Contemporary Clinical Dentistry
   
  Home | About us | Editorial board | Search
Ahead of print | Current Issue | Archives | Advertise
Instructions | Online submission| Contact us | Subscribe |

 

Login  | Users Online: 658  Print this pageEmail this pageSmall font sizeDefault font sizeIncrease font size 



 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 12  |  Issue : 4  |  Page : 389-395  

Comparisonoftime-killassaytoevaluatetheantimicrobialefficacyof garlic (allium sativum) and guava (psidium guajava) extracts on periodontal pathogens


1 Department of Preventive and Restorative Dentistry, College of Dental Medicine, University of Sharjah, Sharjah, UAE
2 Department of Clinical Science, College of Dentistry, Ajman University, Ajman, UAE
3 Department of Preventive Dental Science, College of Dentistry, Gulf Medical University, Ajman, UAE
4 Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, UAE

Date of Submission15-Aug-2020
Date of Decision26-Aug-2020
Date of Acceptance04-Oct-2020
Date of Web Publication21-Dec-2021

Correspondence Address:
Sunaina Shetty
College of Dental Medicine, University of Sharjah, Sharjah
UAE
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ccd.ccd_731_20

Rights and Permissions
   Abstract 


Background: The role of Gram-negative anaerobic periodontal pathogens in periodontal diseases has led to the loss of tooth-supporting structures. These diseases can be prevented by the inhibition of bacterial biofilm on the tooth surfaces. Many treatment modalities have been tried to prevent periodontal diseases. With the rise in resistance to synthetic antimicrobials, there is a requirement to develop natural antimicrobials for the control of periodontitis. Aim: The aim of the study was to evaluate and compare the efficacy of garlic (Allium sativum) and guava (Psidium guajava) extracts on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans using time-kill assay. Materials and Methods: Aqueous garlic extract (AGaE), ethanolic garlic extract (EGaE), aqueous guava extract (AGuE), and ethanolic guava extract (EGuE) were prepared. Time-kill assays were performed on P. gingivalis and A. actinomycetemcomitans. The aqueous and ethanolic extracts of guava and garlic were compared to assess the maximum bactericidal potency. Results: The comparison of time-kill assay of AGaE and AGuE on P. gingivalis showed a statistically significant difference at 2 h (t = 5.29, P < 0.01), 4 h (t = −4.867, P < 0.01), and 6 h (t = −3.647, P < 0.001). The comparison of time-kill assay of EGaE and EGuE on A. actinomycetemcomitans showed a statistically significant difference at 2 h (t = 4.54, P < 0.01) and highly significant difference at 4 h (t = 6.57, P < 0.001). Conclusions: The, judicious use of these phytomedicinal products could be cost-effective and also the adverse effects caused due to the long-term usage of synthetic antimicrobials can be avoided.

Keywords: Aggregatibacter actinomycetemcomitans, Allium sativum, antimicrobial, garlic, guava, Porphyromonas gingivalis, Psidium guajava, time-kill assay


How to cite this article:
Shetty S, Shetty RM, Rahman B, Reddy MS, Shetty SR, Vannala V, Desai V, Halkai R. Comparisonoftime-killassaytoevaluatetheantimicrobialefficacyof garlic (allium sativum) and guava (psidium guajava) extracts on periodontal pathogens. Contemp Clin Dent 2021;12:389-95

How to cite this URL:
Shetty S, Shetty RM, Rahman B, Reddy MS, Shetty SR, Vannala V, Desai V, Halkai R. Comparisonoftime-killassaytoevaluatetheantimicrobialefficacyof garlic (allium sativum) and guava (psidium guajava) extracts on periodontal pathogens. Contemp Clin Dent [serial online] 2021 [cited 2022 Jan 24];12:389-95. Available from: https://www.contempclindent.org/text.asp?2021/12/4/389/333145




