Gelam and Nenas honeys inhibit proliferation of HT 29 colon cancer cells by inducing DNA damage and apoptosis while suppressing inflammation

Gelam and Nenas monofloral honeys were investigated in this study for their chemopreventive effects againstHT 29 colon cancer cells. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2Htetrazolim)assays showed more effective inhibition of colon cancer cells proliferation by Gelam honey with IC50values of 39.0 mg/ml and 85.5 mg/ml respectively after 24 hours of treatment. Alkali comet assays revealed bothhoneys increased DNA damage significantly in a dose dependent manner. In addition, annexin V-FITC/PI flowcytometry demonstrated that at IC50 concentrations and above, both Gelam and Nenas honeys induced apoptosissignificantlyat values higher than for necrosis (p<0.05). Measurement of prostaglandin E2 (PGE2) confirmed thatGelam and Nenas honeys reduced its production in H2O2 inflammation-induced colon cancer cells. In conclusion,our study indicated and confirmed that both Gelam and Nenas honeys are capable of suppressing the growthof HT 29 colon cancer cells by inducing apoptosis and suppressing inflammation.