A Comparative Assessment of the Antibacterial Efficacy of Licorice Mouth-Rinse with Chlorhexidine on Salivary Streptococcus mutans

Abstract

BACKGROUND Dental and periodontal diseases are common problems worldwide. Strong association exists between Streptococcus mutans and dental caries. Mouthwashes like chlorohexidine and extracts of medicinal plants like liquorice have antimicrobial properties. The objective of the study was to compare the antimicrobial efficacy of licorice mouth-rinse with chlorhexidine on salivary Streptococcus mutans. METHODS A randomised control trial was undertaken in the department of Public Health Dentistry, in a tertiary care hospital of Bhubaneswar, Odisha. Children of both sexes, aged 7 to 14 years, with high risk of caries and providing willingness were included. The products used were Aqueous and Ethanolic licorice root extract – 15 gm and 375 mg / 10 ml respectively, Chlorhexidine 0.12 %. MIC of the products against Streptococcus mutans was determined. The children were divided into three groups, fifteen in each. Each participant rinsed with 10 ml of the randomly allocated prepared suspension for 1 min. Five saliva samples were collected from each, one pre-rinse and four post-rinse 2 mins, 30 mins, 1 hour and 2 hours after the intervention. Streptococcus mutans colony count and salivary pH was used to study the efficacy of the mouthwashes. RESULTS The study revealed that ethanolic extract of licorice had better antimicrobial efficacy. The efficacy of antimicrobial action of licorice extract at 30 minutes of rinsing and rise in salivary pH by use of both the preparations of licorice was significant as compared to the chlorhexidine group. CONCLUSIONS The antimicrobial and cariostatic efficacy of licorice extracts which was evident in the present study suggests and recommends that licorice can be used as a preventive regimen in clinical practice for diseases of mouth cavity especially dental caries. KEY WORDS Dental Caries, Streptococcus mutans, Licorice, Chlorhexidine, Mouth Wash

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Jemds.com Original Research Article
J Evolution Med Dent Sci / eISSN - 2278-4802, pISSN - 2278-4748 / Vol. 10 / Issue 15 / Apr. 12, 2021 Page 1042
A Comparative Assessment of the Antibacterial Efficacy of Licorice
Mouth-Rinse with Chlorhexidine on Salivary Streptococcus mutans
Jayashree Pathi1, Kumudini Panigrahi2, Ipsa Mohapatra3, Ratikanta Tripathy4
1Department of Public Health Dentistry, Kalinga Institute of Dental Sciences, KIIT University,
Bhubaneswar, Odisha, India. 2Department of Microbiology, Kalinga Institute of Medical Sciences,
KIIT University, Bhubaneswar, Odisha, India. 3Department of Community Medicine, Kalinga
Institute of Medical Sciences, KIIT University, Bhubaneswar, Odisha, India. 4Department of
Pharmacology, Kalinga Institute of Medical Sciences, KIIT University, Bhubaneswar, Odisha, India.
AB S TR AC T
BACKGROUND
Dental and periodontal diseases are common problems worldwide. Strong
association exists between Streptococcus mutans and dental caries. Mouthwashes like
chlorohexidine and extracts of medicinal plants like liquorice have antimicrobial
properties. The objective of the study was to compare the antimicrobial efficacy of
licorice mouth-rinse with chlorhexidine on salivary Streptococcus mutans.
METHODS
A randomised control trial was undertaken in the department of Public Health
Dentistry, in a tertiary care hospital of Bhubaneswar, Odisha. Children of both sexes,
aged 7 to 14 years, with high risk of caries and providing willingness were included.
The products used were Aqueous and Ethanolic licorice root extract – 15 gm and 375
mg / 10 ml respectively, Chlorhexidine 0.12 %. MIC of the products against
Streptococcus mutans was determined. The children were divided into three groups,
fifteen in each. Each participant rinsed with 10 ml of the randomly allocated prepared
suspension for 1 min. Five saliva samples were collected from each, one pre-rinse and
four post-rinse 2 mins, 30 mins, 1 hour and 2 hours after the intervention.
