Abstract
The present paper describes the development of an HPLC–PDA method for the simultaneous determination of bioactive diterpenoids, andrographolide, isoandrographolide, neoandrographolide, and 14‐deoxy‐11,12‐didehydroandrographolide in plant materials and commercial products of Andrographis paniculata. Separations were achieved using a conventional C18 column with PDA detection at 200–400 nm for UV spectrum and 225 nm for quantification. The mobile phase consists of water and acetonitrile with acetonitrile varying from 20% to 50% over 40 min. The quantification was performed using external standards. The method was validated for linearity, limit of detection (LOD), limit of quantification (LOQ), inter‐day and intra‐day reproducibility, and recovery.