Using Natural Deep Eutectic Solvents (NADES) to Assess Minimal Inhibitory Concentration (MIC) Values and Time-Kill Curves for Flavone

The next big pandemic that might potentially have a negative impact on human health and welfare is antibiotic-resistant bacteria. Flavone or flavonoid is an organic compound extracted from plants and found to have antimicrobial activities that can help to boost the activity of drugs used against microbes. However, it is difficult to use flavone directly due to its high insolubility in water, 30 ug/ml, and hence this project will address how to make the flavone more soluble to be able to use it alongside the current drugs. Flavone is found to be soluble in methanol, however, dissolving it in methanol will lead to the production of harmful substances and therefore an environmentally-friendly and biodegradable alternative to methanol is being processed in this project. Natural deep eutectic solvents (NADES) are the mixture of two natural compounds leading to a lower melting temperature and therefore a liquid at room temperature. While creating the mixture of two or more compounds with a specific molar ratios to form the eutectic solvent, its appearance, pH, NMR, impact on bacterial cell viability and impact on flavone solubility are all taken into consideration and tested. The best eutectic solvent is proline: glycerol (2:5) as it had a pH of 6, slightly acidic and did not show an inhibition on the bacterial (E. Coli C6318) cell growth. In addition, flavone had a better solubility in DES when compared to its solubility in water. As a conclusion, DES can be used to dissolve flavone and then this can be used to boost the antimicrobial drugs.