High-performance thin layer chromatography based assay and stress study of a rare steroidal alkaloid solanopubamine in six species of Solanum grown in Saudi Arabia

The present study describes a method developed for quantification and stability study of a rare steroidal alkaloid solanopubamine (SPN) in aerial parts of six different species of genus Solanum extracted with two different solvents. The Solanum species selected for investigation include S. schimperianum (SS), S. villosum (SV), S. coagulans (SC), S. glabratum (SG), S. incanum (SI) and S. nigrum (SN). The estimation of SPN was done by a validated high-performance thin layer chromatography method. The developed chromatographic system was found to give a sharp spot for solanopubamine at Rf = 0.39 ± 0.01. The steroidal alkaloid SPN was observed to be present only in extracts of aerial parts of S. schimperianum. The sensitivity of developed method produced 40 ng and 115 ng band−1, respectively as LOD and LOQ values. The percentage yield of SPN in aerial parts of S. schimperianum extracted by ethanol (95%) only and a mixture of ethanol and ammonium hydroxide (6:4) was found to be 1.03 w/w and 2.09 w/w, respectively. Stability studies of SPN exhibited the maximum (100%) degradation in an alkaline environment and H2O2 treated samples and 61.4% in acidic conditions. The SPN was found to be significantly stable against UV exposure, photo-oxidation and at room temperature while 13.83% and 57.88% destruction has been observed when exposed to dry heat at 40 °C and 60 °C, respectively.