Assignment of carbon-13 nuclear magnetic resonance spectra of some friedelanes
作者:Amarendra Patra、Swapan Kumar Chaudhuri
DOI:10.1002/mrc.1260250202
日期:1987.2
diacetate and friedelane‐2β‐3β‐diyl diacetate have been made. The carbon signals of 3‐oxofriedelan‐29‐ol and its acetate, methyl 3‐oxofriedelan‐29‐oate, 3‐oxofriedelan‐30‐ol, maytenfoliol, maytensifolin‐A, maytensifolin‐B, pachysonol and pristimerin reported in the literature have also been considered for their specific resonanceassignments. A few signal assignments of somefriedelanes, viz. friedelan‐28‐ol
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.
Hemisynthetic Secofriedelane Triterpenes with Inhibitory Activity against the Growth of Human Tumor Cell Lines in Vitro
作者:Cristina Moiteiro、César Manta、Fátima Justino、Regina Tavares、Maria João M. Curto、Madalena Pedro、Maria São José Nascimento、Madalena Pinto
DOI:10.1021/np0498915
日期:2004.7.1
Seco acids 7 and 9 and hydroxylated analogues 5 and 6 derived from friedelane triterpenes were synthesized stereoselectively in high yields. Compounds 5-9 were evaluated for their ability to inhibit in vitro the growth of three human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and SF-268 (CNS cancer). Only compounds 7 and 9 were found to possess significant growth inhibitory effects, exhibiting GI(50) values that range from 24.6 to 32.8 muM and 10.9 to 17.6 muM, respectively.
Pradhan, Bhim Prasad; Chakraborty, Satyajit; Sinha, Rajendra P, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1991, vol. 30, # 4, p. 395 - 398
作者:Pradhan, Bhim Prasad、Chakraborty, Satyajit、Sinha, Rajendra P、Subba, Gyan Chandra、Weyerstahl, Peter
DOI:——
日期:——
Pradhan; Dutta; Ghosh, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1991, vol. 30, # 1, p. 7 - 12