Streptococcus mutans colony count and salivary pH was used to study the efficacy of
the mouthwashes.
RESULTS
The study revealed that ethanolic extract of licorice had better antimicrobial efficacy.
The efficacy of antimicrobial action of licorice extract at 30 minutes of rinsing and
rise in salivary pH by use of both the preparations of licorice was significant as
compared to the chlorhexidine group.
CONCLUSIONS
The antimicrobial and cariostatic efficacy of licorice extracts which was evident in the
present study suggests and recommends that licorice can be used as a preventive
regimen in clinical practice for diseases of mouth cavity especially dental caries.
KEY WORDS
Dental Caries, Streptococcus mutans, Licorice, Chlorhexidine, Mouth Wash
Corresponding Author:
Dr. Kumudini Panigrahi,
Department of Microbiology,
KIMS, KIIT University,
Bhubaneswar, Odisha, India.
E-mail: kumudini.disha@gmail.com
DOI: 10.14260/jemds/2021/223
How to Cite This Article:
Pathi J, Panigrahi K, Mohapatra I, et al. A
comparative assessment of the
antibacterial efficacy of Licorice mouth-
rinse with Chlorhexidine on salivary
Streptococcus mutans. J Evolution Med
Dent Sci 2021;10(15):1042-1047, DOI:
10.14260/jemds/2021/223
Submission 17-11-2020,
Peer Review 13-02-2021,
Acceptance 19-02-2021,
Published 12-04-2021.
Copyright © 2021 Jayashree Pathi et al.
This is an open access article distributed
under Creative Commons Attribution
License [Attribution 4.0 International (CC
BY 4.0)]

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BA C K GR OU ND
Oral diseases are a major health concern. Dental caries is a
common and chronic childhood disease.1,2 The role of
Streptococcus mutans (S. mutans) is well established in dental
biofilm and caries formation, so preventive strategy has S.
mutans as its target.3,4,5 Mouthwashes help to reduce the
microorganism load in the oral cavity.6 Chlorhexidine
mouthwash is accepted as Gold Standard, but it has many
adverse effects.7,8 Medicinal plants such as Glycyrrhiza glabra
Linn (liquorice) is less costly and relatively safe.8 The Food and
Drug Administration (FDA) lists licorice as GRAS (Generally
Regarded as Safe) and has antimicrobial activities.9,10 But
evidence regarding the antimicrobial efficacy is lacking.
We wanted to compare the antimicrobial efficacy of
licorice mouth-rinse with chlorhexidine on salivary
Streptococcus mutans.
ME T H OD S
This was a randomised control trial, done with three
comparison groups. The present study was carried out in
Department of Public Health Dentistry, in collaboration with
Department of Microbiology, of a medical university over a
period of 3 months [from Oct - 2016 to Dec - 2016].
St u d y Po pu la ti on
Children of both sexes, of age between 7 to 14 years,
voluntarily willing to participate in the study, having a high-
risk caries criteria as established by the modified version of
Axelsson Criteria for High Risk Caries,11 were included in the
study. Subjects with history of taking antibiotics 3 months
prior to or during the course of study, presence of crowns or
restorations, extensive bridges or prosthetic constructions
and orthodontic appliances, known intolerance or allergy to
mouthwashes, age below 7 years were excluded from the
study. The children were randomly allocated to one of the
three groups, fifteen in each group. Group-1 [test] was the
Ethanolic licorice root extract (ELR), Group-2 [positive
control] was the chlorhexidine group (CLX) and Group-3 [test]
was the aqueous licorice root extract (ALR).
Sam pl e S iz e
Total sample size was calculated to be 45, taking alpha - 0.05
(5 %), beta - 0.20 (20 %), power - 0.80 (80 %), effect size - 0.25
(25 %, medium effect size). Total sample size – 45, each group
size –15, calculated using G Power 3.0.10 software.
