**Natural Products as Cytotoxic Agents in Chemotherapy against Cancer Against Cancer**

**Natural Products as Cytotoxic Agents in Chemotherapy** 

DOI: 10.5772/intechopen.72744

Abdelmajid Zyad, Inass Leouifoudi, Mounir Tilaoui, Hassan Ait Mouse, Mouna Khouchani and Abdeslam Jaafari Hassan Ait Mouse, Mouna Khouchani and Abdeslam Jaafari Additional information is available at the end of the chapter

Abdelmajid Zyad, Inass Leouifoudi, Mounir Tilaoui,

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72744

#### **Abstract**

Nature continues to produce a great wealth of natural molecules endowed with cytotoxic activity toward a large panel of tumor cells. Some of these molecules are used in chemotherapy, and others have shown great anti-tumor and anti-metastatic potential in preclinical trials. This review discusses some examples of these molecules that have been studied in our laboratory and others. We report a differential cytotoxic activity of some monoterpenes (carvacrol, tymol, carveol, carvone, and isopulegol) against a panel of tumor cell lines. The carvacrol was the most cytotoxic molecule both *in vitro* and *in vivo* as demonstrated by preclinical studies using the DBA2/P815 mice model. On the other hand, polyphenols were also studied with respect to their cytotoxic effects. Interestingly, these compounds showed a prominent cytotoxic activity toward a panel of cancer cells with differential molecular mechanisms. In addition, we report a very strong antitumor efficacy of artemisinin, a sesquiterpen lactone from *Artemisia annua*, together with an antimetastatic potential as demonstrated by preclinical experiments. Furthermore, some of the molecular mechanisms involved in these effects are described.

**Keywords:** natural products, monoterpenes, polyphenols, artemisinin, cytotoxicity
