Antioxidant and anticancer activities of organic extracts from Platycodon grandiflorum A. De Candolle roots

This study examined the antioxidant and anticancer activities of the petroleum ether extracts from the roots of Platycodon grandiflorum A. DC, which is a plant used as both a herbal medicine and food in Asia. Extracts from Platycodon grandiflorum in petroleum ether were fractionated (fractions I-V) by silica gel column chromatography using gradient solvents (petroleum ether: ethyl ether, 9:1-5:5, v/v). The antioxidant activities of the fractions were evaluated in terms of their inhibition of lipid peroxidation as well as their free radical scavenging activity. Fraction II, which was extracted at an 8:2 mixture of petroleum ether and ethyl ether, exhibited the greatest antioxidant activity among the fractions. On the other hand, the cytotoxicity of each fraction, which was evaluated by the MTT assay using human cancer cell lines (HT-29, HRT-18 and HepG2), was greatest in fraction III, which was extracted with a 7:3 petroleum ether and ethyl ether mixture. Both fractions, II and III, were sub-fractionated by thin layer chromatography, and the sub-fractions each were screened for their antioxidant and anticancer activities. In addition, the antioxidant activity was closely related to the content of phenolic compounds, and the anticancer active fraction exhibited a typical UV absorbance spectrum of polyacetylene.