   Introduction Top


The role of Gram-negative anaerobic periodontal pathogens in periodontal diseases has been well-documented.[1] The Gram-negative anaerobes mainly Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are found to be linked with the onset and/or development of periodontitis. These organisms express a number of virulence factors which have been implicated in causing periodontal attachment loss.[2] Among these virulence factors, cysteine proteases including arg-gingipains play a major role in P. gingivalis virulence by degrading the host tissue and activating the host pro-inflammatory mediators, thus neutralizing the host immune systems.[3] Leukotoxin of A. actinomycetemcomitans is one of the major endotoxins causing periodontal disease.[4] Long-standing exposure of the periodontal tissues to these microbial toxins results in the loss of supporting structures such as periodontal ligament and alveolar bone, ultimately leading to the loss of teeth.[5]

Developing a better diagnosis and a cost-effective way of curing periodontal disease is required. These diseases can be prevented by the inhibition of bacterial biofilm on the tooth surfaces. This includes the mechanical debridement and the use of antimicrobial agents.[6]

Various researches have shown the inhibitory effect of various antimicrobial agents on the oral biofilm. Nevertheless, these antimicrobials might have some ill effects such as staining of teeth, gastrointestinal disturbance, and risk of developing antibacterial resistance. Hence, a naturally available herbal antimicrobial that interferes with the development of dental plaque is the need of the hour.[7]

Garlic (Allium sativum) is considered as an ancient medicine and known to have antimicrobial properties.[8],[9] It has been observed that the resistance to allicin that is one of the active compounds in garlic is thousand times less compared to certain synthetic antimicrobials.[10] Garlic exhibits antimicrobial effect against a variety of oral microorganisms, including Gram-negative periodontal pathogens.[11]

Psidium guajava is a phytotherapic plant commonly known as guava. Guava has been demonstrated for its antimicrobial, antiparasitic, antioxidant, antigenotoxic, anticancer, and antihyperglycemic effects.[12] The leaves of guava have been reported to be used for the maintenance of oral hygiene.[13] The antibacterial activity of guava extract against cariogenic bacteria Lactobacillus acidophilus is reported to be similar to that of chlorhexidine mouthrinse.[14]

Even though guava and garlic are naturally available medicinal plants with proven antimicrobial property, the literature on its effect on periodontal pathogens and their virulence factors and enzymes are scanty. Very few studies have evaluated the efficacy of garlic and guava as phytomedicines against periodontal pathogens.[11],[15],[16],[17] However, there is no literature found regarding comparison of the effect of garlic and guava on oral Gram-negative microbes. Thus, the present study aimed to evaluate and compare the efficacy of guava (P. guajava) and garlic (A. sativum) on P. gingivalis and A. actinomycetemcomitans using time-kill assay.


   Materials and Methods Top


Preparation of guava and garlic extract

Aqueous garlic extract (AGaE), ethanolic garlic extract (EGaE), aqueous guava extract (AGuE), and ethanolic guava extract (EGuE) were prepared equivalent to the previously reported studies in the literature.[15],[16]

Microbes and growth condition

Periodontal pathogens such as P. gingivalis and A. actinomycetemcomitans were utilized from the stock culture for the present study. Kanamycin blood agar was used to isolate and Oxoid anaerobic jar was used for cultivating P. gingivalis. Dentaid agar was used to isolate and candle jar technique was used to cultivate A. actinomycetemcomitans.[15],[16]

Inoculum preparations

The colonies were transferred to the brain heart infusion (BHI) broth with a sterile straight wire. The turbidity of the suspensions of the bacteria was calibrated with a photometric device to 0.5 McFarland turbidity standards.

Growth kill assay

Serial dilutions of garlic/guava (test extracts) were made to estimate the time-kill assay. A set of 10 tubes were taken and numbered from 1 to 10. One milliliter of the extract to be tested was taken in the first tube. BHI broth (0.5 ml) was added to the remaining tubes numbered from 2 to 10. 0.5 ml of the first tube extract was transferred to the second tube which consisted of BHI broth and it was mixed thoroughly. 0.5 ml from the second tube was serially transferred to the third tube until the 9th tube. 0.5 ml was discarded from the 9th tube and the 10th tube, i.e., the last tube, acted as a control [Figure 1].
Figure 1: Serial dilutions performed for time-kill assay

