Antitumour activities of sesquiterpene lactones from Inula helenium and Inula japonica.

It has been well documented that medicinal plants confer considerable anticancer activity against various tumours (Dai and Mumper, 2010). Plants contain abundant compounds which have consistently been shown to be associated with a lower risk of cancers at almost every site, such as lung, colon, rectum, prostate, cervix, stomach, pancreas, breast, and bladder (Steinmetz and Potter, 1991). Efforts, therefore, are being made to identify naturally occurring anticarcinogens which would prevent, slow, and/or reverse the cancer induction and its subsequent development (Chuang et al., 2000). Inula helenium is an important herb traditionally used in the treatment of infl uenza, fever, tuberculotic enterorrhea, and chronic enterogastritis in China, Japan, and Europe (Okuda, 1986; Olechnowicz-Stepien and Skurska, 1960). Plants of the genus Inula have been shown to contain high levels of sesquiterpene lactones (Zhao et al., 2006; Trendafi lova et al., 2010), which recently have received considerable attention in the pharmacological community due to their antineoplastic and anti-infl ammatory effects (Konishi et al., 2002; Won et al., 2004). Many studies indicated that sesquiterpene lactones exhibit antitumour activities in a variety of malignant cells (Ghantous et al., 2010; Chen et al., 2007). In the present study, we investigated the antiproliferative activity of eight sesquiterpene lactones from I. helenium and I. japonica against gynecologic cancer cell lines in vitro. We also explored the antitumour activity against ascite tumour S180 xenografts in mice in vivo.