Comparative Evaluation of Matrix- and Extraction-Dependent Phenolic Assay Responses in Selected Plant Materials

Eight commercial lyophilised plant materials were extracted by maceration, shaking-assisted extraction, or ultrasound-assisted extraction using water, 70% ethanol, or 96% ethanol. Total phenolic content (TPC), total flavonoid content (TFC), total phenolic acid content (TPA), and vanillin-reactive tannins (TANs) were determined spectrophotometrically in three independent extractions per condition. Plant materials were compared across nine extraction systems, and the effects of extraction protocol, solvent system, and their interaction in barberry fruit were assessed by two-way ANOVA. Extraction behaviour was matrix- and response-dependent. Barberry fruit produced the highest TPC and TPA in all systems, whereas TFC and TAN rankings varied among conditions. Water and 70% ethanol generally produced higher assay responses than 96% ethanol. In barberry fruit, extraction protocol, solvent system, and their interaction affected TPC, TFC, and TPA, while the TAN value varied among solvent-defined systems, although cross-solvent comparisons may also reflect differences in colour development caused by the solvent composition of the vanillin reaction mixture. Aqueous ultrasound-assisted extraction produced the highest observed mean TFC, TPA, and TAN responses while retaining a comparatively high TPC response; however, no extraction condition was statistically superior across all four responses. These findings support barberry fruit as a model matrix for targeted chemical characterisation and further extraction studies.