Development of biocarrier for violacein controlled release in the treatment of cancer

Abstract

Violacein is a purple pigment member of the indocarbazole family synthesized by Gram(-) bacteria and displays many beneficial activities for human health. However, the medical use of violacein is very limited since the molecule is extremely hydrophobic. An emulsion of violacein and polyoxyethylene sorbitan monolaurate showed high stability in aqueous solutions at 37 °C for 6 days. Pectin-gelatin coating provides stability to the emulsion in simulated digestive fluids and modifies the violacein kinetic release. Biophysical analyses of hybrid pectin-gelatin microspheres by TEM, DLS, XRD, and DSC revealed a highly homogeneous surface of microspheres, amorphous content of violacein in the matrix, and increased structure stability. Kinetic studies of different pectin-gelatin microsphere formulations were performed under different environmental conditions simulating the digestive tract. Controlled release of Violacein from microspheres were examined using six semi-empirical and structured models. Violacein emulsions drastically decreased the HTC-116 colon cancer cell viability, but the effect was attenuated by the microsphere biopolymer coating.