**1. Introduction**

The genus *Smilax* (Smilacaceae), commonly called sarsaparilla, consists of about 350 species. About 79 species are natives of China, 24 species are from India and 29 species are from Central America. The plants of this genus are climbers, have long, thin, thorny stems and have tendrils which attach to other plants or objects to climb steadily (**Figure 1**).

and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Figure 1.** (A) *S*. *bracteata*, (B) *S*. *china*, (C) *S*. *fluminensis*, (D) *S*. *glyciphylla*, images from https://www.inaturalist.org/taxa. (E) *S*. *campestris*, image courtesy of Mauricio Bonifacino Ph.D. (Universidad de la República, Montevideo, Uruguay). (F)–(I) *S*. *domingensis*.

The rhizome, roots, stems and, occasionally, leaves of sarsaparilla are used as food and in traditional medicine. These plants are known to have immunomodulatory, antioxidant, antibacterial, antifungal and diuretic properties. Additionally, they are used for relief from climatery [1]. Also, the genus *Smilax* has pharmacological properties and is used to treat different types of cancer, diabetes, skin diseases, ulcers, as well as fever, gout and ophthalmic diseases [2].

In recent years, interest in the study of the genus *Smilax* has increased, mainly in Europe and Asia, due to the presence of phenolic compounds. Some species have also proven effective in the prevention and treatment of several cancers. In addition, extracts from the genus *Smilax* exhibit pro-apoptotic activity and antioxidant activity [3].

There are reports about the antioxidant property expressed as DPPH• radical scavenging activity of species of the genus *Smilax*, as *Smilax bockii* [4], *Smilax campestris* [5], *Smilax glabra* [6], *Smilax lanceifolia* [7], *Smilax perfoliata* [8], *Smilax riparia* [9], *Smilax scobinicaulis* [10] and *Smilax sebeana* [11]. This property is attributed to phenolic compounds such as stilbenes, flavones, flavanones, flavonols, smilasides, smiglasides and helionosides, among others. Phenolic compounds have a unique chemical structure for stabilizing free radicals in an aromatic system. Flavonoids and stilbenes have been identified as beneficial agents for the treatment of various diseases such as cardiovascular and neurodegenerative diseases, as well as cancers [12].

Therefore, this review will describe *Smilax* species that have been studied for their antioxidant and anticancer properties with special emphasis on reports of phenolic compounds such as smilasides, smiglasides and helionosides. These compounds are phenols with antioxidant activity and are constituted of a sucrose substituted with feruloyl and coumaril groups. These three groups of compounds are evidence of chemotaxonomy in genus *Smilax*.
