Two new triterpenoids taraxer-14-ene-1α,3β-diol (1) and 3β-hydroxytaraxer-14-ene-1-one (2), together with the known triterpenes taraxerol (3), betulin (4), betulinic acid (5), sumaresinolic acid (6), and 5-hydroxy-2-methoxy-1,4-naphthoquinone (7), 5,7-dihydroxy-6,8-dimethylchromone (8), α-monpalmitin (9), palmitic acid (10), 6β-hydroxystigmast-4-en-3-one (11), β-sitostero1 (12), have been isolated from the petroleum ether fraction of the ethanolic extract of Pterospermum heterophyllum. Their structures were established by spectroscopic methods including IR, MS, 1D, and 2D NMR experiments. Compounds 1–8 were evaluated against several human cancer cell lines. Compound 1 showed in vitro selective cytotoxicity against human lung cancer cell lines (A549) with an IC50 value of 1.22 μM. Compound 7 showed significant cytotoxicity against the A549, HCT-8, Bel7402, BGC-823, and A2780 cancer cell lines with IC50 values of 0.21, 0.55, 0.40, 0.59, and 0.34 μM, respectively. However, the other compounds were inactive (IC50>10 μM).
[1]
Shuai Li,et al.
Mono-, Bi-, and triphenanthrenes from the tubers of Cremastra appendiculata.
,
2006,
Journal of natural products.
[2]
B. Wiedemann,et al.
Two novel triterpenoids from the stemwood of Herrania cuatrecasana
,
1999
.
[3]
W. Setzer,et al.
NMR assignments and conformation of taraxerenes
,
1998
.
[4]
K. S. Lee,et al.
Cytotoxic compounds from the roots of Juglans mandshurica.
,
1998,
Journal of natural products.
[5]
I. Merfort,et al.
A triterpene from the bark of Tamarix aphylla
,
1992
.
[6]
C. Djerassi,et al.
Mass Spectrometry in Structural and Stereochemical Problems. XXXII.1 Pentacyclic Triterpenes
,
1963
.