Abstract
The fast development of multi-drug resistant (MDR) organisms increasingly threatens global health and well-being. Plant natural products have been known for centuries as alternative medicines that can possess pharmacological characteristics, including antimicrobial activities. The antimicrobial activities of essential oil (Calli oil) extracted from the Calligonum comosum plant by hydro-steam distillation was tested either alone or when combined with lawsone, a henna plant naphthoquinone, against MDR microbes. Lawsone showed significant antimicrobial activities against MDR pathogens in the range of 200–300 µg/mL. Furthermore, Calli oil showed significant antimicrobial activities against MDR bacteria in the range of 180–200 µg/mL, Candida at 220–240 µg/mL and spore-forming Rhizopus fungus at 250 µg/mL. Calli oil’s inhibition effect on Rhizopus, the major cause of the lethal infection mucormycosis, stands for 72 h, followed by an extended irreversible white sporulation effect. The combination of Calli oil with lawsone enhanced the antimicrobial activities of each individual alone by at least three-fold, while incorporation of both natural products in a liposome reduced their toxicity by four- to eight-fold, while maintaining the augmented efficacy of the combination treatment. We map the antimicrobial activity of Calli oil to its major component, a benzaldehyde derivative. The findings from this study demonstrate that formulations containing essential oils have the potential in the future to overcome antimicrobial resistance.
Highlights
The emergence of multi-drug resistant (MDR) microbial strains with the lack of development of new antimicrobials endangers the future management of infectious diseases
We investigated the antimicrobial activities of lawsone from Henna and Calli oil from Calligonum comosum, alone or in combination, against several pathogens known for their resistance to antibiotics
We report on the broad-spectrum activity of both lawsone and Calli oil against methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative MDR bacteria, Candida species, and the spore-forming Rhizopus fungus, the major cause of the lethal infection mucormycosis
Summary
The emergence of MDR microbial strains with the lack of development of new antimicrobials endangers the future management of infectious diseases. Alternatives to traditionally-used antibiotics can be of great benefit in combating MDR pathogens. Compounds isolated from natural sources are alternatives to many drugs, including those with antimicrobial activity, mainly because of their reduced side effects compared to synthetic drugs [1]. Molecules 2017, 22, 2223 as privileged structures functionally evolved for the purpose of interaction with specific targets. Many attempts have been made to investigate the potential role of plant extracts and their major active compounds to overcome antibiotic resistance. Naphthoquinones, including lawsone (2-hydroxy-1,4-naphthoquinone), are promising antibacterial and antifungal compounds [2,3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
