Comparative Evaluation of Supercritical CO2 and Methanol Extraction of Ruta graveolens Polyphenolic Compounds: In-vitro Characterization of Antioxidant and Antimicrobial Potentials

Abstract

Plant-derived extracts remain a vital source of bioactive molecules with potential medicinal applications. Ruta graveolens, a phenolic-rich medicinal herb, is recognized for its diverse antioxidant, and antimicrobial activities. Supercritical fluid extraction (SFE) was carried out using carbon dioxide (CO₂) as fluid. This was compared to Soxhlet extraction (SE) with methanol to obtain Ruta graveolens extracts rich in bioactive compounds. High-performance liquid chromatography revealed notable differences in the phenolic profiles of Ruta graveolens extracts depending on the extraction method. SFE yielded higher concentrations of gallic acid (1380 µg/g), chlorogenic acid (522 µg/g), catechin (595 µg/g), and rosmarinic acid (218 µg/g), while SE contained more kaempferol (242 µg/g) and catechin (921 µg/g). The IC₅₀ assessments were 6.59 µg/g for SFE and 1.63 µg/g for methanol, indicating potent anti-inflammatory potentials for both extracts. Based on DPPH radical scavenging assay, SFE and SE of R. graveolens extracts showed concentration-dependent activity. The IC₅₀ values were 5.81 µg/mL (SFE) and 7.86 µg/mL (SE). SFE showed larger inhibition zones than SE (24 ± 0.2 vs 20 ± 0.3 mm for B. subtilis; 17 ± 0.3 vs 11 ± 0.6 mm for P. aeruginosa) and stronger effects on K. pneumoniae and C. albicans.