Factorial design-assisted supercritical carbon-dioxide extraction of cytotoxic active principles from Carica papaya leaf juice

Abstract

The aims of this study are to investigate the selective cytotoxic activity of supercritical carbon dioxide (scCO2)-extracted freeze-dried leaf juice (FDLJ) of Carica papaya on squamous cell carcinoma (SCC25) cells, and to delineate the best small scale extraction parameters allowing maximal extract activity. Using scCO2 as a solvent, six operating parameters were studied and the supercritical fluid extraction (SFE) process investigated using a factorial design 26-2. The processing values promoting cytotoxic activity towards SCC-25 are: high pressure (250 bar), low temperature (35 °C), extended processing time (180 minutes), as well as a large amount of starting material (5 g). The factorial experimental design successfully identified the key parameters controlling the SFE of molecules cytotoxic to SCC cells from C. papaya juice. This study also validated the extraction method and showed that the SFE yield was reproducible. The chromatographic and mass spectrometric profiles of the scCO2 extract acquired with high-resolution quadrupole time-of-flight mass spectrometry (LC-QToF-MS) were used to tentatively identify the bioactive compounds using comparative analysis. The principal compounds were likely to be mainly vitamins and phytosterols, some of which are documented to be cytotoxic to cancer cells.

Chemical Composition, Antioxidant and Cytoprotective Potentials of Carica papaya Leaf Extracts: A Comparison of Supercritical Fluid and Conventional Extraction Methods

“…A total of 11 lipophilic constituents were identified in the CPSCE extract ( Figure 1a). The identified major constituents were α-tocopherol (5), squalene (3), phytol (2), and a mixture of phytosterols such as campesterol (6), stigmasterol (7), and β-sitosterol (8), consistent with those reported in our previous study ( Figure 2) [27]. A number of minor constituents such as hexadecanoic acid (1), γ-tocopherol (4), olean-12ene (9), 13,17-cycloursan-3-one (10), and cycloartenol (11) were also detected in the CPSC extract.…”

“…In addition, the extraction yield of CPSCE extracted by scCO 2 + co-solvent was 150% higher than that of CPSC extracted by scCO 2 alone. Interestingly, the scCO 2 extraction yield of papaya leaves was 1.5-3 fold lower than those found in previous study, despite the use of an additional co-solvent [27]. It might be reasoned that in different geographical locations the soil pH promotes the biosynthesis of bioactive compounds.…”

“…The scCO 2 extraction of air-dried CPL was performed using Supercritical Fluid Preparative scale CO2 extraction equipment (Taiwan Supercritical Technology), and extraction parameters in accordance with a previously optimized method [27]. The scCO 2 extraction was operated with the following parameters: pressure 250 bar, temperature 35 • C, extraction time: 3 h, and with or without 5% ethanol as co-solvent.…”

High-Pressure Supercritical CO2 Extracts of Ganoderma lucidum Fruiting Body and Their Anti-hepatoma Effect Associated With the Ras/Raf/MEK/ERK Signaling Pathway

“…At the same time, the critical CO 2 has unusually high compressibility. Near the critical point, slight changes in pressure or temperature cause obvious changes in density of CO 2 , so that the dissolution of CO 2 can be changed simply by adjusting the temperature or pressure of the system to improve the selectivity of extraction ( Khaw et al, 2019 ). Therefore, increasing the solubility of critical CO 2 by increasing the extraction pressure can become the research direction of process optimization.…”

The plausible mechanisms of action of Carica papaya on Dengue infection: A comprehensive review

“…The leaves were found to be rich in phenolic compounds such as alkaloids, quercetin and kaempferol. On top of that, the leaf extract contains antioxidant compounds such as α-tocopherol, ascorbic acid and flavonoids [19][20][21] . Some case studies reported that the papaya leaves aid for better recovery of dengue in terms of clinical symptoms and platelet counts.…”