Metabolic profiling of medicinal plant-based soft porridge and evaluation of their toxicity

Abstract

Traditional medicinal plants play a crucial role in infants’ healthcare in underdeveloped countries and communities where access to modern medicine is limited. In Limpopo, the Vhavenda tribe has a custom of feeding babies as young as a day old with tshiunza, a very light and warm, soft porridge prepared with medicinal plant extracts, believed to help treat various ailments and boost the immune and digestive systems. However, reports of negative side effects, including vomiting, haematuria, renal inflammation and hospitalisations, highlight safety concerns about the use of medicinal plants in infants’ food. Therefore, the aim of this study was to profile the chemical composition of soft porridge samples prepared in aqueous extracts of medicinal plants reported to be commonly used in infants’ food in the Venda region of Limpopo. These plants include Annona senegalensis (roots), Piliostigma thonningii (leaves), Carissa edulis (roots) and Bauhinia galpinii (leaves). Ultrahigh-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-qTOF-MS) was used for metabolic profiling, followed by compound identification using feature-based molecular networking and a compound fragmentation predictor tool, SIRIUS. To evaluate the toxicity of these plants, a cytotoxicity assay was conducted using plant extracts on renal cells. Different classes of polyphenols, including flavonoids (flavan-3-ols and flavonols) and hydroxycinnamoyl amides, were among the dominant compounds tentatively identified in the methanolic extracts of soft porridge prepared in the four plant extracts. A. senegalensis aqueous extracts had moderate cytostatic action (IC50 >500 μg/mL, 55.57% viability at 500 μg/mL) while P. thonningii showed cytoprotection (105-132% viability). Although no toxic compounds and cytotoxicity were observed in the porridge samples prepared with plant extracts, this does not translate to the safe use of plants in infants’ food, since infants' kidneys are immature. Also, although polyphenols have remarkable health benefits in adults, polyphenol accumulation has been reported to be harmful to immature infant kidneys through enzyme inhibition and impaired clearance. Future studies should employ more analytical instrumentation, such as nuclear magnetic resonance spectroscopy, to comprehensively characterise beyond the commonly studied compounds, including polyphenols, given that some compounds remained unidentified in this study. Moreover, identified compounds should be quantified to fully understand their risk to infant health.