Phenolic chemotypic diversity in Tunisian Hertia cheirifolia populations: influence of plant organs and phenological stages on antioxidant and anti-acetylcholinesterase activities

Background Hertia cheirifolia (L.) Kuntze (Asteraceae), an endemic subshrub of Tunisia and Algeria, is a staple of North African traditional medicine for treating gastrointestinal disorders, hypertension, inflammation, and nervous system complaints. Although its ethnobotanical profile is well documented, a comprehensive quantitative characterisation of its phenolic extracts and the relationship between chemical composition and biological activity has not previously been attempted.è Results Phenolic accumulation ranked consistently as leaves > flower buds > flowers > fruits (TPC up to 94.86 mg GAE/g, TFC up to 21.76 mg ER/g, TFlC up to 12.09 mg EQ/g in leaves). Seasonal monitoring revealed a bimodal polyphenol pattern, peaking in October (146.53 mg GAE/g) and December (123.47 mg GAE/g), while flavonoid content peaked at full flowering (December: 35.20 mg ER/g). Among the nine wild populations, a 3.2-fold range in flavonol content was observed; Khalsa and Siliana populations displayed exceptionally elevated flavonols (25.35–26.89 mg EQ/g) unrelated to geographic proximity. Anti-AChE activity (0.66–10.68 mg Eq donepezil/g) correlated strongly with flavonoid and flavonol content (r = 0.685 and 0.765, respectively; p < 0.05), and FRAP values correlated with flavonols (r = 0.619, p < 0.05). In silico ADMET profiling revealed quercetin as a likely direct AChE inhibitor with acceptable drug-likeness (bioavailability score 0.55), while rutin may serve as a natural pro-drug. Conclusions H. cheirifolia phenolic extracts exhibit potent, mechanism-specific antioxidant activity and promising AChE inhibition, validating traditional use in neurological complaints. Optimal harvest–leaves collected in October-November from Siliana or Kessra populations–maximises both polyphenol yield and neuroprotective potential. These findings establish a phytochemical and pharmacological rationale for further investigation of standardised flavonol-enriched fractions as multi-target agents for Alzheimer's disease and oxidative stress-related pathologies.