Pterolobium macropterum, which belongs to the family
Leguminosae, is a medicinal plant that is found throughout
China, Bhutan, India, Indonesia, and Southeast Asia. In
Thailand, this plant has been used to treat toothache and
fever and to promote wound healing.7 In northeast Thailand,
the plant is known as “nam kra jai”. In a study on the isolation
of cytotoxic agents against CCA from natural sources, it was
observed that crude extracts (hexanes, EtOAc, and MeOH) of
the root bark of P. macropterum exhibited cytotoxicity with IC50
values ranging between 9 and 45 μg/mL. Thus, investigating
the root bark of P. macropterum resulted in the isolation of four
new cassane diterpenoids (1−4) and a new cadinane derivative
(5). All of the pure compounds were evaluated for cytotoxicity
against the CCA, KKU-M136, KKU-M159, and KKU-M216
cell lines