Antibacterial and Antioxidant Activities of Cinnamon (Cinnamomum Zeylanicum), Ginger (Zingiber Officinale) and Sweet Basil (Ocimum Basilicum) Essential Oils

Chai, Pei Wern (2021) Antibacterial and Antioxidant Activities of Cinnamon (Cinnamomum Zeylanicum), Ginger (Zingiber Officinale) and Sweet Basil (Ocimum Basilicum) Essential Oils. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Chemical food preservatives have been widely used in the food industry for the purpose of protecting food against food bacteria. However, due to the overwhelming concern of adverse health effects brought by the long term consumption of chemical food preservatives, this leads to an increasing demand of finding antibacterial agents of natural origin, as is the case of essential oils (EOs), and using them as an alternative to substitute synthetic preservatives in food. The objectives of this research project were to study the antioxidant and antibacterial activities of cinnamon (Cinnamomum zeylanicum), ginger (Zingiber officinale) and sweet basil (Ocimum basilicum) EOs. The antioxidant activity of these three different EOs was assessed via the determination of DPPH radical scavenging activity. Disc diffusion test (DDT) and determination of minimum inhibitory concentration (MIC) were carried out to analyse on the antibacterial property of every EO. From this study, cinnamon EO was found to exhibit the greatest radical scavenging activity, followed by ginger EO and sweet basil EO, with the results of (87.63 ± 0.12%), (35.16 ± 0.00%) and (17.84 ± 0.12%), respectively. Under antibacterial assay, gram-positive bacteria (Staphylococcus aureus) was more susceptible to all the three EOs compared to gram-negative bacteria (Pseudomonas aeruginosa and Salmonella enterica) as a larger inhibition zone and a lower MIC value were observed under S. aureus. The results also revealed that cinnamon EO possessed the strongest antibacterial property, with sweet basil EO being the intermediate and ginger EO being the weakest. There was a significant difference (p-value < 0.05) among all the three EOs. In short, cinnamon, ginger and sweet basil EOs carried different levels of antioxidant and antibacterial activities and these properties were generally contributed by the phenolic compounds present in each EO, with cinnamon EO showing the best results on antioxidant and antibacterial effects.