2. Objectives
In the present study, we evaluated the antibacterial activity of C. bursa-pastoris and its mixture with G. glabra against oral pathogens.
3. Materials and Methods
3.1. Plant Material
3.1.1. Source, Collection and Identification
Total parts of C. bursa-pastoris and roots of G. glabra were collected from Garineh, a village near Neyshabour, Iran, in summer 2011. A voucher specimen was prepared and deposited at Research Institute of Plant Sciences Herbarium, Ferdowsi University of Mashhad, Iran.
3.1.2. Preparation of Extract
Different parts of C. bursa-pastoris (250 g) and roots of G. glabra (250 g) were dried at 25˚C and then powdered using a mechanical grinder separately. Each extraction was prepared using ethanol (80%, v/v) (Merck, Germany) for a period of 72 hours without using any heating procedure. The final volume of the filtrated mass was removed using a rotary vacuum evaporator (Heidolphlaborota 4000, Germany) at 40˚C to produce the concentrated extract, which was frozen and freeze-dried until the next use (2, 10). For preparation of mixed extract, equal amounts(2 mL) of the each extract (100 mg/mL) was thoroughly mixed in a sterile tube. So the concentration of each extract was 50 mg/mL in the mixed extract.
3.2. Antibacterial Activity
3.2.1. Microbial Strains
The microorganisms used in this study included Streptococcus mutans (PTCC 1683), S. sanguis (PTCC 1449), Actinomyces viscosus (PTCC 1202), Enterococcus faecalis (ATCC 29212) as oral pathogens and Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 29922) were used as controls. The bacterial strains were cultured in brain heart infusion (BHI) (Difco, MI, USA) under anaerobic condition in an anaerobic jar with Anaerocult A (Merk SA (Pty) Ltd), at 37˚C for 72 hours and subculturing was performed twice a week. The organisms suspensions were prepared by picking colonies from appropriately incubated agar cultures to sterile broth, to match a McFarland 0.5 turbidity standard (approximately 1.5 x 108 CFU/mL) (11).
4. Results
In vitro antibacterial activity of C. bursa-pastoris extract and the mixture of the C. bursa-pastoris and G. glabra extracts and also their potency were quantitatively and qualitatively assessed by determining the inhibition zone diameter and MIC as given in Tables 1-6. The analysis of C. bursa-pastoris extract showed positive inhibitory activity against six bacteria, in all methods. No strain in this study showed resistance to this extract. Results of antibacterial activity of these plants by agar diffusion method against six bacteria are shown in Tables 1 - 4.The inhibitory zone significantly increased in a dose dependent manner.
4.1. C. bursa-pastoris Extract
In agar dilution method MIC for S. aureus , A. viscosus , E. faecalis and S. sanguis were 15 mg/mL and for E. coli was 35 mg/mL. MIC for S. mutans was 12.5 mg/mL. E. coli demonstrated the greatest resistance to C. bursa-pastoris and appeared to be the most resistant bacterium (Table 5). The results of broth dilution method which are shown in Table 7 are consistent with the findings of the agar dilution method (Table 5).
4.2. Mixed Extract
In agar dilution method MIC for S. aureus , A. viscosus , E. faecalis and S. sanguis were 12.5 mg/mL and this amount for E. coli was 20 mg/mL. MIC for S. mutans was 10 mg/mL. E. coli demonstrated the greatest resistance to mixed extract and appeared to be the most resistant bacterium against C. bursa-pastoris extract (Table 5). In broth dilution method MIC for all of the bacteria were 12.5 mg/mL except E. coli that was 25 mg/mL (Table 6)
4.3. Chlorhexidine
For these microorganisms, MIC of chlorhexidine mouthwash in agar and broth dilution method was 0.0625 mg/mL except for E. coli that was 0.125 mg/mL (Tables 8, 9 and 10).
| Plant Extract a | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| C. bursa-pastoris | 100 | 25.4 ± 0.8 | 21.6 ± 0.5 | 22.8 ± 0.4 | 17.8 ± 0.3 | 26.7 ± 0.3 | 23.6 ± 0.5 |
| 50 | 23 ± 0.0 | 20.3 ± 0.5 | 18.4 ± 0.4 | 16.3 ± 0.5 | 23.4 ± 0.4 | 20.8 ± 0.7 | |
| 25 | 20 ± 0.0 | 17.6 ± 0.3 | 14 ± 0.5 | 14.3 ± 0.5 | 21.6 ± 0.5 | 18 ± 0.0 | |
| 12.5 | 18.1 ± 0.2 | 15 ± 0.0 | 9.4 ± 0.0 | 11 ± 0.0 | 19.3 ± 0.5 | 14.7 ± 0.3 | |
| 6.25 | 16 ± 0.3 | 12.1 ± 0.2 | 8.2 ± 0.5 | 9 ± 0.0 | 15.3 ± 0.5 | 12.7 ± 0.3 | |
| 3.125 | 10.7 ± 1 | 8.2 ± 0.5 | - b | 8.2 ± 0.2 | 9.6 ± 0.3 | 11 ± 0.0 | |
| Negative Control | -b | -b | -b | -b | -b | -b |
a These results showed that antibacterial activity of this extract was significantly greater than negative control (P value less than 0.05).
