Growth Inhibition and G1 Cell Cycle Arrest Mediated by 25-Methoxyhispidol A, a Novel Triterpenoid, Isolated from the Fruit of Poncirus trifoliata in Human Hepatocellular Carcinoma Cells

Abstract

Poncirus trifoliata (Rutaceae) extracts have been known to possess anti-allergic, anti-inflammatory and antiviral activities. However, other biological activities, especially, the anticancer potential of extracts of P. trifoliata or its constituents, have not been fully investigated yet. In this study, we have evaluated the antiproliferative effects of a novel triterpenoid, 25-methoxyhispidol A, isolated from the fruit of P. trifoliata against SK-HEP-1 human hepatocellular carcinoma cells. Flow cytometric analysis indicated that 25-methoxyhispidol A arrests the cell cycle in the G1 phase at the earlier time and subsequently induces apoptosis of the cancer cells. Further study revealed that the cell cycle arrest in the G1 phase by 25-methoxyhispidol A correlated well with the inhibition of phosphorylation of the retinoblastoma (Rb) protein, and with the down-regulation of cyclin D1 and cyclin-dependent kinase cdk4 and the induction of cdk inhibitor p21^WAF1/Cip1 protein. These findings suggest the potential of 25-methoxyhispidol A isolated from the fructus of P. trifoliata as an antitumor agent against human hepatocarcinoma cells by arresting the cell cycle and inducing apoptosis.

Key words

25-Methoxyhispidol A - Poncirus trifoliata (L.) Raf. - Rutaceae - SK-HEP-1 cells - cell growth inhibition

References

• 1 Kim C M, Shin M K, Ahn D G, Lee K S. Chungyak Daesajun, Vol. 8.  Seoul: Jungdam. Publisher;  1997 3969-76
• 2 Chun Y T, Sankawa U. Screening of antiallergic effect in traditional medicinal drugs and active constituents of Aurantii fructus immaturus. .  Shoyakugaku Zasshi. 1989;  43 314-23
• 3 Takase H, Yamamoto K, Hirano H, Saito Y, Yamashita A. Pharmacological profile of gastric mucosal protection by marmin and nobiletin from a traditional herbal medicine, Auratii fructus immaturus. .  Jpn J Pharmacol. 1994;  66 139-47
• 4 Kim D H, Bae E A, Han M J. Anti Helicobacter pylori activity of the metabolites of poncirin from Poncirus trifoliate by human intestinal bacteria.  Biol Pharm Bull. 1999;  22 422-4
• 5 Lee Y M, Kim D K, Kim S H, Shin T Y, Kim H M. Antianaphylactic activity of Poncirus trifoliate fruit extract.  J Ethnopharmacol. 1996;  54 77-84
• 6 Lee H T, Seo E K, Chung S J, Shim C K. Prokinetic activity of an aqueous extract from dried immature fruit of Poncirus trifoliate (L.) Raf.  J Ethnopharmacol. 2005;  102 131-6
• 7 Lee S K, Cui B, Mehta R R, Kinghorn A D, Pezzuto J M. Cytostatic mechanism and antitumor potential of novel 1H-cyclopenta[b]benzofuran lignans isolated from Aglaia elliptica. .  Chem Biol Interact. 1998;  115 215-28
• 8 Lee S K, Heo Y H, Steele V E, Pezzuto J M. Induction of apoptosis by 1,4-phenylenebis(methylene) selenocyanate in cultured human colon cancer cells.  Anticancer Res. 2002;  22 97-102
• 9 Kupchan S M, Lacadie J Á. Hispidols A and B, two new tirucallane triterpenoids.  J Org Chem. 1981;  46 4085-8
• 10 Arisawa M, Fujita A, Morita N, Cox P J, Howie R A, Cordell G A. Triterpenes from Simaba multiflora. .  Phytochemistry. 1987;  26 3301-3
• 11 Majumder P L, Maiti R N, Panda S K, Mal D, Raju M S, Wenkert E. Carbon-13 nuclear magnetic resonance spectroscopy of naturally occurring substances. 64. Structure of moronic acid.  J Org Chem. 1979;  44 2811-42
• 12 Petr D, Marian H, David V, Alica H, Miroslav K, David B. et al . Pharmacological activities of natural triterpenoids and their therapeutic implications.  Nat Prod Rep. 2006;  23 394-411
• 13 Chavez I O, Apan T R, Martinez-Vazquez . Cytotoxic activity and effect on nitric oxide production of tirucallane - type triterpenes.  J Pharm Pharmacol. 2005;  57 1087-92
• 14 Chen G, Lu H, Wang C, Yamashita K, Manabe M, Xu S. et al . Effect of five triterpenoid compounds isolated from leaves of Diospyros kaki on stimulus-induced superoxide generation and tyrosyl phosohorylation in human polymorphonuclear leukocytes.  Clin Chim Acta. 2002;  320 11-6
• 15 Zhou H Y, Shin E M, Guo L Y, Zou L B, Xu G H, Lee S. et al . Anti-inflammatory activity of 21(α,β)-methylmelianodiols, novel compounds from Poncirus trifoliate Rafinesque.  Eur J Pharmacol. 2007;  572 239-48