Sam pl i ng T ec hn iq ue
Convenience sampling, for selection of study participants
(subjects were selected from an orphanage in the study. The
dietary pattern and the socioeconomic strata were thus,
standardised); with blinded allocation of study subjects into
the three study groups. The participant and investigator were
both unaware which group got which mouthwash.
Me t h od ol og y
The study was divided into two parts: In-vitro and in-vivo
phase. Procurement of licorice plant: Root powder of licorice
was collected from a registered ayurvedic centre in the city.
The aqueous and ethanolic extract of licorice mouthwash
was prepared in Department of Pharmacology. Licorice root
powder sample was soaked in distilled water [ratio 15 grams
in 100 ml] and ethyl alcohol [15 grams in 100 ml of 5 % ethyl
alcohol], respectively, for 24 h with intermittent shaking. The
active ingredients that leached out in the solvent were
subsequently filtered. The filtrate for each extract was
concentrated using a rotavapor and freeze dried using
lyophilisation, following which the residues were finely
ground, weighed, and stored at 4°C for further experiments.
In-vitro phase: Evaluation of minimum inhibitory
concentration (MIC): The aqueous and ethanolic extract of
licorice root was prepared and antibacterial activity of these
extracts was assessed by evaluating the MIC and minimum
bactericidal concentration (MBC) against S. mutans.
A stock solution (30 % concentration of the extract in
normal saline) was taken and 10 subsequent doubling
dilutions of each extract was made to obtain concentrations of
15 %, 7.5 %, 3.75 %, 1.88 %, 0.94 %, 0.47 %, 0.23 %, 0.12 %,
0.06 %, and 0.03 %, respectively. To each of the 10 test tubes,
brain heart infusion (BHI) broth and an equal volume of S.
mutans adjusted to 0.5 McFarland was added. After
incubation, MIC was detected by visual inspection.12 The
lowest concentration of the test agent showing no visible
turbidity is considered to be the MIC. Small aliquots were
taken from all the tubes in which no visible bacterial growth
would had been observed, and seeded into Mueller-Hinton
Agar (MHA) and were incubated overnight at 37° C. The
concentration at which no colonies of S. mutans appeared
were inferred to be the MBC.
In-vivo phase: Forty five subjects having, ≥ 105 CFU of S.
mutans per ml of saliva were selected and equally divided into
3 groups
The products used in the present study were: aqueous
licorice root extract - 15 g / 10 ml, ethanolic licorice root
extract - 375 mg / 10 ml and commercially available
Chlorhexidine mouthwash-Conc. of 0.12 %. Each suspension
was dispensed in 10 ml amount at one time. All of the three
mouthwashes were dispensed in similar looking opaque
bottles. All the children participating in the present study were
instructed not to brush their teeth on the day of sampling.
Unstimulated saliva samples were collected 2 h after the meal.
The children were randomly divided into the groups and the
pre-weighed dose of the allocated drug material was delivered
by the examiner for mouth rinsing
Each child was required to rinse with 10 ml of the
randomly allocated prepared suspension in the respective
group for a period of 1 min. Accumulated saliva in the mouth
is collected into sterile, labelled saliva collecting cups. Thus, for
each patient, five saliva samples were collected, i.e. one pre-
rinse sample and four post-rinse samples collected 2 minutes,
30 minutes, 1 hour and 2 hours after the mouth rinsing. The
pH of the unstimulated whole saliva collected at each interval
was analysed using a chair side kit (GC Saliva Check). The pH
paper was dipped in the sample for at least 10 sec and the
colour change was compared with the chart provided by the
manufacturer.

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The salivary samples for each individual were collected in
collecting cups in the Department of Microbiology, where
inoculation was done on Sheep BA plate and incubated in
candle jar at 37 degree C for 24 hours. Confirmation of S.
mutans was performed from colony morphology and Gram
staining finding of the smear done from the colony on SBA and
biochemical tests. Microbial counts were expressed as colony
forming units (CFUs) per millilitre of saliva.
