Table 3. Antimicrobial activity of Asimina triloba extract against gram-negative bacteria
| Strain | Concentration (mg/disc) | Diameter of clear zone (mm)1) |
| PLW2) | PTW | PRW | PLM | PTM | PRM | Kanamycin (30 μg/disc) |
| Campylobacter jejuni | 5 | –3) | – | – | – | – | – | 20.72±1.27 |
| 12.5 | – | – | – | – | 6.33±0.584)a5) | – |
| 25 | – | – | – | – | 8.67±0.58a | 9.00±0.00a |
| 37.5 | – | – | – | – | 10.00±0.00b | 10.83±0.29a |
| 50 | – | – | – | – | 11.00±0.00b | 13.00±1.00a |
| Cronobacter sakazakii | 5 | – | – | – | – | – | – | 22.50±0.42 |
| 12.5 | – | – | – | – | – | – |
| 25 | 6.50±0.87a | – | – | – | – | 6.33±0.58a |
| 37.5 | 7.17±0.29b | – | – | – | – | 9.33±0.58a |
| 50 | 9.83±0.29b | – | – | – | – | 10.67±0.58a |
| Escherichia coli | 5 | – | – | – | – | – | – | 19.78±1.59 |
| 12.5 | – | – | – | – | – | 6.33±0.58a |
| 25 | 6.33±0.58c | 7.33±0.58b | 6.33±0.58c | – | – | 10.33±0.58a |
| 37.5 | 8.00±0.00b | 8.33±0.29b | 8.00±0.00b | – | – | 11.67±0.58a |
| 50 | 8.50±0.50b | 8.83±0.29b | 8.83±0.29b | – | – | 14.67±0.58a |
| Escherichia coli O157:H7 | 5 | 7.00±0.00a | – | – | – | – | 6.33±0.58b | – |
| 12.5 | 8.00±0.00b | 6.33±0.58c | – | – | – | 9.00±0.00a |
| 25 | 9.33±0.58b | 8.67±0.58b | 7.00±1.00c | – | – | 11.67±1.53a |
| 37.5 | 10.33±0.58bc | 9.67±0.58c | 11.00±1.00b | – | – | 13.67±0.58a |
| 50 | 13.00±1.00b | 11.00±1.00c | 13.67±0.58b | – | – | 16.00±1.00a |
| Pseudomonas fluorescens | 5 | – | – | – | – | – | – | 19.00±0.59 |
| 12.5 | – | – | – | – | – | – |
| 25 | 6.00±0.00b | 6.00±0.00b | – | – | – | 8.00±1.00a |
| 37.5 | 8.00±0.00b | 7.67±0.58b | 6.67±0.58c | – | – | 12.67±0.58a |
| 50 | 9.00±0.00b | 8.67±0.58b | 9.33±0.58b | – | – | 15.33±0.58a |
| Proteusvulgaris | 5 | – | – | – | – | – | – | 24.39±0.78 |
| 12.5 | – | – | – | – | – | 9.00±0.00a |
| 25 | – | – | 6.00±0.00b | – | – | 12.00±1.00a |
| 37.5 | 6.00±0.00d | – | 7.67±0.58c | – | 9.00±0.00b | 15.00±1.00a |
| 50 | 7.00±0.00d | – | 9.00±0.00c | – | 11.00±0.00b | 17.33±1.15a |
| Salmonella typhimurium | 5 | – | – | – | – | – | – | 22.39±0.92 |
| 12.5 | 6.67±0.58a | – | – | – | – | – |
| 25 | 8.33±0.58b | 7.33±0.58bc | 6.67±0.58c | – | – | 11.00±1.00a |
| 37.5 | 9.67±0.58b | 10.00±0.00b | 8.33±0.58c | – | – | 12.67±0.58a |
| 50 | 11.33±0.58b | 11.33±0.58b | 9.67±0.58c | – | – | 14.00±1.00a |
| Vibrio fluvialis | 5 | 6.00±0.00b | – | – | – | 6.67±0.58a | – | 17.25±0.45 |
| 12.5 | 8.00±1.00b | – | – | – | 9.00±0.00a | – |
| 25 | 9.67±0.76a | 8.00±1.00b | 6.33±0.58c | 8.00±1.00b | 10.00±0.00a | 8.33±0.58b |
| 37.5 | 10.67±0.58b | 13.33±0.58a | 8.00±1.00c | 10.33±0.58b | 11.00±0.00b | 11.00±0.00b |
| 50 | 12.00±0.00c | 15.67±1.15a | 10.33±0.58d | 12.33±0.58c | 12.00±0.00c | 14.00±0.00b |
| Vibrio parahaemolyticus | 5 | – | – | 7.17±0.29b | – | 9.00±0.50a | 9.17±0.29a | 19.11±0.76 |
| 12.5 | – | – | 9.33±0.58c | – | 11.67±0.58b | 14.17±0.29a |
| 25 | 8.00±0.00d | – | 12.00±0.50c | – | 16.33±0.58b | 17.33±0.58a |
| 37.5 | 10.17±0.29d | 8.17±0.29e | 15.33±0.58c | – | 21.83±0.76b | 24.50±0.50a |
| 50 | 11.50±0.50d | 9.33±0.58e | 20.50±0.50c | – | 25.67±0.58b | 29.50±0.50a |
| Yersinia enterocolitica | 5 | – | – | – | – | – | 8.00±0.00a | 26.56±0.92 |
| 12.5 | 6.00±0.00b | – | 6.00±0.00b | – | 6.00±0.00b | 10.00±0.00a |
| 25 | 8.00±0.00c | 6.33±0.58d | 7.67±0.58c | 6.00±0.00d | 9.00±0.00b | 13.00±0.00a |
| 37.5 | 10.33±0.58b | 8.33±0.58cd | 9.00±0.00c | 8.00±0.00d | 10.17±0.76b | 19.33±0.58a |
| 50 | 15.33±0.58b | 9.67±0.58d | 10.33±0.58cd | 9.33±0.58d | 11.33±0.58c | 21.67±0.58a |
The diameter of the paper disc was 6 mm.
PLW, pawpaw leaf water extract; PTW, pawpaw twig water extract; PRW, pawpaw root water extract; PLM, pawpaw leaf methanolic extract; PTM, pawpaw twig methanolic extract; PRM, pawpaw root methanolic extract.
– indicates a zone of no inhibition.
Values are mean±SD (n=3).
Means with different superscript letters within a row differ significantly at p<0.05 by Duncan’s multiple range test.