Volume 105, July 2016, Pages 133–140
- a Department of Health Sciences, Faculty of Science, University of Mauritius, Réduit, Mauritius
- b Plant Sciences Complex, Office 3-39; Medicinal Plant Science (Department of Plant Science), University of Pretoria, Pretoria 0002, South Africa
- Received 30 August 2015, Accepted 22 January 2016, Available online 12 April 2016
- Edited by V Steenkamp
Highlights
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- P. betle (PB) is commonly chewed as betel quid (paan) and is reputed as a famous medicinal spice.
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- We studied the antibacterial activities of PB extracts and its antibiotic modulating activity.
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- PB were evaluated via the broth microdilution assay against 6 ATCC bacterial strains.
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- Antibiotics modulating effects was assessed using a modified Checkerboard method.
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- Five extracts inhibited at least one of the six bacterial strains tested.
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- Greatest synergy was observed against ATCC strain of Pseudomonas aeruginosa.
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- Lower MICs occurred with increasing phenol and flavonoid content.
Abstract
Piper betle
L., commonly chewed as betel quid (paan), has been extensively
acclaimed in a panoply of countries for both its nutritive and medicinal
values. The present study was geared towards investigating the
antibacterial activities of P. betle extracts and its antibiotic modulating activity. A decoction of P. betle
(AQE) leaves as used traditionally, as well as ethanolic (EE),
ethylacetate (EAE), acetone (ACE), and dichloromethane (DCME) extracts
were evaluated using the broth microdilution assay against six bacterial
ATCC strains. The minimum inhibitory concentration (MIC),
bacteriostatic and bacteriocidal activities of the extracts were
evaluated. Additionally, the ability of the extracts to modulate
conventional antibiotics (synergistic, additive, indifference,
antagonistic) was assessed using a modified Checkerboard method and the
fractional inhibitory concentration index (ƩFIC) was calculated. The
phytochemical profile of each extract was determined and the Pearson’s
correlation coefficient was used to establish any association between
the MIC, ƩFIC, and phytochemical content. All the five extracts
inhibited at least one of the six bacterial strains tested with EAE and
ACE exhibiting the most potent antibacterial activity. The lowest MIC
(0.2500 μg/μl) recorded was against Staphylococcus aureus. Piper betle
has been further shown to exhibit only bacteriostatic effect. Results
from the Checkerboard indicated additive and synergistic effects of P. betle
extracts especially in the 50% EAE-50% antibiotic and 50% ACE-50%
antibiotic combinations. The greatest synergy was observed against Pseudomonas aeruginosa (ƩFIC 0.09) in the 70% ACE-30% Chloramphenicol combination. Synergy was also observed against S. aureus, Propionibacterium acnes, Staphylococcus epidermidis, and Streptococcus pyogenes.
Phytochemical screening revealed that ACE and EAE contain the highest
amount of phenols while DCME contains the highest amount of flavonoids.
Statistical analysis showed that lower MICs occurred with increasing
phenol content (R = − 0.392, p ≤ 0.05) and increasing flavonoid content (R = − 0.551, p ≤ 0.01).
However, no correlation was established between ƩFIC and phytochemical
content which could indicate a different mechanism of action employed by
the combinations. Data amassed have provided insight into the
antibacterial activity, antibiotic modulating activity, and the
phytochemical profile of P. betle.
Keywords
- Piper betle;
- Bacteriocidal;
- Bacteriostatic;
- Antibiotic;
- Checkerboard;
- Phytochemical
© 2016 SAAB. Published by Elsevier B.V. All rights reserved.
