Current Landscape of Methods to Evaluate Antimicrobial Activity of Natural Extracts

Abstract

Natural extracts have been and continue to be used to treat a wide range of medical conditions, from infectious diseases to cancer, based on their convenience and therapeutic potential. Natural products derived from microbes, plants, and animals offer a broad variety of molecules and chemical compounds. Natural products are not only one of the most important sources for innovative drug development for animal and human health, but they are also an inspiration for synthetic biology and chemistry scientists towards the discovery of new bioactive compounds and pharmaceuticals. This is particularly relevant in the current context, where antimicrobial resistance has risen as a global health problem. Thus, efforts are being directed toward studying natural compounds’ chemical composition and bioactive potential to generate drugs with better efficacy and lower toxicity than existing molecules. Currently, a wide range of methodologies are used to analyze the in vitro activity of natural extracts to determine their suitability as antimicrobial agents. Despite traditional technologies being the most employed, technological advances have contributed to the implementation of methods able to circumvent issues related to analysis capacity, time, sensitivity, and reproducibility. This review produces an updated analysis of the conventional and current methods to evaluate the antimicrobial activity of natural compounds.

Effects of Propolis Impregnation on Polylactic Acid (PLA) Scaffolds Loaded with Wollastonite Particles against Staphylococcus aureus, Staphylococcus epidermidis, and Their Coculture for Potential Medical Devices

“…The extract obtained presented a MIC of 1.5 mg/mL against S. aureus and 2.0 mg/mL against S. epidermidis . The MIC obtained in this study proved to be much higher than that of the propolis evaluated in other regions of the world, such as those reported in [ 73 ], where propolis extracts obtained from Algeria (eastern zone) were studied, with MICs of 0.04 and 0.06 mg/mL against S. aureus and S. epidermidis , respectively [ 74 , 75 , 76 , 77 ]. Different types of antimicrobial synthetic and natural compounds have been described, as well as specific active mechanisms and MIC levels [ 74 , 75 , 76 , 77 ].…”

“…The MIC obtained in this study proved to be much higher than that of the propolis evaluated in other regions of the world, such as those reported in [ 73 ], where propolis extracts obtained from Algeria (eastern zone) were studied, with MICs of 0.04 and 0.06 mg/mL against S. aureus and S. epidermidis , respectively [ 74 , 75 , 76 , 77 ]. Different types of antimicrobial synthetic and natural compounds have been described, as well as specific active mechanisms and MIC levels [ 74 , 75 , 76 , 77 ]. However, due to the complexity and variety of the compositional matrix found in propolis, there is no established level of MIC to use as an antimicrobial agent.…”

Antimicrobial activity of stingless bee honey (Tribe: Meliponini) on clinical and foodborne pathogens: A systematic review and meta‐analysis

“…In the evaluation of antimicrobial activity in honey samples, certain considerations must be taken in attention due to the complex matrix of this type of biological sample and the main goal of the experimental settings (see Table 5). In fact, several studies have already reported the benefits and drawbacks of several microbiological techniques applied in honey samples (Balouiri et al., 2016; Gonzalez‐Pastor et al., 2023; Hossain, Lim, et al., 2022). As previous reported by Hossain, Lim, et al.…”

Preparation of Ciprofloxacin-Based Carbon Dots with High Antibacterial Activity

“…To investigate the bacteriostatic effect of Cu-CCDs against S. aureus and E. coli , the operational steps were as follows [ 57 ]. In total, 50 μL of S. aureus and E. coli suspension (1 × 10 8 CFU/mL) and 5 mL of LB broth were incubated with different concentrations (5, 2.5, 2.25, 2, and 1 μg/mL) of Cu-CCDs solution at 37 °C for 12 h. After this, 100 μL of culture solution was dispersed onto LB nutrient agar plates and incubated at 37 °C for 24 h to observe colony formation.…”