Click here to view


The solutions of garlic extract were thus serially diluted and concentrations at 500, 250, 125, 62.5, 31.25, 16.6, 8.3, 4, and 2 mg/ml for EGaE and concentrations at 500, 250, 125, 62.5, 31.25, 16.6, 8.3, 4, and 2 μl/ml for AGaE were obtained. Similarly, the guava extract solutions were serial diluted and concentrations at 500, 250, 125, 62.5, 31.25, 16.6, 8.3, 4, and 2 mg/ml for EGuE and concentrations at 500, 250, 125, 62.5, 31.25, 16.6, 8.3, 4, and 2 μl/ml for AGuE were obtained. 0.1 ml of culture cells (107 cells) were then inoculated into the tube containing test extract. Then directly, it was plated and colonies were observed at 0 h. The minimal inhibitory concentration (MIC) was defined as the lowest concentration of the extract that completely inhibited the growth of the organisms.

The anaerobic jar for P. gingivalis and CO2 jar for A. actinomycetemcomitans were used for culturing. At the end of 2 h again, the first tube was plated. The same procedure was repeated after every 2 h, i.e., after 4 h, 6 h, and 24 h. Then, the plates were incubated in either CO2 jar or anaerobic jar as per the requirement. After 48 h of incubation at 37°C, the plates were taken out and the colonies were calculated.

Statistical analysis

One-way ANOVA was applied to analyze the significance of difference of colonies at various time intervals. Post hoc Bonferronis test was used to determine the pairwise significance of difference in the means of colony formed if the differences across the time intervals were statistically significant. The comparisons of the extracts were analyzed by unpaired t-test. All the analyses were carried out using SPSS version 20.0 (SPSS Version 20.0. Armonk, NY: IBM Corp.) and the statistical significance was tested at a 5% level.


   Results Top


Minimal inhibitory concentration of garlic and guava extracts

The AGaE exhibited MIC at 16.6 μl/ml and EGaE exhibited MIC at 62.5 mg/ml on P. gingivalis. The MIC for the AGaE aqueous extract was determined at 62.5 μl/ml on A. actinomycetemcomitans, whereas A. actinomycetemcomitans was completely resistant to all the concentrations of the EGaEs [Table 1].
Table 1: Minimal inhibitory concentration of garlic and guava extracts

Click here to view


The AGuE exhibited MIC at 4 μl/ml, whereas EGuE exhibited MIC at 2 μl/ml for P. gingivalis. A. actinomycetemcomitans showed lesser resistance to ethanolic extracts. The MIC for the AGuE was determined at 16.6 μl/ml, whereas A. actinomycetemcomitans was completely susceptible to all the concentrations of the EGuE [Table 1].

Time-kill assay of garlic extracts

The garlic extracts exhibited only bacteriostatic activity for both the organisms. Bactericidal effect on P. gingivalis was not evident over the first 2 h of incubation; however, bacteriostatic activity was noticed between 2 and 6 h. The aqueous extract showed greater bacteriostatic activity when compared to the ethanolic extract, followed by a gradual increase in the colony-forming units and bacteriostatic activity was not observed at 24 h [Table 2] and [Figure 2]. The control tube showed no drop in colony count during the same period.
Figure 2: Time-kill assay for Porphyromonas gingivalis by garlic extracts

Click here to view
Table 2: Time-kill assay for Porphyromonas gingivalis by garlic extracts

Click here to view


The A. actinomycetemcomitans showed resistance to the bactericidal activity of the garlic extracts. Bacteriostatic activity was noticed between 0 and 2 h incubation period for aqueous and ethanolic extracts. Later on, a gradual increase in the colonies was observed up to 24 h [Table 3] and [Figure 3].
Figure 3: Time-kill assay for Aggregatibacter actinomycetemcomitans by garlic extracts

Click here to view
Table 3: Time-kill assay for Aggregatibacter actinomycetemcomitans by garlic extracts

Click here to view


Time-kill assay of AGaE and EGaE was compared for both the microbes used in the study [Table 2] and [Table 3]. The comparisons analyzed by unpaired t-test showed statistical significance with P. gingivalis at 2 h (t = −9.205, P < 0.001), 4 h (t = −8.962, P < 0.001), and 6 h (t = −7.046, P < 0.001).

