Simple and reliable methods for the determination of three steroidal glycosides in the eight species of Solanum by reversed-phase HPLC coupled with diode array detection.

Solanum species are important ingredients of many traditional Indian medicines and thus the quality control of their herbal formulations is of paramount concern. To establish a simple and effective high-performance liquid chromatographic (HPLC) method to evaluate the quality of Solanum species and their herbal formulations. A rapid, simple, sensitive, robust and reproducible HPLC method was developed for the determination of three steroidal glycosides (SG); indioside D, solamargine and α-solanine in eight species of the genus Solanum. The analytes were separated on a monolithic performance RP-18e column (100 mm × 4.6 mm i.d.) using a gradient elution of acetonitile-water containing 0.1% trifluoroacetic acid (TFA) as the mobile phase with a flow rate 0.4 mL/min and UV detection at λ 210 nm. The method was linear over the range 3-15 µg/mL (r > 9994). Accuracy, precision and repeatability were all within the required limits. The mean recoveries measured at the three concentrations were higher than 98.8% with RSD < 2% for the targets. The established method is simple and can be used as a tool for quality control of plant material or herbal formulation containing SG.