EFFECT OF AQUEOUS LEAVES EXTRACT OF Vernonia amygdalina ON HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS

Abstract

Vernonia amygdalina (bitter leaf) is a widely used medicinal plant in Africa, traditionally applied in the management of infections as well as inflammation. Despite its extensive ethnomedicinal use, there remains limited scientific evidence on its direct effects on human immune cells, particularly peripheral blood mononuclear cells (PBMCs). This study investigated the effect of different concentrations of the aqueous leaf extract of Vernonia amygdalina on PBMC viability in vitro. Fresh PBMCs were isolated from healthy voluntary donors using density gradient centrifugation, and the cells were exposed to varying concentrations (25, 50, 75 and 100µg/mL) of the extract. Cell viability was assessed using Tryphan blue exclusion method, and results were compared with untreated control cells to determine cytotoxic or protective effects. The findings revealed a concentration-dependent response in PBMC viability following exposure to the extract. Lower concentrations demonstrated mild supportive or neutral effects on PBMC survival, whereas higher concentrations showed a gradual reduction in viability, suggesting potential cytotoxicity at elevated doses. Statistical comparison between treated and untreated cells confirmed that the extract exerted measurable effects on PBMC survival that varied with concentration. Overall, the study provides insight into the immunomodulatory and cytotoxic potential of Vernonia amygdalina, emphasizing the importance of dose considerations in its traditional and therapeutic applications. These findings contribute to ongoing efforts to scientifically validate medicinal plants used in African ethnomedicine and provide a foundation for further research on their immunological safety and benefits.