In-situ one-step extraction of rhubarb anthraquinones using TBAB–polyol deep eutectic solvents: a green process optimized by a hybrid RSM–ANN–GA approach

Abstract

Extracting trace active components from traditional Chinese medicine is challenging due to the robust structure of the biomass cell wall. This study developed an in-situ one-step extraction using quaternary ammonium salt-polyol DESs to greenly and efficiently extract anthraquinone compounds (AQs) from rhubarb. Multivariate data analysis revealed that the DES composed of tetrabutylammonium bromide (TBAB) and triethylene glycol (TEG) exhibited excellent extraction performance for AQs. The optimal conditions were determined through a combination of response surface methodology (RSM) and artificial neural network–genetic algorithm (ANN-GA). A total AQs extraction yield of 23.06 ± 0.54 mg/g was achieved using TBAB–TEG DES (75.4 % TEG molar fraction, 25.5 % water) with a 10.4-min extraction. This yield significantly exceeded that of the Chinese Pharmacopoeia extractant (p < 0.05) and was comparable to the extraction rates of two other newly reported DES extractants (p > 0.05). The method integrates extraction, separation, and purification into one step, simplifying the process. SEM and FT-IR analyses confirmed that cell wall disruption and stable AQs-DES complex formation enhanced extraction efficiency. Sensitivity analysis identified TEG molar fraction (39.89 %), extraction time (31.86 %), and water content (28.24 %) as key factors. The RSM-ANN-GA model outperformed RSM alone, providing a reliable tool for process optimization in the pharmaceutical and food industries.