Acute oral toxicity of damnacanthal and its anticancer activity against colorectal tumorigenesis

Damnacanthal is an anthraquinone, extracted, and purified from the root of Morinda citrifolia in Thailand. This study aimed to measure acute oral toxicity and to investigate the anticancer activity of damnacanthal in colorectal tumorigenesis. We found that the growth of human colorectal cancer cells was inhibited by damnacanthal in a dose- and a time-dependent manner. The growth inhibitory effect of damnacanthal was better than that of 5-FU used as a positive control in colorectal cancer cells, along with the downregulation of cell cycle protein cyclin D1. Similarly, an oral treatment of damnacanthal effectively inhibited the growth of colorectal tumor xenografts in nude mice, which was approximately 2–3-fold higher as compared to 5-FU by tumor size as well as expression of bioluminescence. Furthermore, the study of acute oral toxicity in mice exhibited a relatively low toxicity of damnacanthal with a LD(50) cut-off value of 2500 mg/kg according to OECD Guideline 423. These results reveal the potential therapeutic activity of a natural damnacanthal compound as an anti-colorectal cancer drug.