Abstract
The monoterpene glycoside, 3′-O-galloylpaeoniflorin (1), and four known compounds, 6′-O-galloylalbiflorin (2), pentagalloylglucose (3), 6′-O-benzoylpaeoniflorin (4) and 6′-O-galloylpaeoniflorin (5), were isolated from the roots of Paeonia lactiflora that had been grown and processed in Nara prefecture, Japan, as androgen modulators. Their structures were elucidated based on spectroscopic analysis. Compounds 2 and 3 showed strong androgen receptor (AR) binding activity (IC50 values 33.7 and 4.1 μg/ml, respectively), 1, 4 and 5 showed weak activity (20, 31 and 12% at 120 μg/ml, respectively). However, paeoniflorin (6) and albiflorin (7), the structures of which are related to 1, 2, 4 and 5, showed no activity. These results suggested that both the structure of albiflorin and the galloyl moiety are important for 2 to show strong AR binding activity. Furthermore, compounds 1—5 inhibited growth of an androgen-dependent LNCaP-FGC (prostate cancer cell line), and were indicated to be AR antagonists. Compounds 2 and 3 might be candidates as safe, natural anti-androgens.
