Supercritical CO2 extraction of an immunosuppressant produced by solid-state fermentation

Essential Oil and Supercritical Carbon Dioxide Extract of Grapefruit Peels Formulated for Candida albicans Infections: Evaluation by an in Vitro Model to Study Fungal-Host Interactions

Resistance to currently available antifungal agents raises the need to develop alternative remedies. Candida albicans is the most common opportunistic pathogenic fungus of humans, colonizing in the genital and intestinal mucosa, skin, and oral-nasal cavity and reducing quality of life. Herein, essential oil from grapefruit (Citrus paradise) peels was obtained by hydrodistillation, and the remaining plant material was sequentially subjected to supercritical carbon dioxide (SC-CO₂) extraction to determine the conditions for maximizing phenolic compounds. A statistical design was used to evaluate the effect of temperature (30, 50, 70 °C), pressure (80, 150, 220 bar), and ethanol as a cosolvent (0%, 10%, and 20% v/v). Essential oil and SC-CO₂ extracts were mixed at various ratios to develop an effective antifungal formulation. Subsequently, fungal infection was modeled by coculturing C. albicans with human skin keratinocytes (HaCaT) to mimic dermal mycoses, endothelial cells (HUVEC) to evaluate vascular fate, and cervical adenocarcinoma (HeLa) cells to represent additional genital mycoses. Treatment with essential oil and extract (25:75%) formulation for 8 h exhibited slight cytotoxicity toward HeLa cells, no toxicity toward HaCaT and HUVECs, whereas inhibition of C. albicans. Considering the clinical significance, such in vitro models are essential to screen potential compounds for the treatment of opportunistic fungal infections.

Cytotoxicity screening of supercritical fluid extracted seaweeds and phenylpropanoids

Detached leaves of Posidonia oceanica and Zostera marina creating nuisance at the shores were extracted by means of supercritical CO2 enriched with a co-solvent, compared with that of soxhlet extraction. The extracts and their active compounds which are phenylpropanoids (chicoric, p-coumaric, rosmarinic, benzoic, ferulic and caffeic acids) were screened for cytotoxicity in cancer cell lines including human breast adenocarcinoma (MCF-7, MDA-MB-231, SK-BR-3), human colon adenocarcinoma (HT-29), human cervix adenocarcinoma (HeLa), human prostate adenocarcinoma (PC-3), Mus musculus neuroblastoma (Neuro 2A) cell lines and African green monkey kidney (VERO) as healthy cell line. Supercritical CO2 extracts proved to be more active than soxhlet counterparts. Particularly, Zostera marina extract obtained by supercritical CO2 at 250 bar, 80 °C, 20% co-solvent and a total flow rate of 15 g/min revealed the best IC50 values of 25, 20, 8 μg/ml in neuroblastoma, colon and cervix cancer cell lines. Among the major compounds tested, p-coumaric acid exhibited the highest cytotoxic against colon and cervix cell lines by with IC50 values of 25, 11 μg/ml. As for the effects on healthy cells, the extract was not cytotoxic indicating a selective cytotoxicity. Obtained supercritical CO2 extracts can be utilized as a supplement for preventive purposes.