics like
Penicillin,
Methicillin,
Ampicillin,
CHX,
Erythromycin and Cephalothin against bacteria
SHORT COMMUNICATIONS
125
Table 2Morphological and biochemical characteristics of clinical isolates
Character
Morphological and biochemical characteristics
DC-1
DC-2
DC-3
DC-4
Pigmentation
Pale Yellow
Yellow
Pink
White
Colony shape
Circular
Circular
Circular
Circular
Colony diameter
2 mm
3 mm
1 mm
1 mm
Elevation
Flat
Flat
Elevated
Elevated
Margin
Entire
Entire
Entire
Entire
Opacity
Opaque
Opaque
Opaque
Opaque
Morphology
Cocci
Cocci
Cocci
Rod
Consistency
Moist
Moist
Moist
Moist
Gram’s staining
Gram positive
Gram positive
Gram positive
Gram negative
Motility
Non motile
Non motile
Non motile
Non motile
Starch hydrolysis
+
+
+
+
Urease production
_
_
_
_
Gelatin hydrolysis
_
_
_
_
Glucose utilization
+
+
+
_
Sucrose utilization
+
_
+
_
Xylose utilization
_
_
_
_
Sorbitol utilization
_
_
_
_
Catalase test
+
+
_
_
H2S production
_
_
_
_
Indole production
+
+
+
+
Methyl red test
+
_
+
+
Voges proskauer test
+
+
_
_
Citrate utilization
+
+
+
+
Identified as
S. mitis
S. sanguis
S. mutans
A. actinomycetecomitans
Table 3Antibacterial activity of water extract plants and some of the standard antibiotics against bacteria isolated from dental caries
Plant Extract/Antibiotics
Spilanthes calva
Azadirachta indica A. Juss.
Acacia nilotica (Linn.) Delile subsp. indica (Benth.) Brenan
Ocimum basilicum Linn.
Syzygium aromaticum (Linn.) Merrill & Perry
Emblica officinalis Gaertn.
Hemidesmus indicus R. Br.
Terminalia bellirica Roxb.
Syzygium cuminii (Linn.) Skeels
Ampicillin 25 mcg/disc
Gentamycin 10 mcg/disc
Carbenicillin 100 mcg/disc
Nalidixic acid 30 mcg/disc
Nitrofurontoin 30 mcg/disc
Tetracyclin 200 mcg/disc
S. mitis
10.3±0.57
11.6±0.57
11±0.57
10.6±0.57
19.3±0.57
24.6±0.57
23±00
19.3±0.57
11.3±0.5
11.3±0.5
11.6±0.57
10.3±1.7
11±00
10.3±1.7
causing dental caries. As these antibiotics are active
only against planktonic bacteria, more antimicrobials
are now screened for their effect against oral
bacteria3. Use of plant and plant products are good
alternative to antibiotics. Plant product like clove oil,
fresh twigs of babool and neem, etc. are used by
Zone of inhibition in mm
S. sanguis
S. mutans
A. actinomycomitans
0±00
11.6±0.57
13±1.0
10.6±1.1
13.6±0.57
16.6±0.57
11.3±1.1
19.3±0.57
20.6±0.57
10.6±0.57
14±1.00
10.3±0.57
23.6±1.15
00±00
28.6±1.15
29.6±0.57
29.6±0.57
32.6±0.57
00±00
10.3±0.57
11±0
28.6±1.1
33.6±1.1
36.3±2.3
25±00
26.3±1.15
33.6±1.15
10.6±1.1
10.0±0.0
12.3±1.1
12±00
12.3±1.1
10.6±1.1
11.3±1.15
13±1
12.3±0.57
12.6±0.5
11±00
12±2
0±00
10.6±0.57
10.6±1.1
11.3±0.5
10±00
12.3±1.1
villagers in India and also they have been validated by
various research findings14-15. Many popular tooth
pastes contained extracts of plants which include
clove, menthol, neem and triphala2. Triphala which is
the mixture E. officinalis, T. bellirica and T. chebula
is widely used as a mouthwash and for mouth ulcers.
126
INDIAN J NAT PROD RESOUR, MARCH 2012
Plate 1  Inhibitory effect of aqueous extract of selected plants on dental pathogens
SHORT COMMUNICATIONS
Conclusion
Based on results it is concluded that T. bellirica,
E. officinalis and S. aromaticum possess antimicrobial
activity against pathogens causing dental caries.
Selected plant extracts are 2-3 folds more effective
than common antibiotics and these plants are very
safe and have acceptable taste.
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