Physicochemical Properties and Antibacterial Activity of Castor Oil and Its Derivatives

Abstract

Castor oil is vegetable oil sourced from castor seeds (Ricinus communis Linn). The main content of fatty acids in castor oil are ricinoleic acid (92%), oleic acid (3.53%), linoleic acid (2.90%), stearic acid (1.02%), and myristic acid (0.55%). Research on the antibacterial activity of castor oil and ricinoleic fatty acid has been carried out but for the K-soap and fatty acids methyl esters of castor oil have not been conducted. This research aims to produce castor oil derivatives, namely K-soap, free fatty acids (FFAs) and fatty acids methyl esters of (FAMEs) and evaluate their antibacterial activity. The results of the study included (1) K-soap (solid, white, melting point 168–175°C), (2) free fatty acids (liquid, yellow, boiling point 210°C, density 0.98 g.mL−1, refractive index 1.46, viscosity 693.22 cSt, and the value of acids, saponification, and esters are 145.88, 294.52, 148.64), (3) fatty acids methyl esters (liquid, yellow, boiling point 170°C, density 0.98 g.mL−1, refractive index 1.46, viscosity 27.31 cSt, and the value of acids, saponification and esters are 0.33, 392.7, 392.37). K-soap, free fatty acids, and methyl esters from castor oil have antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria.