Abstract
The pesticidal activity of Solanum sisymbriifolium is attributed to a range of plant secondary metabolites including glycoalkaloids that can be concentrated from plant tissues. While the pesticidal activity of S. sisymbriifolium is documented, the chemical composition of plant tissue and plant extracts are still poorly understood. Plant material is inherently complex, comprising a wide spectrum of metabolites with varying degrees of polarity. Therefore, appropriate sample preparation, especially drying, is crucial for true representation of plant chemistry and for achieving high isolation efficiency of biopesticidal active compounds. Hence, the objective of this research was to evaluate the impacts of different postharvest drying techniques (room drying, freeze drying, and oven drying) on the metabolomic profiles of S. sisymbriifolium extracts. Based on untargeted UPLC-QTOF MS profiles of plant extracts, different methods of biomass drying significantly influence the preservation and extractability of 1366 S. sisymbriifolium secondary metabolites. Oven drying and freeze drying were found to be the most effective methods, with oven drying yielding the highest concentrations of alkaloids, terpenoids, and phenolic compounds. In contrast, room drying generally resulted in reduced metabolite concentrations, likely due to oxidative degradation. The results highlight the importance of selecting appropriate drying methods to achieve the desired metabolic profile and to assure the preservation of biopesticidal activity of the proposed biomass feedstock material.