Evaluation of the Active Ingredient of Campsis radicans Essential Oils and its Antimicrobial Evaluation Against Pathogenic Bacteria

Owing to the resistance of nosocomial pathogens to antibiotics, the need for herbal medicines is felt. The aim of this study was to identify the chemical composition of bark essential oils of Campsis radicans and the effect of its free and encapsulated form on resistant nosocomial pathogens. This plant is a native of Northern Iran. The Bark essential oils of Campsis radicans was first extracted and its antimicrobial effects were investigated. Then, its phytochemical compounds were determined using Gas Chromatography−Mass Spectrometry (GC/MS). Guaiacol (2-methoxy phenol) was selected as the active ingredient among 32 compounds (2.40%). It was encapsulated and the encapsulation efficiency (EE), the particle size, polydispersity index (pdi), Fourier transform infrared (FTIR), release, and stability were determined. Then, the antimicrobial effect of both free and encapsulated forms was evaluated on cotrimoxazole-resistant Pseudomonas aeruginosa, cefixime-resistant Escherichia coli , and fluconazole-resistant Candida albicans . It was observed that both free and encapsulated forms of Guaiacol had an antimicrobial effect on the studied resistant strains, but the encapsulated form had a more antimicrobial effect due to more stability and a more targeted effect. MBC (MFC) ranged from 0.270 to 0.439 µg/ml in the free form and from 0.055 to 0.133 µg/ml in the encapsulated form, EE was 86%, particle size, and pdi were 138 nm and 0.26, respectively. This study showed that this plant can be a suitable alternative to chemical drugs due to its antimicrobial effects.