Antioxidant and Anti-inflammatory Activities Mediate the Radioprotective Effect of Trianthema Portulacastrum L. Extracts

Abstract Ionizing radiation (IR) generates reactive oxygen species (ROS) which leads to oxidative stress and often leads to inflammatory responses in organisms. Trianthema portulacastrum L., a plant commonly growing in India, is rich in antioxidant phytochemicals which is responsible for scavenging free radicals, and may provide radio-protective and anti-inflammatory effects in response to ionizing radiation. The effect of T. portulacastrum extracts was studied in hepatic cells, which are susceptible to radiation-induced damage, and in macrophages which are the primary inflammatory cells of the body. T. portulacastrum stem extracts showed efficient free radical scavenging activity in hepatocytes and reduction of radiation-induced lipid peroxidation in cell and mitochondrial membranes. Treatment of irradiated cells with T. portulacastrum stem extracts enhanced cell viability, although at higher concentrations there was reduction in cell viability. Treatment with low concentration of T. portulacastrum stem extract also reduced cellular ROS generation and increased cellular concentration of the anti-oxidant glutathione. T. portulacastrum extracts also showed a marked anti-inflammatory effect in macrophages activated by the inflammatory agonist bacterial lipopolysaccharide (LPS) by reducing inflammatory gene expression and nitric oxide (NO) production, and increasing glutathione content. LPS treatment lowered expression of Nrf2, a transcription factor involved in regulation of multiple anti-oxidant genes, while treatment with low concentration of T. portulacastrum stem extract significantly restored it. Together, these observations demonstrated a potential radioprotective role of T. portulacastrum extract mediated by both its antioxidant activity on hepatic epithelial cells and its anti-inflammatory activity on immune cells