Introduction: Naphthoquinones; lawsone (1), lawsone methyl ether (2) and methylene-3,3'-bilawsone (3) are the main active compounds of Impatiens balsamina leaves.

Objective: To develop and validate an HPLC method for simultaneous quantitative determination of 1-3 in I. balsamina leaf extracts.

Methodology: The method utilised a Supelco® C(18) column (5 µm, 4.6 × 150 mm) at 25°C with the mixture of 2% aqueous acetic acid : methanol (gradient elution as follows: 0-10 min, 25 : 75; 10-20 min, 32 : 68; 20-35 min, 55 : 45) as the mobile phase at a flow-rate of 1 mL/min, and UV detection at 280 nm. The parameters of linearity, repeatability, reproducibility, accuracy specificity and sensitivity of the method were evaluated.

Results: The recovery of the method was 96-101% and linearity (r(2) ≥ 0.9995) was obtained for all naphthoquinones. A high degree of specificity, as well as repeatability and reproducibility (RSD less than 5%), were also achieved.