Potentiation of doxorubicin (DXR)'s genotoxic activities by ethanolic extract from Thai Plumbago indica roots (EEPIR) in human lymphocytes in vitro
The ethanolic extract of Plumbago indica roots (EEPIR) is used anecdotally in Thai traditional medicine for various purposes especially in antibacterial and antitumor treatments. However, its mechanism of action is still unclear. Our previous study indicated that EEPIR was genotoxic at concentrations of 25 – 100 µg/ml and also induced cell cycle delay . We hypothesized that the genotoxicity of EEPIR might potentially support doxorubicin (DXR), a genotoxic chemotherapeutic agent. The chromosomal study was conducted in vitro to investigate the induction of sister chromatid exchange (SCE) level by EEPIR pretreatments at various concentrations, followed by 0.1 µg/ml DXR in human lymphocytes. Results demonstrated that EEPIR pretreatments, in adjunct to DXR, were able to significantly enhance DXR-induced genotoxicity and also delayed the cell cycle. This outcome suggested that EEPIR might be useful for more effective chemotherapy. In addition, the data revealed that the intake of EEPIR should be limited in order to prevent induction of genetic damage from chemical interactions afterwards.
Acknowledgements: This study was supported by Research Fund, National Research University Project of Thailand. Office of Higher Education Commission and Thammasat University, Thailand.
Keywords: Plumbago indica root, doxorubicin, cell cycle, antigenotoxicity, sister chromatid exchange
 Thitiorul S, Ratanavalachai T, Tanuchit S, Itharat A, Sakpakdeejaroen I. (2013) Genotoxicity and interference with cell cycle activities by an ethanolic extract from Thai Plumbago indica roots in human lymphocytes in vitro. Asian Pacific journal of cancer prevention: APJC, 14, 2487 – 90.