b No inhibition zone
| Plant Extracta | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| Mixed extract | 100 | 29.2 ± 0.5 | 26.6 ± 0.5 | 26 ± 0.0 | 21.2 ± 0.5 | 29.7 ± 0.3 | 28.7 ± 0.5 |
| 50 | 27.4 ± 0.4 | 24.1 ± 0.2 | 23.2 ± 0.5 | 19.3 ± 0.5 | 28 ± 1 | 23 ± 0.0 | |
| 25 | 25 ± 0.0 | 21.8 ± 0.3 | 18 ± 1 | 17 ± 0.0 | 25.6 ± 0.5 | 21 ± 0.0 | |
| 12.5 | 22.6 ± 0.5 | 20.4 ± 0.4 | 14 ± 0.5 | 14.2 ± 0.5 | 22.2 ± 0.5 | 18 ± 1 | |
| 6.25 | 20.8 ± 0.3 | 16.8 ± 0.7 | 10.2 ± 0.5 | 13.1 ± 0.2 | 17.8 ± 0.3 | 15.2 ± 0.5 | |
| 3.125 | 14 ± 0.0 | 12 ± 0.0 | 8 ± 0.0 | 10 ± 0.0 | 13.4 ± 0.8 | 14 ± 0.0 | |
| Negative Control | -b | -b | -b | -b | -b | -b |
a These results showed that antibacterial activity of this extract was significantly greater than negative control (P value less than 0.05).
b No inhibition zone
| Plant extracta | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| C. bursa-pastoris | 100 | 26.3 ± 0.5 | 20.8 ± 0.3 | 23.9 ± 0.5 | 22.1 ± 0.2 | 27 ± 1 | 25 ± 1 |
| 50 | 23.3 ± 0.5 | 19.2 ± 0.2 | 18.8 ± 0.3 | 17 ± 0.0 | 22.3 ± 0.5 | 20.3 ± 0.4 | |
| 25 | 19.4 ± 0.5 | 17.8 ± 0.3 | 14 ± 0.0 | 14 ± 0.0 | 17.6 ± 0.5 | 18 ± 0.0 | |
| 12.5 | 16.3 ± 0.5 | 13.6 ± 0.5 | 11 ± 0.0 | 11 ± 0.3 | 15 ± 0.0 | 14.2 ± 0.2 | |
| 6.25 | 14 ± 0.0 | 9.8 ± 0.3 | 8.4 ± 0.0 | 9.3 ± 0.5 | 13 ± 0.0 | 11 ± 0.0 | |
| 3.125 | 10 ± 0.0 | 7.4 ± 0.5 | -b | 7.4 ± 0.5 | 10 ± 0.0 | 9.4 ± 0.3 | |
| Negative Control | -b | -b | -b | -b | -b | -b |
a The results obtained by above mentioned method confirmed that antibacterial activity of this extract was significantly greater than negative control (P value less than 0.05).
b No inhibition zone
| Plant Extracta | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| Mixed extract | 100 | 30.8 ± 0.3 | 27.1 ± 0.2 | 26.8 ± 0.3 | 22 ± 0.0 | 30 ± 1 | 29.4 ± 0.5 |
| 50 | 27 ± 0.0 | 25 ± 1 | 23 ± 0.0 | 20.1 ± 0.2 | 26.4 ± 0.0 | 24 ± 0.0 | |
| 25 | 25.4 ± 0.5 | 23.7 ± 0.3 | 18.1 ± 0.2 | 17.2 ± 0.2 | 21.8 ± 0.3 | 21.8 ± 0.3 | |
| 12.5 | 20 ± 0.0 | 19.2 ± 0.2 | 14.4 ± 0.5 | 15 ± 1 | 17.8 ±0.3 | 17.3 ± 0.3 | |
| 6.25 | 16.4 ± 0.5 | 14 ± 0.0 | 12.8 ± 0.3 | 13. 3± 0.5 | 15 ± 0.0 | 13 ± 1 | |
| 3.125 | 13 ± 0.0 | 11 ± 0.0 | 12 ± 1 | 11.2 ± 0.2 | 11.2 ± 0.2 | 11.6 ± 0.5 | |
| Negative Control | -b | -b | -b | -b | - b | -b |
a The results obtained by above mentioned method confirmed that antibacterial activity of this extract was significantly greater than negative control (P value less than 0.05).
