Ma. Alnuri et al., PLUMBAGIN, A NATURALLY-OCCURRING NAPHTHOQUINONE - ITS ISOLATION, SPECTROPHOTOMETRIC DETERMINATION IN ROOTS, STEMS, AND LEAVES IN PLUMBAGO-EUROPAEA L, Spectroscopy letters, 27(4), 1994, pp. 409-416
A new method for isolation and spectrophotometric determination of plu
mbagin is presented. Plumbagin was isolated by thin layer chromatograp
hy (TLC) and column chromatography (CC) techniques, as an orange tinge
d yellow long crystalline substances. Plumbagin exhibits two absroptio
n maxima at 410 and 510 nm. Stability of the color, pK(a) value, and t
he effect of pH were studied. Beer's law is obeyed over the range 0.9
- 45 ppm. The method is applied to the determination of plumbagin in r
oots, stems, and leaves of Plumbago europaea L. plant.