Ethanol Extract of Oldenlandia diffusa - an Effective Chemotherapeutic for the Treatment of Colorectal Cancer in Humans: -Anti-Cancer Effects of Oldenlandia diffusa.
OBJECTIVE
Oldenlandia diffusa is traditionally used to relieve the symptoms of and to treat various diseases, but its anti-cancer activity has not been well studied. In the present study, the authors investigated the anti-cancer effects of an ethanol extract of Oldenlandia diffusa (EOD) on HT-29 human adenocarcinoma cells.


METHODS
Cells were treated with different concentrations of an EOD, and cell death was assessed by using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Analyses of the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial membrane depolarizations were conducted to confirm cell death by apoptosis. Also, intracellular reactive oxygen species (ROS) generation was determined using carboxy-H2DCFDA (5-(and-6)-carboxy-20,70-dichlorodihydrofluorescein diacetate).


RESULTS
EOD inhibited the proliferation of HT-29 cells for 24 hours by 78.6% ± 8.1% at 50 μg/mL, 74.4% ± 4.6% at 100 μg/mL, 65.9% ± 5.2% at 200 μg/mL, 51.4% ± 6.2% at 300 μg/mL, and by 41.7% ± 8.9% at 400 μg/mL, and treatment for 72 hours reduced the proliferation at the corresponding concentrations by 43.3% ± 8.8%, 24.3 ± 5.1 mV, 13.5 ± 3.2 mV, 6.5 ± 2.3 mV, and by 2.6 ± 2.3 mV. EOD increased the number of cells in the sub-G1 peak in a dose-dependent manner. The mitochondrial membrane depolarization was elevated by EOD. Also, caspase activities were dose-dependently elevated in the presence of EOD, and these activities were repressed by a pan-caspase inhibitor (zVAD-fmk). The ROS generation was significantly increased by EOD and N-acetyl-L-cysteine (NAC; a ROS scavenger) remarkably abolished EOD-induced cell death. In addition, a combination of sub-optimal doses of EOD and chemotherapeutic agents noticeably suppressed the growth of HT-29 cancer cells.


CONCLUSIONS
These results indicate that EOD might be an effective chemotherapeutic for the treatment of human colorectal cancer.
Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.
Soojin
S
Lee
Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.
Ji Hwan
JH
Shim
Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.
Huijin
H
Gim
Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.
Hyun Soo
HS
Park
Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.
Byung Joo
0000-0001-8835-9103
BJ
Kim
HT-29 human colorectal adenocarcinoma cells; Oldenlandia diffusa; anti-cancer activity