Chemical Composition and Biological Activities of Tunisian Ziziphus lotus Extracts: Evaluation of Drying Effect, Solvent Extraction, and Extracted Plant Parts

Abstract

The Tunisian Ziziphus lotus plant was investigated to determine its phytoconstituents and evaluate its biological activities. In particular, the GC/MS technique was used to describe the chemical composition of Z. lotus active extracts and fractions. Among the obtained extracts, the yields of the dried root methanolic extract (29.80%) and the fruit aqueous extract (48.00%) were the highest ones. The dried root methanolic extract exhibited the highest amount in the total phenolics (186.44 ± 0.26 mg GAE/g DW), total flavonoids (102.50 ± 3.53 mg QE/g DW), and tannins (60.714 ± 2.2 mg catechin/g DW). The root aqueous extracts revealed the highest antioxidant activity with an IC50 of 8.96 ± 0.38 mg/L and 16.46 ± 0.60 mg/L for the ABTS•+ and DPPH• assays, respectively. The total antioxidant capacity was accorded to the methanolic extract of the dried roots with a value of 304.07 ± 1.11 µg AAE/mg. The drying process was found to improve the qualitative and quantitative properties of the Z. lotus extracts. The evaluation of the cytotoxic activity against the SH-SY5Y cell line was carried out using MTT assay. The petroleum ether and dichloromethane extracts of the dried roots showed relevant cytotoxic activities. The thin layer chromatography and the GC-MS/GC-FID analysis led to the identification of the 13-epimanool as a potent cytotoxic compound.