Phenolic acids and flavonoids remain attractive redox-active scaffolds in medicinal chemistry, where they are widely used for early-stage prioritization and intrinsic reactivity ranking. However, direct comparisons under harmonized conditions remain scarce, limiting structure-based assessment. Here, a structurally diverse panel of hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, a flavanone, and synthetic comparators was profiled using Folin–Ciocalteu response, ABTS radical cation scavenging, DPPH radical scavenging, and reducing power assays. The data reveal pronounced assay dependence alongside clear structure–activity trends. Gallic acid showed the strongest DPPH scavenging (half-maximal inhibitory concentration, IC₅₀ = 4.45 µmol/L) and reducing power (17.26 µmol TE/mg), while quercetin was consistently active across all four endpoints. Eriocitrin (IC₅₀ = 2.47 µmol/L) and rutin (IC₅₀ = 2.66 µmol/L) were particularly effective in the ABTS assay, showing that glycosylation does not abolish cation-radical scavenging. Lipinski’s Rule of Five and Veber oral-bioavailability criteria place these findings within a drug-likeness context. The results also highlight the limitations of the Folin–Ciocalteu assay as a standalone measure of total phenolic content, since its response depends strongly on hydroxylation density. Rather than asserting therapeutic efficacy, this work provides a harmonized comparative dataset identifying phenolic substructures with the strongest and most consistent redox activity, together with the structural drivers underlying these patterns.

Mentha species are widely used in foods, cosmetics, and phytopharmaceuticals, and their functional value is closely linked to phenolic constituents, notably rosmarinic acid (RA) and eriocitrin. Comparative quantitative datasets across commercially relevant mint genotypes cultivated under uniform conditions are still limited. Here, aerial parts of nine Mentha × piperita cultivars (‘Piper-1’, ‘Chocolate’, ‘Citaro’, ‘Multimentha’, ‘Swiss’, ‘Yakima’, ‘Basilicuminze’, ‘Black Mitcham’, ‘Granada’), Mentha × dumetorum ‘Dume-1’, and Mentha arvensis ‘Arven-1’ were extracted with 70% (v/v) ethanol. Eleven phenolic compounds were quantified by HPLC–PDA using external calibration, and antioxidant capacity was evaluated by ABTS•⁺ and DPPH• radical-scavenging assays and FRAP and CUPRAC reducing-power assays. Total HPLC-summed phenolics (ΣHPLC) were highest in M. × piperita ‘Citaro’ and ‘Black Mitcham’, driven mainly by eriocitrin and RA, whereas ‘Arven-1’ showed markedly lower ΣHPLC. Antioxidant responses varied by assay: ‘Yakima’ displayed the strongest ABTS•⁺ scavenging and the highest FRAP values, while ‘Swiss’ also ranked highly across ABTS•⁺/FRAP and showed strong DPPH• performance; in contrast, ‘Arven-1’ generally exhibited weaker activity. Correlation analysis (Pearson and Spearman) and principal component analysis indicated that RA, eriocitrin, rutin, and apigenin-7-O-glucoside were key contributors to antioxidant behaviour and clearly discriminated M. × piperita cultivars from M. × dumetorum and M. arvensis . Overall, M. × piperita cultivars—particularly ‘Yakima’, ‘Swiss’, ‘Citaro’, and ‘Black Mitcham’—emerge as elite candidates for producing phenolic-rich extracts with strong in vitro antioxidant potential, supporting their valorisation as natural antioxidant ingredients and strategic resources for sustainable, circular bioeconomy-oriented value chains in Türkiye.

This study aimed to investigate the anticancer effects and underlying mechanisms of an ethanolic extract of Lavandula stoechas L. flowers (LsHE) on colorectal cancer. The extract demon strated high phenolic content (230.31 ± 11.28 mg GAE g ^– ¹ dm) and strong antioxidant activity. HPLC analysis identified rosmarinic acid and quercetin as major constituents. HT-29 colorectal carcinoma cells and HEK-293 healthy kidney epithelial cells were treated with LsHE for 48 h. The concentration of LsHE required to inhibit 50 % of HT-29 cell viability was found to be 86.37 ± 3.07 µg mL ^–1 , whereas a higher concentration of 131.30 ± 9.33 µg mL ^–1 was observed for HEK-293 cells. In HT-29 cells, flow cytometry analysis revealed increased early (9.7 %) and late (6.8 %) apoptotic populations following LsHE treatment ( p < 0.0001). qRT-PCR analysis showed significant upregulation of TP53 and CASP3 compared to the untreated group ( p < 0.05 and p < 0.01, resp.), while BAX expression was unexpectedly downregulated. These findings suggest that LsHE may trigger caspase-3-dependent apoptosis through a p53-mediated mechanism, potentially independent of the BAX/BCL-2 pathway. In conclusion, the present in vitro study highlights the potential of LsHE as a natural agent that still exerts some cytotoxicity toward normal epithelial cells and pro-apoptotic activity in colorectal cancer cells. Our findings provide a molecular basis for further in vivo studies to evaluate the possible therapeutic potential and mechanistic relevance of LsHE in CRC chemoprevention.

This study aimed to evaluate the inhibitory potential of phenolic-rich extracts from selected medicinal plants belonging to the Lamiaceae and Asteraceae families against the furin protease enzyme, a key target in viral and oncogenic pathways. Extracts of Origanum vulgare, Thymus vulgaris, Mentha piperita, Mentha spicata, Salvia officinalis, and Silybum marianum were prepared using hexane, chloroform, and ethyl acetate. Phenolic compounds were quantified using High-Performance Liquid Chromatography (HPLC). Furin inhibition was assessed spectrophotometrically and analyzed statistically with multivariate approaches. The chloroform extract of Origanum vulgare exhibited 97.44 ± 0.12% inhibition, while the ethyl acetate extract of Mentha spicata showed 97.44 ± 0.08% inhibition. Epicatechin and rutin displayed significant synergistic effects, while naringenin negatively affected inhibition (p < 0.05). Solvent polarity significantly influenced phenolic diversity and biological activity, with ternary combinations showing 33% higher inhibition than single compounds. These findings highlight phenolic blends as promising natural furin inhibitors, with chloroform being optimal for broad-spectrum extraction.