Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

Rosmarinic and carnosic acids are the main phenolic compounds present in the non-volatile fraction of the rosemary herb (Rosmarinus officinalis). After essential oil extraction, it is still possible to recover valuable phenolic acids from rosemary material. These phenolic acids exhibit bioactive properties of great value for the prevention of metabolic diseases such as obesity, type 2 diabetes, hypertension, and dyslipidemia. Rosemary extracts can also improve industrial products, especially dermocosmetics and meat-based foods. Due to differences in polarity and specific affinity with eutectic solvents, the aim of this study was to obtain rosmarinic acid (RA) and carnosic acid (CA) in distinguished ultrasound-assisted extracts. The eutectic solvents were produced using the hydrogen bound acceptors (HBA): choline chloride, betaine, L-proline, and ammonium acetate, and the hydrogen bond donors (HBD): 1,4-butanediol and lactic acid. All solvents were prepared using a warm bath with magnetic stirring at 60 °C for 1h, at a molar ratio of 1:2 (HBA:HBD) and 20% water (w/w). Pure water and ethanol were also used for comparison. The extractions were performed with dry rosemary and a solvent-to-feed ratio of 20 mL/g in a 37 kHz ultrasound bath at 580 W for 1h. The ammonium acetate:lactic acid allowed the highest extraction of rosmarinic acid (14.90 ± 0.58 mg RA/ g DW and 1.12 ± 0.14 mg CA/ g DW), while carnosic acid was best extracted by ethanol (8.10 ± 0.24 mg RA/ g DW and 36.0 ± 0.78 mg CA/ g DW). Choline chloride:1,4-butanediol and betaine:1,4-butanediol were not selective, they extracted both compounds, RA and CA. On the other hand, amonium acetate:lactic acid recovery more RA and less CA, producing the purest extract in RA. These results demonstrate how the affinity of a compound for a solvent can separate compounds of interest present in the same sample. RA structure exhibits four peripheral hydroxyl groups while CA contain only two hydroxyl groups. In fact, the presence of water increases the polarity of the solvent and favors RA extraction, whereas CA is better extracted in less polar solvents, such as ethanol. Further experiments are needed to evaluate the effect of sequential extraction with different solvent. The first extraction using ammonium acetate:lactic acid could be performed aiming RA recovery, while a second extraction using ethanol could recover the remaining CA from rosemary.