In vitro enhancement of doxorubicin genotoxic activities and interference with cell cycle delay by Plumbago indica root ethanolic extract in human lymphocytes
Ratanavalachai, T.; Thitiorul, S.; Tanuchit, S.; Itharat, A.; Sakpakdeejaroen, I.
Journal of the Medical Association of Thailand 98 Suppl. 2: S38-S44
2015
ISSN/ISBN: 0125-2208 PMID: 26211102 Document Number: 16597
Combinations of modern medicines with herbal medicines are being developedfor more effectiveness. Data on the safety and drug-herb interactions are needed to be clarified. Ethanolic extract of Plumbago indica root (EEPIR) is medicinally usedfor cancer treatment in Asian traditional medicine. However its mechanism of action is still inconclusive. Our previous study demonstrated that EEPIR was genotoxic and induced cell cycle delay in human lymphocytes in vitro. To investigate genotoxic potency and interference with cell cycle of EEPIR in combination with doxorubicin (DXR), a standard chemotherapeutic agent, in human lymphocytes by in vitro sister chromatid exchange (SCE) assay. Human lymphocytes were pretreated with EEPIR at 6.25-100 mcg/mlfollowed by DXR (0.1 mcg/ml). SCE levels and cell cycle kinetics were evaluated. EEPIR pretreatments (6.5-50 mcg/ml) significantly enhanced genetic damage induced by DXR (p<0. 05). Delaying of the cell cycle was detected and related to EEPIR concentration. EEPIR at 100 mcg/ml, on the contrary, did not enhance DXR-induced genotoxicity but tended to lower genotoxicity compared to DXR treatment alone. It significantly delayed cell cycle the most (p<0.05). EEPIR pretreatments at proper doses enhanced genotoxic damage induced by DXR in human lymphocytes. Delaying cell cycle by EEPIR could lower that potency. Usage of EEPIR, therefore, should be adjusted for safety. Combination of EEPIR with DXR might be usefulfor more efficient cancer treatment with less DXR toxicity. Further in vivo study is needed to support this in vitro evidence.