Nonspecific immune responses of Cathranthus roseus in Oreochromis mossambicus

The present study was performed to determine the efficacy and immune stimulatory effects of crude and water-soluble leaf fraction of Cathranthus roseus in Oreochromis mossambicus. Intraperitoneal injection method was used to administrate the drugs and Sheep Red Blood Cells (SRBC) which is used as an antigen. Lysozyme assay, plate hole diffusion assay, phytochemical analysis and antimicrobial activity screening methods was used to confirm the drug immune responses. In vivo experiments show the significant enhancement of non-specific immune response such as lysozymal activity. Increase in the WBC count was also noticed when animals were exposed into the environment containing crude extract (CE) and water-soluble fraction (WSF) of the target drug. Moreover, biochemical analysis of C. roseus reveals the presence of some important secondary metabolites such as alkaloids, tannins, flavonoids and sterols. In vitro antibacterial activity of different concentration CE and WSF against Aeromonas hydrophila had a potential drug activity. Cathranthus roseus has induced the nonspecific immune responses in Oreochromis mossambicus. Our results suggest the conserved roles of this immune stimulant applicable to higher vertebrates at the infection stage.