Castor oil—based graft copolymers: synthesis, characterization antimicrobial activity and antiproliferative effects against breast cancer cell lines

Castor oil was autoxidized for three months to obtain macroperoxide castor oil (PCO). Since this polymeric oil has peroxide groups and hydroxyl groups, free-radical polymerization (FRP), ring-opening polymerization, and one-pot polymerization both free-radical polymerization (FRP) and ring-opening polymerization in one step methods were used to synthesis of various types of the graft copolymers. PCO-g-Polystyrene, PCO-g-Poly(methyl acrylate), and PCO-g-Poly(tert-buytl acrylate) were synthesized using the free-radical polymerization method. PCO-g-Poly( ε -caprolactone) graft copolymer was obtained via ring-opening polymerization, and PCO-g-Polystyrene-g-Poly( ε -caprolactone) graft copolymer was obtained using one-pot polymerization method. All graft copolymers obtained were characterized by proton nuclear magnetic resonance ( 1 H NMR), Fourier-transform infrared, differential scanning calorimetry, thermal gravimetric analysis, and elemental analysis. After the synthesis of castor oil-based copolymers, we determined the antimicrobial effects of them as well as the antiproliferative effects on breast cancer cell lines. Antimicrobial activity was carried out using the disc diffusion method and the dilution method. As a result of antimicrobial activity, the compounds showed moderate antimicrobial effects on microorganisms compared to standard antibiotics. In particular, the compounds have shown more antibacterial activity than antifungal activity. We also observed a prominent antiproliferative effect of synthesized compounds depending on increasing doses (1–25 µg/mL) and times (24–48 h) in MDA-MB-231 breast cancer cells.