Radermachera xylocarpa: the highly efficient source of lapachol and synthesis of its derivatives.

Isolation and characterization of the major chemical constituents from the stem bark of Radermachera xylocarpa. Chloroform extract of the powdered stem bark contains mainly two components: one is lapachol (91.2%) and second is alpha-lapachone (5.0%), which are reported herewith first time from this plant, in good quantity and purity.