Synthesis, characterization, and antibacterial activity of sunflower (Helianthus annus Linn) seed oil derivatives

Abstract

Sunflower seeds are one of the fourth most widely used sources of edible oil production in the world. The content of unsaturated fatty acids in these oils reaches almost 85%. A previous report showed that a fatty acid can inhibit the growth of bacteria that cause infections which are mostly caused by the nature of bacterial resistance. This study focused on the antibacterial activity of sunflower seed oil derivatives; namely K-salt (K-soap), free fatty acids (FFAs), and fatty acid methyl esters (FAMEs). The fatty acids in sunflower oil is linoleic (49.57%), 11-octadecenoic acid (39.09%), palmitic (9.06%), and stearic (2.28%) acids. The as-synthesized K-soap is solid, white, melting point 167-184 °C, soluble in water and methanol. FFAs are yellow, liquid, boiling point 201 °C, density 0.94 g.cm−3, refractive index 1.46, viscosity 57.30 cSt, soluble in methanol, chloroform, and n-hexane, acid value 171.35, saponification value 176.73, and ester value 5.38. The FAMEs are yellow, liquid, boiling point 185 °C, density 0.89 g.cm−3, refractive index 1.45, viscosity 4.34 cSt, soluble in chloroform and n-hexane. The acid, saponification, and ester values of K-soap, FFAs, and FAMEs are 0.98, 210.96, and 202.98 respectively. They are potential as antibacterial against Escherichia coli and Staphylococcus aureus.