Cytotoxicity of ethanolic extract of plumeria rubra L. Stem bark to cancer cells and lymphocytes

This study aimed to examine the cytotoxicity of a stem bark ethanolic extract of Plumeria rubra L. from East Java, Balongbendo District of Sidoarjo, Indonesia on a model cancer cell line and lymphocytes in vitro. The cancer cells (i.e., T47D cells) and lymphocytes were treated using various concentrations, i.e. 0.3, 0.6, 1.2, 2.4, 4.9, 9.8, 19.5, 39.1, 78.1, 156.1, 312.5, 625, 1,250, 2,500, 5,000 and 10,000 µg/mL of the stem bark P. rubra extract. The number of dead and live cells were determined using direct blue staining after 24 hours of incubation in the extract. The data were analyzed by the Kolmogorov-Smirnov test and probit analysis using SPSS 16.0. The result showed that after administration of the extract of P. rubra, the T47D cells had an LC50 of 275.744 µg/mL with a linear R² = 0.802. Its LC50 to lymphocytes was more than 10,000 µg/mL. It can be concluded that the extract was toxic to the T47D cells, but it was not toxic to the lymphocytes. Thus, the extract of P. rubra seemed to have a high capability of preventing the growth of cancer cells, i.e., T47D cells. The higher toxicity of the extract to T47D cells than to lymphocytes indicates the potential to use the extract as an anticancer agent that is safe for normal cells.