Table 1.
Solvents and methods reported in literature for the extraction of phenolic compounds from rosemary.
| Solvent | Method | Measured Parameters | Main Results | Reference |
|---|---|---|---|---|
| Butanone Ethyl acetate Ethanol (solid/liquid 1/10, w/v) |
CSE (25–50 °C, 0.25–3 h) UAE (probe 20 kHz) UAE (bath 40 kHz) |
CA | CA yield increased with temperature. UAE probe or bath gave similar results and decreased extraction time (0.25 h compared to 3 h at 50 °C by CSE to obtain 15 mg CA/g dry plant) |
[24] |
| Ethanol Methanol (solid/liquid 1/20, w/v) |
CSE UAE (probe 20 kHz) UAE (bath 40 kHz) 25–50 °C, 0.25–2.0 h |
CA RA DPPH |
Ethanol gave higher yield of CA and methanol of RA and antiradical activity. UAE leads to more effective extraction, at lower temperature with less dependence on solvent Scale up (125 L) with ethanol resulted in 22 and 1.6 mg/g dry plant for CA and RA, respectively. |
[26] |
| Hexane Acetone Ethanol Water (solid/liquid 1/10, w/v) |
UAE (probe 20 kHz, 10 min) MAE (under N2, 100 °C, 10 min) UAE: Single or successive extractions |
HPLC | UAE with ethanol or acetone gave the highest terpenoids yield. Highest TPC was obtained with UAE or MAE with ethanol (35 and 36 mg/g dry plant, respectively). UAE with hexane showed a high selectivity in CA extraction, and with acetone low CA oxidation |
[25] |
| Ethanol Methanol Acetone Water mixtures |
CSE (ethanol in water 44.8–95.2%, solid/liquid 1/4.6–1/21.4, m/v, time 4.8–55.2 min) |
CA COH RA |
Ethanol 59% or 70% and acetone 80% gave the best results for all three compounds. Optimum conditions: ethanol 70%, solid/liquid 1/5, extraction time 55 min to obtain highest yield and antioxidant concentration in the extract |
[22] |
| Ethanol in water (0–96%) Acetone in water (0–100%) (solid/liquid 1/20, w/v) |
CSE UAE Pretreatment: deoiling by water-steam distillation, milling, maceration |
TPC HPLC DPPH |
60% ethanol or acetone showed the highest TPC yield and concentration in the extract. Highest RA yield was obtained with water gave, flavonoids with 60% acetone, and terpenes with 80% acetone UAE enhanced TPC extraction and antiradical capacity of the extract, especially with ethanol 60%. Grinding increased the extraction rate. |
[21] |
| Ethanol water (solid/liquid 1/6, w/v) |
CSE (40 °C, 4 h) UAE (probe) MAE Pretreatment: deoiling by solvent free MAE, milling |
Yield TPC CA RA DPPH |
CA not detected in water extracts. Higher yields of TPC, RA and lower EC50 in water extracts. UAE and MAE decreased extraction time. De-oiling and milling increased yield, TPC and RA content in the extract. |
[23] |
| Ethanol in water Water |
CSE (solid/liquid 1/10–1/20, m/v, 27–70 °C, 30–300 min UAE probe (solid/liquid 1/20, m/v, 40–90% ethanol in water, 40 °C, 60–200 W, 3–13 min) |
Yield TPC DPPH |
30 min by CSE or 11 min for UAE were sufficient to obtain the maximum TPC and antiradical efficiency. Combination of CSE (step 1) and UAE (step 2) did not improve results. 56% ethanol presented best results in either CSE or UAE |
[31] |
| Ethanol in water 70%, 90% Water + Tween 20 (solid/liquid 1/15, w/v) |
UAE bath Maceration (90% ethanol, room temperature, 48 h) Percolation |
TPC RA UA OA DPPH |
The highest yield of UA (15.8 mg/g) was obtained by UAE with 90% ethanol, 60 °C, 10 min; RA (15.4 mg/g) by UAE with 70% ethanol, 50 °C, 30 min, or water (at pH 9); and OA (12.2 mg/g) by maceration. Highest TPC was obtained by water extraction. |
[18] |
| Ethanol in water 90% (solid/liquid 1/20, w/v) |