The values of pH and counts of CFUs of S. mutans were
recorded and intergroup comparisons were made at baseline
(pre-rinsing) and after the mouth rinsing procedure.
Study tool for data collection: Proforma was used for
collecting data regarding the participant’s name, age, gender,
oral hygiene practices and dietary habits.
St a ti s ti ca l An al ys is
Statistical analysis was done by SPSS version 23. Data collected
was expressed as percentage, frequencies and means.
Association was found by using paired t-test and one way
ANOVA. Pair wise comparisons by Tukey’s multiple post hoc
procedures. Chi-square and one way analysis of variance were
used to compare the baseline information among the subjects
of 3 study groups. Paired t-test was used to evaluate the
statistical significance of the mean difference in change of pH
between respective time intervals from baseline after using
the mouthwash. Statistically significant differences between
groups were compared using Tukey's multiple post hoc
procedures.
Ethical implication: Ethical clearance and approval were
obtained from the Institutional Ethics Committee.
Participation was voluntary and subjects gave verbal assent
and written informed consent was taken from their guardian /
caregiver, before administering mouth rinse. The caregivers
had been told that the information obtained from them will be
kept completely confidential.
RE S U LT S
In this study, designed to compare the antimicrobial efficacy of
licorice mouth rinse with chlorhexidine on salivary
Streptococcus mutans, a total of 45 children were recruited,
among which males were in overwhelmingly majority,
representing 68.89 %31 of the total population. Mean age for
the ethanolic, chlorhexidine and aqueous groups were 9.27,
9.47 and 9.40 respectively. [Table 1]
It was seen from the data regarding oral hygiene collected
in the proforma that majority of study subjects in group 1 and
3 brushed their teeth twice (53.33 % and 60 % respectively)
and a higher percentage of study subjects in group 2 (53.33 %)
brushed their teeth once a day; but the overall comparison
between groups using chi-square test showed that there was
no significant difference between the groups for frequency of
tooth brushing (between the three groups, Chi-square =
2.0094 and P = 0.7341). (Chart 1)
Group 1
%
Group 2
%
Group 3
%
Total
%
Male
10
66.67
10
66.67
11
73.33
31
68.89
Female
5
33.33
5
33.33
4
26.67
14
31.11
Total
15
100.00
15
100.00
15
100.00
45
100.00
Mean age
9.27
9.47
9.20
9.31
SD age
1.33
1.64
1.70
1.53
Table 1. Distribution of Male and Females with
Mean and SD Age in the Three Study Groups (1, 2, 3)
Groups
Baseline
2 Minutes
30 Minutes
1 Hour
2 Hours
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Group 1
6.67
0.41
9.13
0.93
8.83
0.90
8.30
0.88
8.33
0.88
Group 2
6.53
0.55
7.13
0.61
7.63
0.85
7.83
0.82
7.33
0.70
Group 3
8.10
0.87
8.93
1.19
9.30
1.13
9.57
1.28
8.30
0.98
F-value
27.6874
20.4385
11.8007
11.7405
6.5418
P-value
0.0001*
0.0001*
0.0001*
0.0001*
0.0034*
Pair Wise Comparisons by Tukey’s Multiple Post Hoc Procedures
Group 1
vs. Group
2
P = 0.8362
P = 0.0001*
P = 0.0044*
P = 0.4251
P = 0.0077*
Group 1
vs. Group
3
P = 0.0001*
P = 0.8314
P = 0.3931
P = 0.0040*
P= 0.9939
Group 2
vs. Group
3
P = 0.0001*
P = 0.0001*
P = 0.0002*
P = 0.0002*
P = 0.0101*
Table 2. Comparison of Mean Salivary pH of the Three Study Groups
(1, 2, 3) Collected at 2 Minutes, 30 Minutes, 1 Hour and 2 Hours
Intervals with Respect to Baseline pH by One Way ANOVA
*P < 0.05
Groups
Changes from Baseline to
