Journal of Wood Science

, Volume 49, Issue 4, pp 339–343 | Cite as

5Α-Reductase inhibitory tannin-related compounds isolated from Shorea laeviforia

  • Yoshio Hirano
  • Ryuichiro Kondo
  • Kokki Sakai
ORIGINAL ARTICLE

Abstract

Five tannin-related compounds – gallic acid, flavogallonic acid dilactone, valoneic acid dilactone, gallagyldilactone, ellagic acid – were isolated from the heartwood of Shorea laeviforia, and the inhibitory activity of each against rat liver 5Α-reductase was evaluated. Valoneic acid dilactone and gallagyldilactone exhibited positive inhibitory activity, but gallic acid and ellagic acid did not. Flavogallonic acid dilactone stimulated 5Α-reductase activity, even though this compound is structurally similar to valoneic acid dilactone. The kinetic study of valoneic acid dilactone and gallagyldilactone indicated that the inhibitory behavior of 5Α-reductase were not competitive against the substrate (testosterone) and were partially competitive against the cofactor (NADPH). Additionally, double inhibition analysis of valoneic acid dilactone and NADP+ showed synergetic inhibition. These results suggested that neither valoneic acid dilactone nor gallagyldilactone can affect the binding of testosterone but that either compound could interact with an enzyme–NADP+ complex to inhibit 5Α-reductase.

Key words

Shorea laeviforia Tannin-related compounds Valoneic acid dilactone Gallagyldilactone 5Α-Reductase inhibitor 

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Copyright information

© Springer-Verlag Tokyo 2003

Authors and Affiliations

  • Yoshio Hirano
    • 1
  • Ryuichiro Kondo
    • 2
  • Kokki Sakai
    • 2
  1. 1.Interior Design Research InstituteFukuoka Industrial Technology CenterFukuokaJapan
  2. 2.Department of Forest and Forest Products Sciences, Faculty of AgricultureKyushu UniversityFukuokaJapan

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