Deep Eutectic Solvents in the Efficient Detoxification and Extraction of Alkaloids of Aconiti Lateralis Radix Praeparata

The conversion of diester-diterpenoid alkaloids (DAs) into monoester-diterpenoid alkaloids (MAs) is an effective method to reduce the toxicity of Aconiti Lateralis Radix Praeparata (Fuzi in Chinese, ALRP), a popular traditional Chinese medicine. In the present study, deep eutectic solvents (DESs) were first utilized to simultaneously detoxify ALRP and extract aconitum alkaloids by gas bath thermostatic oscillator-assisted extraction. The effects of extraction parameters, including the extraction time, water content of DESs, temperature, liquid/solid ratio, and pH, on the extraction of MAs were evaluated by single-factor experiments, and the optimal condition was further optimized using response surface methodology. The results indicated that betaine-urea (Bet-Ure, 1:2 mol/mol) was the most appropriate DES to hydrolyze highly toxic DAs into less toxic MAs and improve the extraction efficiency of aconitum alkaloids in one step. The detoxification mechanism study showed that alkaline DESs had an excellent efficiency for DA hydrolysis and MA extraction, and the MA-extraction efficiency enhanced with the increase in pH. Compared with the conventional extraction, the newly developed detoxification process maximized the hydrolysis of DAs and exhibited a higher MA-extraction efficiency (1.913 mg/g vs 0.155 mg/g). The DES-based method offered an ecofriendly, simple, and feasible detoxication strategy for ensuring the safe and effective use of ALRP.