Abstract
Four known friedelane-type triterpenoids, friedelin (1), 3-hydroxy-D:A-friedoolean-3-en-2-one (2), 2β-hydroxy-D:A-friedooleanan-3-one (3), and 3α-hydroxy-D:A-friedooleanan-2-one (4), and two known lupane-type triterpenoids, lupeol (5) and betulin (6), were isolated from the stem bark of Mallotus philippensis. Isolates 1 - 4 and their synthetic analogues, 3-acetoxy-D:A-friedoolean-3-en-2-one (2a) and 3α-acetoxy-D:A-friedooleanan-2-one (4a), were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA)
activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA). The inhibitory effect of compounds 2 (IC50 = 292 mol ratio/32 pmol/TPA) and 4 (IC50 = 288) was stronger than those of the other compounds tested and the positive control,
curcumin (IC50 = 343). Compound 4 strongly inhibited mouse skin tumor promotion in an in vivo two-stage carcinogenesis model. Studies have been conducted to identify the biologically
active compounds extracted from the leaves, bark, and cones of trees that currently
have no specific commercial use and are therefore treated as waste in the forestry
industry.
Key words
Mallotus philippensis
- Euphorbiaceae - stem bark - 3α-hydroxy-D:A-friedooleanan-2-one - Epstein-Barr virus
early antigen - two-stage mouse skin carcinogenesis - DMBA - TPA
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Dr. Reiko Tanaka
Department of Medicinal Chemistry
Osaka University of Pharmaceutical Sciences
4-20-1 Nasahara
Takatsuki
Osaka 569-1094
Japan
Phone: +81-72-690-1084
Fax: +81-72-690-1084
Email: tanakar@gly.oups.ac.jp