2 Minutes
30 Minutes
1 Hour
2 Hours
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Group 1
2.47
0.74
2.17
0.75
1.63
0.77
1.67
0.75
Group 2
0.60
0.39
1.10
0.66
1.30
0.62
0.80
0.59
Group 3
0.83
0.77
1.20
0.86
1.47
1.06
0.20
0.37
% of change
in
Group 1
37.00 % #, P =
0.0001*
32.50 % #, P =
0.0001*
24.50 % #, P =
0.0001*
25.00 % #, P =
0.0001*
% of change
in
Group 2
9.18 % #, P =
0.0001*
16.84 % #, P =
0.0001*
19.90 % #, P =
0.0001*
12.24 % #, P =
0.0001*
% of change
in
Group 3
10.29 % #, P =
0.0001*
14.81 % #, P =
0.0001*
18.11 % #, P =
0.0001*
2.47 % #, P =
0.0541
F-value
35.8734
8.9849
0.5959
23.4077
P-value
0.0001*
0.0006*
0.5557
0.0001*
Pair Wise Comparisons by Tukey’s Multiple Post Hoc Procedures
Group 1 vs.
Group 2
P = 0.0001*
P = 0.0013*
P = 0.5245
P = 0.0008*
Group 1 vs.
Group 3
P = 0.0001*
P = 0.0034*
P = 0.8492
P = 0.0001*
Group 2 vs.
Group 3
P = 0.5987
P = 0.9313
P = 0.8492
P = 0.0216*
Table 3. Comparison of Change in Salivary pH among the Three Study
Groups (1, 2, 3) Collected at 2 Minutes, 30 Minutes, 1 Hour and 2 Hours
Post Rinse Interval with Respect to the Baseline by One Way ANOVA
*P < 0.05, # applied Paired t test
The mean pH values of salivary samples in the three study
groups at the different time intervals was analysed and
observed that there was a rise in salivary pH among all the
three groups with respect to the baseline. (Table 2)
When change in pH is compared among the three groups
in different intervals with respect to base line pH, alcoholic
extract group showed the highest rise in pH up to the 2hr
salivary sample. The group wise comparisons showed highly
statistical significance for all the time intervals. (Table 3)
The three study groups were compared by one way
ANOVA about CFUs grown on blood agar from salivary
samples collected in post rinse 2 minutes, 30 minutes, 1 hour
and 2 hours intervals with respect to baseline.

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Groups
Baseline
2 Minutes
30 Minutes
1 Hour
2 Hours
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Group 1
5.84
0.59
5.61
0.68
0.74
1.19
1.19
1.42
5.53
0.54
Group 2
5.55
0.64
0.03
0.03
1.72
1.33
4.25
0.73
5.33
0.76
Group 3
5.99
0.56
5.95
0.60
3.38
1.15
3.22
1.23
5.49
0.72
F-value
2.1010
603.4460
17.8046
26.8664
0.3601
P-value
0.1350
0.0001*
0.0001*
0.0001*
0.6998
Pair Wise Comparisons by Tukey’s Multiple Post Hoc Procedures
Group 1
vs. Group
2
P = 0.3805
P = 0.0001*
P = 0.0834
P = 0.0001*
P = 0.7040
Group 1
vs. Group
3
P = 0.7816
P = 0.1906
P = 0.0001*
P = 0.0002*
P = 0.9860
Group 2
vs. Group
3
P = 0.1217
P = 0.0001*
P = 0.0018*
P = 0.0514
P = 0.7982
Table 4. Comparison CFUs on BA from Salivary Samples
of the Three Study Groups at Different Intervals with
Respect to Baseline by One Way ANOVA
*P < 0.05
Groups
Changes from Baseline to
2 Minutes
30 Minutes
1 Hour
2 Hours
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Group 1
0.23
0.25
5.10
1.40
4.65
1.38
0.31
0.52
Group 2
5.52
0.62
3.82
1.37
1.30
0.64
0.21
0.44
Group 3
0.03
0.13
2.61
1.07
2.77
1.10
0.49
0.78
% of change in
Group 1
3.88 % #, P =
0.0031*
87.27 % #, P =
0.0001*
79.65 % #, P =
0.0001*
5.25 p =
0.0386*
% of change in
Group 2
99.53 % #, P =
0.0001*
68.91 % #, P =
0.0001*
23.44 % #, P =
0.0001*
3.85 % #, P =
0.0787
% of change in
Group 3
0.56 % #, P =
0.3343
43.54 % #, P =
0.0001*
46.21 % #, P =
0.0001*
8.24 % #, P =
0.0282*
F-value
934.2108
14.0152
36.1659
0.8551
P-value
0.0000
0.0000
0.0000
0.4325
Pair Wise Comparisons by Tukey’s Multiple Post Hoc Procedures
Group 1 vs.
