Phenolic Profiling and Antioxidant-Linked Bioactivity of Solenostemma argel: An Expanded Review

This review provides an integrated analytical overview of the phenolic constituents of Solenostemma argel, with emphasis on extraction efficiency, structural characterization, and antioxidant-linked bioactivity. Because direct studies on argel phenolics remain limited, a broadened inclusion strategy was adopted. Studies were considered when phenolic-solubilizing solvents were used, when antioxidant-related biological effects (such as antidiabetic, anticancer, or neuroprotective activities) were evaluated, or when chromatographic and spectroscopic techniques applicable to phenolic analysis were employed. Comparative findings indicate that moderately polar solvents—particularly ethanol, methanol, and acetone—produce the highest phenolic yields, especially under ultrasound- or microwave-assisted extraction conditions. Reported variations in total phenolic content (TPC) primarily reflect methodological differences; however, higher TPC values consistently correlate with stronger antioxidant activity across assays. Advanced analytical platforms, including HPLC and NMR, provide the highest accuracy for qualitative and quantitative characterization of major phenolic classes. Overall, this expanded review synthesizes current evidence on phenolic profiling, extraction methodologies, analytical applicability, and antioxidant potential of S. argel, underscoring the plant’s promise as a rich and underexplored source of bioactive phenolic compounds.