However, statistical significance was seen only at the beginning at 0 h between AGaE and EGaE on A. actinomycetemcomitans.

Time-kill assay of guava extracts

A statistically significant decrease in the colonies of P. gingivalis was seen up to 6 h in both AGuE and EGuE. Bacteriostatic activity was seen during 4–6 h in case of both the type of guava extracts where there was no statistically significant difference in the colonies count from 4 to 6 h. There was a raise in the colony-forming units with no bacteriostatic activity observed at 24 h [Table 4] and [Figure 4].
Figure 4: Time-kill assay for Porphyromonas gingivalis by guava extracts

Click here to view
Table 4: Time-kill assay for Porphyromonas gingivalis by guava extracts

Click here to view


The A. actinomycetemcomitans colonies count decreased statistically up to 4 h with aqueous extract and there was an increase in the colony-forming units with no bacteriostatic activity at 6 h and 24 h. However, with ethanolic extract, there was a statistically significant decrease in the colonies count up to 6 h with no significant difference from 2 h to 6 h, indicating bacteriostatic activity between 2 and 6 h [Table 5] and [Figure 5]. Control cell suspensions without guava extract showed no drop in viability over the same period.
Figure 5: Time-kill assay for Aggregatibacter actinomycetemcomitans by guava extracts

Click here to view
Table 5: Time-kill assay for Aggregatibacter actinomycetemcomitans by guava extracts

Click here to view


Time-kill assay of AGuE and EGuE was compared for P. gingivalis and A. actinomycetemcomitans [Table 4] and [Table 5]. The comparisons analyzed by unpaired t-test showed statistical significance with P. gingivalis at 0 h (t = 6.485, P < 0.001), 2 h (t = 19.901, P < 0.001), 4 h (t = 10.346, P < 0.001), and 6 h (t = 11.926, P < 0.001) and with A. actinomycetemcomitans at 2 h (t = 2.701, P < 0.05), 4 h (t = −10.1, P < 0.001), and 6 h (t = 10.42, P < 0.001).

Comparison of aqueous extracts of guava and garlic on Porphyromonas gingivalis

Time-kill assay of AGuE and AGaE was compared for P. gingivalis. The comparisons showed statistically significant difference at 2 h (t = 5.29, P < 0.01), 4 h (t = −4.867, P < 0.01), and 6 h (t = −3.647, P < 0.001) [Table 6].
Table 6: Comparison of aqueous extracts of guava and garlic on Porphyromonas gingivalis

Click here to view


Comparison of ethanolic extracts of guava and garlic on Porphyromonas gingivalis

Time-kill assay of EGuE and EGaE was compared for P. gingivalis. The comparisons showed statistically high significant difference at 2 h (t = −32.85, P < 0.001), 4 h (t = −12.45, P < 0.001), and 6 h (t = −11.95, P < 0.001) [Table 7].
Table 7: Comparison of ethanolic extracts of guava and garlic on Porphyromonas gingivalis

Click here to view


Comparison of aqueous extracts of guava and garlic on Aggregatibacter actinomycetemcomitans

Time-kill assay of AGuE and AGaE was compared for A. actinomycetemcomitans. The comparisons showed statistically high significant difference at 2 h (t = 9.62, P < 0.01) and significant difference at 0 h (t = 3.64, P < 0.01) and 6 h (t = 4.59, P < 0.01) [Table 8].
Table 8: Comparison of aqueous extracts of guava and garlic on Aggregatibacter actinomycetemcomitans

Click here to view


Comparison of ethanolic extracts of guava and garlic on Aggregatibacter actinomycetemcomitans

