Comparative Study of Green Sub- and Supercritical Processes to Obtain Carnosic Acid and Carnosol-Enriched Rosemary Extracts with in Vitro Anti-Proliferative Activity on Colon Cancer Cells

Abstract

In the present work, four green processes have been compared to evaluate their potential to obtain rosemary extracts with in vitro anti-proliferative activity against two colon cancer cell lines (HT-29 and HCT116). The processes, carried out under optimal conditions, were: (1) pressurized liquid extraction (PLE, using an hydroalcoholic mixture as solvent) at lab-scale; (2) Single-step supercritical fluid extraction (SFE) at pilot scale; (3) Intensified two-step sequential SFE at pilot scale; (4) Integrated PLE plus supercritical antisolvent fractionation (SAF) at pilot scale. Although higher extraction yields were achieved by using PLE (38.46% dry weight), this extract provided the lowest anti-proliferative activity with no observed cytotoxic effects at the assayed concentrations. On the other hand, extracts obtained using the PLE + SAF process provided the most active rosemary extracts against both colon cancer cell lines, with LC50 ranging from 11.2 to 12.4 µg/mL and from 21.8 to 31.9 µg/mL for HCT116 and HT-29, respectively. In general, active rosemary extracts were characterized by containing carnosic acid (CA) and carnosol (CS) at concentrations above 263.7 and 33.9 mg/g extract, respectively. Some distinct compounds have been identified in the SAF extracts (rosmaridiphenol and safficinolide), suggesting their possible role as additional contributors to the observed strong anti-proliferative activity of CA and CS in SAF extracts.

Potato Peels as a Source of Novel Green Extracts Suitable as Antioxidant Additives for Fresh-Cut Fruits

“…The application of conventional solvent extraction methods (CSE) to extract phenols from plant material is widely diffused, but it usually requires long extraction times, large amounts of organic solvents, and high temperatures that can cause the degradation of thermo-sensible molecules as well as contamination with trace amounts of potentially toxic solvents [14]. Moreover, the sustainability of the extraction technology and the safety of the extract is of the utmost importance [15,16].…”

Purification of Natural Products by Selective Precipitation Using Supercritical/Gas Antisolvent Techniques (SAS/GAS)

“…Polyphenols from rosemary (Rosmarinus officinalis) are used by the food industry as antioxidants. Their effect in the treatment of cancer and neurodegenerative diseases has also been studied (52)(53)(54). Therefore, there is an interest in developing processes to efficiently extract and purify the antioxidant fraction from rosemary leaves.…”

“…Therefore, there is an interest in developing processes to efficiently extract and purify the antioxidant fraction from rosemary leaves. The literature shows that rosmarinic acid can be precipitated from water/ethanol extracts (52,53) when in contact with scCO2, while phenolic diterpenes like carnosic acid can only be recovered as the soluble fraction from ethanolic (55) or water/ethanol (52,53) extracts. The best conditions to fractionate an ethanol rosemary extract were 50 °C and…”

A Simplified Method to Estimate Sc-CO2 Extraction of Bioactive Compounds from Different Matrices: Chili Pepper vs. Tomato By-Products

“…This method usually requires long extraction times, large amounts of organic solvents and high temperatures, which can lead to extensive degradation of thermo-sensible molecules, as well as leave trace amounts of potentially toxic solvents in the extract [17]. Moreover, the sustainability of the extraction process and the purification of the bioactive compounds is of the utmost importance [19].…”

“…In 2014 there were more than 150 SFE industrial plants with a total extraction volume of more than 500 L in the world [19]. Many of these production plants are generally devoted to the SFE process involving a preliminary Sc-CO 2 extraction of natural products, leading to the recovery of high-value products which provide interesting options for their use in the nutraceutical and functional food industry [20].…”