The hydrophobic deep eutectic solvents for extraction of curcuminoids and ar-turmerone from the Curcuma longa L.

The curcuminoids of Curcuma longa L. (CL) are curcumin (Cur) and derivatives such as bisdemethoxycurcumin (Bis) and demethoxycurcumin (Dem). Curcuminoids exhibit bioactivity against oxidative stress, inflammatory, infection, and cancer [1]. Curcumin and essential turmeric oils together give superior anti-inflammation than curcumin alone [2]. Although mentioned compounds play a significant function in biological activity, however, the extraction processes and utility of turmeric phytochemicals are challenged by their water insolubility, poor stability, and poor absorption. Therefore, tremendous strategies have been developed for the mentioned issues. The hydrophobic DESs were prepared using the mixture of menthol and a fatty acid [octanoic acid (OA), decanoic acid (DA), and dodecanoic acid (DDA)] at mole ratios (1:2, 1:1, and 2:1).

The DES compose of specific molar ratios of components, the hydrogen bond, and van der Waals forces are the interaction between menthol and fatty acid. The thermograms of DSC analysis indicated that the different mole ratios of menthol:OA and menthol:DA influence the shift of peak. These different ratios of components affect the extraction efficacy of curcuminoids and ar-Tur as well. The longer the hydrocarbon chain of fatty acid produced DES, with less effective the extraction of curcuminoids. The high yield of ar-

Tur, on the other hand, was obtained with menthol:OA and menthol:DA. Among the investigated hydrophobic DES, the menthol:OA (2:1) demonstrated the highest extraction efficacy with Bis, Dem, Cur, and ar-turmerone concentration of 3.38±0.24, 4.51±0.42, 6.53±0.58, and 6.48±0.45 µg/mL, while the yields of mentioned compounds at 3.07±0.01, 7.54±0.37, 15.9±0.27, and 6.21±0.05 µg/mL, respectively, were obtained using methanol as the solvent. The results were obtained when 0.2 g of dry CL rhizome was extracted with 1 mL of solvent. Therefore, the hydrophobic DESs are suitable for the extraction of curcuminoids and ar-turmerone from the CL.

Publication History

Article published online:
13 December 2021

• References

• 1 Jelinski T, Przybylek M, Cysewski P. Natural Deep Eutectic Solvents as Agents for Improving Solubility, Stability and Delivery of Curcumin. Pharm Res 2019; 36: 116
• 2 Toden S, Theiss AL, Wang X. et al. Essential turmeric oils enhance anti-inflammatory efficacy of curcumin in dextran sulfate sodium-induced colitis. Scientific Reports 2017; 7: 814