Antibacterial activity of peanut oil (Arachis hypogaea Linn) and its derivatives (K-soap, FFAs, and FAMEs) against Staphylococcus aureus and Escherichia coli

Abstract

The research objectives are the antibacterial activity of peanut oil and its derivatives determination. The derivatives are potassium salt (K-salt or K-soap), free fatty acids (FFAs), and fatty acid methyl esters (FAMEs) against Staphylococcus aureus and Escherichia coli bacteria. Peanut oil is a liquid light yellow, having density of 0.9372 g.cm-3, viscosity of 230.88 cSt, boiling point of 188 °C, refractive index of 1.4689, soluble in n-hexane, chloroform, and ethanol, but insoluble in methanol and water. The fatty acid contents are palmitic, and stearic acids of 11.46, 16.14, 67.44, and 4.96% respectively. Synthesized K-salts are solid-state and white, have melting point of 208-217 °C, are soluble in water, ethanol, and methanol, but are insoluble in n-hexane and chloroform. There are two FFAs, namely liquid and soft solid. Liquid FFAs are yellowish-white, have density of 0.9560 g.cm-3, viscosity of 462.17 cSt, boiling point of 192 °C, and refractive index of 1.4683. Soft solid FFAs are yellowish-white, and have melting point of 30-35 °C. The FAMEs are liquid yellowish-white, have density of 0.9009 g.cm-3, viscosity of 23.50 cSt, boiling point of 170 °C, and refractive index of 1.4580. The FFAs (liquid and soft solid) and FAMEs are soluble in ethanol, methanol, chloroform, and n-hexane, yet insoluble in water. FFAs and K-salt are active as antibacterial with MIC < 0.2%.