Supercritical CO₂ extraction of Clinacanthus nutans: Enhanced bioactive recovery and cytotoxicity against cervical cancer cells

This study optimized supercritical CO₂ extraction (SCE) of Clinacanthus nutans leaves, with or without 80:20 ethanol–water co-solvent (CoS), and benchmarked it against ethanol maceration (MCE). MCE yielded 17.10% crude extract, while CoS SCE at 35 MPa/60°C achieved 5.98%, but with higher enrichment of flavonoids (88 mg QE/g, 2.1-fold above MCE) and retention of lipophilic phytosterols and terpenoids. MCE remained superior in total phenolic and saponin extraction. The selected SCE extract demonstrated dose- and time-dependent cytotoxicity against HeLa cells (IC₅₀ = 158 µg/mL, 48 h), but limited selectivity over hTERT-HME1 cells (SI ≈ 1.2). These findings underscore CoS SCE as a greener, rapid method for selectively recovering moderately polar bioactives from C. nutans , warranting bio-guided fractionation to enhance therapeutic specificity.