In vitro Evaluation of Antimicrobial Properties of Extracts of Pterocarpus Santalinus against Oral Pathogens and its Synergistic Effect with Ciprofloxacin and Fluconazole.

Crude extracts of Pterocarpus santalinus extracted with Petroleum ether, methanol, n-butanol, chloroform and ethanol were tested for antibacterial activity against 8 isolates viz. Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, C. glabrata, C. parapsilosis and C. tropicalis known to cause oral infections. Zone of inhibition produced by different extracts against the selected strains was measured and compared with standard antibiotic Ciprofloxacin (1%) and Fluconazole (1%). The antibacterial sensitivity of crude extracts were tested by the disc diffusion test, and results showed that ethanol extracts and methanol extracts had average inhibition zones ranged from 18-23 and 10-16 mm in diameter, respectively while no activity was observed for other extracts. Minimum Inhibitory Concentrations (MIC) of ethanol extract was evaluated against these oral pathogens ranged from 4- 8 mg/ml while MIC of methanol extract ranged from 6-10 mg/ml. The synergy testing of ethanol extract was also carried out with known antimicrobial agents using agar well diffusion method. The results of conducted experiments using agar well diffusion demonstrated synergistic effects between antibiotics and plant extracts with significant reduction in the MICs of the test antibiotics against these strains. This study suggests the possibility of concurrent use of these antimicrobial drugs and extracts in combination in treating infections caused by these oral pathogens.