Two new compounds from endemic Centaurea paphlagonica (Bornm.) Wagenitz and their cytotoxic activities

Centaurea paphlagonica (Bornm.) Wagenitz is an endemic plant in Turkey. Pyrocatechol, vanillic acid, 3,4-dihydroxy benzoic acid, 5-O-caffeoylshikimic acid, tamarixetin, chlorogenic acid methyl ester, quercetin, 1,3-dicaffeoylquinic acid, tamarixetin-7-O-beta-D-glucopyranoside, quercimetrin, daucosterin, paphlagonicanin B, tamarixetin-7-O-beta-rutinoside, rutin, chlorogenic acid, isoorientin, orientin, 3-O- feruloylquinic acid, quercetagetin-3-methyl ether 6-O-beta-glucopyranoside, diosmetin 6-C-beta-glucopyranoside, quercetagetin 4 '-methyl ether 7-O-beta-glucopyranoside, paphlagonicanin A, nepetin, cirsiliol, desacylcynaropicrin, and 8 alpha-O-(2 ',3 '- dihydroxyisobutyryl) desacylcynaropicrin were isolated from both flower and aerial parts of C. paphlagonica. These compounds were identified using 1D and 2D NMR methods and ESI-MS. The MTT assay assessed the antiproliferative activities of all isolated (known and new compounds) compounds on Caco-2, LNCaP, A549, HeLa, and HEK-293 cell lines. The 8 alpha-O-(2 ',3 '-dihydroxyisobutyryl) desacylcynaropicrin demonstrated the highest activity against CaCo-2 and HeLa cancer cell lines.