Antimicrobial activities of widely consumed herbal teas, alone or in combination with antibiotics: anin vitrostudy

Abstract

BackgroundBecause of increasing antibiotic resistance, herbal teas are the most popular natural alternatives for the treatment of infectious diseases, and are currently gaining more importance. We examined the antimicrobial activities of 31 herbal teas both alone and in combination with antibiotics or antifungals against some standard and clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, methicillin susceptible/resistant Staphylococcus aureus and Candida albicans.MethodsThe antimicrobial activities of the teas were determined by using the disk diffusion and microbroth dilution methods, and the combination studies were examined by using the microbroth checkerboard and the time killing curve methods.ResultsRosehip, rosehip bag, pomegranate blossom, thyme, wormwood, mint, echinacea bag, cinnamon, black, and green teas were active against most of the studied microorganisms. In the combination studies, we characterized all the expected effects (synergistic, additive, and antagonistic) between the teas and the antimicrobials. While synergy was observed more frequently between ampicillin, ampicillin-sulbactam, or nystatine, and the various tea combinations, most of the effects between the ciprofloxacin, erythromycin, cefuroxime, or amikacin and various tea combinations, particularly rosehip, rosehip bag, and pomegranate blossom teas, were antagonistic. The results of the time kill curve analyses showed that none of the herbal teas were bactericidal in their usage concentrations; however, in combination with antibiotics they showed some bactericidal effect.DiscussionSome herbal teas, particularly rosehip and pomegranate blossom should be avoided because of their antagonistic interactions with some antibiotics during the course of antibiotic treatment or they should be consumed alone for their antimicrobial activities.

Antiviral activity of a novel mixture of natural antimicrobials, in vitro, and in a chicken infection model in vivo

“…Understanding the mechanisms involved in the anti-viral and anti-infectious activity of biochemical compounds require extensive in vivo testing in order to prove their efficiency in reducing the clinical signs of disease without a negative impact on animal health. We hypothesized that given the fact that in combination natural antimicrobials can act antagonistically against each other 18 a detailed scientific report is often required, allowing the end user to design informed interventions at farm level. In the present study we examined the in vitro activity of a mixture of citrus extract, maltodextrin, sodium chloride, lactic acid and citric acid (AuraShield L) against viruses causing infectious bronchitis (B1648), Newcastle disease (ATCC, 699), avian influenza (H9N2, ATCC, VR-1642), porcine reproductive and respiratory syndrome (ATCC, VR-2386) and bovine coronavirus (ATCC, VR-874).…”

Interaction of some plant extracts with some antibiotics against E.coli from chickens

“…Markov et al, (2009) as extracts from dill seeds shows higher antimicrobial activity on E. coli compared to amoxicillin antibiotics and this contrast with Ljiljana P. et al, (2016) which reported that dill effect was observed the highest effect on Gram-positive m.o. On the other hand in this study, doxycycline antibiotic and Mint combinations may be recommended for E.coli infections, Similarly, Tuysuz et al, (2017) examined the antimicrobial activities of 31 different herbal teas for examples (Mint) both alone and in combination with antibiotics while Lee et al, (2005), also showed that Mint and ciprofloxacin combinations were synergistic against E. coli.…”

Effect of Mongolian Herbal Tea on Growth of <i>Candida albicans</i>

“…Tea polyphenols, as a natural extract of tea, have been shown to exert an inhibitory effect on the growth of fungi 7,22) . It has been reported that tea catechins demonstrate antibacterial activity against various pathogenic bacteria, as well 8,9) . The results of the present study showed that polyphenols were present in the tea extract, and that the higher the concentration, the higher the amount of polyphenols, that is to say, amount was concentration-dependent.…”