b No inhibition zone
| S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli | |
|---|---|---|---|---|---|---|
| C.bursa-pastoris Extract | ||||||
| MIC | 12.5 | 15 | 15 | 15 | 15 | 35 |
| C. bursa-pastoris Extract | ||||||
| MIC | 12.5 | 25 | 25 | 25 | 25 | 50 |
| MBC | 12.5 | 25 | 25 | 25 | 25 | 50 |
| Mixed Extract | ||||||
| MIC | 10 | 12.5 | 12.5 | 12.5 | 12.5 | 20 |
| Plant Extract | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| Chlorhexidine | 2 | 26.2 ± 0.2 | 17.2 ± 0.2 | 23 ± 0.0 | 25.2 ± 0.2 | 26 ± 1 | 24 ± 0.2 |
| 1 | 22.2 ± 0.2 | 16 ± 0.0 | 17.7 ± 0.4 | 22.2 ± 0.1 | 23 ± 0.5 | 21.2 ± 0.0 | |
| 0.5 | 18 ± 0.0 | 15.2 ± 0.2 | 13.7 ± 1 | 17.4 ± 0.7 | 19 ± 0.0 | 18.4 ± 0.99 | |
| 0.25 | 14 ± 0.0 | 11.7 ± 0.99 | 11.7 ± 0.4 | 11 ± 0.0 | 15.4 ± 0.7 | 15 ± 0.0 | |
| 0.125 | 10 ± 0.0 | 10 ± 0.0 | 9.5 ± 0.7 | 8.2 ± 0.2 | 11.2 ± 0.2 | 12 ± 0.0 | |
| 0.625 | 8.5 ± 0.5 | - | 7.2 ± 0.2 | 6 ± 0.0 | 8 ± 1 | - | |
| Negative Control | - | - | - | - | - | - |
| Plant Extract | Concentration, mg/mL | S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli |
|---|---|---|---|---|---|---|---|
| Chlorhexidine | 2 | 26.2 ± 0.2 | 17.2 ± 0.2 | 23 ± 0.0 | 25.2 ± 0.2 | 26 ± 1 | 24 ± 0.2 |
| 1 | 22.2 ± 0.2 | 16 ± 0.0 | 17.7 ± 0.4 | 22.2 ± 0.1 | 23 ± 0.5 | 21.2 ± 0.0 | |
| 0.5 | 18 ± 0.0 | 15.2 ± 0.2 | 13.7 ± 1 | 17.4 ± 0.7 | 19 ± 0.0 | 18.4 ± 0.99 | |
| 0.25 | 14 ± 0.0 | 11.7 ± 0.99 | 11.7 ± 0.4 | 11 ± 0.0 | 15.4 ± 0.7 | 15 ± 0.0 | |
| 0.125 | 10 ± 0.0 | 10 ± 0.0 | 9.5 ± 0.7 | 8.2 ± 0.2 | 11.2 ± 0.2 | 12 ± 0.0 | |
| 0.625 | 8.5 ± 0.5 | - | 7.2 ± 0.2 | 6 ± 0.0 | 8 ± 1 | - | |
| Negative Control | - | - | - | - | - | - |
| Plant Extract | Concentration, mg/mL | S. mutans, Mean ± SD | S. sanguis, Mean ± SD | A. viscosus, Mean ± SD | E. faecalis, Mean ± SD | S. aureus, Mean ± SD | E. coli, Mean ± SD |
|---|---|---|---|---|---|---|---|
| Chlorhexidine | 2 | 28.2 ± 0.2 | 20 ± 0.0 | 22.2 ± 0.2 | 26 ± 0.0 | 26.8 ± 0.2 | 25 ± 0.2 |
| 1 | 23.9 ± 0.7 | 16.7 ± 0.4 | 18.2 ± 0.2 | 23.2 ± 0.1 | 24.6 ± 0.5 | 23 ± 0.0 | |
| 0.5 | 20.2 ± 0.2 | 14.2 ± 0.2 | 14.7 ± 0.4 | 18 ± 0.0 | 21 ± 0.0 | 22.2 ± 0.2 | |
| 0.25 | 14.4 ± 0.0 | 11.2 ± 0.2 | 12.5 ± 0.1 | 13 ± 0.2 | 16.7 ± 0.4 | 16.8 ± 0.0 | |
| 0.125 | 12 ± 0.0 | 9.7 ± 0.4 | 10.2 ± 0.2 | 10.8 ± 0.0 | 13.2 ± 0.2 | 12.8 ± 0.0 | |
| 0.625 | 9.4 ± 0.5 | - | 8 ± 0.0 | - | - | - | |
| Negative control | - | - | - | - | - | - |
| S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli | |
|---|---|---|---|---|---|---|
| MIC | 0.0625 | 0.0625 | 0.0625 | 0.0625 | 0.0625 | 0.125 |
| S. mutans | S. sanguis | A. viscosus | E. faecalis | S. aureus | E. coli | |
|---|---|---|---|---|---|---|
| MIC, mg/mL | 0.0625 | 0.0625 | 0.0625 | 0.0625 | 0.0625 | 0.125 |
| MBC, mg/mL | 0.125 | 0.125 | 0.0625 | 0.125 | 0.125 | 0.125 |