Antimicrobial activity of cranberry juice (Vaccinium macrocarpon L.) ethanol extract against uropathogenic bacteria

Abstract

Background: Cranberry fruit (Vaccinium macrocarpon L) contains a mixture of phytochemicals such as flavonoids which consist of flavonoids, anthocyanins, proanthocyanidins, catechins, phenolic acids, and triterpenoids, all of which have possible antimicrobial (antibacterial, antifungal, and antiviral) activity. Aim: This study aimed to determine the antibacterial effect of the ethanol extract of cranberry juice (CJ) against uropathogen commonly found in urinary tract infections (UTIs) associated with pregnancy. Methods: Cranberry fruits were purchased from local markets and juiced, filtered, and dried. The dried powder was extracted with 70% ethanol for 8–10 days. The bacterial isolates used in this study [Escherichia coli, Proteus vulgaris, Staphylococcus aureus, Enterococcus sp., and coagulase-negative Staphylococci (CNS)] were collected from the Maternity and Children Hospital in Al-Diwaniyah City, Iraq. The antibacterial activity of the ethanol extract of CJ was measured using a standard Disc diffusion method. Sterile paper discs were soaked in 20 µl of different concentrations (12.5, 25, 50, and 100 mg/ml) of the extract, placed in Mueller–Hinton agar plates, and inoculated with bacterial cultures adjusted to 0.5 McFarland standards. Amoxicillin (30 µg) was used as a positive control, and 70% ethanol was used as a negative control. Results: The ethanol solution of CJ displayed a significant (p < 0.05) inhibitory activity against all tested bacteria. The CNS showed the highest sensitivity with 100% inhibition, followed by S. aureus (90%), Enterococcus sp. (85%), P. vulgaris (75%), and E. coli (60%). The effect was dose dependent, as increasing the extract concentration resulted in broader inhibition zones. Conclusion: The results show that the ethanol extract of CJ has potent antibacterial activity against uropathogenic bacteria, suggesting a possible role for CJ ethanol extract in treating UTIs when combined with recently emerging facts about increasing antibiotic resistance.