Target-oriented mechanisms of novel herbal therapeutics in the chemotherapy of gastrointestinal cancer and inflammation.

A prominent group of effective cancer chemopreventive drugs has been derived from natural products having low toxicity while possessing apparent benefit in the disease process. It is plausible that there are multiple target molecules critical to cancer cell survival. Herbal terpenoids have demonstrated excellent target-specific anti-neoplastic functions by suppression of cell proliferation and induction of apoptosis. Transcriptional molecules in the NF-κB, MEK/ERK and PI3K/Akt/mTOR pathways are important molecular targets of chemotherapy that play distinctive roles in modulating the apoptosis cascades. It is recently suggested that NSAID-activated gene (NAG-1), a novel proapoptotic protein, is the upstream anti-carcinogenic target of NSAIDs, PPAR ligands and herbal chemotherapeutic agents that triggers some of the events mentioned above. Besides, angiogenesis, oxidative stress as well as inflammation are important factors that contribute to the development and metastasis of cancer, which could be actively modulated by novel agents of plant origin. The aim of the present review is to discuss and summarize the contemporary use of herbal therapeutics and phytochemicals in the treatment of human cancers, in particular that of the colon. The major events and signaling pathways in the carcinogenesis process being potentially modulated by natural products and novel herbal compounds will be evaluated, with emphasis on some terpenoids. Advances in eliciting the precise cellular and molecular mechanisms during the anti-tumorigenic process of novel herbal therapeutics will be of imperative clinical significance to increase the efficacy and reduce prominent adverse drug effects in cancer patients through target-specific therapy.