Enhanced Antibacterial Activity of Echinacea angustifolia Extract against Multidrug-Resistant Klebsiella pneumoniae through Niosome Encapsulation

Abstract

With the increased occurrence of antibiotic-resistant bacteria, alternatives to classical antibiotics are urgently needed for treatment of various infectious diseases. Medicinal plant extracts are among the promising candidates due to their bioactive components. The aim of this study was to prepare niosome-encapsulated Echinacea angustifolia extract and study its efficacy against multidrug-resistant Klebsiella pneumoniae strains. Encapsulation was first optimized by Design of Experiments, followed by the empirical study. The obtained niosomes were further characterized for the size and morphology using dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Spherical niosomes had a diameter of 142.3 ± 5.1 nm, as measured by DLS. The entrapment efficiency (EE%) of E. angustifolia extract reached up to 77.1% ± 0.3%. The prepared niosomes showed a controlled drug release within the tested 72 h and a storage stability of at least 2 months at both 4 and 25 °C. The encapsulated E. angustifolia displayed up to 16-fold higher antibacterial activity against multidrug-resistant K.pneumoniae strains, compared to the free extract. Additionally, the niosome exhibited negligible cytotoxicity against human foreskin fibroblasts. We anticipate that the results presented herein could contribute to the preparation of other plant extracts with improved stability and antibacterial activity, and will help reduce the overuse of antibiotics by controlled release of natural-derived drugs.

Streptomycin Sulfate–Loaded Niosomes Enables Increased Antimicrobial and Anti-Biofilm Activities

“…During the 72-h test, the loaded niosomes displayed highest antibacterial activity compared to the unloaded niosomes and free streptomycin (Figure 6). The results further demonstrate that the direct interaction of the niosomal carrier with bacteria (likely cell membrane) could be a reason for the greater antibacterial property in the niosomes, as reported previously (Zille et al, 2015;Raza et al, 2016;Ghafelehbashi et al, 2019;Moghtaderi et al, 2021).…”

“…These results suggest that lower concentrations of niosomal streptomycin sulfate are needed to inhibit bacterial growth than free streptomycin sulfate. This could be caused by the possibility that niosomes can protect drug against the effects of bacterial enzymes and facilitate niosome fusion with the bacterial membrane, as reported previously (Mugabe et al, 2005;Moammeri et al, 2021;Moghtaderi et al, 2021).…”

“…In the structure of the niosomes, the size of the vesicles and the efficiency of streptomycin sulfate encapsulation are highly dependent on the type of surfactant and the ratio of surfactant to cholesterol. For a suitable drug delivery system, it is desired to have a small size and a high encapsulation efficiency (EE) ( Moghaddam et al, 2021 ; Moghtaderi et al, 2021 ). A variety of niosomal formulations synthesized with different ratios of surfactant to cholesterol and Span 60 to Tween 60 were prepared and compared ( Table 1 ).…”

“…For this purpose, two factors were considered: the surfactant-to-cholesterol ratio and the Span 60-to-Tween 60 M ratio as test variables, and the nanoparticle size, polydispersity index (PDI), and encapsulation efficiency (% EE) as test responses. These variables were selected on the basis of information obtained from previous studies ( Moghtaderi et al, 2021 ) and initial screening tests.…”

An Optimized and Well-Characterized Niosome-Based Nanocarrier for Letrozole: A Brand- New Hybrid Therapy for Breast Cancer

“…AFM samples were prepared by placing 5μl of diluted niosomes on 1cm 2 glass slides and left to dry at room temperature. Prepared samples were visualized with a Nanowizard II atomic force microscope (JPK Instruments, Berlin, Germany) with a low-stress silicon nitride cantilevers (AppNano, USA) using AC mode at 66k Hz scan [17,18] .…”