Optimization in the Aqueous Two Phase Extraction of a Toxic Metabolite, Solasodine, From S. Mauritianum and Analysis via UHPLC-qTOF-MS

Abstract

Aqueous two phase extraction (ATPE) was applied in the extraction of an allelochemical, solasodine, from an invasive plant, Solanum mauritianum. Central composite design was performed which included numerical parameters such as time and mass of plant powder. The categorical factors included the type of salt used in aiding extraction such as the chaotrope (NaCl) and kosmotrope (Na2CO3). Fitting the central composite design response surface model to the experimental data generated a quadratic model with a good fit (R2 = 0.925). The linear effect of mass of plant powder was a statistically significant (p < 0.05) parameter for solasodine extraction. The optimized conditions for the extraction of solasodine in the presence of NaCl or Na2CO3 were time: 10 min and mass of plant powder: 1.2 g. Corresponding to these conditions, the maximal mean extraction based on multiple reaction monitoring (MRM) transition of solasodine (m/z 414 → 396) on the UHPLC-qTOF-MS was 233.65 mg kg-1 and 413.50 mg kg-1 for NaCl and Na2CO3, respectively. The greater extraction ability of the kosmotrope was due to the higher negative charge density of the carbonate ion during salting-out. Furthermore, the synergistic effect of mass of plant powder and salting-out was shown to enhance extraction of solasodine compared to the chaotrope. The kosmotrope assisted solasodine ATPE extracts from Solanum mauritianum, can potentially be applied as antipathogenic agents in medicine while simultaneously limiting the allelopathic impact of Solanum mauritianum.