Journal of Medicinal Plants Research Vol. 6(5), pp. 825-832, 9 February, 2012 Available online at http://www.academicjournals.org/JMPR DOI: 10.5897/JMPR11.1471 ISSN 1996-0875 ©2012 Academic Journals Full Length Research Paper Determination of saikosaponin, phenolic and podophyllotoxin contents of five endemic Bupleurum root extracts and their effects on MCF-7 cells Gökhan Kars 1 *, Meltem Demirel Kars 2,3 , Mehtap Akin 1 , Hatice Taner Saraçoğlu 1 and Ufuk Gündüz 4 1 Department of Biology, Faculty of Science, Selçuk University, 42075 Konya, Turkey. 2 Sarayönü Vocational High School, Selçuk University, 42430 Konya, Turkey. 3 Advanced Research and Application Center, Selçuk University, 42075 Konya, Turkey. 4 Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey. Accepted 1 December, 2011 Bupleurum species are among the plants used in Chinese medicine for phytotherapy. Various compounds obtained from plants have been found to exhibit anticancer activity. In this study, phenolic compounds, saikosaponins and podohyllotoxin contents of total root extracts from endemic Bupleurum species (Bupleurum sulphureum, Bupleurum lycaonicum, Bupleurum turcicum, Bupleurum heldreichii, Bupleurum pauciradiatum) were determined by high-performance liquid chromatography (HPLC). Total phenol content and free radical scavenging activities of total extracts were also identified. Finally, the effects of plant root extracts on viability of P-gp overexpressing paclitaxel resistant (MCF-7/Pac) and vincristine resistant (MCF-7/Vinc) MCF-7 mammary carcinoma cell lines and their parental line (MCF- 7/S) were evaluated by cytotoxicity tests. Results showed that saikosaponin A, saikosaponin D and isoquercitrin contents of the root extracts were higher compared to podophyllotoxin, catechin and quercetin. While, B. lycaonicum root extract has about 1.5 fold more total phenol content with respect to others, B. turcium root extract has the highest free radical scavenging activity. According to cytotoxicity tests, B. turcicum and B. pauciradiatum root extracts were more toxic to the MCF-7/Pac cell line than the root extracts of other three species. In addition, B. heldrechii extract has been found to be the most toxic to the MCF-7/Vinc cell line among the others. Key words: Bupleurum species, plant phenolics, saikosaponin, podophyllotoxin, high-performance liquid chromatography (HPLC), MCF-7. INTRODUCTION Bupleurum species is among the plants used in traditional Chinese medicine (Yano et al., 1994) and major bioactive compounds have been found to be saikosaponins, phenolics, volatile oils and less polar substances (Zhang et al., 2010). Bupleurum scorzonerifolium is known as anti-inflammatory and anti- hepatotoxic plant and it was shown that saikosaponins found in plant root had anti-inflammatory and anti- carcinogenic activities (Mahato et al., 1988; Hsu et al., *Corresponding author. E-mail: gkars2004@yahoo.com. Tel: +90 3322232771. 2004). In addition, total root extract of B. scorzonerifolium has been proven to decrease the telomerase activity in lung carcinoma cell line by activating apoptosis (Cheng et al., 2003). Plant chemicals (phytochemicals) like polyphenols, organosulfurs, carotenoids, saponins, phytosterols, alkaloids, terpenes and more than thirty thousand types are the potential active ingredients exerting their effects on variety of the cells. Quercetin, rutin, isoquercitrin, catechin, robinin, tannin are examples for plant phenolic compounds which have antioxidant and chemopreventive activities (Cai et al., 2004). Saponins are glycosides with aglycan and glycan parts (Sparg et al., 2004). Saponins have been recently reported to possess anticancer activities by making complex with