Group 2
P = 0.0001
P = 0.0259
P = 0.0001
P = 0.9042
Group 1 vs.
Group 3
P = 0.3805
P = 0.0001
P = 0.0002
P = 0.6707
Group 2 vs.
Group 3
P = 0.0001
P = 0.0350
P = 0.0018
P = 0.4119
Table 5. Comparison among the Three study Groups (1, 2, 3) with
Respect to Changes in CFUS on Blood Agar Culture [in 105] from
Baseline by One Way ANOVA
*P < 0.05, # applied Paired t test
The colony counts reduced from the baseline value in all
the subsequent time intervals for the three groups. The
number of colonies for alcoholic group was 1.19 ± 1.42 at 1
hour from baseline, was 0.03 ± 0.03 at 2 minutes from baseline
for the chlorhexidine group and for the aqueous group it was
3.38 ± 1.15 at 30 minutes from baseline. (Table 4)
Comparison of CFUs on blood agar from post rinse salivary
samples collected at 2 minutes, 30 minutes, 1 hour and 2 hours
interval from Baseline among the three study groups was done
by one way ANOVA. The mean reduction of colony counts for
the aqueous group was 0.23, for chlorhexidine was 5.52 and
for alcoholic group was 0.03 colonies in 105 units. (Table 5)
The highest reduction of colonies for aqueous group was at 30
min. from baseline, for chlorhexidine group it was at 2 mins
from baseline. Similarly for alcoholic group, the highest
reduction was at 1 hour from baseline.
Figure 1. Comparison of Frequency of Daily
Tooth Brushing of Three Study Groups (1, 2, 3)
DI S C US SI ON
The present study was done to compare the antimicrobial
efficacy of Licorice mouth rinse with chlorhexidine on salivary
Streptococcus mutans carried out in department of public
health dentistry in a tertiary care hospital.
In this study, a total of 45 children were recruited, among
which males were in overwhelmingly majority, representing
68.89 % (31) of the total population. Mean age for the
ethanolic, chlorhexidine and aqueous groups were 9.27, 9.47
and 9.40 respectively. The efficacy of licorice extracts was
evaluated in vitro as well as after a single topical application in
the oral cavity, using chlorhexidine as a positive control.
Results of the in vitro experiment revealed that ethanolic
extract of licorice had better antimicrobial activity than the
aqueous extracts. These findings are in agreement with the
observations of Ahmad et al., who concluded that alcohol is a
better solvent than water.13 This might be attributed to the
polar nature of the solvent, i.e. ethanol, which resulted in
leaching of more active ingredients during extraction.
Variation of susceptibility of the pathogens to aqueous and
ethanolic extracts indicates the involvement of more than one
active principle of biological significance.
