Synthesis and Surface-Active Properties of Sodium N‑Acylphenylalanines and Their Cytotoxicity

Sodium N-acylphenylalanines (NaNAPhe) were synthesized using a mixture of fatty acids obtained from coconut, palm, karanja, Sterculia fetida, and high oleic sunflower oils via the Schotten–Baumann reaction in 60–78% yield to see the influence of the hydrophobic group of fatty acyl group functionality with headgroup phenylalanine on their surface-active properties. The products were characterized by chromatographic (thin-layer, column, and gas) and spectral (IR, NMR, and mass) techniques. The synthesized products were evaluated for their surface-active properties such as surface tension, wetting power, foaming characteristics, emulsion stability, calcium tolerance, critical micelle concentration (CMC), and thermodynamic properties. The results showed that all of the products exhibited superior surface-active properties like CMC (0.018–0.00041 mmol/L), calcium tolerance (26.5–65.8 ppm), and emulsion stability (262–844 s) compared to the reference sodium lauryl sulfate. All of NaNAPhe except sodium N-coconut fatty acylphenylalanines exhibited promising cytotoxicity against human cancer cell lines. These new vegetable oil based surfactants have potential in personal care, pharmaceutical, and industrial applications.