Evaluation of Antibacterial Activities of Citrus limon, Citrus reticulata, and Citrus grandis Against Pathogenic Bacteria

Abstract

Background Nowadays, bacteria are considered as the main cause of morbidity and mortality in many developing countries, especially amongst children. Among the bacterial pathogens, Escherichia coli, Salmonella spp, and Staphylococcus aureus are most prevalent. 1 In the recent decades despite developments of different types of antibiotics by pharmacological industries, resistance to antibiotics has been increased significantly in many bacterial pathogens. In general, bacteria have several genetic mechanisms to transmit and acquire resistance to antibiotics. 2-4 The antibacterial resistance in the bacterial populations is rapidly spreading; this is a serious threat to successful treatment of infectious diseases. 1,5 On the other hand, the side effects associated with the commercial antibiotics are frequently reported. 6 In this regard, there is an urgent and continuous need for finding and investigating novel antimicrobial compounds. Most of the antibiotics have been developed from microorganisms. Moreover, the plant materials remain an important resource for finding the novel antimicrobial compounds. 1,7 There are many published reports on the antibacterial effectiveness of the traditional herbs against the gram-positive and gram-negative bacteria. 1 Microbial cells are negatively affected by plant-derived substances via various mechanisms of actions as these substances at-Abstract Background: Microorganisms resistant to most antibiotics are rapidly spreading, and there is an urgent and continuous need for novel antimicrobial compounds. The genus Citrus belongs to the family Rutaceae and has many biologically active secondary metabolites. Objectives: The purpose of this study was to evaluate the antimicrobial activity of essential oil and extract of Lemon (Citrus limon), Mandarin (Citrus reticulata), and Pummelo (Citrus grandis) against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Salmonella typhi. Materials and Methods: The fresh Citrus leaves were shade-dried and powdered. Then, their antimicrobial metabolites were extracted by 80% methanol, and a Clevenger-type apparatus was used for essential oil. Eight different concentrations of each leaf extract and essential oil were prepared. The antimicrobial susceptibility of Citrus leaf metabolites were assayed against 4 bacterial strains by agar disc diffusion and E-test method. Results: In this study, minimum inhibitory concentrations (MICs) of different Citrus leaf extracts were determined against all four food-borne pathogens. The C. grandis leaf essential oil had potent antimicrobial activity against all four pathogens, and the C. limon leaf essential oil was effective on Gram positive bacteria. Salmonella typhi was resistant against these two leaves' essential oils. Conclusion: The results showed that the extracts had no antimicrobial effect on tested bacteria. In this study, the antibacterial effect of essential oil of Citrus leaves on four strains of pathogenic microorganisms was confirmed. The C. grandis leaf essential oil had the most powerf...

Chemical Composition and Biological Activities of Lemon (Citrus limon) Leaf Essential Oil

“…Indeed, the lemon leaf essential oil was less effective against Gram-negative compared to Gram positive bacteria. The result obtained in this work is consistent with the result observed by Saeb et al (2016) in which S. typhi was the resistant bacteria against the essential oil of C. limon leaf. A similar study was conducted by Hamdan et al (2013) on the antimicrobial activity of the essential oil of the peel and leaf of the Egyptian Cleopatra mandarin.…”

“…Although the growth of all examined microorganisms was inhibited by different concentrations of lemon leaf essential oil, the result of disc diffusion showed B. cereus and S. typhi were the most sensitive and resistant bacteria against the essential oil, respectively. Similar results were also reported by others indicating that the essential oil of citrus leaf was active against both Gram positive and Gram negative bacteria, thought it was more effective on Gram-positive strains (33,(36)(37)(38). Indeed, the lemon leaf essential oil was less effective against Gram-negative compared to Gram positive bacteria.…”

Antibacterial Properties of Citrus limon and Pineapple Extracts on Oral Pathogenic Bacteria (Streptococcus mutans and Streptococcus sanguis)

“…The antibacterial activity of the essential oils obtained from C. limon leaf was higher against Gram-pos itive bacteria such as S. aureus and B. subtilis than against gram-negative bacteria like E. coli and S. typhimurium. 10 Lawal et al conducted phytochemical analysis and evaluated the antibacterial activities of C. senensis peel extract against Salmonella paratyphi and Aeromonas hydrophila. The results of the phytochemical analysis showed the presence of flavonoids, alkaloids, saponins, tannins, triterpenoids, phytosterols and steroids and found that the bacterial isolates were sensitive to the C. senensis peel extract with MIC of 0.25-2.5 mg/mL and MBC of 0.5-5.0 mg/ml.…”

“…6 Many Citrus species are known for their antimicrobial activity and phytochemical compounds. [7][8][9][10] In addition, Pandey et al reported antifungal activity and phytochemical compounds of the hydroalcoholic extracts of C. limon peel. Some studies have shown the presence of tannins, reducing sugar and flavonoids in the C. limon peels, whereas glycosides and saponins were absent.…”

Antibacterial activity of bacterial cellulose-based edible film incorporated with Citrus spp essential oil

“…Some studies showed that limonene and other metabolites which is belong to alkaloids, flavonoids, steroids, terpenoids, saponins, cardiac glycosides as active compound of Citrus spp could inhibit the growth of E. coli, S. aureus, Salmonella thypiimurium and Bacillus cereus cells [4,16,17]. Another study showed that the essential oils of cinnamon, oregano, thyme, and clove attribute to the existence of cinnamaldehyde, carvacrol, thymol, and eugenol, which is possess similar activities against L. monocytogenes, Salmonella typhimurium, E. coli, Brochothrix thermosphacta, and Pseudomonas fluorescens [18].…”