In vitro: |
Toxicol In Vitro . 2012 Oct;26(7):1216-1223. | Methyl nomilinate from citrus can modulate cell cycle regulators to induce cytotoxicity in human colon cancer (SW480) cells in vitro[Pubmed: 22728232] | Limonoids are triterpenoids found in citrus and possess cancer preventive properties in in vitro and in vivo assays. Although several mechanisms for the chemopreventive properties of limonoids have been postulated, the specific mechanisms involved in the anti-cancer effects have not been explored. In the present study, limonoids, including methyl nomilinate, isoobacunoic acid, isolimonexic acid (ILNA), and limonexic acid (LNA), were purified, identified by LC-MS and NMR spectral data and evaluated for their biological effects on SW480 human colon adenocarcinoma cells. Methyl nomilinate was the most potent inhibitor of cell metabolic activity in MTT and EdU incorporation assays. These limonoids did not affect apoptotic markers such as caspase-3 and PARP, but methyl nomilinate treatment resulted in significant induction of G0/G1 cell cycle arrest. Furthermore, methyl nomilinate suppressed CDK4/6 and cyclin D3 and the expression of CDK inhibitors. Taken together, the results suggest inhibition of cell proliferation by methyl nomilinate occurs due to G1 cell cycle arrest, indicating that methyl nomilinate has potential as a chemopreventive agent. | Eur J Pharmacol . 2011 Nov 16;670(1):44-49. | Structure-function relationships of citrus limonoids on p38 MAP kinase activity in human aortic smooth muscle cells[Pubmed: 21924259] | Limonoids, abundantly present in citrus fruits, have potential role in reducing risk of different type of cancer. In the present study, we hypothesized that seven structurally different limonoids would involve in inflammatory pathway via modulating p38 MAP kinase activity at various extent in vascular smooth muscle cells. Results demonstrated that the different functional groups containing limonoids had differential effects on the p38 MAP kinase activity in human aortic smooth muscle cells. Among seven limonoids, nomilin exhibited the highest (38%) inhibition of p38 MAP kinase activity, followed by limonin (19%), deacetyl nomilin (19%), and defuran nomilin (17%). While defuran limonin and methyl nomilinate showed no significant decrease in p38 MAP kinase activity, obacunone significantly increased the p38 MAP kinase activity by 38%. Furthermore, TNF-α induced p38 MAP kinase activity in the smooth muscle cells was completely inhibited by nomilin. Thus our data provide the first evidence that nomilin is the potent natural inhibitor for p38 MAP kinase activity in human aortic smooth muscle cells. These data also suggest that a seven-membered A ring with acetoxy group, present in nomilin, seems to be essential for its inhibitory activity on p38 MAP kinase. |
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