Effect of soil type on chemical composition and antioxidant properties of Solanum nigrum (L.) shoot oil extracts

Purpose: To investigate the effect of different soil textures on chemical composition and antioxidant properties of essential oils from Solanum nigrum. Methods: Four soils of differing texture were formulated from soil under fallow to cultivate S. nigrum in a glasshouse. Essential Oil was extracted from fresh shoots by solvent-free microwave extraction (SFME) and analysed using gas chromatography-mass spectrometry (GC-MS). Antioxidant properties were assayed (DPPH) and ABTS Results: GC-MS profiling revealed variations in the quality index (QI), number of chemical constituents and antioxidant results of S. nigrum oil. Geraniol and citronellol were the two principal components. The highest activity of the antioxidant was found in plants cultivated on clay loam soil. Fifty percent (50%) Inhibitory Concentration (IC50) ranged from 1.196 to 1.594 μg/mL and 0.067 to 3.59 μg /mL in DPPH and ABTS assays, respectively. Conclusions: This research work indicates that soil texture influences the oil quality, quantity and chemical composition of oil extracted from S. nigrum shoots. Essential oil extracts from S. nigrum grown on clay loam soils recorded the highest antioxidant properties