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.
Highlights
Non-ionic surfactants and cholesterol could arrange a biologically acceptable structure called niosome [1,2,3], which were first applied in L’Oréal’s cosmetic commodities assignable to their weak excitability potential [4]
The interaction between cholesterol and surfactant is through the formation of hydrogen bonds between hydroxyl groups and the alkyl chain of surfactant molecules, which can change the fluidity of the chains in two layers, by increasing the transfer temperature of the vesicles and improving the stability [20,25]
The results presented in this study show that with increasing temperature, the amount of drug leakage from nanocarriers increases because the membranes of vesicles are more fluid at high temperatures [50]
Summary
Non-ionic surfactants and cholesterol (lipid) could arrange a biologically acceptable structure called niosome [1,2,3], which were first applied in L’Oréal’s cosmetic commodities assignable to their weak excitability potential [4]. Nanomaterials 2021, 11, 1573 can be altered to optimize the formulation size and the drug encapsulation efficiency to achieve high desired activity for each drug [7,8]. Various drugs have been formulated in the form of niosomes. Many of them focus on the encapsulation of conventional antibiotics or metal-based agents, these drugs can have toxic side effects, and may even promote the development of antibiotic-resistant bacteria strains due to the sub-inhibitory dose delivery [9].
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