Four New Podocarpane-Type Trinorditerpenes from the Bark of Taiwania cryptomerioides

Yueh-Hsiung Kuo, Shih-Chang Chien, Shou-Ling Huang
2002 Chemical and pharmaceutical bulletin  
Taiwania cryptomerioides HAYATA (Taxodiaceae) is an endemic plant and also an important building material. It grows at elevations from 1800 to 2600 m in the central mountains in Taiwan. The heartwood of T. cryptomerioides is yellowishred with distinct purplish-pink streaks. In the previous investigation, various sesquiterpenes, lignans, and abietane-type diterpenes were analyzed from the heartwood 1-3) and bark 4,5) of this plant. Lignans are distributed widely in the plant kingdom. Much
more » ... t has been focused on their effectiveness as antineoplastic agents. Taiwanin E methyl ester isolated from Justicia ciliata exhibited significant in vitro cytotoxicity against human cervical carcinoma. 6) a-Cardinol isolated from T. cryptomerioides showed selectivity for human colon tumor cell lines. 7) The lignans and sesquiterpenes from T. cryptomerioides heartwood isolated by us were investigated for cytotoxic activity. 8) Because it is a decay-resistant tree, the antifungal characterics were also investigated. a-Cardinol has the highest activity against Coriolus versicolor (white-rot fungi) and Laetiporous suphurens (brown-rot fungi) with 100% antifungal indices at 100 ppm. 9) Podocarpane diterpenes do not occur extensively in nature but are present in several genera, such as Azadirachta, [10] [11] [12] [13] [14] Humirianther, 15) Micrandropsis, 16) and Podocarpus. 17) Lin et al. 18) first isolated the podocarpane derivative 1b,13,14-trihydroxy-8,11,13-podocarpatrien-7-one from the leaves of this plant. Many novel skeleton compounds were also found in Lin et al. 's research, 18-21) and we were encouraged to investigate its bark. Fourteen new podocarpane derivatives [22] [23] [24] were discovered. In the present study of the more polar fraction, four new compounds, 1b,13-dihydroxy-8,11,13podocarpatriene (1), 14,18-dihydroxy-13-methoxy-8,11,13podocarpatriene (2), 1b,14-dihydroxy-13-methoxy-8,11,13podocarpatriene-2,7-dione (3), and 3b ,14-dihydroxy-13methoxy-8,11,13-podocarpatrien-7-one (4), together with the known, 1b ,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (5), 18) were observed. In this paper we deal with their structural elucidation. Compound 1 has the molecular formula C 17 H 24 O 2 (based on peak matching of the molecular ion and 13 C-NMR spectroscopy). The IR spectrum of 1 displayed peaks for hydroxyl (3421 cm Ϫ1 ) and aromatic (1615, 1498 cm Ϫ1 ) groups. The Further studies on the bark of Taiwania cryptomerioides found four new podocarpane derivatives, 1b b,13-di- hydroxy-8,11,13-podocarpatriene (1), 14,18-dihydroxy-13-methoxy-8,11,13-podocarpatriene (2), 1b b,14-dihydroxy-13-methoxy-8,11,13-podocarpatriene-2,7-dione (3), and 3b b,14-dihydroxy-13-methoxy-8,11,13-podocarpatrien-7one (4), together with a known 1b b,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (5). Those structures were elucidated principally from spectral evidence.
doi:10.1248/cpb.50.544 pmid:11964007 fatcat:o4jpiokvf5gvrbvq64jm7dwdwi