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 against HT 29 colon cancer cells. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolim) assays showed more effective inhibition of colon cancer cells proliferation by Gelam honey with IC₅₀ values of 39.0 mg/ml and 85.5 mg/ml respectively after 24 hours of treatment. Alkali comet assays revealed both honeys increased DNA damage significantly in a dose dependent manner. In addition, annexin V-FITC/PI flow cytometry demonstrated that at IC₅₀ concentrations and above, both Gelam and Nenas honeys induced apoptosis significantlyat values higher than for necrosis (p<0.05). Measurement of prostaglandin E₂ (PGE₂) confirmed that Gelam 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 growth of HT 29 colon cancer cells by inducing apoptosis and suppressing inflammation.