Terpene-Strengthened Ginkgo biloba Extract as a Platelet-Activating Factor Antagonist

  • Published : 2006.09.25

Abstract

Since platelet-activating factor (PAF) is involved in inflammation, allergic response and anaphylactic shock, PAF receptor antagonists may have potential for controlling these disease conditions. The extract of the leaves of Ginkgo biloba having a higher content of terpenoids (12%) with flavonoids (24%) (YY1224) was prepared in order to obtain the increasing PAF antagonistic activity. As expected, YY1224 showed a higher PAF antagonistic binding affinity ($IC_{50}\;=\;0.09\;{\mu}g/ml$) using $[^3H]PAF$ and rabbit platelets as ligand and receptor source, compared with an $IC_{50}$ of $>\;100\;{\mu}g/ml$ by Egb 761, a standardized extract. YY1224 also showed a higher inhibitory activity against PAF-induced platelet aggregation and NO production from lipopolysaccharide-treated RAW 264.7 cells. In addition, it protected PAF-induced death in mice by oral administration at 15 mg/kg. All these results suggest that YY1224 may show favorable effects on PAF-related disorders.

Keywords

References

  1. Akiba, S., Murata, K., Kitatani, K. and Sato, T. (2000). Involvement of lipoxygenase pathway in docosapentaenoic acidinduced inhibition of platelet aggregation. Biol. Pharm. Bull. 23, 1293-1297 https://doi.org/10.1248/bpb.23.1293
  2. Bourgain, R. H., Andries, R., Esanu, A. and Braquet, P. (1992). PAF-aceter induced arterial thrombosis and the effect of specific antagonists. Adv. Exp. Med. Biol. 316, 427-440
  3. Cheung, F., Siow, Y. L. and O, K. (2001). Inhibition by ginkgolides and bilobalides of the production of nitric oxide in macrophages (THP-1) but not in endothelial cells (HUVEC). Biochem. Pharmacol. 61, 503-510 https://doi.org/10.1016/S0006-2952(00)00567-0
  4. Chi, Y. S., Cheon, B. S. and Kim, H. P. (2001). Effect of wogonin, a plant flavone from Scutellaria radix, on the suppression of cyclooxygenase and the induction of inducible nitric oxide synthase in lipopolysaccharide-treated RAW 264.7 cells. Biochem. Pharmacol. 61, 1195-1203 https://doi.org/10.1016/S0006-2952(01)00597-4
  5. DeFeudis, F. V. (1991). Ginkgo biloba extract (Egb761): pharma-cological activities and clinical applications. Elsevier, Paris
  6. Hanahan, D. J. (1987). Platelet activating factor: A biologically active phosphoglyceride. Ann. Rev. Biochem. 55, 483-509 https://doi.org/10.1146/annurev.bi.55.070186.002411
  7. Koltai, M., Hosford, D. and Braquet, P. G. (1996). Platelet-acti-vating factor and its antagonists in allergic and inflammatory disorders. Clin. Allergy Immunol. 8, 463-489
  8. Myers, A. K., Nakanishi, T. and Ramwell, P. (1988). Antagonism of PAF-induced death in mice. Prostaglandins 35, 447-458 https://doi.org/10.1016/0090-6980(88)90135-9
  9. Prescott, S. M., Zimmerman, G. A. and McIntyre, T. M. (1991). Platelet-activating factor. J. Biol. Chem., 17381-17384
  10. Redl, H., Vogl, C., Schiesser, A., Paul, E., Thurnher, M., Bahrami, S. and Schlag, G. (1990). Effect of the PAF antagonist BN 52021 in ovine endotoxin shock. J. Lipid Mediat. 2 Suppl, S195-S201
  11. Terashita, Z., Kawamura, M., Takatani, M., Tsushima, S., Imura, Y. and Nishikawa, K. (1992). Beneficial effects of TCV-309, a novel potent and selective platelet activating factor antagonist in endotoxin and anaphylactic shock in rodents. J. Pharmacol. Exp. Ther. 260, 748-755
  12. Tesch, H. and Konig, W. (1979). Origin and biological role of lipid mediators during inflammation. Immun Infekt. 7, 157-164
  13. Valone, F. H., Coles, E., Reinhold, V. R. and Goetzl, E. J. (1982). Specific binding of phospholipid platelet-activating factor by human platelets. J. Immunol. 129, 1637-1641