A highly unsaturated alkaloid, cepharanone A also occurs in the callus tissue of
Stephania cepharantha. It forms a pale yellow amorphous powder having a sharp
melting point and gives a blue fluorescence. The ultraviolet spectrum in EtOHhas absorption maxima at 225, 232, 265, 277, 283, 328, 341, 376 and 393 nm.
Chemical and spectroscopic evidence has shown it to be a lactam of aristolochic
acid.
Aristololactam II, a metabolite of Aristolochic acid II (AAII), is an excretion product found in the urine, which is considered to be detoxification metabolite of AAII[1].
Akasu, Itokawa, Fujita, Tetrahedron Lett., 3609 (1974)
