The anti-proliferative efficacy of t,t-conjugated linoleic acid (t,t-CLA), c9,t11-CLA, and t10,c12-CLA was compared in several human cancer cell lines. Gastric NCI-N87, liver Hep3B, pancreas Capan-2, and lung NCI-H522 cancer cells were incubated with 50 μM CLA isomers over a period of 6 days. The t,t-CLA inhibited the growth of all cancer cell lines to different extents, but c9,t11-CLA and t10,c12-CLA inhibited or stimulated the growth of the cancer cell lines. NCI-N87 cells were the most sensitive to growth inhibition and apoptosis from all CLA isomers tested. In NCI-N87 cells, CLA isomers reduced the release of arachidonic acid (AA) via the inhibition of cytosolic phospholipase A2 (cPLA2 ) activity, consequently reducing the production of PGE2 through the inhibition of cyclooxygenase-2 (COX-2). The efficacies of CLA isomers were in the following order (from most to least effective): t,t-CLA, t10,c12-CLA and c9,t11-CLA. Overall, these results imply that the anti-proliferative efficacy of t,t-CLA on cancer cells, especially NCI-N87 cells, was greater than other CLA isomers due to its induction of apoptosis through the inhibition of cPLA2 and COX-2 activities.

Chrysanthemum boreale Makino (C. boreale) is widely distributed in Asian countries, and has traditionally been used to treat various inflammatory diseases including bronchitis. In this study, we aimed to isolate biologically active compounds from leaves and stems of C. boreale. Chemical components were purified by column chromatograpy and recyclic HPLC, and characterized from their spectral data (IR, MS, NMR). Biological activity experiments were conducted for Farnesyl-protein transferase (FPTase) activity, apoptosis and nitirc oxide (NO) release. As a results, three sesquiterpene lactones were isolated. Compound 1 (4-methoxy-8-O-acetyl-10-hydroxy-2,11(13)-guaiadiene-12,6-olide) showed strong cytotoxic activities having an average growth inhibition of 50% (GI50) value of 1.89 ㎍/㎖against human colon adenocarcinoma cells. Compound 1 also showed a low half maximal inhibitory concentration (IC50) value of 10 ㎍/㎖ for NO release. In the caspase 3 activity, compound 1 and compound 2 (8-O-(2-carbonyl-2-butyl)-3,10-dihydroxy-4,11(13) -guaiadiene-12,6-olide) exhibited 94% and 90% apoptosis inhibition activity, respectively. Compound 3 (4,8-O-diacetyl -10-hydroxy-2(3),11(13)-guaiadiene-12,6-olide) showed a strong inhibitory effect on FPTase activity with 90% inhibitory activity at a concentration of 100 ㎍/㎖. These results clearly show the presence of lactone compounds in the leaves and stems, which may partially contribute to the pharmacological activity of C. boreale.