Heat reflux extraction (78 °C, 0.5 or 5 h) Maceration (40 °C, 0.5 h) UAE bath/reactor/probe (40 °C, 0.5 h) MAE under reflux (78 °C, 0.5 h) under N2 pressure under vapor pressure |
RA CA UA COH |
Heat reflux extraction for 0.5 h resulted in extraction yield of 19%, compared to 10% obtained by maceration. UAE with probe showed similar yield to heat reflux extraction but higher recovery of CA and UA. In MAE, extraction and RA yields increased with temperature but CA and UA yield decreased. Pressure does not enhance extraction. |
[29] |
| Ethanol in water 30–96% (solid/liquid 1/5, w/v) |
Maceration (3 days with occasional shaking) Percolation |
TPC DPPH |
Highest TPC obtained with 50%, no significant differences in antiradical activity Percolation gave higher TPC yield but lower antiradical activity. |
[28] |
| Water Methanol:water (60:40) Acetone:water (60:40) Ethyl acetate:water (60:30) (solid/liquid 1/40, w/v, 1/20 in MAE) |
MAE (4 min, under N2) Heat reflux extraction (90 °C, 2 h, under N2) |
TPC HPLC |
MAE gave comparable TPC yield to conventional extraction at shorter time Acetone in water presented highest TPC yield in MAE. Water presented the highest TPC in heat reflux extraction followed by methanol, acetone and ethyl acetate in water mixtures. Content of individual phenolics was similar in either method |
[32] |
| Methanol:water 50:50–100:0 Ethanol:water (70:30) Acetone:water (70:30) Ethyl acetate:water (70:30) (solid/liquid 1/5, w/v) |
MAE (2 × 1–2 × 15 min) UAE bath (2 × 5 min) Soxhlet (1–5 h) |
TPC flavonoids, anthocyanins | MAE gave comparable TPC yield with the optimum obtained in Soxhlet extraction (3 h), and 2-fold higher than UAE. Maximum TPC with methanol:water, 70:30, flavonoids with ethanol:water, 70:30, anthocyanins ethanol:water, 70:30 + 1% HCl, for 2 × 5 min. |
[33] |
| Methanol in water 32–88% | Maceration (1/50, w/v, 80% methanol, room temperature, overnight) ASE (66–200 °C, 103 atm) |
TPC, HPLC FRAP |
Optimum conditions through RSM: 56% methanol, 129 °C. TPC (101.7 mg/g dry herb) and antioxidant recovery at optimum ASE conditions were higher than those obtained by solid/liquid extraction. |
[30] |
| Ethanol Water (solid/liquid 1/10, w/v) CO2 CO2 + 7% ethanol |
ASE (50–200 °C, 100 bar, 20 min) SFE (40 °C, 100–400 bar, 300 min) WEPO |
TPC DPPH HPLC |
ASE with water gave the highest yield and antioxidant activity of the extract. TPC, yield and antiradical activity increased with temperature and water was more efficient than ethanol. The extract obtained by SFE with CO2 + 7% ethanol had good TPC and antiradical activity but low yield. |
[34] |
| Ethanol Water (solid/liquid 1/10, w/v) CO2 CO2 + 6.6% ethanol |
ASE (150 °C with ethanol, 100 or 200 °C with water, 100 bar, 20 min) SFE (40 °C, 150, 400 bar) |
HPLC | SFE extracted compounds of low polarity. RA was extracted by ASE with either solvent, while most flavonoid glycosides were extracted only by ASE with water |
[19] |
| Ionic liquids in water (solid/liquid 1/20, w/v) |
UAE (bath 100–250 W, 0.5 h, after 2 h soaking) | CA RA |
The extraction efficiency was comparable to 80% ethanol used in UAE (0.5 h), solvent extraction (24 h) or CSE (24 h). | [35] |
ASE: accelerated solvent extraction, CA: carnosic acid, COH: carnosol, CSE: conventional solvent extraction, DPPH: 1,1-diphenyl-2-picrylhydrazyl radical, FRAP: ferric reducing antioxidant power, MAE: microwave assisted extraction, OA: oleanolic acid, RA: rosmarinic acid, SFE: supercritical fluid extraction, TPC: total phenolic content, UA: ursolic acid, UAE: ultrasound assisted extraction, WEPO: pressurized water extraction with particle on-line formation.