In vitro cytotoxic and toxicological activities of ethanolic extract of Kaempferia galanga Linn. and its active component, ethyl-p-methoxycinnamate, against cholangiocarcinoma

Objective: To evaluate the cytotoxic, apoptotic, mutagenic and immunomodulatory activities of Kaempferia galanga Linn. (KG) extract and ethyl-p-methoxycinnamate (EPMC) in vitro. Methods: The present study investigated the cytotoxic [using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphe nyl-2-H-tetrazolium bromide test], apoptotic (using a mitochondrial membrane potential assay), mutagenic (using a micronucleus test) and immunomodulatory (using flow cytometry) activities of the ethanolic extract of KG and its bioactive component, EPMC, against two cholangiocarcinoma (CCA) cell lines, CL-6 and HuCCT1, and one normal human cell line, OUMS-36T-1F. Results: Both KG extract and EPMC exhibited moderate cytotoxic activity against both CCA cells. The cytotoxic activity was supported by their concentration-dependent induction of apoptosis. CL-6 was most sensitive (3-4 fold) and selective to 5-fluorouracil (5-FU), compared with KG extract and EPMC [median half inhibiting concentration (IC50) and selectivity index (SI) were 23.01 mu g/mL and 17.32; 78.41 mu g/mL and 4.44; 100.76 mu g/mL and 2.20, respectively for 5-FU vs. KG extract vs. EPMC]. HuCCT1 was relatively more sensitive and selective to 5-FU and EPMC than KG extract [median IC50 and SI were 66.03 mu g/mL and 6.04; 60.90 mu g/mL and 3.65; 156.60 mu g/mL and 2.23, respectively for 5-FU vs. EPMC vs. KG extract]. EPMC produced relatively potent cytotoxic activity against polymorphonuclear cells (IC50 = 92.20 mu g/mL). KG extract and EPMC exhibited concentration-dependent mutagenic activity, as well as inhibition of tumor necrosis factor-alpha and interleukin-6. Conclusion: Considering cytotoxic, apoptotic, immunomodulatory and mutagenic activities, further development of KG as a drug candidate is likely to focus on the oral pharmaceutical formulation of a standardized KG extract rather than isolated compounds. (C) 2020 Shanghai Changhai Hospital. Published by Elsevier B.V. All rights reserved.