Simultaneous determination of anthraquinone distribution in Cassia tora using high performance liquid chromatography

A reversed-phase HPLC method has been developed and validated for the quantitative determination of four anthraquinones (AQs): aloe-emodin (1), emodin (2), chrysophanol (3) and physcion (4) in various part of Cassia tora. The method utilised a TSK-gel ODS-80Tm column (5µm, 4.6×150mm) at 25°C. The mobile phase composed of 2% aqueous acetic acid (A) and methanol (B) (gradient elution as follows: 0–10min, 70% B –80% B; 10–30min, 80% B to 70% B), at a flow-rate of 1 mL/min, and UV detection at 266nm. From the validation results, the HPLC method showed good linearity (r² >0.9996), high precision (intra-day R.S.D. <1%, inter-day R.S.D. <2%) and high recovery rates (95.34 to 105.91%). Various parts of C. tora including leaves, roots, flowers, stems, young seeds and mature seeds were examined in order to compare the AQ content in each tissue. The mature seed extract was accumulated the highest amount of total AQs (30.53mg/g DW), while the other tissues were consisted of only (2) in low amount (1.20–1.82mg/g DW). Moreover, the mature seed extract was capable of producing of total AQ (30.53mg/g DW) higher than the young seed extract (4.92mg/g DW). Major AQs found in the seed extract were (3) (13.64mg/g DW) and (4) (14.27mg/g DW) whereas (2) was the minor one (2.62mg/g DW).