In vitro activities of leaf and root extracts of Catharanthus roseus (L.) G. Don. on human peripheral blood mononuclear cells

Catharanthus roseus (L.) G.Don. is widely used to treat hypertension, diabetes, poor digestion and dysentery, and fever. However, studies on the pharmacological effects on the immunomodulatory of C. roseus have been limited. The objective of this study was to investigate the immunomodulatory activity of leaf and root extracts of C. roseus on human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from 10 mL of EDTA–coagulated whole blood collected from the healthy volunteers. The effects of 96% ethanol extracts and the fractions (n-Hexan, chloroform, ethyl acetate, water) from leaves and roots of C. roseus on PBMCs proliferation of after 24, 48, 72 hours were evaluated using 2,5-diphenyl-2H-tetrazolium bromide assay. The inhibition on interleukin-1beta (IL-1β) and interleukin-6 (IL-6) secretion from PBMCs by leaf and root extracts of C. roseus for 48 hours was evaluated using enzyme-linked immunosorbent assays. After 48 hours, the crude extracts and the fractions from leaves and roots of C. roseus showed the strongest inhibitory effects on PBMCs proliferation, with the IC50 concentrations of the crude extracts from leaves and roots and the ethyl acetate fractions being 6.10, 51.17, 76.52 ppm, respectively. Water fraction from C. roseus roots inhibited IL-1β production with IC50 value of 38.46 ppm. Chloroform fractions from C. roseus leaves strongly inhibited IL-6 production secreted by PBMCs with IC50 value of 41.37 ppm. Extracts from the leaves and roots of C. roseus exhibited inhibitory effects on PBMC proliferation and interleukin secretion from PBMCs.