Eurycoma longifolia, also known as "Tongkat Ali", is an herbal medicinal plant found in Southeast Asia,
including Thailand. The active compounds of E. longifolia root are classified into a group of quassinoids, canthin-6-one alkaloids, and beta-carboline
alkaloids [1]. Eurycomanone is the major quassinoid found in E. longifolia root extracts, which has been reported to improve male sexual performance [2]. Natural deep eutectic solvents (NADES) are new solvents mainly composed of redundant
primary metabolites found in nature. They're a potential alternative to toxic organic
solvents in chemical processes, including extraction [3].
This study aimed to develop NADES for microwave-assisted extraction of aphrodisiac
compounds from E. longifolia root. There were fifteen different NADES systems evaluated, each with three or four
components. The analytes were identified and quantified after extraction using high-performance
liquid chromatography with ultraviolet-visible detection (HPLC-UV) that has been developed.
Eurycomanone, the aphrodisiac substance in E. longifolia root, was used as a biomarker for extraction. The HPLC-UV method was reliable and
applicable for the determination of eurycomanone and other active compounds of E. longifolia root. The results showed that 50% w/w of water: choline chloride: propionic acid
(1:1:1) extracted the largest amount of eurycomanone, 1.19 and 19.60 times more than
extraction with water and ethanol, respectively. The extraction efficiency of the
other NADES was improved 1.03-1.18 times that of water and 17.02-19.47 times that
of ethanol. This research shows the effectiveness of NADES in the extraction of bioactive
chemicals from natural sources.
