Extraction, Isolation and Characterization of Bioactive Compounds from Euphorbia neriifolia (L.) Leaf and Evaluation of their Antioxidant Activity

Background: Amidst the identification of numerous secondary chemicals from Euphorbia neriifolia, there is a desperate need for the development of primary metabolite separation techniques. Objectives: In order to do that, bioactive chemicals from Euphorbia neriifolia (L.) leaf were extracted, isolated, and characterized. Subsequently, their antioxidant activity was evaluated. Methods: In this study, the determination of linoleic acid (LA) in petroleum ether extract (PEE) of Euphorbia neriifolia leaf (ENL) was carried out the first time by using thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) methods. Results: The chromatographic analysis of the PEE of ENL shows better spots and well-separated peak of LA with 0.49 retention factor (Rf) value and 22.54 ng LA content. The linearity of the calibration curve ranges from 5-25 ng/spot with a high correlation coefficient. The proposed method was characterized by better accuracy close to 99.5%, well robustness, and good precision range from 0.183% (intra-day) to 0.242% (inter-day). The percentage (%) RSD, which determined the stability of standard LA, did not exceed 2% after time period of 12, 24, 36, 48, and 72 h. The GC-MS analysis revealed the presence of different types of low or high-molecular-weight phytocompounds of varying quantities from the fractions of ENL. The FT-IR spectrum of ICs showed various peaks that confirmed the presence of C=C bending, C-H stretching, O-H stretching, CH2 stretching, and a carboxyl group. The 1H-NMR spectrum of the ICs from ENL confirmed the presence of octadecanoic in IC1, L-(+)-ascorbic acid dihexadecanoate in IC2, hexadecanoic acid in IC3, linoleic acid in IC4, and oleic acid in IC5, respectively. IC-4 showed greater antioxidant activity in comparison to other compounds with an IC50 value of 3.9 ± 0.01 μg mL-1. Conclusion: Thus, the present study identified five different phytocompounds that may be utilized as an effective option for the cure of different diseases.