The effect of Longan seed polyphenols on colorectal carcinoma cells

Eur J Clin Invest. 2010 Aug;40(8):713-21. doi: 10.1111/j.1365-2362.2010.02322.x. Epub 2010 Jun 14.


Background: Polyphenol-rich longan seed extract (LSP) is a free radical scavenger and antioxidant. However, the effect of LSP on the growth of human colorectal carcinoma cells (CRC) has not yet been evaluated.

Materials and methods: Polyphenols of longan seeds were extracted and measured by colorimetry. Four CRC cell lines (Colo 320DM, SW480, HT-29 and LoVo) were treated with LSP and assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for apoptosis by annexin V labelling and for changes in the levels of proteins involved in cell cycle control or apoptosis by immunoblotting.

Results: Total phenol content of LSP was 695 mg g(-1) and total flavonoids were 150 mg g(-1). LSP inhibited the proliferation (25 microg mL(-1)-200 microg mL(-1)) of Colo 320DM, SW480 and HT-29, but not LoVo. LSP inhibited the proliferation by blocking cell cycle progression during the DNA synthesis phase and inducing apoptotic death. Western blotting indicated that LSP blocks the S phase, reducing the expression of cyclin A and cyclin D1. Colo 320DM and SW480 treated with LSP also showed the activation of caspase 3 and increased Bax : Bcl-2 ratio.

Conclusion: LSP induces S phase arrest of the cell cycle and apoptotic death in three CRC cell lines. The results indicate that LSP is a potential novel chemoprevention and treatment agent for colorectal cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Blotting, Western
  • Carcinoma / drug therapy
  • Carcinoma / pathology*
  • Caspase 3 / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / pathology*
  • Cyclin A / metabolism
  • Cyclin D1 / metabolism
  • Flavonoids / analysis
  • Flavonoids / pharmacology*
  • Flow Cytometry
  • Humans
  • Phenols / pharmacology*
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Polyphenols
  • S Phase / drug effects
  • Sapindaceae / chemistry*


  • Cyclin A
  • Flavonoids
  • Phenols
  • Plant Extracts
  • Polyphenols
  • Cyclin D1
  • Caspase 3