Antibacterial activity evaluation of selected essential oils in liquid and vapor phase on respiratory tract pathogens

Abstract

BackgroundThe increasing number of multidrug-resistant bacteria and the fact of antibiotic resistance is leading to a continuous need for discovering alternative treatments against infections, e.g. in the case of respiratory tract diseases. Essential oils (EOs), because of their volatility, can easily reach both the upper and lower parts of the respiratory tract via inhalation. Therefore, the aim of the present study was the antibacterial evaluation of clove, cinnamon bark, eucalyptus, thyme, scots pine, peppermint, and citronella EOs against respiratory tract pathogens such as Streptococcus pneumoniae, S. mutans, S. pyogenes, Haemophilus influenzae, H. parainfluenzae, and Moraxella catarrhalis. Furthermore, we wanted to compare the antibacterial effect of these EOs in two different test systems to provide data for the development of an appropriate product formulation.MethodsMinimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with in vitro vapor phase test (VPT) and broth macrodilution test (BDT). The chemical and percentage compositions of the EOs were determined by GC-MS and GC-FID analysis.ResultsAmong the EOs, thyme was the most effective against S. mutans (MIC: 0.04 mg/mL in BDT, but cinnamon bark and clove oils also presented high inhibition in liquid medium with MIC values of 0.06 mg/mL and 0.1 mg/mL against S. pneumoniae and S. pyogenes, respectively. M. catarrhalis was the most sensitive to thyme EO (MIC: 0.09 mg/mL). Cinnamon bark EO was the most effective against Haemophilus spp. (MIC: 0.06 mg/mL). In the VPT, cinnamon bark was the most effective oil against all investigated pathogens with MIC values in the range of 15.62–90 μl/L. Surprisingly, the eucalyptus and scots pine showed weak activity against the test bacteria in both test systems.ConclusionsThe EO of thyme, clove and cinnamon bark may provide promising antibacterial activity against respiratory tract pathogens either in liquid medium or in vapor phase. However, their effect is lower than that of the reference antibiotics. The combination of EOs and antibiotics may be beneficial in the alternative treatment of respiratory tract diseases. In vivo studies are necessary to calculate the effective dose of EOs in patients and determine their possible side effects and toxicity.

Oxidative Stress-Induced DNA Damage and Apoptosis in Clove Buds-Treated MCF-7 Cells

“…Clove, a spice obtained from the dried flower of the tree Syzygium aromaticum L., has been used in traditional medicine for centuries as an antiseptic, analgesic, or in dental care [1]. Nowadays, several studies document a broad range of biological effects of clove including antibacterial [2,3], antifungal [4], antimutagenic [5], antihistaminic [6], antiinflammatory [7], or antioxidant [8]. Moreover, the antiproliferative activity of clove essential oil or eugenol, its main component, has also been described [9,10].…”

Striking essential oil: tapping into a largely unexplored source for drug discovery

“…EOCs also have unique properties that might be useful for some therapeutic applications, e.g. for lung or airway diseases [71][72][73][74] , for transdermal administration 75,76 and diseases of the central nervous system [77][78][79] .…”

Новые Терапевтические Возможности Фитопрепаратов При Лечении Острых Респираторных Инфекций У Детей

“…Так, в исследовании К. Ács с соавт. [8] была оценена антибактериальная активность нескольких растительных эфирных масел в сравнении с тимьяном и антибактериальными препаратами против наиболее распространенных респираторных патогенов: Streptococcus pneumoniae, S.mutans, S.pyogenes, Haemophilus influenzae, H.parainfluenzae и Moraxella catarrhalis, с определением минимальной ингибирующей концентрации (МИК) и минимальной бактерицидной концентрации (МБК) в тесте макродилюции бульона.…”

“…Эвкабал БАЛЬЗАМ. Наиболее выраженный антибактериальный эффект эвкалиптового масла, которое содержится в препарате Эвкабал БАЛЬЗАМ, наблюдался против бактерий Haemophilus influenzae [8]. Однако использование эвкалиптового масла и его паров является более перспективным против респираторных вирусов (например, вирус гриппа типа A и вирус эпидемического паротита), их антивирусный эффект в нескольких исследованиях был выше, чем антибактериальная активность [33].…”

“…Максимальный бактерицидный эффект эфирного масла сосны отмечался против бактерий Haemo philus influenzae и Moraxella catarrhalis: с МИК = 0,34 мг/мл, тогда как против бактерий Streptococcus pyogenes и Streptococcus mutans МИК = 1,35 мг/мл, что свидетельствует, по мнению К. Ács с соавт. [8], о наличии более выраженного бактериостатического влияния на данные микроорганизмы. В то же время сохраняется достаточная степень бактерицидной активности против S.pneumoniae: МИК = 0,68 мг/мл.…”