In the present study, chlorhexidine was used in a
concentration of 0.12 % in accordance with the MBC assessed
for the study. Segreto et al. also concluded that 0.1 % twice
daily administration offers the same clinical benefits as a 0.2
% chlorhexidine solution.14
In this study, the pH levels of the saliva samples were seen
to be significantly correlated with frequency of tooth brushing
for the ethanolic extract. This might be due to the fact that
tooth brushing increased the secretion of the parotid gland,
probably via the activation of periodontal
mechanoreceptors.15 Hoek et al. demonstrated that salivary
flow increased 15 % after tooth brushing.16 In another study,
tooth brushing increased the production of saliva in patients
affected by xerostomia.17
Licorice is also known to be an alkaline food and has a
protective effect in gastro oesophageal reflux disease (GERD).
Stimulated saliva contains greater concentration of
bicarbonate ions and, thus, has increased buffering capacity.
The salivary pH of study groups (1, 2, 3) were compared
with respect to baseline and 2 minutes, 30 minutes, 1 hour and
2 hours post rinse and estimated by one way ANOVA.
Estimation of pH of the salivary samples indicated that a single
exposure to licorice aqueous as well as ethanolic extracts
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
Group 1 Group 2 Group 3
40.00 53.33 40.00
53.33 40.00
60.00
6.67 6.67 0.00
Percentage
Once Twice Thrice

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resulted in a rise in the pH of saliva, whereas chlorhexidine,
which is established to have a neutral pH, led to a very slight
increase in pH of immediate (2 mins) post rinse salivary
samples, which was statistically significant. Soldering et al.
reported that in an in vivo acid production test, licorice-
containing gel was shown to inhibit acid production.18
The colony forming units (CFU) on blood agar (BA) from
post rinse salivary samples collected at 2 minutes, 30 minutes,
1 hour and 2-hour intervals were compared among the three
study groups with respect to baseline by one way ANOVA. The
colony counts reduced from the baseline value in all the
subsequent time intervals for the three groups. The number of
colonies for alcoholic group was 1.19 ± 1.42 at 1 hour from
baseline, was 0.03 ± 0.03 at 2 minutes from baseline for the
Chlorhexidine group and for the aqueous group it was 3.38 ±
1.15 at 30 minutes from baseline.
Streptococcus mutans is a contributor to an acidic response
and to the initiation of dental caries and high counts of
Streptococcus mutans is responsible for the low buffer capacity
of saliva.19 Moreover, infection with mutans streptococci in
young children is associated with inadequate tooth-
brushing.20 In the current study, the microbial count was
significantly correlated with the frequency of tooth brushing
for the ethanolic extract. This finding can be attributed to the
increased production of saliva by the mechanical brushing
action. In a study done by Kaneko N et al. fluorides in
dentifrices had shown to affect the detectable levels of mutans
streptococci.21
The antimicrobial activity of Licorice may be mostly due to
phytochemicals like tannins, triterpenoid saponins and
flavonoids. The presence of glycyrrhizin, an active principle is
known to reduce bacterial growth and acid production.10 The
present study shows licorice extracts can be used as
preventive regimen for diseases of mouth cavity as it has both
antimicrobial and cariostatic efficacy.
CO N C LU SI ON S
Present study revealed that ethanolic extract of licorice had
better antimicrobial activity than aqueous extract. The efficacy
of antimicrobial action of licorice at 30 minutes of rinsing and
rise in salivary pH by use of both the preparations of licorice is
significant as compared to the chlorhexidine group. Hence the
antimicrobial and cariostatic efficacy of licorice extracts which
was evident in the present study suggests and recommends
that licorice can be used for prevention in clinical practice for
diseases of mouth cavity especially dental caries.
Data sharing statement provided by the authors is available with the
full text of this article at jemds.com.
Financial or other competing interests: None.
Disclosure forms provided by the authors are available with the full
text of this article at jemds.com.
The authors would like to acknowledge all the study participants and
the departments of Public Health Dentistry, Pharmacology and
Microbiology.
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