In Vitro evaluation of the Antimicrobial Activity of Thyme and Cinnamon Essential Oils against Respiratory Infection causing Bacteria and its Cytotoxicity Analysis

Abstract

Respiratory tract infection (RTI) is among one of the common infections in human beings with life-threatening complications. Respiratory tract infection causes approximately 50 million deaths globally. The present study aimed to analyze two essential oils' anti-proliferative and antimicrobial activities against some common respiratory tract infection-causing microbes. The antibacterial activity of two essential oils including thyme and cinnamon oil, against the six RTI bacterial species, namely, Streptococcus pneumonia, Streptococcus pyogenes, Pseudomonas aeruginosa, Haemophilus influenza, Moraxella catarrhalis and Staphylococcus aureus, was assessed by cut well diffusion method. Cytotoxicity/anti-proliferative activity of essential oil (thyme and cinnamon) was investigated by using the SW480 cell line. The antibacterial activity of the oils was calculated by measuring the inhibitory zone and the maximum zone of 40.33 mm of cinnamon oil against H. influenza followed by a 40 mm zone of thyme oil against S. aureus and a minimum zone of 16.33 mm of cinnamon was observed against the S. pneumonia. The MIC value of the oils ranges from 0.10-0.60 mg/ml. The SW480 epithelial cells treated with the oils show an increase in cytotoxicity in a concentration-dependent manner. The in vitro cytotoxicity and antimicrobial activity results show that both the essential oils possess antimicrobial activity. The evidence shows that thyme oil has shown a little higher activity against respiratory tract infection. So, it can be used as an alternative to treat upper and lower respiratory infection-causing bacteria.