Antioxidant and antimicrobial activity of lipoamide ricinoleic-ethanolamine.

The unique structure of ricinoleic acid has been modified through esterification, amidation, hydration, epoxidation, oxidation, and hydrogenation reactions. The ricinoleic derivatives have been proven to have several biological activities such as anti-inflammatory, antitumor, antioxidant, and antimicrobial. In this research, methyl ricinoleate was prepared using methanol in the presence of acid as the catalyst. The methyl ricinoleate was purified using flash column chromatography with hexane-ethyl acetate 10:1 as the eluent to obtain 22.2% pure methyl ricinoleate. The methyl ricinoleate was subjected to an amidation reaction using ethanolamine to form a lipoamide. The reaction progress was monitored by TLC. The spot of lipoamide was lower than that of the methyl ricinoleate due to its higher polarity. The FTIR spectrum of lipoamide exhibited the presence of N-H absorption in the range of 3500-3000 cm−1, C=O amide absorption at 1644 cm−1, and C-N absorption at 1061 cm−1. The lipoamide showed higher antioxidant activity than ricinoleic acid based on the DPPH assay. The synthesized lipoamide exhibited weak antimicrobial activity against Staphylococcus aureus and Escherichia coli. [ABSTRACT FROM AUTHOR]