Time-kill assay of EGuE and EGaE was compared for A. actinomycetemcomitans. The comparisons showed statistically significant difference at 2 h (t = 4.54, P < 0.01) and highly significant difference at 4 h (t = 6.57, P < 0.001) [Table 9].
Table 9: Comparison of ethanolic extracts of guava and garlic on Aggregatibacter actinomycetemcomitans

Click here to view



   Discussion Top


Periodontal disease is known as an immune modulatory disease which results in the destruction of periodontal tissue, loss of attachment, and alveolar bone resorption. P. gingivalis and A. actinomycetemcomitans are known to be associated with periodontitis.[18] P. gingivalis is one of the most important bacteria causing periodontal disease, and it can colonize in the subgingival area, which may begin the process of periodontal disease, thereby activating other Gram-negative bacteria species to colonize and further infect periodontal tissue. Inhibition or elimination of the subgingival periodontopathogens like P. gingivalis and A. actinomycetemcomitans is the key for the successful treatment of periodontitis.[18],[19],[20]

In the present study, the inhibitory effect of aqueous and ethanolic extracts of garlic and guava on P. gingivalis and A. actinomycetemcomitans was evaluated using the time-kill assay. The efficacy of aqueous extracts of guava was compared with that of garlic; similarly, the ethanolic extracts of guava were compared with that of garlic.

Time-kill assay of AGaE and EGaE was compared for both the microorganisms revealed statistical significance for P. gingivalis at 2 h, 4 h, and 6 h. However, statistical significance was seen only at the beginning at 0 h between aqueous and EGaEs on A. actinomycetemcomitans.

Thus, garlic extract elicited its antimicrobial activity in a time-dependent manner exhibiting distinct time-kill assay, suggesting differences in the growth inhibitory response in tested isolates to it. Similar responses were observed by Yin et al.[21] and Iwalokun et al.[22] However, the exceptionality of time-kill assay on Gram-negative pathogens in the present study may be due to the structural variability between these two microorganisms.

The A. actinomycetemcomitans colonies count decreased statistically up to 4 h with aqueous extract and there was a raise in the colony-forming units with no bacteriostatic activity at 6 h and 24 h. However, with ethanolic extract, there was statistically significant decrease in the colonies count up to 6 h with no significant difference from 2 h to 6 h, indicating bacteriostatic activity between 2 and 6 h. Time-kill assay of AGuE and EGuE was compared for both the microorganisms. The comparisons revealed statistically significant results for P. gingivalis at 0 h, 2 h, 4 h, and 6 h, whereas A. actinomycetemcomitans showed statistically significant difference at 2 h, 4 h, and 6 h.

These observations interpreted that the guava extract showed its antimicrobial activity in a time-dependent fashion producing distinct time-kill assay, suggestive of differences in the growth inhibitory response of the tested microorganisms to guava extracts.

The guava extracts showed a better time-kill profile on A. actinomycetemcomitans compared to garlic extracts. Similar findings were reported by Kwamin et al.[4] stating that extracts of guava leaves and twigs contain components that efficiently neutralize the leukotoxicity of A. actinomycetemcomitans. Toma and Genet[23] showed that this leukotoxin-neutralizing activity of guava extract is stable and persist for at least 24 h; probably, this would have been one of the reasons for guava extract showing better time-kill profile on A. actinomycetemcomitans than garlic. However, in the present study, the time-kill potency of A. actinomycetemcomitans was between 2 and 6 h.

In the present study, the AGaE was more potent than the ethanolic extract, similar to observations of Roy et al.,[24] Jaber et al.,[25] and El-Mahmood and Amey[26] but in contrast with that of Debnath.[27] One of the probable explanations for this could be the evaporation of volatile components of EGaE when it was heated at 800°C.

