author(s) : Amr M. Saadeldeen and Abdel-Fattah M. Rizk

The family Equisetaceae (horsetail family) is the only extant family of the order Equisetales, with one surviving genus, Equisetum, which comprises about 20 species.
The name “horsetail” because of the branched species somewhat resemble a horse’s tail. Similarly, the scientific name Equisetum was derived from the Latin Equus (horse) and Seta (bristle) (Boulos 1999).
Various phytochemical constituents were found in Equisetum plants including phenolic compounds, sterols, terpenoids, saponins and alkaloids (Sandhu et al., 2010).
Valuable pharmacological and biological activities were also reported including antioxidant (YingChao et al., 2010), cytotoxic (Četojević-Simin et al., 2010), hepatoprotective (Oh et al., 2004), antimicrobial (Čanadanović-Brunet et al., 2009), anti-diabetic (Safiyeh et al., 2007) and anti-inflammatory (Yesilada and Gurbuz, 2010) activities.