Abstract

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.