The efficacy of ethanolic guava leaf extract was found to be better than aqueous guava leaf extract. Ethanolic extract contains tannins as well as flavonoids, whereas aqueous extract contains tannins but not flavonoids. This difference in composition of ethanolic and aqueous extract can be attributed to the difference in the solubility of various components of guava leaves in water and organic solvents.[28]

Thus, AGaE showed significant antimicrobial activity against P. gingivalis and EGuE showed maximum bactericidal activity on A. actinomycetemcomitans. However, the combination of both garlic and guava extract has to be tried out in future. Further studies and clinical trials need to be undertaken to explore the efficacy of guava and garlic in humans. Mouthwashes can be prepared and the effects can be compared with the synthetic mouthwashes available in the market. Combination of guava and garlic extract should be tried and evaluated. Garlic and guava extracts could be used as mouthwashes, local drug delivery agents in the form of gel; chip and threads could treat and manage both localized and generalized periodontitis. Hence, using these phytomedicinal extracts as an adjunct with surgical and nonsurgical therapy might result in the elimination of periodontal pathogens.

Limitations of the study

This present study is an in-vitro microbiological study; there still lies a void in research with respect to the clinical trials of these phytomedicinal agents in periodontal diseases. A second limitation is regarding the therapeutic usefulness of these phytomedicinal extracts that the constituents of garlic/guava might form a complex with blood proteins and its efficacy in the presence of bleeding at a periodontal site was not evaluated. Future targeted long-term clinical trials of these phytomedicinal remedies are required.


   Conclusions Top


Garlic and guava extract displayed a significant antimicrobial effect on P. gingivalis and A. actinomycetemcomitans. Garlic was found to be most effective against P. gingivalis, whereas guava showed the highest efficacy on A. actinomycetemcomitans. Time-kill assay results revealed probable use of garlic and guava as a suitable adjuvant to synthetic antimicrobials. Thus, judicious use of these naturally occurring phytomedicinal products could be cost-effective and also the adverse effects caused due to the long-term usage of synthetic antimicrobials can be avoided.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Slots J, Genco RJ. Black-pigmented Bacteroides species, Capnocytophaga species, and Actinobacillus actinomycetemcomitans in human periodontal disease: Virulence factors in colonization, survival, and tissue destruction. J Dent Res 1984;63:412-21.  Back to cited text no. 1
    
2.
Holt SC, Bramanti TE. Factors in virulence expression and their role in periodontal disease pathogenesis. Crit Rev Oral Biol Med 1991;2:177-281.  Back to cited text no. 2
    
3.
Kuramitsu HK, Yoneda M, Madden T. Proteases and collagenases of Porphyromonas gingivalis. Adv Dent Res 1995;9:37-40.  Back to cited text no. 3
    
4.
Kwamin F, Gref R, Haubek D, Johansson A. Interactions of extracts from selected chewing stick sources with Aggregatibacter actinomycetemcomitans. BMC Res Notes 2012;5:203.  Back to cited text no. 4
    
5.
Laine ML, Crielaard W, Loos BG. Genetic susceptibility to periodontitis. Periodontol 2000 2012;58:37-68.  Back to cited text no. 5
    
6.
Slots J. Selection of antimicrobial agents in periodontal therapy. J Periodontal Res 2002;37:389-98.  Back to cited text no. 6
    
7.
Sharma S, Prakash S. To detect the minimum inhibitory concentration and time-kill curve of shiitake mushroom on periodontal pathogens: An in vitro study. J Indian Soc Periodontol 2019;23:216-9.  Back to cited text no. 7
[PUBMED]  [Full text]  
8.
Block E. The chemistry of garlic and onions. Sci Am 1985;252:114-9.  Back to cited text no. 8
    
9.
Ankri S, Mirelman D. Antimicrobial properties of allicin from garlic. Microbes Infect 1999;1:125-9.  Back to cited text no. 9
    
10.
Gupta KC, Viswanthan R. Combined action of streptomycin and chloramphenicol with plant antibiotics against tubercle bacilli. I. Streptomycin and chloramphenical with cepharanthine. II. Streptomycin and allicin. Antibiot Chemother 1995;5:24-7.  Back to cited text no. 10
    
11.
Bakri IM, Douglas CW. Inhibitory effect of garlic extract on oral bacteria. Arch Oral Biol 2005;50:645-51.  Back to cited text no. 11
    
12.
Gupta GK, Chahal J, Arora D. Psidium guajava Linn: Current research and future prospects. J Pharm Res 2011;4:42-6.  Back to cited text no. 12
    
