Abietane Diterpenoids from the Cones of Larix kaempferi and their Inhibitory Effects on Epstein-Barr Virus Activation

Authors:
  • RTReiko Tanaka
    Reiko Tanaka
  • YIYasuko In
    Yasuko In
  • SMShunyo Matsunaga
    Shunyo Matsunaga
  • HTHarukuni Tokuda
    Harukuni Tokuda
  • HNHoyoku Nishino
    Hoyoku Nishino
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Abstract
Four known (1 - 3, 8) and four new abietane diterpenes, 15-hydroxy-8α,14α,12α,13α-diepoxyabietan-18-oic acid (4), 7α,8α,13β,14β-diepoxyabietan-18-oic acid (5), 18-nor-abieta-8,11,13-triene-4α,7α,15-triol (6), and abieta-8,11,13-triene-7α,15,18-triol (7) were isolated from the CHCl3 extract of the cones of Larix kaempferi. A known compound, 13,14-seco-13,14-dioxoabiet-13-en-18-oic acid (8) was isolated from natural sources for the first time. Their structures were determined by chemical and spectroscopic methods including 1D and 2D NMR techniques. The absolute stereostructure of 5 was determined by X-ray crystallographic analysis. The inhibitory effects of these compounds on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), were examined as a primary screening for antitumor promotors.