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Taccalonolides are a class of microtubule-stabilizing agents isolated from ''Tacca chantrieri'' that has been shown to have selective cancer-fighting properties. Other examples of microtubule-stabilizing agents include taxanes and epothilones, both of which prevent cancer cells from dividing by interfering with tubulin.〔Tinley, T.L., Randall-Klubek, D.A., Leal, R.M., Jackson, E.M., Cessac, J.W., Quada, J.C., Hemscheidt, T.K., Mooberry, S.L. Taccalonolides E and A: Plant-derived steroids with microtubule-stabilizing activity. ''Cancer Res'' 63 (2003), 3211-3220.〕 While taxanes like Paclitaxel and docetaxel have been used successfully against breast, ovarian, prostate, and non–small-cell lung cancers, intrinsic and acquired drug resistance limit their anticancer properties. Unlike taxanes, taccalonolides appear to work through a different mechanism of action that does not involve tubulin, although recently isolated taccalonolides AF and AJ have shown tubulin-interaction activity.〔Buey, R.M., Barasoain, I., Jackson, E., Meyer, A., Giannakakou, P., Paterson, I., Mooberry, S., Andreu, J.M., Diaz, J.F. Microtubule interactions with chemically diverse stabilizing agents: thermodynamics of binding to the Paclitaxel site predicts cytotoxicity. ''Chem. Biol.'' 12 (12) (2005), 1269-1279.〕〔Li, J., Risinger, A.L., Peng, J., Chen, Z., Hu, L., Mooberry, S.L. Potent Taccalonolides, AF and AJ, Inform Significant Structure–Activity Relationships and Tubulin as the Binding Site of These Microtubule Stabilizers. ''J. Am. Chem. Soc.'', 2011, 133 (47), pp 19064–19067.〕 The discovery of taccalonolides opens up new possibilities to treat cancer cells, especially ones that are taxane or epithilone resistant. == Discovery == The first taccalonolide was isolated in 1963 from the tubers of ''Tacca leontopetaloides'' when researchers were exploring the "bitter principle" of the plant.〔Scheuer, P.J., Swanholm, C.E., Madamba, L.A., Hudgins, W.R. The constituents of Tacca leontopetaloides. ''Lloydia'', 26 (3) (1963), pp. 133–140.〕 Named taccalin, the bitter, light yellow powder and its hypothesized properties would help build the infrastructure for the elucidation of the structure of taccaolonolides 24 years later. The structures of taccalonolides A and B were elucidated in 1987 as a complex pentacyclic steroidal-like structure with the molecular formula of C36H46O14 and taccolonolide E was isolated in 1991.〔Chen, Z.L., Wang, B.D., Chen, M.Q. Steroidal bitter principles from Tacca plantaginea. Structures of taccalonolide A and B. Tetrahedron ''Lett.'', 28 (1987), 1673-1678.〕〔Shen, J., Chen, Z., and Gao, Y. The pentacyclic steroidal constituents of Tacca plantaginea: taccalonolide E and F. ''Chinese J. Chem''., 9: 92–94, 1991.〕 The most recent taccalonolides, AC-AF and H2, were elucidated using spectroscopic methods in 2011.〔 Each taccalonolide contains a C2-C3 epoxide and all except taccalonolide C have a C23-C26 lactone ring.〔Risinger, A.L, & Mooberry, S.L. Taccalonolides: Novel microtubule stabilizers with clinical potential. ''Cancer Letters'' 291 (1) (2010), 14-19.〕 Taccalonolides in the cancer-fighting context were discovered in a mechanism-based screening program designed to identify microtubule-disrupting agents from natural products.〔 After a crude extract with Taxol-like microtubule binding properties was identified, bioassay-directed purification yielded taccalonolides E and A. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Taccalonolide」の詳細全文を読む スポンサード リンク
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