13.
Jebashree HS, Kingsley SJ, Sathish ES, Devapriya D. Antimicrobial activity of few medicinal plants against clinically isolated human cariogenic pathogens – An in vitro study. ISRN Dent 2011;2011:541421.  Back to cited text no. 13
    
14.
Jain D, Dasar P, Nagarajappa S, Kumar S, Airen B, Warhekar S. In vitro activity of ethanolic and water extract of guava leaves at various concentrations against Lactobacillus acidophilus. J Indian Assoc Public Health Dent 2014;12:232-6.  Back to cited text no. 14
  [Full text]  
15.
Shetty S, Thomas B, Shetty V, Bhandary R, Shetty RM. An in-vitro evaluation of the efficacy of garlic extract as an antimicrobial agent on periodontal pathogens: A microbiological study. Ayu 2013;34:445-51.  Back to cited text no. 15
[PUBMED]  [Full text]  
16.
Shetty YS, Shankarapillai R, Vivekanandan G, Shetty RM, Reddy CS, Reddy H, et al. Evaluation of the efficacy of guava extract as an antimicrobial agent on periodontal pathogens. J Contemp Dent Pract 2018;19:690-7.  Back to cited text no. 16
    
17.
Shetty S, Shetty RM, Rahman B, Vannala V, Desai V, Shetty SR. Efficacy of Psidium guajava and Allium sativum extracts as antimicrobial agents against periodontal pathogens. J Pharm Bioall Sci 2020;12:S589-94.  Back to cited text no. 17
    
18.
Ezzo PJ, Cutler CW. Microorganisms as risk indicators for periodontal disease. Periodontol 2000 2003;32:24-35.  Back to cited text no. 18
    
19.
Hajishengallis G, Darveau RP, Curtis MA. The keystone-pathogen hypothesis. Nat Rev Microbiol 2012;10:717-25.  Back to cited text no. 19
    
20.
Cohen J. The immunopathogenesis of sepsis. Nature 2002;420:885-91.  Back to cited text no. 20
    
21.
Yin MC, Chang HC, Tsao SM. Inhibitory effects of aqueous garlic extract, garlic oil and four diallyl sulphides against four enteric pathogens. J Food Drug Anal 2002;10:120-6.  Back to cited text no. 21
    
22.
Iwalokun BA, Ogunledun A, Ogbolu DO, Bamiro SB, Jimi-Omojola J. In vitro antimicrobial properties of aqueous garlic extract against multi drug resistant bacteria and candida species from Nigeria. J Med Food 2004;7:327-33.  Back to cited text no. 22
    
23.
Toma C, Genet K. The Interaction between Guava-extract and Aggregatibacter actinomycetemcomitans Leukotoxin [Internet] [Dissertation]. 2014. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-102414. [Last accessed on 2020 Oct 22].  Back to cited text no. 23
    
24.
Roy J, Shakaya DM, Callery PS, Thomas JG. Chemical constituents and antimicrobial activity of a traditional herbal medicine containing garlic and black cumen. Afr J Trad 2006;3:1-7.  Back to cited text no. 24
    
25.
Jaber MA, Al-Mossawi A. Susceptibility of some multiple resistant bacteria to garlic extract. Afr J Biotechnol 2007;6:771-6.  Back to cited text no. 25
    
26.
El-Mahmood AM, Amey JM. In vitro antibacterial activity of Parkia biglobosa (Jacq) root bark extract against some microorganisms associated with urinary infections. Afr J Biotechnol 2007;6:1272-5.  Back to cited text no. 26
    
27.
Debnath M. Clonal propagation and antimicrobial activity of an endemic medicinal plant Steria rebaudiana. J Med Plants Res 2005;2:48-58.  Back to cited text no. 27
    
28.
Cowan MM. Plant products as antimicrobial agents. Clin Microbiol Rev 1999;12:564-82.  Back to cited text no. 28
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusions
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed140    
    Printed0    
    Emailed0    
    PDF Downloaded32    
    Comments [Add]    

Recommend this journal